Discussion:
[OT] Asymmetrical changes to sunrise/sunset
(too old to reply)
HVS
2019-01-14 15:44:01 UTC
Permalink
I’ve been (non-obsessionally) monitoring the changes to the times of sunrise
and sunset since the solstice, and don’t understand why the changes to those
times are asymmetrical.

On 21 December, the sunrise and sunset times for my location (51.2665 N/
1.0924W) were 08:06 and 15:58. Today (14 January) they’re 08:02 and 16:23.
So sunrise has become 4 minutes earlier in that time, while sunset is 25
minutes later.

Checking for the other end of the year, the times for 21 June are 04:48 and
21:23, and for 14 July are 05:04 and 21:15 – sunrise is 16 minutes later;
sunset is 8 minutes earlier.

So how come the times of sunrise and sunset don’t change at the same rate?

And why is the asymmetry more marked in December/January than in June/July?
--
Cheers, Harvey
CanEng (30yrs) and BrEng (34yrs),
indiscriminately mixed
Madrigal Gurneyhalt
2019-01-14 16:49:20 UTC
Permalink
I’ve been (non-obsessionally) monitoring the changes to the times of sunrise
and sunset since the solstice, and don’t understand why the changes to those
times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665 N/
1.0924W) were 08:06 and 15:58. Today (14 January) they’re 08:02 and 16:23.
So sunrise has become 4 minutes earlier in that time, while sunset is 25
minutes later.
Checking for the other end of the year, the times for 21 June are 04:48 and
21:23, and for 14 July are 05:04 and 21:15 – sunrise is 16 minutes later;
sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don’t change at the same rate?
And why is the asymmetry more marked in December/January than in June/July?
The answer to all such questions is very simple. The Earth does not take 24
hours to complete a rotation. Even if the Earth did not tilt and the sun was
forever fixed over the Equator, therefore, sunrise and sunset times would
still shift as long as you use a 24 hour day length. This means that the shifts
you now see are the sum of two variations. Hence the complexity and the
lack of symmetry.

Before anybody suggests that we eliminate the difference between measured
day length and actual day length by changing the definition of an hour, for
example, you might like to consider what that would mean in terms of the
height of the sun on two days six months apart (remembering that we're
orbiting it!)
CDB
2019-01-14 18:35:44 UTC
Permalink
Post by Madrigal Gurneyhalt
I’ve been (non-obsessionally) monitoring the changes to the times
of sunrise and sunset since the solstice, and don’t understand why
the changes to those times are asymmetrical.
On 21 December, the sunrise and sunset times for my location
(51.2665 N/ 1.0924W) were 08:06 and 15:58. Today (14 January)
they’re 08:02 and 16:23. So sunrise has become 4 minutes earlier in
that time, while sunset is 25 minutes later.
Checking for the other end of the year, the times for 21 June are
04:48 and 21:23, and for 14 July are 05:04 and 21:15 – sunrise is
16 minutes later; sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don’t change at the same rate?
Geographic features like hills or rising land between the apparent
position of the sun and the observer? Or the observation being made
from a shallow depression? Irregularities in the blocking features
would make the day-to-day progression uneven as the sun moved north or
south.
Post by Madrigal Gurneyhalt
And why is the asymmetry more marked in December/January than in June/July?
Geographic irregularities again? The sun rises and sets in different
places in the two seasons, IIRC. Is your report applicable to other
locations?
Post by Madrigal Gurneyhalt
The answer to all such questions is very simple. The Earth does not
take 24 hours to complete a rotation. Even if the Earth did not tilt
and the sun was forever fixed over the Equator, therefore, sunrise
and sunset times would still shift as long as you use a 24 hour day
length. This means that the shifts you now see are the sum of two
variations. Hence the complexity and the lack of symmetry.
Before anybody suggests that we eliminate the difference between
measured day length and actual day length by changing the definition
of an hour, for example, you might like to consider what that would
mean in terms of the height of the sun on two days six months apart
(remembering that we're orbiting it!)
Apologies for the piggyback.
J. J. Lodder
2019-01-14 19:37:42 UTC
Permalink
I've been (non-obsessionally) monitoring the changes to the times of sunrise
and sunset since the solstice, and don't understand why the changes to those
times are asymmetrical.
See under 'equation of time'.
On 21 December, the sunrise and sunset times for my location (51.2665 N/
1.0924W) were 08:06 and 15:58. Today (14 January) they're 08:02 and 16:23.
So sunrise has become 4 minutes earlier in that time, while sunset is 25
minutes later.
Checking for the other end of the year, the times for 21 June are 04:48 and
21:23, and for 14 July are 05:04 and 21:15 - sunrise is 16 minutes later;
sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don't change at the same rate?
See under 'equation of time'
And why is the asymmetry more marked in December/January than in June/July?
Earth is at periheliom early in januari.
You won't live long enough to see that change,

Jan
Quinn C
2019-01-15 22:45:07 UTC
Permalink
Post by HVS
I’ve been (non-obsessionally) monitoring the changes to the times of sunrise
and sunset since the solstice, and don’t understand why the changes to those
times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665 N/
1.0924W) were 08:06 and 15:58. Today (14 January) they’re 08:02 and 16:23.
So sunrise has become 4 minutes earlier in that time, while sunset is 25
minutes later.
Even more interestingly, there is a period when they both move in the
same direction.

For example, for my location, the earliest sunset this winter was
around Dec 10, while the latest sunrise occurred around January 4.

Dec 10: 07:23 - 16:10
Jan 3: 07:34 - 16:23
--
... man muss oft schon Wissenschaft infrage stellen bei den Wirt-
schaftsmenschen [...] das Denken wird haeufig blockiert von einem
ideologischen Ueberbau [...] Es ist halt in vielen Teilen eher
eine Religion als eine Wissenschaft. -- Heiner Flassbeck
Jerry Friedman
2019-01-16 04:38:07 UTC
Permalink
I’ve been (non-obsessionally) monitoring the changes to the times of sunrise
and sunset since the solstice, and don’t understand why the changes to those
times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665 N/
1.0924W) were 08:06 and 15:58. Today (14 January) they’re 08:02 and 16:23.
So sunrise has become 4 minutes earlier in that time, while sunset is 25
minutes later.
Checking for the other end of the year, the times for 21 June are 04:48 and
21:23, and for 14 July are 05:04 and 21:15 – sunrise is 16 minutes later;
sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don’t change at the same rate?
And why is the asymmetry more marked in December/January than in June/July?
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).

When the Earth makes one exact rotation, the stars appear in the same
places in the sky, but the Sun does not. That's because the Earth has
moved in its orbit during that time. The Earth rotates in the same
direction as it moves in its orbit, counterclockwise as seen from the
north [*], so it has to rotate slightly farther for the Sun to be in the
same position in the sky. If we ignore the elliptical shape of the
Earth's orbit and the tilt of its axis, it has to go farther by 1/365
[**] of a day every day in order for the Sun to go around once in a
year. That's 24/365 of an hour, or 60*24/365 minutes, which is about 4
minutes. We define the /average/ time for the Sun to return to
approximately the same position as a day, so a day is about 4 minutes
longer than the rotation period of the Earth. In other words, the time
for one rotation, called the sidereal day because it's relative to the
stars, is about 23 hours and 56 minutes.

However, the Earth's orbit is an ellipse with the Sun off center, and
when the Earth is close to the Sun (it's closest about Jan. 4, whether
it feels close to the Sun then or not), it moves faster. So during that
time, the Earth has to rotate a little farther to bring the Sun into the
same position in the sky, and the interval between one noon and the next
is a little more than 24 hours. Thus sundials run slow, and in the
northern hemisphere sunsets get later faster than sunrises get earlier.
When the Earth is farther from the Sun (it's farthest around July 6),
the opposite happens.

Got that? Also, the Earth's axis is tilted with respect to the plane of
its orbit. Now if we could pretend the orbit is a circle again, the
apparent position of the Sun relative to the stars would move at the
same speed all year. However, at the solstices it's moving directly
east [***], making the difference between the 24-hour day and the
sidereal day more than 4 minutes and making sundials run slow. In
contrast, at the March equinox the Sun is moving northeast and at the
September equinox it's moving southeast, so it makes less progress east,
and the difference between the 24-hour day and the sidereal day is less
than 4 minutes; sundials run fast.

Those two effects combine to control the times of sunrise and sunset.
As Jan said, a good search term if you want to know more is "equation of
time". "Analemma" might help too. I found this helpful:

https://in-the-sky.org/article.php?term=equation_of_time

Do you deal with sundials in your work? This is the sort of thing
sundial experts know about. (ObVocab: Gnomonists.)

[*] Almost by definition. The Earth rotates counterclockwise as seen
from the north, so the Sun appears to us to move clockwise in the
northern hemisphere, so shadows move clockwise, and sundials are
numbered clockwise--and clock dials are numbered the same way as
northern-hemisphere sundials.

[**] Closer to 1/365.25, you pedants, but I'm going to give the answer
to one significant figure.

[***] The solstices (solstitia) are when the sun is "standing still".
Standing still and moving directly east? The Sun at local noon is
always due north or south (or overhead, in the tropics, and kindly allow
me to ignore the Arctic and Antarctic). When the ancients looked at the
position of the Sun at noon, they didn't see the eastward motion (which
is defined only relative to the stars, seldom visible at noon). They
saw only that at the solstices, the noonday Sun reached its most
northern point and its most southern point, so it briefly stopped moving
(north or south) as it turned around.
--
Jerry Friedman
HVS
2019-01-16 11:19:09 UTC
Permalink
Post by Jerry Friedman
I’ve been (non-obsessionally) monitoring the changes to the times of
sunrise and sunset since the solstice, and don’t understand why the
changes to those times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665
N/ 1.0924W) were 08:06 and 15:58. Today (14 January) they’re 08:02
and 16:23. So sunrise has become 4 minutes earlier in that time, while
sunset is 25 minutes later.
Checking for the other end of the year, the times for 21 June are 04:48
and 21:23, and for 14 July are 05:04 and 21:15 – sunrise is 16
minutes later; sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don’t change at the same
rate?
And why is the asymmetry more marked in December/January than in June/July?
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).
When the Earth makes one exact rotation, the stars appear in the same
places in the sky, but the Sun does not. That's because the Earth has
moved in its orbit during that time. The Earth rotates in the same
direction as it moves in its orbit, counterclockwise as seen from the
north [*], so it has to rotate slightly farther for the Sun to be in the
same position in the sky. If we ignore the elliptical shape of the
Earth's orbit and the tilt of its axis, it has to go farther by 1/365
[**] of a day every day in order for the Sun to go around once in a
year. That's 24/365 of an hour, or 60*24/365 minutes, which is about 4
minutes. We define the /average/ time for the Sun to return to
approximately the same position as a day, so a day is about 4 minutes
longer than the rotation period of the Earth. In other words, the time
for one rotation, called the sidereal day because it's relative to the
stars, is about 23 hours and 56 minutes.
However, the Earth's orbit is an ellipse with the Sun off center, and
when the Earth is close to the Sun (it's closest about Jan. 4, whether
it feels close to the Sun then or not), it moves faster. So during that
time, the Earth has to rotate a little farther to bring the Sun into the
same position in the sky, and the interval between one noon and the next
is a little more than 24 hours. Thus sundials run slow, and in the
northern hemisphere sunsets get later faster than sunrises get earlier.
When the Earth is farther from the Sun (it's farthest around July 6),
the opposite happens.
Got that? Also, the Earth's axis is tilted with respect to the plane of
its orbit. Now if we could pretend the orbit is a circle again, the
apparent position of the Sun relative to the stars would move at the
same speed all year. However, at the solstices it's moving directly
east [***], making the difference between the 24-hour day and the
sidereal day more than 4 minutes and making sundials run slow. In
contrast, at the March equinox the Sun is moving northeast and at the
September equinox it's moving southeast, so it makes less progress east,
and the difference between the 24-hour day and the sidereal day is less
than 4 minutes; sundials run fast.
Those two effects combine to control the times of sunrise and sunset.
As Jan said, a good search term if you want to know more is "equation of
https://in-the-sky.org/article.php?term=equation_of_time
Do you deal with sundials in your work? This is the sort of thing
sundial experts know about. (ObVocab: Gnomonists.)
[*] Almost by definition. The Earth rotates counterclockwise as seen
from the north, so the Sun appears to us to move clockwise in the
northern hemisphere, so shadows move clockwise, and sundials are
numbered clockwise--and clock dials are numbered the same way as
northern-hemisphere sundials.
[**] Closer to 1/365.25, you pedants, but I'm going to give the answer
to one significant figure.
[***] The solstices (solstitia) are when the sun is "standing still".
Standing still and moving directly east? The Sun at local noon is
always due north or south (or overhead, in the tropics, and kindly allow
me to ignore the Arctic and Antarctic). When the ancients looked at the
position of the Sun at noon, they didn't see the eastward motion (which
is defined only relative to the stars, seldom visible at noon). They
saw only that at the solstices, the noonday Sun reached its most
northern point and its most southern point, so it briefly stopped moving
(north or south) as it turned around.
Many thanks, Jerry -- I shall print that off and sit down with a strong cup
of tea to see if I can visualise/understand it!
--
Cheers, Harvey
CanEng (30yrs) and BrEng (34yrs), indiscriminately mixed
Lewis
2019-01-16 13:40:50 UTC
Permalink
Post by HVS
Post by Jerry Friedman
I’ve been (non-obsessionally) monitoring the changes to the times of
sunrise and sunset since the solstice, and don’t understand why the
changes to those times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665
N/ 1.0924W) were 08:06 and 15:58. Today (14 January) they’re 08:02
and 16:23. So sunrise has become 4 minutes earlier in that time, while
sunset is 25 minutes later.
Checking for the other end of the year, the times for 21 June are 04:48
and 21:23, and for 14 July are 05:04 and 21:15 – sunrise is 16
minutes later; sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don’t change at the same rate?
And why is the asymmetry more marked in December/January than in June/July?
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).
When the Earth makes one exact rotation, the stars appear in the same
places in the sky, but the Sun does not. That's because the Earth has
moved in its orbit during that time. The Earth rotates in the same
direction as it moves in its orbit, counterclockwise as seen from the
north [*], so it has to rotate slightly farther for the Sun to be in the
same position in the sky. If we ignore the elliptical shape of the
Earth's orbit and the tilt of its axis, it has to go farther by 1/365
[**] of a day every day in order for the Sun to go around once in a
year. That's 24/365 of an hour, or 60*24/365 minutes, which is about 4
minutes. We define the /average/ time for the Sun to return to
approximately the same position as a day, so a day is about 4 minutes
longer than the rotation period of the Earth. In other words, the time
for one rotation, called the sidereal day because it's relative to the
stars, is about 23 hours and 56 minutes.
However, the Earth's orbit is an ellipse with the Sun off center, and
when the Earth is close to the Sun (it's closest about Jan. 4, whether
it feels close to the Sun then or not), it moves faster. So during that
time, the Earth has to rotate a little farther to bring the Sun into the
same position in the sky, and the interval between one noon and the next
is a little more than 24 hours. Thus sundials run slow, and in the
northern hemisphere sunsets get later faster than sunrises get earlier.
When the Earth is farther from the Sun (it's farthest around July 6),
the opposite happens.
Got that? Also, the Earth's axis is tilted with respect to the plane of
its orbit. Now if we could pretend the orbit is a circle again, the
apparent position of the Sun relative to the stars would move at the
same speed all year. However, at the solstices it's moving directly
east [***], making the difference between the 24-hour day and the
sidereal day more than 4 minutes and making sundials run slow. In
contrast, at the March equinox the Sun is moving northeast and at the
September equinox it's moving southeast, so it makes less progress east,
and the difference between the 24-hour day and the sidereal day is less
than 4 minutes; sundials run fast.
Those two effects combine to control the times of sunrise and sunset.
As Jan said, a good search term if you want to know more is "equation of
https://in-the-sky.org/article.php?term=equation_of_time
Do you deal with sundials in your work? This is the sort of thing
sundial experts know about. (ObVocab: Gnomonists.)
[*] Almost by definition. The Earth rotates counterclockwise as seen
from the north, so the Sun appears to us to move clockwise in the
northern hemisphere, so shadows move clockwise, and sundials are
numbered clockwise--and clock dials are numbered the same way as
northern-hemisphere sundials.
[**] Closer to 1/365.25, you pedants, but I'm going to give the answer
to one significant figure.
[***] The solstices (solstitia) are when the sun is "standing still".
Standing still and moving directly east? The Sun at local noon is
always due north or south (or overhead, in the tropics, and kindly allow
me to ignore the Arctic and Antarctic). When the ancients looked at the
position of the Sun at noon, they didn't see the eastward motion (which
is defined only relative to the stars, seldom visible at noon). They
saw only that at the solstices, the noonday Sun reached its most
northern point and its most southern point, so it briefly stopped moving
(north or south) as it turned around.
Many thanks, Jerry -- I shall print that off and sit down with a strong cup
of tea to see if I can visualise/understand it!
It's one of the better explanations I've ever read, so I'd rate your
chances as excellent. Wish something that clear had been in my
textbooks.

But if you want to be REALLY confused, remember the sun is hurtling
through space itself, and all the planets are, essentially, chasing it.

Just to throw an entirely new vector into the pot, so to speak.



But we can pretty much ignore that since the planets, all of them, are
on the same plane relative to the sun (this is a mystery with, as far as
I know, no consensus solution).
--
Cogito cogito, ergo cogito sum, cogito
Jerry Friedman
2019-01-16 15:32:53 UTC
Permalink
Post by Lewis
Post by HVS
Post by Jerry Friedman
I’ve been (non-obsessionally) monitoring the changes to the times of
sunrise and sunset since the solstice, and don’t understand why the
changes to those times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665
N/ 1.0924W) were 08:06 and 15:58. Today (14 January) they’re 08:02
and 16:23. So sunrise has become 4 minutes earlier in that time, while
sunset is 25 minutes later.
Checking for the other end of the year, the times for 21 June are 04:48
and 21:23, and for 14 July are 05:04 and 21:15 – sunrise is 16
minutes later; sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don’t change at the same rate?
And why is the asymmetry more marked in December/January than in June/July?
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).
When the Earth makes one exact rotation, the stars appear in the same
places in the sky, but the Sun does not. That's because the Earth has
moved in its orbit during that time. The Earth rotates in the same
direction as it moves in its orbit, counterclockwise as seen from the
north [*], so it has to rotate slightly farther for the Sun to be in the
same position in the sky. If we ignore the elliptical shape of the
Earth's orbit and the tilt of its axis, it has to go farther by 1/365
[**] of a day every day in order for the Sun to go around once in a
year. That's 24/365 of an hour, or 60*24/365 minutes, which is about 4
minutes. We define the /average/ time for the Sun to return to
approximately the same position as a day, so a day is about 4 minutes
longer than the rotation period of the Earth. In other words, the time
for one rotation, called the sidereal day because it's relative to the
stars, is about 23 hours and 56 minutes.
However, the Earth's orbit is an ellipse with the Sun off center, and
when the Earth is close to the Sun (it's closest about Jan. 4, whether
it feels close to the Sun then or not), it moves faster. So during that
time, the Earth has to rotate a little farther to bring the Sun into the
same position in the sky, and the interval between one noon and the next
is a little more than 24 hours. Thus sundials run slow, and in the
northern hemisphere sunsets get later faster than sunrises get earlier.
When the Earth is farther from the Sun (it's farthest around July 6),
the opposite happens.
Got that? Also, the Earth's axis is tilted with respect to the plane of
its orbit. Now if we could pretend the orbit is a circle again, the
apparent position of the Sun relative to the stars would move at the
same speed all year. However, at the solstices it's moving directly
east [***], making the difference between the 24-hour day and the
sidereal day more than 4 minutes and making sundials run slow. In
contrast, at the March equinox the Sun is moving northeast and at the
September equinox it's moving southeast, so it makes less progress east,
and the difference between the 24-hour day and the sidereal day is less
than 4 minutes; sundials run fast.
Those two effects combine to control the times of sunrise and sunset.
As Jan said, a good search term if you want to know more is "equation of
https://in-the-sky.org/article.php?term=equation_of_time
Do you deal with sundials in your work? This is the sort of thing
sundial experts know about. (ObVocab: Gnomonists.)
[*] Almost by definition. The Earth rotates counterclockwise as seen
from the north, so the Sun appears to us to move clockwise in the
northern hemisphere, so shadows move clockwise, and sundials are
numbered clockwise--and clock dials are numbered the same way as
northern-hemisphere sundials.
[**] Closer to 1/365.25, you pedants, but I'm going to give the answer
to one significant figure.
[***] The solstices (solstitia) are when the sun is "standing still".
Standing still and moving directly east? The Sun at local noon is
always due north or south (or overhead, in the tropics, and kindly allow
me to ignore the Arctic and Antarctic). When the ancients looked at the
position of the Sun at noon, they didn't see the eastward motion (which
is defined only relative to the stars, seldom visible at noon). They
saw only that at the solstices, the noonday Sun reached its most
northern point and its most southern point, so it briefly stopped moving
(north or south) as it turned around.
Many thanks, Jerry -- I shall print that off and sit down with a strong cup
of tea to see if I can visualise/understand it!
It's one of the better explanations I've ever read, so I'd rate your
chances as excellent. Wish something that clear had been in my
textbooks.
Very kind!
Post by Lewis
But if you want to be REALLY confused, remember the sun is hurtling
through space itself, and all the planets are, essentially, chasing it.
Also that the Moon affects the Earth's motion in an almost periodic way
and the other planets perturb it.
Post by Lewis
Just to throw an entirely new vector into the pot, so to speak.
http://youtu.be/0jHsq36_NTU
Why not?
Post by Lewis
But we can pretty much ignore that since the planets, all of them, are
on the same plane relative to the sun (this is a mystery with, as far as
I know, no consensus solution).
--
Jerry Friedman
Peter Moylan
2019-01-17 02:09:26 UTC
Permalink
Post by Lewis
But if you want to be REALLY confused, remember the sun is hurtling
through space itself, and all the planets are, essentially, chasing it.
Now can we have your liver?
--
Peter Moylan http://www.pmoylan.org
Newcastle, NSW, Australia
Kerr-Mudd,John
2019-01-17 09:38:31 UTC
Permalink
On Thu, 17 Jan 2019 02:09:26 GMT, Peter Moylan
Post by Peter Moylan
Post by Lewis
But if you want to be REALLY confused, remember the sun is hurtling
through space itself, and all the planets are, essentially, chasing it.
<insert url to Utube of Eric Idle's Galaxy Song>
Post by Peter Moylan
Now can we have your liver?
a pound of flesh is all I want.
--
Bah, and indeed, Humbug.
Dr. HotSalt
2019-01-17 09:11:54 UTC
Permalink
Post by Lewis
Post by HVS
Post by Jerry Friedman
I’ve been (non-obsessionally) monitoring the changes to the times of
sunrise and sunset since the solstice, and don’t understand why the
changes to those times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665
N/ 1.0924W) were 08:06 and 15:58. Today (14 January) they’re 08:02
and 16:23. So sunrise has become 4 minutes earlier in that time, while
sunset is 25 minutes later.
Checking for the other end of the year, the times for 21 June are 04:48
and 21:23, and for 14 July are 05:04 and 21:15 – sunrise is 16
minutes later; sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don’t change at the same rate?
And why is the asymmetry more marked in December/January than in June/July?
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).
When the Earth makes one exact rotation, the stars appear in the same
places in the sky, but the Sun does not. That's because the Earth has
moved in its orbit during that time. The Earth rotates in the same
direction as it moves in its orbit, counterclockwise as seen from the
north [*], so it has to rotate slightly farther for the Sun to be in the
same position in the sky. If we ignore the elliptical shape of the
Earth's orbit and the tilt of its axis, it has to go farther by 1/365
[**] of a day every day in order for the Sun to go around once in a
year. That's 24/365 of an hour, or 60*24/365 minutes, which is about 4
minutes. We define the /average/ time for the Sun to return to
approximately the same position as a day, so a day is about 4 minutes
longer than the rotation period of the Earth. In other words, the time
for one rotation, called the sidereal day because it's relative to the
stars, is about 23 hours and 56 minutes.
However, the Earth's orbit is an ellipse with the Sun off center, and
when the Earth is close to the Sun (it's closest about Jan. 4, whether
it feels close to the Sun then or not), it moves faster. So during that
time, the Earth has to rotate a little farther to bring the Sun into the
same position in the sky, and the interval between one noon and the next
is a little more than 24 hours. Thus sundials run slow, and in the
northern hemisphere sunsets get later faster than sunrises get earlier.
When the Earth is farther from the Sun (it's farthest around July 6),
the opposite happens.
Got that? Also, the Earth's axis is tilted with respect to the plane of
its orbit. Now if we could pretend the orbit is a circle again, the
apparent position of the Sun relative to the stars would move at the
same speed all year. However, at the solstices it's moving directly
east [***], making the difference between the 24-hour day and the
sidereal day more than 4 minutes and making sundials run slow. In
contrast, at the March equinox the Sun is moving northeast and at the
September equinox it's moving southeast, so it makes less progress east,
and the difference between the 24-hour day and the sidereal day is less
than 4 minutes; sundials run fast.
Those two effects combine to control the times of sunrise and sunset.
As Jan said, a good search term if you want to know more is "equation of
https://in-the-sky.org/article.php?term=equation_of_time
Do you deal with sundials in your work? This is the sort of thing
sundial experts know about. (ObVocab: Gnomonists.)
[*] Almost by definition. The Earth rotates counterclockwise as seen
from the north, so the Sun appears to us to move clockwise in the
northern hemisphere, so shadows move clockwise, and sundials are
numbered clockwise--and clock dials are numbered the same way as
northern-hemisphere sundials.
[**] Closer to 1/365.25, you pedants, but I'm going to give the answer
to one significant figure.
[***] The solstices (solstitia) are when the sun is "standing still".
Standing still and moving directly east? The Sun at local noon is
always due north or south (or overhead, in the tropics, and kindly allow
me to ignore the Arctic and Antarctic). When the ancients looked at the
position of the Sun at noon, they didn't see the eastward motion (which
is defined only relative to the stars, seldom visible at noon). They
saw only that at the solstices, the noonday Sun reached its most
northern point and its most southern point, so it briefly stopped moving
(north or south) as it turned around.
Many thanks, Jerry -- I shall print that off and sit down with a strong cup
of tea to see if I can visualise/understand it!
It's one of the better explanations I've ever read, so I'd rate your
chances as excellent. Wish something that clear had been in my
textbooks.
But if you want to be REALLY confused, remember the sun is hurtling
through space itself, and all the planets are, essentially, chasing it.
Just to throw an entirely new vector into the pot, so to speak.
http://youtu.be/0jHsq36_NTU
But we can pretty much ignore that since the planets, all of them, are
on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around just a little bit as seen from Earth. Sirius, for instance, has moved about the apparent width of the Moon since the Egyptians used it to time the Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed the Solar System being conserved.


Dr. HotSalt
Kerr-Mudd,John
2019-01-17 09:39:43 UTC
Permalink
Post by HVS
Post by Lewis
Post by HVS
Post by Jerry Friedman
I’ve been (non-obsessionally) monitoring the changes to the t
imes of
Post by Lewis
Post by HVS
Post by Jerry Friedman
sunrise and sunset since the solstice, and don’t understand w
hy the
Post by Lewis
Post by HVS
Post by Jerry Friedman
changes to those times are asymmetrical.
On 21 December, the sunrise and sunset times for my location
(51.2665 N/ 1.0924W) were 08:06 and 15:58. Today (14 January)
they’re
08:02
Post by Lewis
Post by HVS
Post by Jerry Friedman
and 16:23. So sunrise has become 4 minutes earlier in that time,
whil
e
Post by Lewis
Post by HVS
Post by Jerry Friedman
sunset is 25 minutes later.
Checking for the other end of the year, the times for 21 June are
48
Post by Lewis
Post by HVS
Post by Jerry Friedman
and 21:23, and for 14 July are 05:04 and 21:15 – sunrise is 1
6
Post by Lewis
Post by HVS
Post by Jerry Friedman
minutes later; sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don’t change at t
he same
Post by Lewis
Post by HVS
Post by Jerry Friedman
rate?
And why is the asymmetry more marked in December/January than in June/July?
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).
When the Earth makes one exact rotation, the stars appear in the same
places in the sky, but the Sun does not. That's because the Earth has
moved in its orbit during that time. The Earth rotates in the
same direction as it moves in its orbit, counterclockwise as seen
from the
north [*], so it has to rotate slightly farther for the Sun to be
in t
he
Post by Lewis
Post by HVS
Post by Jerry Friedman
same position in the sky. If we ignore the elliptical shape of
the Earth's orbit and the tilt of its axis, it has to go farther
by 1/365
[**] of a day every day in order for the Sun to go around once in
a year. That's 24/365 of an hour, or 60*24/365 minutes, which is
about
4
Post by Lewis
Post by HVS
Post by Jerry Friedman
minutes. We define the /average/ time for the Sun to return to
approximately the same position as a day, so a day is about 4 minutes
longer than the rotation period of the Earth. In other words, the
tim
e
Post by Lewis
Post by HVS
Post by Jerry Friedman
for one rotation, called the sidereal day because it's relative to the
stars, is about 23 hours and 56 minutes.
However, the Earth's orbit is an ellipse with the Sun off center, and
when the Earth is close to the Sun (it's closest about Jan. 4, whether
it feels close to the Sun then or not), it moves faster. So
during th
at
Post by Lewis
Post by HVS
Post by Jerry Friedman
time, the Earth has to rotate a little farther to bring the Sun
into t
he
Post by Lewis
Post by HVS
Post by Jerry Friedman
same position in the sky, and the interval between one noon and
the ne
xt
Post by Lewis
Post by HVS
Post by Jerry Friedman
is a little more than 24 hours. Thus sundials run slow, and in
the northern hemisphere sunsets get later faster than sunrises get
earlier
.
Post by Lewis
Post by HVS
Post by Jerry Friedman
When the Earth is farther from the Sun (it's farthest around July 6),
the opposite happens.
Got that? Also, the Earth's axis is tilted with respect to the
plane
of
Post by Lewis
Post by HVS
Post by Jerry Friedman
its orbit. Now if we could pretend the orbit is a circle again, the
apparent position of the Sun relative to the stars would move at the
same speed all year. However, at the solstices it's moving directly
east [***], making the difference between the 24-hour day and the
sidereal day more than 4 minutes and making sundials run slow. In
contrast, at the March equinox the Sun is moving northeast and at the
September equinox it's moving southeast, so it makes less progress
eas
t,
Post by Lewis
Post by HVS
Post by Jerry Friedman
and the difference between the 24-hour day and the sidereal day is
les
s
Post by Lewis
Post by HVS
Post by Jerry Friedman
than 4 minutes; sundials run fast.
Those two effects combine to control the times of sunrise and sunset.
As Jan said, a good search term if you want to know more is
"equation
of
Post by Lewis
Post by HVS
Post by Jerry Friedman
https://in-the-sky.org/article.php?term=equation_of_time
Do you deal with sundials in your work? This is the sort of thing
sundial experts know about. (ObVocab: Gnomonists.)
[*] Almost by definition. The Earth rotates counterclockwise as seen
from the north, so the Sun appears to us to move clockwise in the
northern hemisphere, so shadows move clockwise, and sundials are
numbered clockwise--and clock dials are numbered the same way as
northern-hemisphere sundials.
[**] Closer to 1/365.25, you pedants, but I'm going to give the answer
to one significant figure.
[***] The solstices (solstitia) are when the sun is "standing still".
Standing still and moving directly east? The Sun at local noon is
always due north or south (or overhead, in the tropics, and kindly
all
ow
Post by Lewis
Post by HVS
Post by Jerry Friedman
me to ignore the Arctic and Antarctic). When the ancients looked
at t
he
Post by Lewis
Post by HVS
Post by Jerry Friedman
position of the Sun at noon, they didn't see the eastward motion
(whic
h
Post by Lewis
Post by HVS
Post by Jerry Friedman
is defined only relative to the stars, seldom visible at noon).
They
saw only that at the solstices, the noonday Sun reached its most
northern point and its most southern point, so it briefly stopped
movi
ng
Post by Lewis
Post by HVS
Post by Jerry Friedman
(north or south) as it turned around.
Many thanks, Jerry -- I shall print that off and sit down with a
strong
cup
Post by Lewis
Post by HVS
of tea to see if I can visualise/understand it!
It's one of the better explanations I've ever read, so I'd rate your
chances as excellent. Wish something that clear had been in my
textbooks.
But if you want to be REALLY confused, remember the sun is hurtling
through space itself, and all the planets are, essentially, chasing it.
Just to throw an entirely new vector into the pot, so to speak.
http://youtu.be/0jHsq36_NTU
But we can pretty much ignore that since the planets, all of them,
are on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around
just a little bit as seen from Earth. Sirius, for instance, has
moved about the apparent width of the Moon since the Egyptians used
it to time the Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed
the Solar System being conserved.
disc of accreting particles innit? Same way that galaxies form.
Post by HVS
Dr. HotSalt
--
Bah, and indeed, Humbug.
Kerr-Mudd,John
2019-01-17 10:26:06 UTC
Permalink
On Thu, 17 Jan 2019 09:39:43 GMT, "Kerr-Mudd,John"
[]
Sorry about that lack of snippage earlier
Post by Kerr-Mudd,John
Post by Dr. HotSalt
Post by Lewis
But we can pretty much ignore that since the planets, all of them,
are on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around
just a little bit as seen from Earth. Sirius, for instance, has
moved about the apparent width of the Moon since the Egyptians used
it to time the Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed
the Solar System being conserved.
disc of accreting particles innit? Same way that galaxies form.
Post by Dr. HotSalt
Dr. HotSalt
--
Bah, and indeed, Humbug.
Katy Jennison
2019-01-17 14:44:09 UTC
Permalink
Post by Kerr-Mudd,John
On Thu, 17 Jan 2019 09:39:43 GMT, "Kerr-Mudd,John"
[]
Sorry about that lack of snippage earlier
Good lad! Apology accepted (on my part, anyway).

I'd been seriously thinking of getting round to posting a "FFS!" post
imploring, exhorting, beseeching, entreating, enjoining and adjuring
everyone to cut, snip, trim and generally act considerately, rather than
leaving the reader to scroll through screensful of past posts in the
hope of reaching a final pearl of something-or-other at the bottom. So
thank you.
--
Katy Jennison
Snidely
2019-01-17 14:53:41 UTC
Permalink
Post by Katy Jennison
Post by Kerr-Mudd,John
On Thu, 17 Jan 2019 09:39:43 GMT, "Kerr-Mudd,John"
[]
Sorry about that lack of snippage earlier
Good lad! Apology accepted (on my part, anyway).
I'd been seriously thinking of getting round to posting a "FFS!" post
imploring, exhorting, beseeching, entreating, enjoining and adjuring everyone
to cut, snip, trim and generally act considerately, rather than leaving the
reader to scroll through screensful of past posts in the hope of reaching a
final pearl of something-or-other at the bottom. So thank you.
Sorry, my newsreaders let me ignore the probem (GG tends to collapse
the older parts behind a '+', MesNews has a "show 3 levels" (or 2 or 9)
filter. And even though the compose-reply window unfilters all those
layers of nacre, it also puts the starting insert point at the proper
space ... down below everything, so Peter and Jerry and Lewis are out
of sight until I scroll up to interject.

(similarity to 'less +G' for reading implied)

/dps
--
"That's a good sort of hectic, innit?"

" Very much so, and I'd recommend the haggis wontons."
-njm
Lewis
2019-01-18 02:59:23 UTC
Permalink
Post by Katy Jennison
Post by Kerr-Mudd,John
On Thu, 17 Jan 2019 09:39:43 GMT, "Kerr-Mudd,John"
[]
Sorry about that lack of snippage earlier
Good lad! Apology accepted (on my part, anyway).
I'd been seriously thinking of getting round to posting a "FFS!" post
imploring, exhorting, beseeching, entreating, enjoining and adjuring
everyone to cut, snip, trim and generally act considerately, rather than
leaving the reader to scroll through screensful of past posts in the
hope of reaching a final pearl of something-or-other at the bottom. So
thank you.
Most modern newsreaders (that is, ones less than 30 years old) will
collapse quotes automatically, making the excessive quoting far less of
an issue.
--
I WON'T NOT USE NO DOUBLE NEGATIVES Bart chalkboard Ep. BABF02
Jerry Friedman
2019-01-18 04:24:47 UTC
Permalink
Post by Kerr-Mudd,John
On Thu, 17 Jan 2019 09:39:43 GMT, "Kerr-Mudd,John"
[]
Sorry about that lack of snippage earlier
Good lad!  Apology accepted (on my part, anyway).
I'd been seriously thinking of getting round to posting a "FFS!" post
imploring, exhorting, beseeching, entreating, enjoining and adjuring
everyone to cut, snip, trim and generally act considerately, rather than
leaving the reader to scroll through screensful of past posts in the
hope of reaching a final pearl of something-or-other at the bottom.  So
thank you.
I always snip judiciously, except when I don't.
--
Jerry Friedman
Kerr-Mudd,John
2019-01-18 10:39:11 UTC
Permalink
On Fri, 18 Jan 2019 04:24:47 GMT, Jerry Friedman
Post by Jerry Friedman
Post by Kerr-Mudd,John
On Thu, 17 Jan 2019 09:39:43 GMT, "Kerr-Mudd,John"
On Thu, 17 Jan 2019 09:11:54 GMT, "Dr. HotSalt"
[]
Sorry about that lack of snippage earlier
Good lad!  Apology accepted (on my part, anyway).
I'd been seriously thinking of getting round to posting a "FFS!" post
imploring, exhorting, beseeching, entreating, enjoining and adjuring
everyone to cut, snip, trim and generally act considerately, rather
than leaving the reader to scroll through screensful of past posts in
the hope of reaching a final pearl of something-or-other at the
bottom.  So thank you.
I always snip judiciously, except when I don't.
YAM,YA
--
Bah, and indeed, Humbug.
Jerry Friedman
2019-01-18 14:55:51 UTC
Permalink
Post by Kerr-Mudd,John
On Fri, 18 Jan 2019 04:24:47 GMT, Jerry Friedman
...
Post by Kerr-Mudd,John
Post by Jerry Friedman
I always snip judiciously, except when I don't.
YAM,YA
What's the M for?
--
Jerry Friedman
Kerr-Mudd,John
2019-01-18 21:16:21 UTC
Permalink
On Fri, 18 Jan 2019 14:55:51 GMT, Jerry Friedman
Post by Jerry Friedman
Post by Kerr-Mudd,John
On Fri, 18 Jan 2019 04:24:47 GMT, Jerry Friedman
...
Post by Kerr-Mudd,John
Post by Jerry Friedman
I always snip judiciously, except when I don't.
YAM,YA
What's the M for?
Me

You Are Me, You Are
(perhaps it's a lesser meme)
--
Bah, and indeed, Humbug.
Jerry Friedman
2019-01-18 21:32:23 UTC
Permalink
Post by Kerr-Mudd,John
On Fri, 18 Jan 2019 14:55:51 GMT, Jerry Friedman
Post by Jerry Friedman
Post by Kerr-Mudd,John
On Fri, 18 Jan 2019 04:24:47 GMT, Jerry Friedman
...
Post by Kerr-Mudd,John
Post by Jerry Friedman
I always snip judiciously, except when I don't.
YAM,YA
What's the M for?
Me
You Are Me, You Are
(perhaps it's a lesser meme)
Hehe.
--
Jerry Friedman
Peter T. Daniels
2019-01-19 03:39:32 UTC
Permalink
Post by Kerr-Mudd,John
On Fri, 18 Jan 2019 14:55:51 GMT, Jerry Friedman
Post by Jerry Friedman
Post by Kerr-Mudd,John
On Fri, 18 Jan 2019 04:24:47 GMT, Jerry Friedman
Post by Jerry Friedman
I always snip judiciously, except when I don't.
YAM,YA
What's the M for?
Me
You Are Me, You Are
(perhaps it's a lesser meme)
Hehe.
Oh, you!
Lewis
2019-01-17 10:38:26 UTC
Permalink
Post by Dr. HotSalt
Post by Lewis
Post by HVS
Post by Jerry Friedman
I’ve been (non-obsessionally) monitoring the changes to the times of
sunrise and sunset since the solstice, and don’t understand why the
changes to those times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665
N/ 1.0924W) were 08:06 and 15:58. Today (14 January) they’re 08:02
and 16:23. So sunrise has become 4 minutes earlier in that time, while
sunset is 25 minutes later.
Checking for the other end of the year, the times for 21 June are 04:48
and 21:23, and for 14 July are 05:04 and 21:15 – sunrise is 16
minutes later; sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don’t change at the same rate?
And why is the asymmetry more marked in December/January than in June/July?
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).
When the Earth makes one exact rotation, the stars appear in the same
places in the sky, but the Sun does not. That's because the Earth has
moved in its orbit during that time. The Earth rotates in the same
direction as it moves in its orbit, counterclockwise as seen from the
north [*], so it has to rotate slightly farther for the Sun to be in the
same position in the sky. If we ignore the elliptical shape of the
Earth's orbit and the tilt of its axis, it has to go farther by 1/365
[**] of a day every day in order for the Sun to go around once in a
year. That's 24/365 of an hour, or 60*24/365 minutes, which is about 4
minutes. We define the /average/ time for the Sun to return to
approximately the same position as a day, so a day is about 4 minutes
longer than the rotation period of the Earth. In other words, the time
for one rotation, called the sidereal day because it's relative to the
stars, is about 23 hours and 56 minutes.
However, the Earth's orbit is an ellipse with the Sun off center, and
when the Earth is close to the Sun (it's closest about Jan. 4, whether
it feels close to the Sun then or not), it moves faster. So during that
time, the Earth has to rotate a little farther to bring the Sun into the
same position in the sky, and the interval between one noon and the next
is a little more than 24 hours. Thus sundials run slow, and in the
northern hemisphere sunsets get later faster than sunrises get earlier.
When the Earth is farther from the Sun (it's farthest around July 6),
the opposite happens.
Got that? Also, the Earth's axis is tilted with respect to the plane of
its orbit. Now if we could pretend the orbit is a circle again, the
apparent position of the Sun relative to the stars would move at the
same speed all year. However, at the solstices it's moving directly
east [***], making the difference between the 24-hour day and the
sidereal day more than 4 minutes and making sundials run slow. In
contrast, at the March equinox the Sun is moving northeast and at the
September equinox it's moving southeast, so it makes less progress east,
and the difference between the 24-hour day and the sidereal day is less
than 4 minutes; sundials run fast.
Those two effects combine to control the times of sunrise and sunset.
As Jan said, a good search term if you want to know more is "equation of
https://in-the-sky.org/article.php?term=equation_of_time
Do you deal with sundials in your work? This is the sort of thing
sundial experts know about. (ObVocab: Gnomonists.)
[*] Almost by definition. The Earth rotates counterclockwise as seen
from the north, so the Sun appears to us to move clockwise in the
northern hemisphere, so shadows move clockwise, and sundials are
numbered clockwise--and clock dials are numbered the same way as
northern-hemisphere sundials.
[**] Closer to 1/365.25, you pedants, but I'm going to give the answer
to one significant figure.
[***] The solstices (solstitia) are when the sun is "standing still".
Standing still and moving directly east? The Sun at local noon is
always due north or south (or overhead, in the tropics, and kindly allow
me to ignore the Arctic and Antarctic). When the ancients looked at the
position of the Sun at noon, they didn't see the eastward motion (which
is defined only relative to the stars, seldom visible at noon). They
saw only that at the solstices, the noonday Sun reached its most
northern point and its most southern point, so it briefly stopped moving
(north or south) as it turned around.
Many thanks, Jerry -- I shall print that off and sit down with a strong cup
of tea to see if I can visualise/understand it!
It's one of the better explanations I've ever read, so I'd rate your
chances as excellent. Wish something that clear had been in my
textbooks.
But if you want to be REALLY confused, remember the sun is hurtling
through space itself, and all the planets are, essentially, chasing it.
Just to throw an entirely new vector into the pot, so to speak.
http://youtu.be/0jHsq36_NTU
But we can pretty much ignore that since the planets, all of them, are
on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around just a little bit as seen from Earth. Sirius, for instance, has moved about the apparent width of the Moon since the Egyptians used it to time the Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed the Solar System being conserved.
That is a theory, yes.
--
Nihil est--in vita priore ego imperator Romanus fui.
J. J. Lodder
2019-01-17 11:39:23 UTC
Permalink
[-]
Post by Lewis
Post by Dr. HotSalt
Post by Lewis
But we can pretty much ignore that since the planets, all of them, are
on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around just
a little bit as seen from Earth. Sirius, for instance, has moved about
the apparent width of the Moon since the Egyptians used it to time the
Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed
the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,

Jan
Lewis
2019-01-17 12:30:09 UTC
Permalink
Post by J. J. Lodder
[-]
Post by Lewis
Post by Dr. HotSalt
Post by Lewis
But we can pretty much ignore that since the planets, all of them, are
on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around just
a little bit as seen from Earth. Sirius, for instance, has moved about
the apparent width of the Moon since the Egyptians used it to time the
Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed
the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
The explanation for why all the planets are on the same plane, and why
most galaxies tend to be on a (relative) plane is a theory.
--
The real American folksong is a rag -- a mental jag A rhythmic tone for
the chronic blues
Snidely
2019-01-17 14:39:26 UTC
Permalink
Post by Lewis
Post by J. J. Lodder
Post by Lewis
On Wednesday, January 16, 2019 at 5:40:53 AM UTC-8, Lewis wrote: [-]
Post by Lewis
But we can pretty much ignore that since the planets, all of them, are
on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around just
a little bit as seen from Earth. Sirius, for instance, has moved about
the apparent width of the Moon since the Egyptians used it to time the
Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed
the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
The explanation for why all the planets are on the same plane, and why
most galaxies tend to be on a (relative) plane is a theory.
Sure, but the quibbles tend to be not about the disk but about how some
planets ended up closer or farther than the expected distance.
"Gravity assist" isn't just a space probe fly-by technique, it applies
to proto-planets and planets as well, and detailed calculations give
support to the idea that Jupiter and Saturn crawled inwards for a while
and then sailed outwards again. Orbital synchronization is part of how
this happens.

"Sculpting Our Planetary System"
<URL:https://www.americanscientist.org/article/sculpting-our-planetary-system>
Steve Raymond, Laboratoire de'Astrophique de Bordeaux
(The Grand Tack and More ... "'The Scars of The Solar System'"


See also, "Why Do Galaxies Start Out as Cosmic Pickles"
_American Scientist_, Sep-Oct 2018.
(Cross-thread alert for our other-Pondian contingents: our idea of a
gherkin is much too small for this article ... the ex-cucumber needs to
be the 6-8" dill variety, not a thumb-sized horse dove, and certainly
not sweet pickle "chips".)


Alien invasion from another thread:
"Greenland's Vanished Vikings",
_Scientific American_, June 2017
(climate and economics)


/dps
--
"What do you think of my cart, Miss Morland? A neat one, is not it?
Well hung: curricle-hung in fact. Come sit by me and we'll test the
springs."
(Speculative fiction by H.Lacedaemonian.)
Lewis
2019-01-18 02:55:06 UTC
Permalink
Post by Snidely
Post by Lewis
Post by J. J. Lodder
Post by Lewis
On Wednesday, January 16, 2019 at 5:40:53 AM UTC-8, Lewis wrote: [-]
Post by Lewis
But we can pretty much ignore that since the planets, all of them, are
on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around just
a little bit as seen from Earth. Sirius, for instance, has moved about
the apparent width of the Moon since the Egyptians used it to time the
Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed
the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
The explanation for why all the planets are on the same plane, and why
most galaxies tend to be on a (relative) plane is a theory.
Sure, but the quibbles tend to be not about the disk but about how some
planets ended up closer or farther than the expected distance.
Since we have one solar system to model on, the theory is just a theory.
And not all galaxies are disks, so there's obviously no universal rule
to them.

The point isn't that there aren't theories that try to explain this, it is
that they are theories that are unproved, based on a limited sample
size, and there are competing theories.

Here is one system that violates the planetary plane model:

<https://www.nasa.gov/mission_pages/hubble/science/outofwack.html>
--
when you're no longer searching for beauty or love, just some kind of
life with the edges taken off. When you can't even define what it is
that you're frightened of...
J. J. Lodder
2019-01-18 09:31:25 UTC
Permalink
Post by Lewis
Post by Snidely
Post by Lewis
Post by J. J. Lodder
Post by Lewis
On Wednesday, January 16, 2019 at 5:40:53 AM UTC-8, Lewis wrote: [-]
Post by Lewis
But we can pretty much ignore that since the planets, all of them, are
on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around just
a little bit as seen from Earth. Sirius, for instance, has moved about
the apparent width of the Moon since the Egyptians used it to time the
Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed
the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
The explanation for why all the planets are on the same plane, and why
most galaxies tend to be on a (relative) plane is a theory.
Sure, but the quibbles tend to be not about the disk but about how some
planets ended up closer or farther than the expected distance.
Since we have one solar system to model on, the theory is just a theory.
And not all galaxies are disks, so there's obviously no universal rule
to them.
Elliptical galaxies are believed to be the result of mergers
of spiral galaxies.
Post by Lewis
The point isn't that there aren't theories that try to explain this, it is
that they are theories that are unproved, based on a limited sample
size, and there are competing theories.
<https://www.nasa.gov/mission_pages/hubble/science/outofwack.html>
That's a binary star sytem, so another game altogether,

Jan
Kerr-Mudd,John
2019-01-18 10:47:54 UTC
Permalink
Post by J. J. Lodder
Post by Lewis
Post by Snidely
Post by Lewis
Post by J. J. Lodder
In message
On Wednesday, January 16, 2019 at 5:40:53 AM UTC-8, Lewis wrote: [-]
Post by Lewis
But we can pretty much ignore that since the planets, all of
them, are on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around just
a little bit as seen from Earth. Sirius, for instance, has
moved about the apparent width of the Moon since the Egyptians
used it to time the Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed
the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
The explanation for why all the planets are on the same plane, and
why most galaxies tend to be on a (relative) plane is a theory.
Sure, but the quibbles tend to be not about the disk but about how
some planets ended up closer or farther than the expected distance.
Since we have one solar system to model on, the theory is just a
theory. And not all galaxies are disks, so there's obviously no
universal rule to them.
Elliptical galaxies are believed to be the result of mergers
of spiral galaxies.
Post by Lewis
The point isn't that there aren't theories that try to explain this,
it is that they are theories that are unproved, based on a limited
sample size, and there are competing theories.
<https://www.nasa.gov/mission_pages/hubble/science/outofwack.html>
That's a binary star sytem, so another game altogether,
there's a lot of that about.

but it's plantary system is anoumoulous (sp!) i.e. almost all *are*
planar.

My theory (which is mine) is that the biggest lump determines the plane;
anything else then is pulled (up or down) to that level by closish
encounters and also pulled or pushed into a regular Bode orbit
(eventually).
--
Bah, and indeed, Humbug.
J. J. Lodder
2019-01-18 13:28:07 UTC
Permalink
Post by Kerr-Mudd,John
Post by J. J. Lodder
Post by Lewis
Post by Snidely
Post by Lewis
Post by J. J. Lodder
In message
On Wednesday, January 16, 2019 at 5:40:53 AM UTC-8, Lewis wrote: [-]
Post by Lewis
But we can pretty much ignore that since the planets, all of
them, are on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around just
a little bit as seen from Earth. Sirius, for instance, has
moved about the apparent width of the Moon since the Egyptians
used it to time the Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed
the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
The explanation for why all the planets are on the same plane, and
why most galaxies tend to be on a (relative) plane is a theory.
Sure, but the quibbles tend to be not about the disk but about how
some planets ended up closer or farther than the expected distance.
Since we have one solar system to model on, the theory is just a
theory. And not all galaxies are disks, so there's obviously no
universal rule to them.
Elliptical galaxies are believed to be the result of mergers
of spiral galaxies.
Post by Lewis
The point isn't that there aren't theories that try to explain this,
it is that they are theories that are unproved, based on a limited
sample size, and there are competing theories.
<https://www.nasa.gov/mission_pages/hubble/science/outofwack.html>
That's a binary star sytem, so another game altogether,
there's a lot of that about.
but it's plantary system is anoumoulous (sp!) i.e. almost all *are*
planar.
My theory (which is mine) is that the biggest lump determines the plane;
Yes, of course.
That biggest lump carries most of the angular momentum of the system.
Post by Kerr-Mudd,John
anything else then is pulled (up or down) to that level by closish
encounters and also pulled or pushed into a regular Bode orbit
(eventually).
I'm afraid orbital mechanics is a bit more subtle than that.
But I share your expectation that we will see more surprises
as more planetary systems are found.
It can't be as dull all over the cosmos as it is here,

Jan
Lewis
2019-01-18 13:28:19 UTC
Permalink
Post by J. J. Lodder
Post by Lewis
Post by Snidely
Post by Lewis
Post by J. J. Lodder
Post by Lewis
On Wednesday, January 16, 2019 at 5:40:53 AM UTC-8, Lewis wrote: [-]
Post by Lewis
But we can pretty much ignore that since the planets, all of them, are
on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around just
a little bit as seen from Earth. Sirius, for instance, has moved about
the apparent width of the Moon since the Egyptians used it to time the
Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed
the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
The explanation for why all the planets are on the same plane, and why
most galaxies tend to be on a (relative) plane is a theory.
Sure, but the quibbles tend to be not about the disk but about how some
planets ended up closer or farther than the expected distance.
Since we have one solar system to model on, the theory is just a theory.
And not all galaxies are disks, so there's obviously no universal rule
to them.
Elliptical galaxies are believed to be the result of mergers
of spiral galaxies.
"believed to be"
Post by J. J. Lodder
Post by Lewis
The point isn't that there aren't theories that try to explain this, it is
that they are theories that are unproved, based on a limited sample
size, and there are competing theories.
<https://www.nasa.gov/mission_pages/hubble/science/outofwack.html>
That's a binary star sytem, so another game altogether,
It's a system with three "Jupiter sized" planets not on a plentary
plane orbiting a single star. The binary is not orbited by any of the
planets, and the second star is much smaller and quite far away (outside
the orbits of the planets).

But regardless, the point is that there is no consensus solution, which
is what I said in the first place.

Hell, even in our system we have a planet that doesn't fit at all with
the others, since Uranus spins on an axis at nearly 90 degrees to the
rest of the system.

And yes, there are various theories as to why this might be, but they
are certainly not elevated to Theory of Gravity levels.
--
2+2=5 for sufficiently large values of 2.
J. J. Lodder
2019-01-19 22:24:54 UTC
Permalink
Post by Lewis
Post by J. J. Lodder
Post by Lewis
Post by Snidely
Post by Lewis
Post by J. J. Lodder
Post by Lewis
On Wednesday, January 16, 2019 at 5:40:53 AM UTC-8, Lewis wrote: [-]
Post by Lewis
But we can pretty much ignore that since the planets, all of
them, are on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move
around just a little bit as seen from Earth. Sirius, for
instance, has moved about the apparent width of the Moon since
the Egyptians used it to time the Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed
the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
The explanation for why all the planets are on the same plane, and why
most galaxies tend to be on a (relative) plane is a theory.
Sure, but the quibbles tend to be not about the disk but about how some
planets ended up closer or farther than the expected distance.
Since we have one solar system to model on, the theory is just a theory.
And not all galaxies are disks, so there's obviously no universal rule
to them.
Elliptical galaxies are believed to be the result of mergers
of spiral galaxies.
"believed to be"
Some beliefs have more reason behind them than others.
You shouldn't convert an understatement
into an argument for something.
Post by Lewis
Post by J. J. Lodder
Post by Lewis
The point isn't that there aren't theories that try to explain this, it is
that they are theories that are unproved, based on a limited sample
size, and there are competing theories.
<https://www.nasa.gov/mission_pages/hubble/science/outofwack.html>
That's a binary star sytem, so another game altogether,
It's a system with three "Jupiter sized" planets not on a plentary
plane orbiting a single star. The binary is not orbited by any of the
planets, and the second star is much smaller and quite far away (outside
the orbits of the planets).
They say orbit unknown.
The companion may be in an eccentric orbit
and dive in every now and then to perturb things.
Post by Lewis
But regardless, the point is that there is no consensus solution, which
is what I said in the first place.
Starting out with a gas disk is rather inevitable.
Post by Lewis
Hell, even in our system we have a planet that doesn't fit at all with
the others, since Uranus spins on an axis at nearly 90 degrees to the
rest of the system.
Running the supercomputers shows that gravity can do strange things,
in nascent planetary systems,

Jan
Lewis
2019-01-20 05:02:04 UTC
Permalink
Post by J. J. Lodder
Post by Lewis
Post by J. J. Lodder
Post by Lewis
Post by Snidely
Post by Lewis
Post by J. J. Lodder
Post by Lewis
On Wednesday, January 16, 2019 at 5:40:53 AM UTC-8, Lewis wrote: [-]
Post by Lewis
But we can pretty much ignore that since the planets, all of
them, are on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move
around just a little bit as seen from Earth. Sirius, for
instance, has moved about the apparent width of the Moon since
the Egyptians used it to time the Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed
the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
The explanation for why all the planets are on the same plane, and why
most galaxies tend to be on a (relative) plane is a theory.
Sure, but the quibbles tend to be not about the disk but about how some
planets ended up closer or farther than the expected distance.
Since we have one solar system to model on, the theory is just a theory.
And not all galaxies are disks, so there's obviously no universal rule
to them.
Elliptical galaxies are believed to be the result of mergers
of spiral galaxies.
"believed to be"
Some beliefs have more reason behind them than others.
You shouldn't convert an understatement
into an argument for something.
Pot? have you MET kettle?

I am not arguing FOR anything. I am saying this is not a settled issue.
You keep pretending it is.

It is not.
--
'Do you know what they call a sausage-in-a-bun in Quirm?' 'No?' said Mr
Tulip 'They called it le sausage-in-le-bun.' 'What, in a --ing foreign
language? You're --ing kidding!'
J. J. Lodder
2019-01-20 11:32:03 UTC
Permalink
Post by Lewis
Post by J. J. Lodder
Post by Lewis
Post by J. J. Lodder
Post by Lewis
Post by Snidely
Post by Lewis
Post by J. J. Lodder
Post by Lewis
Post by Dr. HotSalt
Post by Lewis
But we can pretty much ignore that since the planets, all of
them, are on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move
around just a little bit as seen from Earth. Sirius, for
instance, has moved about the apparent width of the Moon since
the Egyptians used it to time the Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that
formed the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
The explanation for why all the planets are on the same plane,
and why most galaxies tend to be on a (relative) plane is a
theory.
Sure, but the quibbles tend to be not about the disk but about how
some planets ended up closer or farther than the expected
distance.
Since we have one solar system to model on, the theory is just a theory.
And not all galaxies are disks, so there's obviously no universal rule
to them.
Elliptical galaxies are believed to be the result of mergers
of spiral galaxies.
"believed to be"
Some beliefs have more reason behind them than others.
You shouldn't convert an understatement
into an argument for something.
Pot? have you MET kettle?
I am not arguing FOR anything. I am saying this is not a settled issue.
You keep pretending it is.
It is not.
OK. So what is your preferred alternative
to the idea that planetary systems (and galaxies)
condense from gas and dust disks?
Or that elliptical systems result from mergers
and/or collisions of previously formed galaxies?

Jan
Lewis
2019-01-20 18:27:05 UTC
Permalink
Post by J. J. Lodder
Post by Lewis
Post by J. J. Lodder
Post by Lewis
Post by J. J. Lodder
Post by Lewis
Post by Snidely
Post by Lewis
Post by J. J. Lodder
Post by Lewis
Post by Dr. HotSalt
Post by Lewis
But we can pretty much ignore that since the planets, all of
them, are on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move
around just a little bit as seen from Earth. Sirius, for
instance, has moved about the apparent width of the Moon since
the Egyptians used it to time the Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that
formed the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
The explanation for why all the planets are on the same plane,
and why most galaxies tend to be on a (relative) plane is a
theory.
Sure, but the quibbles tend to be not about the disk but about how
some planets ended up closer or farther than the expected
distance.
Since we have one solar system to model on, the theory is just a theory.
And not all galaxies are disks, so there's obviously no universal rule
to them.
Elliptical galaxies are believed to be the result of mergers
of spiral galaxies.
"believed to be"
Some beliefs have more reason behind them than others.
You shouldn't convert an understatement
into an argument for something.
Pot? have you MET kettle?
I am not arguing FOR anything. I am saying this is not a settled issue.
You keep pretending it is.
It is not.
OK. So what is your preferred alternative
to the idea that planetary systems (and galaxies)
condense from gas and dust disks?
Or that elliptical systems result from mergers
and/or collisions of previously formed galaxies?
Please do try to keep up. perhaps reread what I JUST SAID.
--
A dyslexic walks into a bra...
J. J. Lodder
2019-01-20 21:49:26 UTC
Permalink
Post by Lewis
Post by J. J. Lodder
Post by Lewis
Post by J. J. Lodder
Post by Lewis
Post by J. J. Lodder
Post by Lewis
Post by Snidely
Post by Lewis
Post by J. J. Lodder
Post by Lewis
Post by Dr. HotSalt
Post by Lewis
But we can pretty much ignore that since the planets, all of
them, are on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move
around just a little bit as seen from Earth. Sirius, for
instance, has moved about the apparent width of the Moon since
the Egyptians used it to time the Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that
formed the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
The explanation for why all the planets are on the same plane,
and why most galaxies tend to be on a (relative) plane is a
theory.
Sure, but the quibbles tend to be not about the disk but about how
some planets ended up closer or farther than the expected
distance.
Since we have one solar system to model on, the theory is just a
theory. And not all galaxies are disks, so there's obviously no
universal rule to them.
Elliptical galaxies are believed to be the result of mergers
of spiral galaxies.
"believed to be"
Some beliefs have more reason behind them than others.
You shouldn't convert an understatement
into an argument for something.
Pot? have you MET kettle?
I am not arguing FOR anything. I am saying this is not a settled issue.
You keep pretending it is.
It is not.
OK. So what is your preferred alternative
to the idea that planetary systems (and galaxies)
condense from gas and dust disks?
Or that elliptical systems result from mergers
and/or collisions of previously formed galaxies?
Please do try to keep up. perhaps reread what I JUST SAID.
OK again. So you have nothing to offer,

Jan
J. J. Lodder
2019-01-18 09:31:25 UTC
Permalink
Post by Lewis
Post by J. J. Lodder
[-]
Post by Lewis
Post by Dr. HotSalt
Post by Lewis
But we can pretty much ignore that since the planets, all of them, are
on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around just
a little bit as seen from Earth. Sirius, for instance, has moved about
the apparent width of the Moon since the Egyptians used it to time the
Nile floods.
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed
the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
The explanation for why all the planets are on the same plane, and why
most galaxies tend to be on a (relative) plane is a theory.
A model is a better word here. You must assume some initial conditions.
But given those, the laws of physics apply.
They are not just theories that can one can take or leave.

In particular, the cloud you start with will have an angular momentum.
The planetary cloud, and later planetary system that forms
must have the same angular momentum. (or shed some mass)
So the rotation around the axis cannot get lost.
OTOH motions perpendicular to the central plane
can (and will) be damped by collisions,
because there is no net angular momentum to begin with.

So the net effect will be a concentration of mass
in the equatorial plane,

Jan
Madhu
2019-01-17 14:42:06 UTC
Permalink
Post by J. J. Lodder
Post by Lewis
Post by Dr. HotSalt
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that
formed the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
I don't see how conservation restricts it to a plane. It makes sense
from the point of view of angular momentum being introduced in 2
dimensions: point mass on a disk, but does it automatically follow when
angular momentum is generalized to 3 dimensions?

From another What would have had to happen at the birth of the solar
system if the orbits were to have turned out to be non-planar? if they
were were instead to be like the how the orbials of electrons were
pictured?

I've forgotten any rotational dynamics I may have learnt, poorly so a
reply may not be useful to me

[BTW this reminded me of the pop-descriptions of the curvature of
space-time by spreading out a blanket and showing how a football would
make it curve which I consider to be case of begging the question
Snidely
2019-01-17 14:54:39 UTC
Permalink
Post by Madhu
Post by J. J. Lodder
Post by Lewis
Post by Dr. HotSalt
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that
formed the Solar System being conserved.
That is a theory, yes.
Conservation of angular momentum is not just a theory,
I don't see how conservation restricts it to a plane. It makes sense
from the point of view of angular momentum being introduced in 2
dimensions: point mass on a disk, but does it automatically follow when
angular momentum is generalized to 3 dimensions?
From another What would have had to happen at the birth of the solar
system if the orbits were to have turned out to be non-planar? if they
were were instead to be like the how the orbials of electrons were
pictured?
I've forgotten any rotational dynamics I may have learnt, poorly so a
reply may not be useful to me
[BTW this reminded me of the pop-descriptions of the curvature of
space-time by spreading out a blanket and showing how a football would
make it curve which I consider to be case of begging the question
What happens near the pole of a sphere? Is the Earth a sphere?

/dps
--
"What do you think of my cart, Miss Morland? A neat one, is not it?
Well hung: curricle-hung in fact. Come sit by me and we'll test the
springs."
(Speculative fiction by H.Lacedaemonian.)
Snidely
2019-01-17 15:00:39 UTC
Permalink
Post by Snidely
Post by Madhu
Post by J. J. Lodder
Conservation of angular momentum is not just a theory,
I don't see how conservation restricts it to a plane.
[...]
Post by Snidely
Post by Madhu
[BTW this reminded me of the pop-descriptions of the curvature of
space-time by spreading out a blanket and showing how a football would
make it curve which I consider to be case of begging the question
Whoops, missed this section ... why is it begging the question to
provide a visualization? Of course the visualization is imperfect, but
we aren't good at making 4-D drawings yet

The visualization attempts to capture the implications of the GToR, and
the question for GToR is how does it explain what we see? The
acceptance of GToR is based on comparing its predictions to
observations, and so far it has done very well, but the
blanket-and-football (urp, soccer ball) aren't used for predictions.
Post by Snidely
What happens near the pole of a sphere? Is the Earth a sphere?
/dps
--
But happiness cannot be pursued; it must ensue. One must have a reason
to 'be happy.'"
Viktor Frankl
Lewis
2019-01-18 02:58:23 UTC
Permalink
Post by Snidely
Post by Madhu
Post by J. J. Lodder
Conservation of angular momentum is not just a theory,
I don't see how conservation restricts it to a plane.
[...]
Post by Madhu
[BTW this reminded me of the pop-descriptions of the curvature of
space-time by spreading out a blanket and showing how a football would
make it curve which I consider to be case of begging the question
Whoops, missed this section ... why is it begging the question to
provide a visualization? Of course the visualization is imperfect, but
we aren't good at making 4-D drawings yet
Beginning the question is structuring a statement in a way that forces a
specific question. The football on a blanket is a good example because
people do not understand it is a 3D model of a non 3D effect. To
understand that ball on the blanket you have to understand that it
represents all possible inclinations and angles of the blanket at the
same time.
--
BART BUCKS ARE NOT LEGAL TENDER Bart chalkboard Ep. 8F06
Madhu
2019-01-18 04:04:32 UTC
Permalink
[the original issue about planarity of the solar system and angular
momentum elided. next:]
Post by Snidely
Post by Snidely
Post by Madhu
[BTW this reminded me of the pop-descriptions of the curvature of
space-time by spreading out a blanket and showing how a football
would make it curve which I consider to be case of begging the
question
Whoops, missed this section ... why is it begging the question to
provide a visualization? Of course the visualization is imperfect,
but we aren't good at making 4-D drawings yet
The visualization attempts to capture the implications of the GToR,
and the question for GToR is how does it explain what we see? The
acceptance of GToR is based on comparing its predictions to
observations, and so far it has done very well, but the
blanket-and-football (urp, soccer ball) aren't used for predictions.
I agree. "begging the question" is not the apt phrase here. I guess my
point was that the mechanism for the actual deformation of the blanket
is because of the newton's-apple-garden variety of gravity. But as it
really is just a visualization tool (to "explain gravity - as
curvature") I should not call that detail into account.
Post by Snidely
Post by Snidely
What happens near the pole of a sphere? Is the Earth a sphere?
that is explained by rotation *and* gravitation. but my commment on the
GTR example is unrelated it is motivated only because I saw an
analogue(?) with(?) how the angular-momentum-on-a-plane example was
being used to explain the planar solar system. [The earlier posts by
JJL on GTR are still on my mind - GTR validating the applications
vs. the successful applications validating GTR]
J. J. Lodder
2019-01-17 10:43:18 UTC
Permalink
[-]
Post by Dr. HotSalt
Post by Lewis
It's one of the better explanations I've ever read, so I'd rate your
chances as excellent. Wish something that clear had been in my
textbooks.
But if you want to be REALLY confused, remember the sun is hurtling
through space itself, and all the planets are, essentially, chasing it.
Just to throw an entirely new vector into the pot, so to speak.
http://youtu.be/0jHsq36_NTU
But we can pretty much ignore that since the planets, all of them, are
on the same plane relative to the sun
True, but it is one of the reasons the "fixed stars" move around just a
little bit as seen from Earth. Sirius, for instance, has moved about the
apparent width of the Moon since the Egyptians used it to time the Nile
floods.
Not just the sun, everything moves.
Jan Oort (of Oort Cloud fame) was the first to sort this out,
and he derived the rotation of the galaxy from it by averaging.
All this has been in the news again recently
because of the Gaia project.
The Gaia satellite is providing very accurate position and velocity data
for billions of stars.
The results are new insights into the history of the galaxy,
such as the discovery of a recent collision
a mere 500 million years ago.
Post by Dr. HotSalt
Post by Lewis
(this is a mystery with, as far as
I know, no consensus solution).
It's down to the angular momentum of the cloud-o'-stuff that formed the
Solar System being conserved.
With most of the angular momentum going to the planets.

Jan

PS Mach's 'fixsterne' (E. somtimes also 'fixsterne')
have been replaced as reference first by 'the distant galaxies,
and nowadays by 'the distant quasars'.
Despit enormous increases in range Mach's principle still holds.
J. J. Lodder
2019-01-16 17:47:43 UTC
Permalink
Post by HVS
Post by Jerry Friedman
I've been (non-obsessionally) monitoring the changes to the times of
sunrise and sunset since the solstice, and don't understand why the
changes to those times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665
N/ 1.0924W) were 08:06 and 15:58. Today (14 January) they are 08:02
and 16:23. So sunrise has become 4 minutes earlier in that time, while
sunset is 25 minutes later.
Checking for the other end of the year, the times for 21 June are 04:48
and 21:23, and for 14 July are 05:04 and 21:15 and sunrise is 16
minutes later; sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don't change at the same
rate?
And why is the asymmetry more marked in December/January than in June/July?
[many non-ASCII characters rectified]
Post by HVS
Post by Jerry Friedman
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).
When the Earth makes one exact rotation, the stars appear in the same
places in the sky, but the Sun does not. That's because the Earth has
moved in its orbit during that time. The Earth rotates in the same
direction as it moves in its orbit, counterclockwise as seen from the
north [*], so it has to rotate slightly farther for the Sun to be in the
same position in the sky. If we ignore the elliptical shape of the
Earth's orbit and the tilt of its axis, it has to go farther by 1/365
[**] of a day every day in order for the Sun to go around once in a
year. That's 24/365 of an hour, or 60*24/365 minutes, which is about 4
minutes. We define the /average/ time for the Sun to return to
approximately the same position as a day, so a day is about 4 minutes
longer than the rotation period of the Earth. In other words, the time
for one rotation, called the sidereal day because it's relative to the
stars, is about 23 hours and 56 minutes.
However, the Earth's orbit is an ellipse with the Sun off center, and
when the Earth is close to the Sun (it's closest about Jan. 4, whether
it feels close to the Sun then or not), it moves faster. So during that
time, the Earth has to rotate a little farther to bring the Sun into the
same position in the sky, and the interval between one noon and the next
is a little more than 24 hours. Thus sundials run slow, and in the
northern hemisphere sunsets get later faster than sunrises get earlier.
When the Earth is farther from the Sun (it's farthest around July 6),
the opposite happens.
Got that? Also, the Earth's axis is tilted with respect to the plane of
its orbit. Now if we could pretend the orbit is a circle again, the
apparent position of the Sun relative to the stars would move at the
same speed all year. However, at the solstices it's moving directly
east [***], making the difference between the 24-hour day and the
sidereal day more than 4 minutes and making sundials run slow. In
contrast, at the March equinox the Sun is moving northeast and at the
September equinox it's moving southeast, so it makes less progress east,
and the difference between the 24-hour day and the sidereal day is less
than 4 minutes; sundials run fast.
Those two effects combine to control the times of sunrise and sunset.
As Jan said, a good search term if you want to know more is "equation of
https://in-the-sky.org/article.php?term=equation_of_time
Do you deal with sundials in your work? This is the sort of thing
sundial experts know about. (ObVocab: Gnomonists.)
[*] Almost by definition. The Earth rotates counterclockwise as seen
from the north, so the Sun appears to us to move clockwise in the
northern hemisphere, so shadows move clockwise, and sundials are
numbered clockwise--and clock dials are numbered the same way as
northern-hemisphere sundials.
[**] Closer to 1/365.25, you pedants, but I'm going to give the answer
to one significant figure.
[***] The solstices (solstitia) are when the sun is "standing still".
Standing still and moving directly east? The Sun at local noon is
always due north or south (or overhead, in the tropics, and kindly allow
me to ignore the Arctic and Antarctic). When the ancients looked at the
position of the Sun at noon, they didn't see the eastward motion (which
is defined only relative to the stars, seldom visible at noon). They
saw only that at the solstices, the noonday Sun reached its most
northern point and its most southern point, so it briefly stopped moving
(north or south) as it turned around.
Many thanks, Jerry -- I shall print that off and sit down with a strong cup
of tea to see if I can visualise/understand it!
It may help if you think of Phileas Fogg, who did just the same.
You may remember that Fogg, traveling eastwards around the world,
gained a day on going around once.
(for the plot's sake, to his great surpise)
When did he gain this day?
A moments thought should convince you that the answer is:
a little bit on all days that he travelled,
on average 18 minutes a day.

Next question: did Fogg gain the same amount on all days he travelled?
No of course, on days he travelled fast, by train,
he gained more than average, when on elephant, less.
And next, asuming that he travelled at his average speed for a day,
he gained more when travelling due east
than when his course would be south-east or north-west.

Hope this helps,

Jan
Jerry Friedman
2019-01-16 18:01:26 UTC
Permalink
Post by J. J. Lodder
Post by Jerry Friedman
I've been (non-obsessionally) monitoring the changes to the times of
sunrise and sunset since the solstice, and don't understand why the
changes to those times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665
N/ 1.0924W) were 08:06 and 15:58. Today (14 January) they are 08:02
and 16:23. So sunrise has become 4 minutes earlier in that time, while
sunset is 25 minutes later.
Checking for the other end of the year, the times for 21 June are 04:48
and 21:23, and for 14 July are 05:04 and 21:15 and sunrise is 16
minutes later; sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don't change at the same
rate?
And why is the asymmetry more marked in December/January than in June/July?
[many non-ASCII characters rectified]
What? In my post, or in Harvey's?
Post by J. J. Lodder
Post by Jerry Friedman
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).
...
--
Jerry Friedman
Lars Enderin
2019-01-16 18:35:55 UTC
Permalink
Post by Jerry Friedman
Post by J. J. Lodder
[many non-ASCII characters rectified]
What? In my post, or in Harvey's?
Your post was properly labeled as UTF-8. Harvey's was not labeled at all
(no MIME headers) but was automatically treated as ISO-8859-1, or just
8-bit, regardless of the cited UTF-8 content. I use the ascii apostrophe
instead of acute accent in "it's" for example, to avoid those abonimations.
--
Lars Enderin
Jerry Friedman
2019-01-16 18:51:46 UTC
Permalink
Post by Lars Enderin
Post by Jerry Friedman
Post by J. J. Lodder
[many non-ASCII characters rectified]
What? In my post, or in Harvey's?
Your post was properly labeled as UTF-8. Harvey's was not labeled at all
(no MIME headers) but was automatically treated as ISO-8859-1, or just
8-bit, regardless of the cited UTF-8 content.
Thanks.
Post by Lars Enderin
I use the ascii apostrophe
instead of acute accent in "it's" for example, to avoid those abonimations.
Me too.
--
Jerry Friedman
Lars Enderin
2019-01-16 18:49:53 UTC
Permalink
Post by Jerry Friedman
Post by J. J. Lodder
[many non-ASCII characters rectified]
What? In my post, or in Harvey's?
Your post was properly labeled as UTF-8. Harvey's was not labeled at all
(no MIME headers) but was automatically treated as ISO-8859-1, or just
8-bit, regardless of the cited UTF-8 content. I use the ascii apostrophe
instead of acute accent in "it's" for example, to avoid those abonimations.
--
Lars Enderin
Lars Enderin
2019-01-16 19:10:43 UTC
Permalink
2019-01-16 19:49 skrev Lars Enderin:
[duplicate caused by unreliable Internet connection]
Sorry!
--
Lars Enderin
J. J. Lodder
2019-01-16 20:47:49 UTC
Permalink
Post by Jerry Friedman
Post by J. J. Lodder
I've been (non-obsessionally) monitoring the changes to the times of
sunrise and sunset since the solstice, and don't understand why the
changes to those times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665
N/ 1.0924W) were 08:06 and 15:58. Today (14 January) they are 08:02
and 16:23. So sunrise has become 4 minutes earlier in that time, while
sunset is 25 minutes later.
Checking for the other end of the year, the times for 21 June are 04:48
and 21:23, and for 14 July are 05:04 and 21:15 and sunrise is 16
minutes later; sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don't change at the same
rate?
And why is the asymmetry more marked in December/January than in June/July?
[many non-ASCII characters rectified]
What? In my post, or in Harvey's?
Originally Harvey's but you made it worse.
Two of yours for one of Harvey,

Jan
Lars Enderin
2019-01-16 22:57:00 UTC
Permalink
Post by J. J. Lodder
Post by Jerry Friedman
What? In my post, or in Harvey's?
Originally Harvey's but you made it worse.
Two of yours for one of Harvey,
1) Harvey's User-Agent: Xnews/2005.10.03
does not provide MIME headers to show text encoding.
2) His ’-s should actually be '-s (ascii apostrophes, not some cute accent).

When Jerry quoted a "’", it was translated into three weird 8-bit
characters "’", the internal bytes for "’" in Unicode, but only if
viewed as Western encoding. Jerry's MIME headers specify UTF-8, which is
essential if you want to include, e g, Chinese characters or phonetic
symbols. US-ASCII is not enough for Usenet.

Your (Jan's) news client also errs in not specifying MIME headers.
For some reason, Thunderbird assumes that your text encoding is
Windows-1252, and replies in that same encoding when I compose this:

Content-Type: text/plain; charset=windows-1252
--
Lars Enderin
Jerry Friedman
2019-01-18 04:31:09 UTC
Permalink
Post by Lars Enderin
Post by J. J. Lodder
Post by Jerry Friedman
What? In my post, or in Harvey's?
Originally Harvey's but you made it worse.
Two of yours for one of Harvey,
1) Harvey's User-Agent: Xnews/2005.10.03
does not provide MIME headers to show text encoding.
2) His ’-s should actually be '-s (ascii apostrophes, not some cute accent).
When Jerry quoted a "’", it was translated into three weird 8-bit
characters "’", the internal bytes for "’" in Unicode, but only if
viewed as Western encoding. Jerry's MIME headers specify UTF-8, which is
essential if you want to include, e g, Chinese characters or phonetic
symbols. US-ASCII is not enough for Usenet.
Your (Jan's) news client also errs in not specifying MIME headers.
For some reason, Thunderbird assumes that your text encoding is
Content-Type: text/plain; charset=windows-1252
Neither T-bird nor GG shows any Euro symbols or strange things like that.

I don't understand this stuff, but is the message that the only thing I
could change is noticing characters such as ’ and rewriting them as '?
Which I often do when I'm copypasting from Web pages, but don't
guarantee to do when responding here.
--
Jerry Friedman
J. J. Lodder
2019-01-18 09:31:25 UTC
Permalink
Post by Jerry Friedman
Post by Lars Enderin
Post by J. J. Lodder
Post by Jerry Friedman
What? In my post, or in Harvey's?
Originally Harvey's but you made it worse.
Two of yours for one of Harvey,
1) Harvey's User-Agent: Xnews/2005.10.03
does not provide MIME headers to show text encoding.
2) His '-s should actually be '-s (ascii apostrophes, not some cute accent).
When Jerry quoted a "'", it was translated into three weird 8-bit
characters "’", the internal bytes for "'" in Unicode, but only if
viewed as Western encoding. Jerry's MIME headers specify UTF-8, which is
essential if you want to include, e g, Chinese characters or phonetic
symbols. US-ASCII is not enough for Usenet.
Your (Jan's) news client also errs in not specifying MIME headers.
For some reason, Thunderbird assumes that your text encoding is
Content-Type: text/plain; charset=windows-1252
Neither T-bird nor GG shows any Euro symbols or strange things like that.
I don't understand this stuff, but is the message that the only thing I
could change is noticing characters such as ' and rewriting them as '?
Which I often do when I'm copypasting from Web pages, but don't
guarantee to do when responding here.
The bottom line is that usenet was born under ASCII,
and still is ASCII,
despite various half-hearted attempts at generalisation.

Since writing Newsclients is a forgotten art by now
this is likely to remain the case till the end,

Jan
Bob Martin
2019-01-18 13:21:25 UTC
Permalink
Post by J. J. Lodder
The bottom line is that usenet was born under ASCII,
and still is ASCII,
despite various half-hearted attempts at generalisation.
Since writing Newsclients is a forgotten art by now
this is likely to remain the case till the end,
I've just written the news client I'm using now.
Text based, written in ooRexx and ncurses.
BugHunter
2019-01-18 14:00:49 UTC
Permalink
Post by Bob Martin
Post by J. J. Lodder
The bottom line is that usenet was born under ASCII,
and still is ASCII,
despite various half-hearted attempts at generalisation.
Since writing Newsclients is a forgotten art by now
this is likely to remain the case till the end,
I've just written the news client I'm using now.
Text based, written in ooRexx and ncurses.
What is happen if someone react at your article
with a client without UTF-8 ?
--
\ / http://nieuwsgroepen.tk
-------------///----------------------------------
/ \ Bye, BugHunter
Lewis
2019-01-18 13:38:57 UTC
Permalink
Post by J. J. Lodder
Post by Jerry Friedman
Post by Lars Enderin
Post by J. J. Lodder
Post by Jerry Friedman
What? In my post, or in Harvey's?
Originally Harvey's but you made it worse.
Two of yours for one of Harvey,
1) Harvey's User-Agent: Xnews/2005.10.03
does not provide MIME headers to show text encoding.
2) His '-s should actually be '-s (ascii apostrophes, not some cute accent).
When Jerry quoted a "'", it was translated into three weird 8-bit
characters "’", the internal bytes for "'" in Unicode, but only if
viewed as Western encoding. Jerry's MIME headers specify UTF-8, which is
essential if you want to include, e g, Chinese characters or phonetic
symbols. US-ASCII is not enough for Usenet.
Your (Jan's) news client also errs in not specifying MIME headers.
For some reason, Thunderbird assumes that your text encoding is
Content-Type: text/plain; charset=windows-1252
Neither T-bird nor GG shows any Euro symbols or strange things like that.
I don't understand this stuff, but is the message that the only thing I
could change is noticing characters such as ' and rewriting them as '?
Which I often do when I'm copypasting from Web pages, but don't
guarantee to do when responding here.
The bottom line is that usenet was born under ASCII,
True.
Post by J. J. Lodder
and still is ASCII,
Not true. USENET is UTF-8, and long has supported the old code page
model (like ISO-8859-1 and Windows-1252). The only part of USENET that
is still ascii only are the names of the groups and the post headers, or
at least some of the post headers, or maybe it's the labels of the
headers; I forget.

The issues come in when any one of several things happens:

o badly coded clients do not include an encoding
o badly coded clients do not respect an encoding
o badly coded clients do not properly recode old
encoding to new encoding
o old or poorly designed clients do not support UTF-8
Post by J. J. Lodder
despite various half-hearted attempts at generalisation.
Not half-hearted at all. There are newsgroups for all sorts of different
languages, and these groups work because USENET understands far more
than just ASCII.
--
'They're the cream!' Rincewind sighed. 'Cohen, they're the cheese.'
Tak To
2019-01-18 19:36:48 UTC
Permalink
Post by Lewis
Post by J. J. Lodder
Post by Jerry Friedman
Post by Lars Enderin
Post by J. J. Lodder
Post by Jerry Friedman
What? In my post, or in Harvey's?
Originally Harvey's but you made it worse.
Two of yours for one of Harvey,
1) Harvey's User-Agent: Xnews/2005.10.03
does not provide MIME headers to show text encoding.
2) His '-s should actually be '-s (ascii apostrophes, not some cute accent).
When Jerry quoted a "'", it was translated into three weird 8-bit
characters "’", the internal bytes for "'" in Unicode, but only if
viewed as Western encoding. Jerry's MIME headers specify UTF-8, which is
essential if you want to include, e g, Chinese characters or phonetic
symbols. US-ASCII is not enough for Usenet.
Your (Jan's) news client also errs in not specifying MIME headers.
For some reason, Thunderbird assumes that your text encoding is
Content-Type: text/plain; charset=windows-1252
Neither T-bird nor GG shows any Euro symbols or strange things like that.
I don't understand this stuff, but is the message that the only thing I
could change is noticing characters such as ' and rewriting them as '?
Which I often do when I'm copypasting from Web pages, but don't
guarantee to do when responding here.
The bottom line is that usenet was born under ASCII,
True.
Post by J. J. Lodder
and still is ASCII,
Not true. USENET is UTF-8, and long has supported the old code page
model (like ISO-8859-1 and Windows-1252). The only part of USENET that
is still ascii only are the names of the groups and the post headers, or
at least some of the post headers, or maybe it's the labels of the
headers; I forget.
[Sigh] This has been explained numerous times before.

NNTP (RFC3977) is a transport protocol and is UTF-8. The
NetNews Article format (RFC5536), which is based on the Internet
Message format (RFC5322), is OTOH still 7-bit ASCII, albeit with
various extensions.

Thus, in the absence of encoding info, the "body" of an article
is to be treated as ASCII. However, there is no standard on
what to with when an out-of-range entity[1] is found[2]. Some
servers would just delete it. Some would pass it along. Some
would replace it with another entity. Some would encode it
in, say, UFT-8. On the top of that, some server would patch
the encoding info and others would not.

[1] Sorry for the jargon, but an entity need not be 8-bit
wide.

[2] OK, there may be a standard. My memory is a bit vague.
In any case, the standard is not followed by everyone.
Post by Lewis
o badly coded clients do not include an encoding
o badly coded clients do not respect an encoding
o badly coded clients do not properly recode old
encoding to new encoding
o old or poorly designed clients do not support UTF-8
Or a faulty NNTP server.

Note that GG is an NNTP server with an HTTP front end. Thus
there is also the possibility of a faulty browser (or one
with faulty settings).
Post by Lewis
Post by J. J. Lodder
despite various half-hearted attempts at generalisation.
Not half-hearted at all. There are newsgroups for all sorts of different
languages, and these groups work because USENET understands far more
than just ASCII.
--
Tak
----------------------------------------------------------------+-----
Tak To ***@alum.mit.eduxx
--------------------------------------------------------------------^^
[taode takto ~{LU5B~}] NB: trim the xx to get my real email addr
Quinn C
2019-01-22 22:41:28 UTC
Permalink
Post by Tak To
NNTP (RFC3977) is a transport protocol and is UTF-8. The
NetNews Article format (RFC5536), which is based on the Internet
Message format (RFC5322), is OTOH still 7-bit ASCII, albeit with
various extensions.
Thus, in the absence of encoding info, the "body" of an article
is to be treated as ASCII. However, there is no standard on
what to with when an out-of-range entity[1] is found[2].
Yes, there is; it's called MIME. it was thoroughly established as a
standard when the art of writing Usenet clients took a dive, and the
clients that over 90% of people here use adhere to it (some with bugs,
notably Google.)

JJ's client, MacSOUP, was known for not dealing with ISO-8859
properly, replacing it byte-by-byte with a Mac-specific character set,
instead of translating. Exactly the thing people like making fun of
when it's done on Windows.

MacSOUP is also known to post line-wrapped links. The proposed standard
to put those together automatically has never been thoroughly
established.
--
Everyone gets one personality tic that's then expanded into an
entire character, in the same way that a balloon with a smiley
face will look like a person if at some point you just stop
caring. -- David Berry, NatPost (on the cast of Criminal Minds)
Lewis
2019-01-22 23:52:40 UTC
Permalink
Post by Quinn C
Post by Tak To
NNTP (RFC3977) is a transport protocol and is UTF-8. The
NetNews Article format (RFC5536), which is based on the Internet
Message format (RFC5322), is OTOH still 7-bit ASCII, albeit with
various extensions.
Thus, in the absence of encoding info, the "body" of an article
is to be treated as ASCII. However, there is no standard on
what to with when an out-of-range entity[1] is found[2].
Yes, there is; it's called MIME.
Which REQUIRES a content-type to be declared.

And that content-type should be UTF-8 for maximum compatibility and
usability and flexibility and several other -ity words I can't think of
right now.
Post by Quinn C
JJ's client, MacSOUP, was known for not dealing with ISO-8859
properly, replacing it byte-by-byte with a Mac-specific character set,
instead of translating. Exactly the thing people like making fun of
when it's done on Windows.
MacSOUP was a disaster from the start. It was written by mac developers
who really didn't know anything about usenet.
Post by Quinn C
MacSOUP is also known to post line-wrapped links. The proposed standard
to put those together automatically has never been thoroughly
established.
No one seems to do this consistently. Even slrn cannot deal with a
delimited URL with a line break in it.
--
Love is like oxygen / You get too much / you get too high / Not enough
and you're gonna die
J. J. Lodder
2019-01-23 11:40:00 UTC
Permalink
Post by Lewis
Post by Quinn C
Post by Tak To
NNTP (RFC3977) is a transport protocol and is UTF-8. The
NetNews Article format (RFC5536), which is based on the Internet
Message format (RFC5322), is OTOH still 7-bit ASCII, albeit with
various extensions.
Thus, in the absence of encoding info, the "body" of an article
is to be treated as ASCII. However, there is no standard on
what to with when an out-of-range entity[1] is found[2].
Yes, there is; it's called MIME.
Which REQUIRES a content-type to be declared.
And that content-type should be UTF-8 for maximum compatibility and
usability and flexibility and several other -ity words I can't think of
right now.
Post by Quinn C
JJ's client, MacSOUP, was known for not dealing with ISO-8859
properly, replacing it byte-by-byte with a Mac-specific character set,
instead of translating. Exactly the thing people like making fun of
when it's done on Windows.
MacSOUP was a disaster from the start. It was written by mac developers
who really didn't know anything about usenet.
How can you get everything so completely the wrong way round?
MacSoup is more fanatic about usenet norms
than even the most fanatic keeper of those norms.
It is better than GNKSA 2.0 compliant.
<https://en.wikipedia.org/wiki/Good_Netkeeping_Seal_of_Approval>
It is the rest of the world that has forgotten what good netkeeping is.

OTOH, MacSoup's author, Stefan Haller,
flaunted all human interface guidelines that Apple had put up.
He ignores even bog-standard Apple key combos like Cmd-{ for back,
and uses Cmd-B instead.
Post by Lewis
Post by Quinn C
MacSOUP is also known to post line-wrapped links. The proposed standard
to put those together automatically has never been thoroughly
established.
Of course. MacSoup refuses to emit lines that are longer tha 72 chars
without deliberate user intervention.
Post by Lewis
No one seems to do this consistently. Even slrn cannot deal with a
delimited URL with a line break in it.
Properly delimited links < > should be handled
also with returns inside the < >
MacSoup can, most others can't,

Jan
Lewis
2019-01-23 18:21:19 UTC
Permalink
Post by J. J. Lodder
Post by Lewis
Post by Quinn C
Post by Tak To
NNTP (RFC3977) is a transport protocol and is UTF-8. The
NetNews Article format (RFC5536), which is based on the Internet
Message format (RFC5322), is OTOH still 7-bit ASCII, albeit with
various extensions.
Thus, in the absence of encoding info, the "body" of an article
is to be treated as ASCII. However, there is no standard on
what to with when an out-of-range entity[1] is found[2].
Yes, there is; it's called MIME.
Which REQUIRES a content-type to be declared.
And that content-type should be UTF-8 for maximum compatibility and
usability and flexibility and several other -ity words I can't think of
right now.
Post by Quinn C
JJ's client, MacSOUP, was known for not dealing with ISO-8859
properly, replacing it byte-by-byte with a Mac-specific character set,
instead of translating. Exactly the thing people like making fun of
when it's done on Windows.
MacSOUP was a disaster from the start. It was written by mac developers
who really didn't know anything about usenet.
How can you get everything so completely the wrong way round?
MacSoup is more fanatic about usenet norms
than even the most fanatic keeper of those norms.
And yet it constantly posted malformed posts, especially when quoting
previous posts.
Post by J. J. Lodder
Post by Lewis
Post by Quinn C
MacSOUP is also known to post line-wrapped links. The proposed standard
to put those together automatically has never been thoroughly
established.
Of course. MacSoup refuses to emit lines that are longer tha 72 chars
without deliberate user intervention.
Which i not an issue unless you cannot properly fold a URL and then
unfold it, which MacSoup could not.
Post by J. J. Lodder
Post by Lewis
No one seems to do this consistently. Even slrn cannot deal with a
delimited URL with a line break in it.
Properly delimited links < > should be handled
also with returns inside the < >
Yes, should.
Post by J. J. Lodder
MacSoup can,
Not in my (albeit limited) experience it could not.
--
The most perfidious way of harming a cause consists of defending it
deliberately with faulty arguments.
Quinn C
2019-01-23 18:44:53 UTC
Permalink
Post by J. J. Lodder
Post by Lewis
Post by Quinn C
JJ's client, MacSOUP, was known for not dealing with ISO-8859
properly, replacing it byte-by-byte with a Mac-specific character set,
instead of translating. Exactly the thing people like making fun of
when it's done on Windows.
MacSOUP was a disaster from the start. It was written by mac developers
who really didn't know anything about usenet.
How can you get everything so completely the wrong way round?
MacSoup is more fanatic about usenet norms
than even the most fanatic keeper of those norms.
It is better than GNKSA 2.0 compliant.
<https://en.wikipedia.org/wiki/Good_Netkeeping_Seal_of_Approval>
The GNKSA has wrong priorities. Xnews passed it at 100%, and is
famously unusable - without external help - for languages other than
English and Dutch.
Post by J. J. Lodder
It is the rest of the world that has forgotten what good netkeeping is.
OTOH, MacSoup's author, Stefan Haller,
flaunted all human interface guidelines that Apple had put up.
He ignores even bog-standard Apple key combos like Cmd-{ for back,
and uses Cmd-B instead.
Post by Lewis
Post by Quinn C
MacSOUP is also known to post line-wrapped links. The proposed standard
to put those together automatically has never been thoroughly
established.
Of course. MacSoup refuses to emit lines that are longer tha 72 chars
without deliberate user intervention.
How arbitrary. The standard says

| Each line of characters MUST be no more than
| 998 characters, and SHOULD be no more than 78 characters, excluding
| the CRLF.

My software is configurable, and I have set the line length to 71
characters currently, but it will not apply that - without deliberate
user intervention - to quoted text or to URLs. That is very sensible.
Post by J. J. Lodder
Post by Lewis
No one seems to do this consistently. Even slrn cannot deal with a
delimited URL with a line break in it.
Properly delimited links < > should be handled
also with returns inside the < >
MacSoup can, most others can't,
And that's why even if it was technically correct, it's anti-social.
The only other Newsreader that I'm sure can do it is Gnus. Also, FWIF,
I've never seen a specification for that.

And let's not overstate the meaning of formal standards in general. The
accepted standard for a Usenet server is "what INN does".
--
There are two ways of constructing a software design. One way is
to make it so simple that there are obviously no deficiencies.
And the other way is to make it so complicated that there are no
obvious deficiencies. The first method is far more difficult.
-- C. A. R. Hoare
Sam Plusnet
2019-01-23 21:06:48 UTC
Permalink
Post by J. J. Lodder
OTOH, MacSoup's author, Stefan Haller,
flaunted all human interface guidelines that Apple had put up.
It seems to me that the use of "flaunted" in place of "flouted" is
becoming more common.

P.S. J. J. Lodder has a better command of English than I do, but I
wanted to raise the question.
--
Sam Plusnet
J. J. Lodder
2019-01-25 11:13:27 UTC
Permalink
Post by Sam Plusnet
Post by J. J. Lodder
OTOH, MacSoup's author, Stefan Haller,
flaunted all human interface guidelines that Apple had put up.
It seems to me that the use of "flaunted" in place of "flouted" is
becoming more common.
P.S. J. J. Lodder has a better command of English than I do, but I
wanted to raise the question.
Strange. I was having just the opposite impression.

[on Flaunting-flouting]
I used 'flaunting' because Stefan Haller claimed to know better,
and that Apple's guidelines are WRONG.
IIRC he insisted thAT only letters may be used,
and that Apple's use of Cmd-[ for 'Go Back' is somehow Wrong,
so he replaced it with Cmd-B.

You can of course disagree,

Jan
Peter T. Daniels
2019-01-25 14:44:34 UTC
Permalink
Post by J. J. Lodder
Post by Sam Plusnet
Post by J. J. Lodder
OTOH, MacSoup's author, Stefan Haller,
flaunted all human interface guidelines that Apple had put up.
It seems to me that the use of "flaunted" in place of "flouted" is
becoming more common.
P.S. J. J. Lodder has a better command of English than I do, but I
wanted to raise the question.
Strange. I was having just the opposite impression.
Strange. JJ can't recognize irony.
Post by J. J. Lodder
[on Flaunting-flouting]
I used 'flaunting' because Stefan Haller claimed to know better,
and that Apple's guidelines are WRONG.
IIRC he insisted thAT only letters may be used,
and that Apple's use of Cmd-[ for 'Go Back' is somehow Wrong,
so he replaced it with Cmd-B.
That is "flout," not "flaunt."

(Since I don't see what Stefan posts, did he say how he tells the machine
to apply boldface?)
Post by J. J. Lodder
You can of course disagree,
Only people who know English would do so.
Peter Moylan
2019-01-26 00:31:08 UTC
Permalink
Post by J. J. Lodder
Post by Sam Plusnet
Post by J. J. Lodder
OTOH, MacSoup's author, Stefan Haller,
flaunted all human interface guidelines that Apple had put up.
It seems to me that the use of "flaunted" in place of "flouted" is
becoming more common.
P.S. J. J. Lodder has a better command of English than I do, but I
wanted to raise the question.
Strange. I was having just the opposite impression.
[on Flaunting-flouting]
I used 'flaunting' because Stefan Haller claimed to know better,
and that Apple's guidelines are WRONG.
IIRC he insisted thAT only letters may be used,
and that Apple's use of Cmd-[ for 'Go Back' is somehow Wrong,
so he replaced it with Cmd-B.
That's an example where "flout" is the correct word.
--
Peter Moylan http://www.pmoylan.org
Newcastle, NSW, Australia
J. J. Lodder
2019-01-26 08:47:33 UTC
Permalink
Post by Peter Moylan
Post by J. J. Lodder
Post by Sam Plusnet
Post by J. J. Lodder
OTOH, MacSoup's author, Stefan Haller,
flaunted all human interface guidelines that Apple had put up.
It seems to me that the use of "flaunted" in place of "flouted" is
becoming more common.
P.S. J. J. Lodder has a better command of English than I do, but I
wanted to raise the question.
Strange. I was having just the opposite impression.
[on Flaunting-flouting]
I used 'flaunting' because Stefan Haller claimed to know better,
and that Apple's guidelines are WRONG.
IIRC he insisted thAT only letters may be used,
and that Apple's use of Cmd-[ for 'Go Back' is somehow Wrong,
so he replaced it with Cmd-B.
That's an example where "flout" is the correct word.
I am not sure. Haller was displaying his superior insights,
not just breaking some of the rules,

Jan
Jerry Friedman
2019-01-26 23:22:25 UTC
Permalink
Post by J. J. Lodder
Post by Peter Moylan
Post by J. J. Lodder
Post by Sam Plusnet
Post by J. J. Lodder
OTOH, MacSoup's author, Stefan Haller,
flaunted all human interface guidelines that Apple had put up.
It seems to me that the use of "flaunted" in place of "flouted" is
becoming more common.
P.S. J. J. Lodder has a better command of English than I do, but I
wanted to raise the question.
Strange. I was having just the opposite impression.
[on Flaunting-flouting]
I used 'flaunting' because Stefan Haller claimed to know better,
and that Apple's guidelines are WRONG.
IIRC he insisted thAT only letters may be used,
and that Apple's use of Cmd-[ for 'Go Back' is somehow Wrong,
so he replaced it with Cmd-B.
That's an example where "flout" is the correct word.
I am not sure. Haller was displaying his superior insights,
not just breaking some of the rules,
Then he was flaunting his insights, not flaunting the guidelines.
--
Jerry Friedman
Quinn C
2019-01-28 14:00:31 UTC
Permalink
Post by Jerry Friedman
Post by J. J. Lodder
Post by Peter Moylan
Post by J. J. Lodder
Post by Sam Plusnet
Post by J. J. Lodder
OTOH, MacSoup's author, Stefan Haller,
flaunted all human interface guidelines that Apple had put up.
It seems to me that the use of "flaunted" in place of "flouted" is
becoming more common.
P.S. J. J. Lodder has a better command of English than I do, but I
wanted to raise the question.
Strange. I was having just the opposite impression.
[on Flaunting-flouting]
I used 'flaunting' because Stefan Haller claimed to know better,
and that Apple's guidelines are WRONG.
IIRC he insisted thAT only letters may be used,
and that Apple's use of Cmd-[ for 'Go Back' is somehow Wrong,
so he replaced it with Cmd-B.
That's an example where "flout" is the correct word.
I am not sure. Haller was displaying his superior insights,
not just breaking some of the rules,
Then he was flaunting his insights, not flaunting the guidelines.
The usage that most here regard as wrong has made it into
Merriam-Webster, though:

| 1 :to display ostentatiously or impudently : PARADE
| // flaunting his superiority
|
| 2 :to treat contemptuously
| // flaunted the rules
| — Louis Untermeyer
<https://www.merriam-webster.com/dictionary/flaunt>

Cf.:

| : to treat with contemptuous disregard : SCORN
| // flouting the rules
<https://www.merriam-webster.com/dictionary/flout>

(the only meaning)

Synonymous, though, not subtly different.

| For some time now flaunt has been used in the sense "to show contempt
| for," even by educated users of English. But this usage is still
| widely seen as erroneous. In our 2009 survey, 73 percent of the
| Usage Panel rejected it

<https://www.ahdictionary.com/word/search.html?q=flaunt>
--
Certain writers assert very decidedly that no pronouns are
needed beyond those we already possess, but this is simply a
dogmatic opinion, unsupported by the facts.
-- Findlay (OH) Jeffersonian (1875)
Peter T. Daniels
2019-01-28 14:57:39 UTC
Permalink
Post by Quinn C
Post by Jerry Friedman
Post by J. J. Lodder
Post by Peter Moylan
Post by J. J. Lodder
Post by Sam Plusnet
Post by J. J. Lodder
OTOH, MacSoup's author, Stefan Haller,
flaunted all human interface guidelines that Apple had put up.
It seems to me that the use of "flaunted" in place of "flouted" is
becoming more common.
P.S. J. J. Lodder has a better command of English than I do, but I
wanted to raise the question.
Strange. I was having just the opposite impression.
[on Flaunting-flouting]
I used 'flaunting' because Stefan Haller claimed to know better,
and that Apple's guidelines are WRONG.
IIRC he insisted thAT only letters may be used,
and that Apple's use of Cmd-[ for 'Go Back' is somehow Wrong,
so he replaced it with Cmd-B.
That's an example where "flout" is the correct word.
I am not sure. Haller was displaying his superior insights,
not just breaking some of the rules,
Then he was flaunting his insights, not flaunting the guidelines.
The usage that most here regard as wrong has made it into
| 1 :to display ostentatiously or impudently : PARADE
| // flaunting his superiority
|
| 2 :to treat contemptuously
| // flaunted the rules
| — Louis Untermeyer
<https://www.merriam-webster.com/dictionary/flaunt>
I suspect Untermeyer, who was a rather distinguished writer, was chagrinned
to find himself quoted for that sense. James Michener in his scathing review
of the *Third International* confessed to having been quoted for the 'happen'
sense of "transpire."

Real dictionaries (unlike AHD) report what _is_, not what _should_.
Post by Quinn C
| : to treat with contemptuous disregard : SCORN
| // flouting the rules
<https://www.merriam-webster.com/dictionary/flout>
(the only meaning)
Synonymous, though, not subtly different.
| For some time now flaunt has been used in the sense "to show contempt
| for," even by educated users of English. But this usage is still
| widely seen as erroneous. In our 2009 survey, 73 percent of the
| Usage Panel rejected it
<https://www.ahdictionary.com/word/search.html?q=flaunt>
J. J. Lodder
2019-01-19 10:36:02 UTC
Permalink
Post by Lewis
Post by J. J. Lodder
Post by Jerry Friedman
Post by Lars Enderin
Post by J. J. Lodder
Post by Jerry Friedman
What? In my post, or in Harvey's?
Originally Harvey's but you made it worse.
Two of yours for one of Harvey,
1) Harvey's User-Agent: Xnews/2005.10.03
does not provide MIME headers to show text encoding.
2) His '-s should actually be '-s (ascii apostrophes, not some cute accent).
When Jerry quoted a "'", it was translated into three weird 8-bit
characters "’", the internal bytes for "'" in Unicode, but only if
viewed as Western encoding. Jerry's MIME headers specify UTF-8, which
is essential if you want to include, e g, Chinese characters or
phonetic symbols. US-ASCII is not enough for Usenet.
Your (Jan's) news client also errs in not specifying MIME headers.
For some reason, Thunderbird assumes that your text encoding is
Content-Type: text/plain; charset=windows-1252
Neither T-bird nor GG shows any Euro symbols or strange things like that.
I don't understand this stuff, but is the message that the only thing I
could change is noticing characters such as ' and rewriting them as '?
Which I often do when I'm copypasting from Web pages, but don't
guarantee to do when responding here.
The bottom line is that usenet was born under ASCII,
True.
Post by J. J. Lodder
and still is ASCII,
Not true. USENET is UTF-8, and long has supported the old code page
model (like ISO-8859-1 and Windows-1252).
Sure would be nice, but saying so doesn't make it so.
Post by Lewis
The only part of USENET that
is still ascii only are the names of the groups and the post headers, or
at least some of the post headers, or maybe it's the labels of the
headers; I forget.
The labels are all ASCII. Header content often turns into a mess
when some good-willing soul tries to include non-ASCII.
Post by Lewis
o badly coded clients do not include an encoding
o badly coded clients do not respect an encoding
o badly coded clients do not properly recode old
encoding to new encoding
o old or poorly designed clients do not support UTF-8
The system is flawed anyway because the encoding header
doesn't have to match quoted text.
Post by Lewis
Post by J. J. Lodder
despite various half-hearted attempts at generalisation.
Not half-hearted at all. There are newsgroups for all sorts of different
languages, and these groups work because USENET understands far more
than just ASCII.
Do have a look at the French language group.
Despite it being mostly ISO things still turn to a mess
every now and then,

Jan
Lewis
2019-01-19 16:10:07 UTC
Permalink
Post by J. J. Lodder
Do have a look at the French language group.
Despite it being mostly ISO things still turn to a mess
every now and then,
Not surprising if they are still using ISO code pages.
--
There's no present. There's only the immediate future and the recent
past.
Lars Enderin
2019-01-18 19:10:09 UTC
Permalink
Post by Jerry Friedman
Post by Lars Enderin
Post by J. J. Lodder
What?  In my post, or in Harvey's?
Originally Harvey's but you made it worse.
Two of yours for one of Harvey,
1) Harvey's User-Agent: Xnews/2005.10.03
does not provide MIME headers to show text encoding.
2) His ’-s should actually be '-s (ascii apostrophes, not some cute accent).
When Jerry quoted a "’", it was translated into three weird 8-bit
characters "’", the internal bytes for "’" in Unicode, but only if
viewed as Western encoding. Jerry's MIME headers specify UTF-8, which is
essential if you want to include, e g, Chinese characters or phonetic
symbols. US-ASCII is not enough for Usenet.
Your (Jan's) news client also errs in not specifying MIME headers.
For some reason, Thunderbird assumes that your text encoding is
Content-Type: text/plain; charset=windows-1252
Neither T-bird nor GG shows any Euro symbols or strange things like that.
No, they wouldn't.
I was partly wrong about Harvey. He actually produces UTF-8, using GG,
but GG fails to provide MIME headers saying so.
Thus Jan's inadequate news reader reads Harvey's message as
Windows-1252. Hence his "corrections".
--
Lars Enderin
Lewis
2019-01-18 21:14:54 UTC
Permalink
Post by Lars Enderin
Post by Jerry Friedman
Post by Lars Enderin
Post by J. J. Lodder
What?  In my post, or in Harvey's?
Originally Harvey's but you made it worse.
Two of yours for one of Harvey,
1) Harvey's User-Agent: Xnews/2005.10.03
does not provide MIME headers to show text encoding.
2) His ’-s should actually be '-s (ascii apostrophes, not some cute accent).
When Jerry quoted a "’", it was translated into three weird 8-bit
characters "’", the internal bytes for "’" in Unicode, but only if
viewed as Western encoding. Jerry's MIME headers specify UTF-8, which is
essential if you want to include, e g, Chinese characters or phonetic
symbols. US-ASCII is not enough for Usenet.
Your (Jan's) news client also errs in not specifying MIME headers.
For some reason, Thunderbird assumes that your text encoding is
Content-Type: text/plain; charset=windows-1252
Neither T-bird nor GG shows any Euro symbols or strange things like that.
No, they wouldn't.
I was partly wrong about Harvey. He actually produces UTF-8, using GG,
but GG fails to provide MIME headers saying so.
Thus Jan's inadequate news reader reads Harvey's message as
Windows-1252. Hence his "corrections".
A newsreader should interpret a message with no encoding as UTF-8,
since that is a super-set of ASCII. If the message is ASCII, the message
is treated properly., If it is not, it is treated predictably.

A message without an encoding that is not 7 bit ASCII is malformed by
definition, so there is no "right" answer, so a default of UTF-8 is
reasonable.
--
You may be anti anti-spam-kook if: Despite having invented the FUSSP you
not only don't know the difference between the SMTP envelope and SMTP
headers; you doubt there is such a thing as the SMTP envelop because
email doesn't involve paper.
Madhu
2019-01-19 13:25:17 UTC
Permalink
Post by Lewis
Post by Lars Enderin
No, they wouldn't.
I was partly wrong about Harvey. He actually produces UTF-8, using GG,
but GG fails to provide MIME headers saying so.
Thus Jan's inadequate news reader reads Harvey's message as
Windows-1252. Hence his "corrections".
A newsreader should interpret a message with no encoding as UTF-8,
since that is a super-set of ASCII. If the message is ASCII, the message
is treated properly., If it is not, it is treated predictably.
Reductio Ad Hitlerium.

UTF-8 is not 8-bit clean. You cannot encode binary data to utf-8 and
decode it back. But You can do it with latin-1. By Using UTF-8 as
default you only irrevocably lose data.
Post by Lewis
A message without an encoding that is not 7 bit ASCII is malformed by
definition, so there is no "right" answer, so a default of UTF-8 is
reasonable.
It is not.
Lewis
2019-01-19 16:17:23 UTC
Permalink
Post by Madhu
Post by Lewis
Post by Lars Enderin
No, they wouldn't.
I was partly wrong about Harvey. He actually produces UTF-8, using GG,
but GG fails to provide MIME headers saying so.
Thus Jan's inadequate news reader reads Harvey's message as
Windows-1252. Hence his "corrections".
A newsreader should interpret a message with no encoding as UTF-8,
since that is a super-set of ASCII. If the message is ASCII, the message
is treated properly., If it is not, it is treated predictably.
Reductio Ad Hitlerium.
UTF-8 is not 8-bit clean. You cannot encode binary data to utf-8 and
decode it back. But You can do it with latin-1. By Using UTF-8 as
default you only irrevocably lose data.
Strange that this never happens then. You are aware the UTF-8 uses 8
bits specifically>? That's what the 8 means.
Post by Madhu
Post by Lewis
A message without an encoding that is not 7 bit ASCII is malformed by
definition, so there is no "right" answer, so a default of UTF-8 is
reasonable.
It is not.
'Tis because anything else is unpredictable. The codepoint char(140) is
different in every code page, so using anything beyond 7-bit ASCII is
unpredictable. If you posts using a Cyrillic code page and someone
replies with their editor set to, say, Hebrew, eveything beyond the 127
ASCII characters will be mangled.

Or both of them use UTF-8 and everything works.
--
'It is always useful to face an enemy who is prepared to die for his
country,' he read. 'This means that both you and he have exactly the
same aim in mind.'
Lars Enderin
2019-01-19 20:36:39 UTC
Permalink
Post by Lewis
Post by Madhu
UTF-8 is not 8-bit clean. You cannot encode binary data to utf-8 and
decode it back. But You can do it with latin-1. By Using UTF-8 as
default you only irrevocably lose data.
Strange that this never happens then. You are aware the UTF-8 uses 8
bits specifically>? That's what the 8 means.
Post by Madhu
Post by Lewis
A message without an encoding that is not 7 bit ASCII is malformed by
definition, so there is no "right" answer, so a default of UTF-8 is
reasonable.
It is not.
'Tis because anything else is unpredictable. The codepoint char(140) is
different in every code page, so using anything beyond 7-bit ASCII is
unpredictable. If you posts using a Cyrillic code page and someone
replies with their editor set to, say, Hebrew, eveything beyond the 127
ASCII characters will be mangled.
Or both of them use UTF-8 and everything works.
UTF-8 is made for text (characters), not arbitrary binary content, so
Madhu has no point. If you want to send binary content over an SMTP
channel, you encode it in Base64, for example, and provide the proper
MIME headers.
But it's not safe to assume UTF-8 in the absense of MIME headers, but if
you do, it's fairly easy to see if the text is not UTF-8. Some
ISO-8859-*, or Windows-1252, is a better bet.
--
Lars Enderin
Madhu
2019-01-20 01:45:55 UTC
Permalink
Post by Lars Enderin
Post by Lewis
Post by Madhu
UTF-8 is not 8-bit clean. You cannot encode binary data to utf-8 and
decode it back. But You can do it with latin-1. By Using UTF-8 as
default you only irrevocably lose data.
Strange that this never happens then. You are aware the UTF-8 uses 8
bits specifically>? That's what the 8 means.
Consider how this differs from iso-latin-1 which is also 8-bit. Any
8-bit binary stream will be preserved if it is treated as iso-latin-1.
This is the original notion of "clean" from which the notion of 8-bit
clean is derived. This does not work with utf-8.
Post by Lars Enderin
Post by Lewis
Post by Madhu
Post by Lewis
A message without an encoding that is not 7 bit ASCII is malformed by
definition, so there is no "right" answer, so a default of UTF-8 is
reasonable.
It is not.
'Tis because anything else is unpredictable. The codepoint char(140) is
different in every code page, so using anything beyond 7-bit ASCII is
unpredictable.
If you posts using a Cyrillic code page and someone
replies with their editor set to, say, Hebrew, eveything beyond the 127
ASCII characters will be mangled.
You can predictably recover the original cyrillic (or original
any-other-encoding) even if it is encoded as latin-1 because 8-bits of
the character are preserved as the same 8-bits . With utf-8 there is no
such guarantee, you have lost the original bitpattern once it is
converted to utf-8.
Post by Lars Enderin
Post by Lewis
Or both of them use UTF-8 and everything works.
If everybody is blonde-eyed and blue-haired everything will just work.
Post by Lars Enderin
UTF-8 is made for text (characters), not arbitrary binary content, so
Madhu has no point.
UTF-8 is made for unicode and is not meant for any other text encoding.
For unicode all other text encodings fall into the "Other" category of
which "binary" is most general. The same issues that apply to "binary"
apply to all these "other text encodings"
Post by Lars Enderin
If you want to send binary content over an SMTP channel, you encode it
in Base64, for example, and provide the proper MIME headers.
That is besides the point.

If some text is in an unknown encoding and intermediaries assume that
the encoding is latin-1 then no information is lost. If they assume
utf-8 they lose.
Post by Lars Enderin
But it's not safe to assume UTF-8 in the absense of MIME headers, but
if you do, it's fairly easy to see if the text is not UTF-8. Some
ISO-8859-*, or Windows-1252, is a better bet.
Which was my point.
Lewis
2019-01-20 05:11:45 UTC
Permalink
Post by Madhu
Post by Lewis
Or both of them use UTF-8 and everything works.
If everybody is blonde-eyed and blue-haired everything will just work.
What the hell are you talking about. UTF-8 contains characters for
hundreds, if not thousands of languages. Some of the more esoteric ones
are Sanskrit, Cherokee, Siddham, Tangut, and Mro, and Cuniform.

I am not sure there is is a written language that cannot be represented
in UTF-8.
--
These budget numbers are not just estimates, these are the actual
results for the fiscal year that ended February the 30th. - GWB
Quinn C
2019-01-22 19:15:14 UTC
Permalink
Post by Lewis
Post by Madhu
Post by Lewis
Post by Lars Enderin
No, they wouldn't.
I was partly wrong about Harvey. He actually produces UTF-8, using GG,
but GG fails to provide MIME headers saying so.
Thus Jan's inadequate news reader reads Harvey's message as
Windows-1252. Hence his "corrections".
A newsreader should interpret a message with no encoding as UTF-8,
since that is a super-set of ASCII. If the message is ASCII, the message
is treated properly., If it is not, it is treated predictably.
Reductio Ad Hitlerium.
UTF-8 is not 8-bit clean. You cannot encode binary data to utf-8 and
decode it back. But You can do it with latin-1. By Using UTF-8 as
default you only irrevocably lose data.
Strange that this never happens then. You are aware the UTF-8 uses 8
bits specifically>? That's what the 8 means.
Yes, but it uses one or more bytes per character. The problem is that
not every 8-bit sequence is valid UTF-8. In fact, most text that isn't
encoded in UTF-8 isn't, so can't be interpreted as UTF-8 without
additional assumptions.

An ideal client would try to decode as UTF-8, accept if that works, but
use an 8-bit character set fallback otherwise.

My client doesn't use a fallback, but I can choose, per group, what it
assumes. In German groups, Win-1252 works best, here, I set it to
UTF-8. If I see that it messes up, I can still manually switch.
--
The need of a personal pronoun of the singular number and common
gender is so desperate, urgent, imperative, that ... it should long
since have grown on our speech -- The Atlantic Monthly (1878)
Lewis
2019-01-22 21:23:40 UTC
Permalink
Post by Quinn C
Post by Lewis
Post by Madhu
Post by Lewis
Post by Lars Enderin
No, they wouldn't.
I was partly wrong about Harvey. He actually produces UTF-8, using GG,
but GG fails to provide MIME headers saying so.
Thus Jan's inadequate news reader reads Harvey's message as
Windows-1252. Hence his "corrections".
A newsreader should interpret a message with no encoding as UTF-8,
since that is a super-set of ASCII. If the message is ASCII, the message
is treated properly., If it is not, it is treated predictably.
Reductio Ad Hitlerium.
UTF-8 is not 8-bit clean. You cannot encode binary data to utf-8 and
decode it back. But You can do it with latin-1. By Using UTF-8 as
default you only irrevocably lose data.
Strange that this never happens then. You are aware the UTF-8 uses 8
bits specifically>? That's what the 8 means.
Yes, but it uses one or more bytes per character. The problem is that
not every 8-bit sequence is valid UTF-8. In fact, most text that isn't
encoded in UTF-8 isn't, so can't be interpreted as UTF-8 without
additional assumptions.
An ideal client would try to decode as UTF-8, accept if that works, but
use an 8-bit character set fallback otherwise.
Which will fail in nearly all cases because there are many, and they are
not compatible at all. Many things, including IE, used to simply assume
Windows' bullshit code page, and that broke nearly everything.
Post by Quinn C
My client doesn't use a fallback, but I can choose, per group, what it
assumes. In German groups, Win-1252 works best, here, I set it to
UTF-8. If I see that it messes up, I can still manually switch.
If someone posts a non-ASCII message without declaring the encoding, the
post is broken. HOW it breaks is up to the software trying to deal with
the idiot client that posted a broken message.
--
Are you a lucky little lady in the city of light Or just another lost
angel?
Quinn C
2019-01-22 22:41:27 UTC
Permalink
Post by Lewis
Post by Quinn C
An ideal client would try to decode as UTF-8, accept if that works, but
use an 8-bit character set fallback otherwise.
Which will fail in nearly all cases because there are many, and they are
not compatible at all. Many things, including IE, used to simply assume
Windows' bullshit code page, and that broke nearly everything.
Not in practice. This being an English-speaking group, there are only
about 3 relevant 8-bit encodings, and they are very similar.
Post by Lewis
Post by Quinn C
My client doesn't use a fallback, but I can choose, per group, what it
assumes. In German groups, Win-1252 works best, here, I set it to
UTF-8. If I see that it messes up, I can still manually switch.
If someone posts a non-ASCII message without declaring the encoding, the
post is broken. HOW it breaks is up to the software trying to deal with
the idiot client that posted a broken message.
I'm trying to follow the principle "be conservative in what you send,
liberal in what you accept." In practice, almost all posts here become
at least decipherable by choosing one of UTF-8 or Win-1252, and I do
manual switching between the two maybe about once a month. And then,
instead of complaining about their formatting, I can complain about
their English usage, and be on topic.
--
The generation of random numbers is too important to be left to
chance.
Robert R. Coveyou
J. J. Lodder
2019-01-23 11:40:00 UTC
Permalink
Post by Quinn C
Post by Lewis
Post by Quinn C
An ideal client would try to decode as UTF-8, accept if that works, but
use an 8-bit character set fallback otherwise.
Which will fail in nearly all cases because there are many, and they are
not compatible at all. Many things, including IE, used to simply assume
Windows' bullshit code page, and that broke nearly everything.
Not in practice. This being an English-speaking group, there are only
about 3 relevant 8-bit encodings, and they are very similar.
Post by Lewis
Post by Quinn C
My client doesn't use a fallback, but I can choose, per group, what it
assumes. In German groups, Win-1252 works best, here, I set it to
UTF-8. If I see that it messes up, I can still manually switch.
If someone posts a non-ASCII message without declaring the encoding, the
post is broken. HOW it breaks is up to the software trying to deal with
the idiot client that posted a broken message.
I'm trying to follow the principle "be conservative in what you send,
liberal in what you accept." In practice, almost all posts here become
at least decipherable by choosing one of UTF-8 or Win-1252, and I do
manual switching between the two maybe about once a month. And then,
instead of complaining about their formatting, I can complain about
their English usage, and be on topic.
There is more UTF than that.
I happen to know, because MacSoup is Deutsch-Grundlich und Normgerecht.
(another of those nice German words without direct equivalent)

It refuses to emit a UFT-8 character without putting up a warning first,
even in cases where it has received that character without a problem,
(don't send, re-edit, or send anyway, re-edit is default)

Jan
Lewis
2019-01-17 00:05:09 UTC
Permalink
Post by J. J. Lodder
Post by HVS
Post by Jerry Friedman
I've been (non-obsessionally) monitoring the changes to the times of
sunrise and sunset since the solstice, and don't understand why the
changes to those times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665
N/ 1.0924W) were 08:06 and 15:58. Today (14 January) they are 08:02
and 16:23. So sunrise has become 4 minutes earlier in that time, while
sunset is 25 minutes later.
Checking for the other end of the year, the times for 21 June are 04:48
and 21:23, and for 14 July are 05:04 and 21:15 and sunrise is 16
minutes later; sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don't change at the same
rate?
And why is the asymmetry more marked in December/January than in June/July?
[many non-ASCII characters rectified]
Post by HVS
Post by Jerry Friedman
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).
When the Earth makes one exact rotation, the stars appear in the same
places in the sky, but the Sun does not. That's because the Earth has
moved in its orbit during that time. The Earth rotates in the same
direction as it moves in its orbit, counterclockwise as seen from the
north [*], so it has to rotate slightly farther for the Sun to be in the
same position in the sky. If we ignore the elliptical shape of the
Earth's orbit and the tilt of its axis, it has to go farther by 1/365
[**] of a day every day in order for the Sun to go around once in a
year. That's 24/365 of an hour, or 60*24/365 minutes, which is about 4
minutes. We define the /average/ time for the Sun to return to
approximately the same position as a day, so a day is about 4 minutes
longer than the rotation period of the Earth. In other words, the time
for one rotation, called the sidereal day because it's relative to the
stars, is about 23 hours and 56 minutes.
However, the Earth's orbit is an ellipse with the Sun off center, and
when the Earth is close to the Sun (it's closest about Jan. 4, whether
it feels close to the Sun then or not), it moves faster. So during that
time, the Earth has to rotate a little farther to bring the Sun into the
same position in the sky, and the interval between one noon and the next
is a little more than 24 hours. Thus sundials run slow, and in the
northern hemisphere sunsets get later faster than sunrises get earlier.
When the Earth is farther from the Sun (it's farthest around July 6),
the opposite happens.
Got that? Also, the Earth's axis is tilted with respect to the plane of
its orbit. Now if we could pretend the orbit is a circle again, the
apparent position of the Sun relative to the stars would move at the
same speed all year. However, at the solstices it's moving directly
east [***], making the difference between the 24-hour day and the
sidereal day more than 4 minutes and making sundials run slow. In
contrast, at the March equinox the Sun is moving northeast and at the
September equinox it's moving southeast, so it makes less progress east,
and the difference between the 24-hour day and the sidereal day is less
than 4 minutes; sundials run fast.
Those two effects combine to control the times of sunrise and sunset.
As Jan said, a good search term if you want to know more is "equation of
https://in-the-sky.org/article.php?term=equation_of_time
Do you deal with sundials in your work? This is the sort of thing
sundial experts know about. (ObVocab: Gnomonists.)
[*] Almost by definition. The Earth rotates counterclockwise as seen
from the north, so the Sun appears to us to move clockwise in the
northern hemisphere, so shadows move clockwise, and sundials are
numbered clockwise--and clock dials are numbered the same way as
northern-hemisphere sundials.
[**] Closer to 1/365.25, you pedants, but I'm going to give the answer
to one significant figure.
[***] The solstices (solstitia) are when the sun is "standing still".
Standing still and moving directly east? The Sun at local noon is
always due north or south (or overhead, in the tropics, and kindly allow
me to ignore the Arctic and Antarctic). When the ancients looked at the
position of the Sun at noon, they didn't see the eastward motion (which
is defined only relative to the stars, seldom visible at noon). They
saw only that at the solstices, the noonday Sun reached its most
northern point and its most southern point, so it briefly stopped moving
(north or south) as it turned around.
Many thanks, Jerry -- I shall print that off and sit down with a strong cup
of tea to see if I can visualise/understand it!
It may help if you think of Phileas Fogg, who did just the same.
You may remember that Fogg, traveling eastwards around the world,
gained a day on going around once.
(for the plot's sake, to his great surpise)
When did he gain this day?
a little bit on all days that he travelled,
on average 18 minutes a day.
Next question: did Fogg gain the same amount on all days he travelled?
No of course, on days he travelled fast, by train,
he gained more than average, when on elephant, less.
And next, asuming that he travelled at his average speed for a day,
he gained more when travelling due east
than when his course would be south-east or north-west.
While Phileas Fogg was a fictional character, Nellie Bly was not, and she
did her "Around the World in 80 days" inspired journey in, IIRC, 72
days.

Her other claim to fame was checking herself into an insane asylum to
write an exposé on the conditions she encountered (She did this while
working for Pulitzer in NYC).

Nellie Bly was a pen name, but I do not remember her actual name.
--
"It's like those French have a different word for *everything*" - Steve
Martin
Jack
2019-01-16 22:33:37 UTC
Permalink
Post by HVS
Post by Jerry Friedman
Post by HVS
I’ve been (non-obsessionally) monitoring the changes to the times of
sunrise and sunset since the solstice, and don’t understand why the
changes to those times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665
N/ 1.0924W) were 08:06 and 15:58. Today (14 January) they’re 08:02
and 16:23. So sunrise has become 4 minutes earlier in that time, while
sunset is 25 minutes later.
Checking for the other end of the year, the times for 21 June are 04:48
and 21:23, and for 14 July are 05:04 and 21:15 – sunrise is 16
minutes later; sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don’t change at the same rate?
And why is the asymmetry more marked in December/January than in June/July?
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).
When the Earth makes one exact rotation, the stars appear in the same
places in the sky, but the Sun does not. That's because the Earth has
moved in its orbit during that time. The Earth rotates in the same
direction as it moves in its orbit, counterclockwise as seen from the
north [*], so it has to rotate slightly farther for the Sun to be in the
same position in the sky. If we ignore the elliptical shape of the
Earth's orbit and the tilt of its axis, it has to go farther by 1/365
[**] of a day every day in order for the Sun to go around once in a
year. That's 24/365 of an hour, or 60*24/365 minutes, which is about 4
minutes. We define the /average/ time for the Sun to return to
approximately the same position as a day, so a day is about 4 minutes
longer than the rotation period of the Earth. In other words, the time
for one rotation, called the sidereal day because it's relative to the
stars, is about 23 hours and 56 minutes.
However, the Earth's orbit is an ellipse with the Sun off center, and
when the Earth is close to the Sun (it's closest about Jan. 4, whether
it feels close to the Sun then or not), it moves faster. So during that
time, the Earth has to rotate a little farther to bring the Sun into the
same position in the sky, and the interval between one noon and the next
is a little more than 24 hours. Thus sundials run slow, and in the
northern hemisphere sunsets get later faster than sunrises get earlier.
When the Earth is farther from the Sun (it's farthest around July 6),
the opposite happens.
Got that? Also, the Earth's axis is tilted with respect to the plane of
its orbit. Now if we could pretend the orbit is a circle again, the
apparent position of the Sun relative to the stars would move at the
same speed all year. However, at the solstices it's moving directly
east [***], making the difference between the 24-hour day and the
sidereal day more than 4 minutes and making sundials run slow. In
contrast, at the March equinox the Sun is moving northeast and at the
September equinox it's moving southeast, so it makes less progress east,
and the difference between the 24-hour day and the sidereal day is less
than 4 minutes; sundials run fast.
Those two effects combine to control the times of sunrise and sunset.
As Jan said, a good search term if you want to know more is "equation of
https://in-the-sky.org/article.php?term=equation_of_time
Do you deal with sundials in your work? This is the sort of thing
sundial experts know about. (ObVocab: Gnomonists.)
[*] Almost by definition. The Earth rotates counterclockwise as seen
from the north, so the Sun appears to us to move clockwise in the
northern hemisphere, so shadows move clockwise, and sundials are
numbered clockwise--and clock dials are numbered the same way as
northern-hemisphere sundials.
[**] Closer to 1/365.25, you pedants, but I'm going to give the answer
to one significant figure.
[***] The solstices (solstitia) are when the sun is "standing still".
Standing still and moving directly east? The Sun at local noon is
always due north or south (or overhead, in the tropics, and kindly allow
me to ignore the Arctic and Antarctic). When the ancients looked at the
position of the Sun at noon, they didn't see the eastward motion (which
is defined only relative to the stars, seldom visible at noon). They
saw only that at the solstices, the noonday Sun reached its most
northern point and its most southern point, so it briefly stopped moving
(north or south) as it turned around.
Many thanks, Jerry -- I shall print that off and sit down with a strong cup
of tea to see if I can visual
J. J. Lodder
2019-01-16 20:47:46 UTC
Permalink
Post by Jerry Friedman
I've been (non-obsessionally) monitoring the changes to the times of sunrise
and sunset since the solstice, and don't understand why the changes to those
times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665 N/
1.0924W) were 08:06 and 15:58. Today (14 January) they're 08:02 and 16:23.
So sunrise has become 4 minutes earlier in that time, while sunset is 25
minutes later.
Checking for the other end of the year, the times for 21 June are 04:48 and
21:23, and for 14 July are 05:04 and 21:15 sunrise is 16 minutes later;
sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don't change at the same rate?
And why is the asymmetry more marked in December/January than in June/July?
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).
[-]

One could add that the irregular motion of the sun
was already known to the Babylonians,
despite them not having accurate clocks.

From the 18th century onwards 'equation clocks'
and idem watches have been made.
These either had a mechanism to make a pendulum clock
show true solar time, or they had two minute hands
to show both the mean and the true solar time.

In remote areas where time signals were not available
this was useful to set the clock to the right time from a sundial.
Conversely some sundials have the equation of time
engraved as a table or a graph.

By themselves pendulum clocks were not very stable,
and they neded frequent adjustment,

Jan
Jerry Friedman
2019-01-18 19:37:29 UTC
Permalink
Post by J. J. Lodder
Post by Jerry Friedman
I've been (non-obsessionally) monitoring the changes to the times of sunrise
and sunset since the solstice, and don't understand why the changes to those
times are asymmetrical.
On 21 December, the sunrise and sunset times for my location (51.2665 N/
1.0924W) were 08:06 and 15:58. Today (14 January) they're 08:02 and 16:23.
So sunrise has become 4 minutes earlier in that time, while sunset is 25
minutes later.
Checking for the other end of the year, the times for 21 June are 04:48 and
21:23, and for 14 July are 05:04 and 21:15 sunrise is 16 minutes later;
sunset is 8 minutes earlier.
So how come the times of sunrise and sunset don't change at the same rate?
And why is the asymmetry more marked in December/January than in June/July?
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).
[-]
One could add that the irregular motion of the sun
was already known to the Babylonians,
despite them not having accurate clocks.
Pretty impressive. I assume they tracked the sun against the stars
by dead-reckoning from the visible stars near where the sun rose and
set?
Post by J. J. Lodder
From the 18th century onwards 'equation clocks'
and idem watches have been made.
These either had a mechanism to make a pendulum clock
show true solar time, or they had two minute hands
to show both the mean and the true solar time.
...

I did not know that.
--
Jerry Friedman
J. J. Lodder
2019-01-19 22:24:55 UTC
Permalink
Post by Jerry Friedman
Post by J. J. Lodder
Post by Jerry Friedman
tl;dr: It's because the Earth's orbit is an ellipse, not a circle, and
because the Earth's axis is tilted (causing the seasons).
[-]
One could add that the irregular motion of the sun
was already known to the Babylonians,
despite them not having accurate clocks.
Pretty impressive. I assume they tracked the sun against the stars
by dead-reckoning from the visible stars near where the sun rose and
set?
I don't know, would have to look into it.
From deep down: I think Ptolemy tabulates it,
and that he says it is of relevance for fast-moving bodies
like the moon only.
So I would guess it can be obtained
by opserving the motions of the moon accurately.
Post by Jerry Friedman
Post by J. J. Lodder
From the 18th century onwards 'equation clocks'
and idem watches have been made.
These either had a mechanism to make a pendulum clock
show true solar time, or they had two minute hands
to show both the mean and the true solar time.
...
I did not know that.
They are quite rare, rather expensive antiques,
and museum pieces mostly, I guess,

Jan

PS This is where the differential gears were invented.
They really implemet a difference.
John Varela
2019-01-18 21:49:29 UTC
Permalink
Post by J. J. Lodder
By themselves pendulum clocks were not very stable,
and they neded frequent adjustment,
Tell me about it. We have three antique pendulum clocks, one of
which no longer works. The two functional ones have to be readjusted
spring and autumn as the indoor temperature fluctuates. Once we
settle down into air conditioning season or heating season and the
temperature stops fluctuating they keep good to excellent time (one
stays within 10 seconds a week). The now non-functional clock has a
wooden shaft on the pendulum and it varied with both temperature and
humidity.
--
John Varela
J. J. Lodder
2019-01-19 11:37:35 UTC
Permalink
Post by John Varela
Post by J. J. Lodder
By themselves pendulum clocks were not very stable,
and they neded frequent adjustment,
Tell me about it. We have three antique pendulum clocks, one of
which no longer works. The two functional ones have to be readjusted
spring and autumn as the indoor temperature fluctuates.
Good pendulum clocks (and chronometers) have temperature compensation.
Yours is apparently not quite what it should be.
They had to, for it got real cold in those stately homes.
The best have a mercury pendulum.
Post by John Varela
Once we
settle down into air conditioning season or heating season and the
temperature stops fluctuating they keep good to excellent time (one
stays within 10 seconds a week).
That is about what you can expect, for a good pendulum clock.
Astronomical clocks and regulators
could be an order of magnitude better.
OTOH, only the best, and therefore expensive, clocks could achieve this.
Ordinary 'household' clocks like cuckoo clocks were far worse,
and needed far more frequent adjustment.
Post by John Varela
The now non-functional clock has a wooden shaft on the pendulum and it
varied with both temperature and humidity.
I imagine that in a rural village
everyone would take the right time from the church tower.
The one who took care of that had to find the right time in some way,
perhaps from a sundial.

Jan

PS There is no progress here.
Jeff Bezos' 10 000 Year Clock will be sundial controlled too.
(through a clever mechanical linkage)
It's just a sundial with an elaborate counter that interpolates.

And FYA, the oldest still firing guns are two Dutch smoothbores
installed on Signal Hill, Cape Town.
They have been firing precisely at noon every day since 1806.
<https://en.wikipedia.org/wiki/Noon_Gun>
Sam Plusnet
2019-01-19 19:26:21 UTC
Permalink
Post by J. J. Lodder
And FYA, the oldest still firing guns are two Dutch smoothbores
installed on Signal Hill, Cape Town.
They have been firing precisely at noon every day since 1806.
<https://en.wikipedia.org/wiki/Noon_Gun>
extracted from that wiki page

"On the 9th of April 2013, a Twitter account was created for the Noon
Gun that sends a single message reading "BANG!" everyday (except Sundays
and public holidays)."
--
Sam Plusnet
J. J. Lodder
2019-01-20 18:18:55 UTC
Permalink
Post by Sam Plusnet
Post by J. J. Lodder
And FYA, the oldest still firing guns are two Dutch smoothbores
installed on Signal Hill, Cape Town.
They have been firing precisely at noon every day since 1806.
<https://en.wikipedia.org/wiki/Noon_Gun>
extracted from that wiki page
"On the 9th of April 2013, a Twitter account was created for the Noon
Gun that sends a single message reading "BANG!" everyday (except Sundays
and public holidays)."
Even Trump should be able to understand that one,

Jan
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