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Solstice trivia question (APOD 22 Dec 2007)
Posted: Sat Dec 22, 2007 11:57 pm
by richard schumacher
At a solstice, what points on Earth have day and night of exactly equal length?
http://antwrp.gsfc.nasa.gov/apod/ap071222.html
Posted: Sun Dec 23, 2007 12:20 am
by rigelan
What do you mean points?
Lattitude & Longitude?
Posted: Sun Dec 23, 2007 12:48 am
by Qev
Wouldn't that be the Tropics?
Posted: Sun Dec 23, 2007 2:19 am
by starnut
Qev wrote:Wouldn't that be the Tropics?
Yes, at the Tropic of Cancer during the northern summer solistice and the Tropic of Capricorn during the southern summer solistice.
Posted: Sun Dec 23, 2007 5:45 pm
by rigelan
And somewhere in between at somewhen inbetween
Posted: Mon Dec 24, 2007 12:34 am
by auroradude
And everywhere on the equinoxes.
Of course, this is all theoretical since in actuality the length of a day will also depend on atmospheric refraction, the horizon and the altitude of an observer.
Posted: Mon Dec 24, 2007 1:17 am
by rigelan
Hah! Sure. Does the equal day refer to the time between the peeking of the sun over the horizon or from the full sun appearing? And besides, I'm not so sure I get a full 180 degree view of the horizon here in the rolling hills of Iowa
Posted: Mon Dec 24, 2007 5:42 am
by BMAONE23
starnut wrote:Qev wrote:Wouldn't that be the Tropics?
Yes, at the Tropic of Cancer during the northern summer solistice and the Tropic of Capricorn during the southern summer solistice.
I was under the impression thet the Solstices were the days of Most daylight time (summer) & least daylight time (winter). At the Northern Summer Solstice, (JUNE 21st or so) the Sun is shining directly on the Tropic of Cancer but the length of day is still slightly longer than night at the tropic. The time of equal day and night still occur at the Equator, it just gets less Direct Sunlight. Same for the Northern Winter Solstice when the sun is shining directly on the Tropic of Capricorn. This is the time of the longest Southern hemisphere day. But it is also with Equal day/night hours at the Equator
notice where the equitorial line meets the terminator in this image
![Image](http://upload.wikimedia.org/wikipedia/commons/thumb/c/c8/Earth-lighting-summer-solstice_EN.png/800px-Earth-lighting-summer-solstice_EN.png)