Longest night ever, but for which timezone?

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Longest night ever, but for which timezone?

Postby Lopsidation » Mon Dec 22, 2014 3:54 am UTC

I heard that this solstice is the longest (or second longest) night ever (i.e. in the entire history of the Earth), because of the varying speed of the rotation of the Earth.

It seems to me like this depends on which timezone you live in. Like, if your timezone's midnight lines up perfectly with the solstice point in Earth's orbit, you get the longest possible solstice night. If your timezone's noon lines up with Earth's solstice point, then you instead get two pretty long nights on either side.

So, which lucky timezone gets the longest night ever?

EDIT: In the far north/south, of course the winter night lasts months. Let's ignore this and consider points near the equator. I think the answer should be the same timezone for everybody living at a reasonable latitude.

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Re: Longest night ever, but for which timezone?

Postby thoughtfully » Mon Dec 22, 2014 8:28 am UTC

Find the exact UTC for the solstice, then work out where solar noon/midnight would be.

The US Naval Observatory has some cool software, NOVAS, that you could use to get precise information. Looks like they now come with Python bindings. I had to SWIG my own "back in the day".
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Re: Longest night ever, but for which timezone?

Postby Angua » Mon Dec 22, 2014 9:21 am UTC

I thought this was a cool observation re: solstices and day lengths.

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Re: Longest night ever, but for which timezone?

Postby gmalivuk » Tue Dec 23, 2014 8:47 pm UTC

Incidentally, this year's solstice wasn't the longest night, because overall average slowing due to the Moon's tidal forces isn't the only thing affecting day length, though it is the one that will dominate long-term.

The longest night so far happened in 1912.

But otherwise you'd be correct that it's whichever longitude is directly opposite the sun at the moment of solstice, which isn't quite the same as which timezone had midnight at the moment of solstice, since midnight only corresponds exactly to the moment when the sun is directly opposite your longitude four times a year.
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