NASA's Spitzer Space Telescope has made the first measurements of the day and night temperatures of a planet outside our solar system. The infrared observatory revealed that the Jupiter-like gas giant planet circling very close to its sun is always as hot as fire on one side, and potentially as cold as ice on the other.
"The temperature difference between the day and night sides tells about how energy flows in the planet's atmosphere. Essentially, we're studying weather on an exotic planet."
NASA's Spitzer Sees Day and Night on Exotic World