Solstice trivia question (APOD 22 Dec 2007)

richard schumacher · Post by **richard schumacher** » Sat Dec 22, 2007 11:57 pm

At a solstice, what points on Earth have day and night of exactly equal length?

http://antwrp.gsfc.nasa.gov/apod/ap071222.html

rigelan · Post by **rigelan** » Sun Dec 23, 2007 12:20 am

What do you mean points?

Lattitude & Longitude?

Qev · Post by **Qev** » Sun Dec 23, 2007 12:48 am

Wouldn't that be the Tropics?

starnut · Post by **starnut** » Sun Dec 23, 2007 2:19 am

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.

rigelan · Post by **rigelan** » Sun Dec 23, 2007 5:45 pm

And somewhere in between at somewhen inbetween

auroradude · Post by **auroradude** » Mon Dec 24, 2007 12:34 am

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.

rigelan · Post by **rigelan** » Mon Dec 24, 2007 1:17 am

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

BMAONE23 · Post by **BMAONE23** » Mon Dec 24, 2007 5:42 am

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