Friday, January 12, 2007

On Some Planets, the Winds Go Supersonic

The highest winds that you have ever experienced are but a puff compared to terrifyingly strong winds on some extrasolar planets. There are gas giants out there, that experience winds as strong as 14,400 kph (9,000 mph).

A team of American astronomers used the Spitzer Space Telescope to measure the infrared light of the planets at eight different positions in their orbit in 2005. They measured the brightness when the planets were facing the Earth, and then when they were facing away. Amazingly, they found no variations. It is conventional wisdom that a planet locked facing in one direction will have a hot side and a cold side. The only argument that seems to explain the anomaly is that the convection currents on the bright side generate such strong winds that they are able to mix the atmosphere on the dark side, warming it to levels matching those on the bright side.

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