Posted: Wed, Feb 22, 2012, 7:44 AM ET (1244 GMT)
Astronomers aalyzing Hubble observations have concluded one known extrasolar planet has a thick atmosphere of water vapor and likely far more water than the Earth. Astronomers discovered the planet, GJ1214b, in 2009, and observations a year later suggested that it has either at atmosphere of water vapor or a haze layer. Follow-up infrared observations by Hubble as the planet transited its star confirmed the presence of water vapor in the atmosphere, based on the lack of features observed over a range of infrared wavelengths. The planet is a so-called "super Earth" with a diameter 2.7 times that of the Earth and seven times as massive. The resulting density suggests the planet has a larger fraction of water than the Earth.
