What's On the Dark Side of the Moon

Well, today's NASA Image of the Day shows the ISS on the Dark Side of the Moon.

Remember the ISS is not really that close to the Moon. It orbits only about 350km away from Earth and the Moon is about 380,000km, or roughly 1,000 times farther away.

This is a pretty impressive shot. When most people watch the ISS cross the sky for the first time, they remark about how fast it appears to be moving. The ISS crosses the entire face of the Moon in about .4 seconds which means it passes the dark side in this photo in a little under .2 seconds (the Moon is appears slightly over half lit here). It takes some timing to get that shot!

The ISS is currently making passes over the U.S. in the morning now. It will appear brighter than usual since the Shuttle is docked at it which makes it larger and hence brighter. You can find predicted pass times at Heavens Above.

Racine has a least one pass each morning from now until April 16th. Some mornings you get two (we rarely get two passes in a day since we are farther south...farther north, they can even get three passes sometimes in the summer).

Reprinted with permission from the Half-Astrophysicist Blog.