Looking for the remnants of the world that made our Moon
NASA Science News for April 9, 2009
NASA's twin STEREO probes are entering a mysterious region of space to look for remains of an ancient planet which might have orbited the Sun not far from Earth. If they find anything, it could solve a major puzzle--the origin of the Moon.
FULL STORY at
http://science.nasa.gov/headlines/y2009/09apr_theia.htm?list1094208