Thursday, August 13, 2009

Strange backward orbiting planet discovered


Tim Sayell sends in an odd article from Yahoo News. I will probably get this wrong, but let me see if I can set it up right. It is a given that planetary systems like ours are made up of interstellar dust that that condenses and becomes stars and sometimes planets. Planets orbit the primary in the same direction as the primary which is simple Newtonian physics which in this case means that any angular velocity is retained as the material of the system condenses. Which means that whatever way the primary is spinning, the planets will spin for the most part in the same direction. Whats more, the system as a whole will spin in the same direction as the original cloud's motion. So whatever way the parent star rotates, so do the planets and the planets will orbit in that very same direction.

Except for a recently discovered planet that orbits the wrong way, backward compared to the rotation of its host star. Discovered by the UK's Wide Area Search for Planets, W.A.S.P. 17, as it has been designated, is 1000 L.Y.s away, and may have had a close encounter with another huge planet that may have acted like a sling-shot, throwing WASP 17 into a retrograde orbit. Another option is that WASP 17 may have been a rogue planet that was captured by its sun in its odd orbit. It is thought that this was the case with Neptune's large moon Triton.

Post by Tim Sayell

Space.com's article

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