Is our-type solar system a common one?
Beer and his colleagues are now arguing that the alien systems might not have formed in the same way as our solar system. It is possible that the hot-Jupiter systems might have come about when the dusty discs around stars became unstable and suddenly fragmented, with the individual fragments collapsing under their own weight to form planets. This process naturally creates more elliptical orbits and would be unlikely to form Earth-like planets, they say.
“It will be another five years or so before we know whether the solar system is truly different,” says Beer. “But if it is, we may have to revise our theories of planet formation, since the existing theories are largely based on information gathered in the solar system.” There might be more than one way to make a world.