Researchers using NASA’s Spitzer Space Telescope used the infrared telescope to map temperature variations over the surface of a giant gas planet, HD 189733b, revealing it likely is whipped by roaring winds. Using the data they have created what they call the first weather map of an exoplanet.
You can read more in their Letter to Nature.
“We have mapped the temperature variations across the entire surface of a planet that is so far away, its light takes 60 years to reach us,” said Heather Knutson of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.
The two planets are “hot Jupiters” gas giant planets that orbit around their stars at very short diatances. Roughly 50 of the more than 200 known planets outside our solar system are hot Jupiters. Since 2005, Spitzer has been revolutionizing the study of exoplanets’ atmospheres by examining their infrared light, or heat. HD 189733b is located 60 light-years away and is the closest known transiting planet. That means that it crosses in front and behind its star when viewed from Earth. It orbits its star every 2.2 days.
The observations reveal that temperatures on this balmy world are fairly even, ranging from 650 degrees Celsius (1,200 Fahrenheit) on the dark side to 930 degrees Celsius (1,700 Fahrenheit) on the sunlit side. Since the planet’s overall temperature variation is mild, scientists believe winds must be spreading the heat from its permanently sunlit side around to its dark side. Such winds might rage across the surface at up to 9600 kilometers per hour (6,000 miles per hour). The jet streams on Earth travel at 322 kilometers per hour (200 miles per hour).
You can find more detail at their press release, from which this blog entry was created.
You can also download a nice little movie explaining how the map was created (Quicktime or Windows Media).
Orbiting Frog 
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