Moon’s Transit of Earth
Posted in Astronomy at 19:35 on 9 August 2015
This isn’t a view any human of even the relatively recent past could ever have seen: the Moon passing in front of the Earth:-

From Astronomy Picture of the Day 7/8/15, this photo – taken by NASA’s Deep Space Climate Observatory (DSCOVR) spacecraft – is captioned Full Moon, Full Earth, but of course it’s a New Moon; from the surface of the Earth all of the Moon would appear dark. The hemisphere of the Moon seen in the photo is of course its far side (which isn’t dark, except briefly: it gets as much sunlight as the near side does, only in reverse proportion.)
The DSCOVR spacecraft is situated at the Earth-Sun L1 Lagrange Point (see diagram – not to scale – below) where the orbit of a satellite is stable. As such it is perfectly placed to observe the Moon transit the Earth as above, which from its perspective occurs twice a year.
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Tags: APOD, Astronomy, Astronomy Picture of the Day, Deep Space Climate Observatory, DSCOVR, Lagrange Points, the Moon
