An artist's illustration of the alien planet GJ 1214b, a 'super-Earth' more than six times the mass of Earth that appears to be covered with high clouds, according to Hubble Space Telescope data. Image released Dec. 31, 2013.
Scientists have found evidence of extraterrestrial clouds blanketing two of the most common types of planets in our Milky Way galaxy, NASA officials say.
Two teams of researchers used the Hubble Space Telescope to characterize the atmospheres of the two exoplanets. One of the alien planets is a so-called "super-Earth" larger than the Earth, while the other has been dubbed a "warm Neptune." Studying both types of worlds can help scientists learn to classify the atmospheres on other Earth-like planets in the future.
"Both planets are telling us something about the diversity of planet types that occur outside of our own solar system; in this case we are discovering we may not know them as well as we thought," Heather Knutson of the California Institute of Technology said in a statement. [The Strangest Alien Planets (Gallery).
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