File:NASA-Apollo8-Dec24-Earthrise.jpg

Summary

English: Taken by Apollo 8 crewmember Bill Anders on December 24, 1968, while in orbit around the Moon, showing the Earth rising above the lunar horizon. Note that this phenomenon is only visible to an observer in motion relative to the lunar surface. Because of the Moon's synchronous rotation relative to the Earth (i.e., the same side of the Moon is always facing Earth), the Earth appears to be stationary (measured in anything less than a geological timescale) in the lunar "sky". In order to observe the effect of Earth rising or setting over the Moon's horizon, an observer must travel towards or away from the point on the lunar surface where the Earth is most directly overhead (centred in the sky). Otherwise, the Earth's apparent motion/visible change will be limited to: 1. Growing larger/smaller as the orbital distance between the two bodies changes. 2. Rotation of the Earth (the Moon's rotation is synchronous relative to the Earth, the Earth's rotation is not synchronous relative to the Moon). 3. Atmospheric & surface changes on Earth (i.e.: weather patterns, changing seasons, etc.).

Français : "Lever de terre" sur la lune. Photo prise le 24 décembre 1968 par Bill Anders, et montrant la terre semblant se lever derrière l'horizon lunaire. Ce phénomène n'est visible que par quelqu'un en orbite autour de l'astre. A cause de la rotation synchrone de la lune, qui montre toujours la même face vers la terre, on ne voit pas la terre se lever ou se coucher depuis la surface de la lune.

Русский: Фото, полученное Уильямом Андерсом, пилотом корабля «Аполлон-8» 24 декабря, 1968, показана видимая часть Земли, поднимающаяся над лунной поверхностью. Заметим, что это явление видимо только на некоторых орбитах Луны. Из-за синхронного вращения Луны вокруг Земли (т.е. та же сторона Луны всегда обращена к Земле), восход Земли над линией горизонта (Earthrise) нельзя наблюдать ни в какой точке Луны.

Copyright status:

This file is in the public domain because it was created by NASA. NASA copyright policy states that "NASA material is not protected by copyright unless noted".

Source:

http://www.nasa.gov/vision/earth/features/bm_gallery_4.html