Astronomers Say Moons Like Ours Are Uncommon

The next time you take a moonlit stroll, or admire a full, bright-white moon looming in the night sky, you might count yourself lucky. New observations from NASA's Spitzer Space Telescope suggest that moons like Earth's -- that formed out of tremendous collisions -- are uncommon in the universe, arising at most in only 5 to 10 percent of planetary systems.

The Spitzer Space Telescope is a NASA mission managed by the Jet Propulsion Laboratory. This website is maintained by the Spitzer Science Center, located on the campus of the California Institute of Technology and part of NASA's Infrared Processing and Analysis Center. Privacy Policy