The more new planets we find, and the tally of confirmed planets orbiting other stars is now more than 500, the less we seem to know about how planetary systems are born.

We're heading for a golden age of discovery, says Geoffrey Marcy of the University of California, Berkeley in National Geographic, but that bonanza has been a headache for theoreticians because many of the newly discovered star systems defy existing models of how planets form.

The eight planets of our solar system all have roughly circular orbits, and models of planet-forming disks suggest most other star systems should be the same.

In reality, though, only about one in three of the known exoplanets has a circular or near-circular orbit.



Read the scoop on theoretical astronomy's sturm and drang at National Geographic.