What day/exact time does Sun start to move again? (1980 Winter Solstice)

[UniversalEnergy03]

I found a website (link listed below) that gives date and time of the Winter Solstice of 1980. The date (12/21/1980). The time (UT 16:52).
Being that the Sun stays in the same position for 3 days, what is the exact day & time it starts to move again? Anyone know where to find this information or where it is recorded?

https://scienceworld.wolfram.com/astronomy/WinterSolstice.html

Side note: I live in the Northeastern region of the US. 12/21/1980 at UT 16:52 is when the sun is the most south and after 3 days it starts to move North correct?

Appreciate your feedback and knowledge!
Thank you in advance!

 

[sysprog]

I found a website (link listed below) that gives date and time of the Winter Solstice of 1980. The date (12/21/1980). The time (UT 16:52).
Being that the Sun stays in the same position for 3 days, what is the exact day & time it starts to move again? Anyone know where to find this information or where it is recorded?

https://scienceworld.wolfram.com/astronomy/WinterSolstice.html

Side note: I live in the Northeastern region of the US. 12/21/1980 at UT 16:52 is when the sun is the most south and after 3 days it starts to move North correct?

Appreciate your feedback and knowledge!
Thank you in advance!

Where did you get the idea that "the Sun stays in the same position for 3 days"? The discourse at the site to which you linked doesn't say that $-$ the sun is never non-moving with respect to any point of view on Earth $-$ as for when the season change occurs, that site says:

Note that the times below were calculated using WinterSolstice[] in the Mathematica application package http://www.wolfram.com/products/applications/astronomer/, which is accurate to within only an hour or so, and in practice gives times that differ by up to 15 minutes from those computed by the U.S. Naval Observatory (which computes December 22, 1999 at 07:44 UT instead of 07:32 UT and December 21, 2000 at 13:37 UT instead of 13:23).​

​

That means that we can easily resolve the season change date and time to an accuracy of "an hour or so" $\dots$

​

 

[Orodruin]

12/21/1980 at UT 16:52 is when the sun is the most south and after 3 days it starts to move North correct?

Not correct. The Sun never stops moving. It is just that the velocity at the solstice is zero but directly after it will start going the other way.

 

[russ_watters]

It's probably somebody's idea of "doesn't move enough to notice".

 

[Orodruin]

It's probably somebody's idea of "doesn't move enough to notice".

Sure, but that is highly subjective.

 

[sysprog]

From: https://www.space.com/24014-winter-solstice-sun-movement-explained.html

Because of the tilt in the Earth’s axis of rotation, the sun appears to rise and fall in our sky over the course of a year. It’s not the sun itself moving, but the Earth moving relative to the sun.​

. . .​

On Dec. 21, the sun stops moving southward, pauses, and then starts moving northward. This pause is called the "solstice," from the Latin words "sol" for "sun" and "sisto" for "stop." Similarly, on June 21 the sun stops moving northward and starts moving southward.​

​

As @Orodruin said, the (Northward or Southward) velocity goes to zero, but only momentarily $-$ then the velocity increases until it maximizes at the equinox.

 

[UniversalEnergy03]

From: https://www.space.com/24014-winter-solstice-sun-movement-explained.html

Because of the tilt in the Earth’s axis of rotation, the sun appears to rise and fall in our sky over the course of a year. It’s not the sun itself moving, but the Earth moving relative to the sun.​

. . .​

On Dec. 21, the sun stops moving southward, pauses, and then starts moving northward. This pause is called the "solstice," from the Latin words "sol" for "sun" and "sisto" for "stop." Similarly, on June 21 the sun stops moving northward and starts moving southward.​

​

As @Orodruin said, the (Northward or Southward) velocity goes to zero, but only momentarily $-$ then the velocity increases until it maximizes at the equinox.

what is the exact day & time it starts to move again in 1980?

 

[UniversalEnergy03]

12/21/1980 at UT 16:52 is when the sun is the most south and after 3 days it starts to move North. Does that mean it starts to move again on December 24th? Again what is the day and time it starts to move again?

 

[Orodruin]

Did you actually read the answers you got already? The Sun does not stop moving north/south for three days so the entire premise of your question is flawed. The north/south velocity is technically zero only for a moment of zero duration.

 

[jack action]

Does this calculator help? Try moving the day of year slider to see the north-south motion of the sun (Look for the elevation angle). Try also the option Keep previous plots and overlay new plot while moving the slider.

I tried in Chicago at noon, and the sun's elevation angles are:

Dec 18 -> 24.61°
Dec 19 -> 24.60°
Dec 20 -> 24.60°
Dec 21 -> 24.61°

So the sun does moves north-south-north, but so very little for a period of 2-3 days that it seems like it stands still.

 

[Orodruin]

Dec 18 -> 24.61°
Dec 19 -> 24.60°
Dec 20 -> 24.60°
Dec 21 -> 24.61°

To clarify: If one added more decimals to these numbers 19 and 20 would be different. The difference is just too small to notice with this precision.

 

[sophiecentaur]

I tried in Chicago at noon, and the sun's elevation angles are:

Dec 18 -> 24.61°
Dec 19 -> 24.60°
Dec 20 -> 24.60°
Dec 21 -> 24.61°

The OP should realize that the Sun will be at its lowest point at different times for all observer longitudes. There will be a place on Earth where the observed 'lowest point' is on two adjacent days (missing, entirely, the actual lowest point). That point will be 180 degrees longitude away from the location where the Sun (at a given latitude) is lower, at its local solstice, than for anywhere else at that latitude.
I have just been working out a form of words to use to point out, to a group of 'Young Astronomers', the way the Sun behaves at solstice and relating this to how the ancients decided on an appropriate 'leap year' rule because of the problem of actually identifying which day (of just two) to start the next year on.
The flatness of the curve for the Sun's height will be similar to the flatness of a Cos curve at zero degrees. Cos (0) =1 and Cos (1) = 0.99985. (One day being very near to one degree) Would you ever spot the difference without modern optical aids, I wonder? Those old experimenters certainly used some clever techniques and not a telescope in sight!

 

[UniversalEnergy03]

https://www.physicsforums.com/threa...ng-about-the-suns-movement-in-the-sky.175972/

 

[PeterDonis]

https://www.physicsforums.com/threa...ng-about-the-suns-movement-in-the-sky.175972/

The key word in the quote given in the OP of that thread is "seems".

To summarize the answers you have already received:

Strictly speaking, if the winter solstice in 1980 was on 12/21/1980 at 16:52 UTC, then at 16:53 UTC the Sun is moving north again. So if you're looking for an "exact" answer (and you used the word "exact" in your OP), that is the "exact" time the Sun starts to move again. If you want an "exact" answer, the "exact" answer is that the Sun does not stay still for 3 days; it only stays still for an instant.

If you want a fuzzier answer about when the Sun "seems" to start moving again, that's going to depend on what kind of observations you are using to judge the "seems". To the average person's unaided eye, it might indeed "seem" that the Sun stands still for 3 days at the solstice. But if that's the criterion you're using, asking for the "exact" time the Sun starts to move again is pointless, because the observations you're making aren't "exact", they're fuzzy subjective judgments.

And since that sums up what has already been said in a number of previous posts, and it addresses the question of this thread sufficiently, this thread is now closed.