Three Theories of Planet Formation Busted, Expert Says: "The more new planets we find, the less we seem to know about how planetary systems are born, according to a leading planet hunter.
With the tally of confirmed planets orbiting other stars now more than 500, planet hunters are heading for a golden age of discovery, said Geoffrey Marcy of the University of California, Berkeley. (Explore an interactive of the known planets.)
But that bonanza has been a headache for theoreticians, he said, because many of the newly discovered star systems defy existing models of how planets form. (Related: 'New Planet Found; Star's Fourth World Stumps Astronomers.')
Current theory holds that planets are made from disks of gas and dust left over after star birth."
