Scientists have found what appears to be the smallest Earth-like planet outside the solar system. It's five times the mass and whirls around its sun every 13 days, but it appears to be the only one discovered so far that inhabits the "sweet spot" where temperatures and light should be just right to allow liquid water to exist, potentially making it a place where life could exist. The upcoming Spitzer telescope should be sensitive enough to gather more data on this enigmatic object.