A Planet That Orbits Its Star the Wrong Way

Smivs writes "BBC News is reporting that astronomers have discovered the first planet that orbits in the opposite direction to the spin of its star. Planets form out of the same swirling gas cloud that creates a star, so they are expected to orbit in the same direction that the star rotates. The new planet is thought to have been flung into its 'retrograde' orbit by a close encounter with either another planet or with a passing star. The work has been submitted to the Astrophysical Journal for publication. Co-author Coel Hellier, from Keele University in Staffordshire, UK, said planets with retrograde orbits were thought to be rare. 'With everything [in the star system] swirling around the same way and the star spinning the same way, you have to do quite a lot to it to make it go in the opposite direction.' Professor Hellier said a near-collision was probably responsible for this planet's unusual orbit. 'If you have a near-collision, then you'll have a large gravitational slingshot from that interaction,' he explained. 'This is the likeliest explanation. But it might be possible you can do it by gradually perturbing the orbit through the influence of a second planet. So far, we haven't found any evidence of a second planet there.'"

Comments

Re:Why do they blame the planet?

[arminw]

....the PLANET's orbit changed...

May be theory of how planets form this wrong. Maybe planets do not form out of a cloud of dust that rotates, but in some other way and with other and additional forces, such as electricity, besides gravity. Too often these days, when scientists come across an anomaly, the idea that this might mean that a cherished theory is totally wrong or at least needs adjusting does not come into their mind at all.