Using Hubble, astronomers led by Laura Kreidberg and Jacob Bean of the University of Chicago took a closer look at GJ 1214b. They found what they consider definitive evidence of high clouds blanketing the planet and hiding information about the composition and behavior of the lower atmosphere and surface. The new Hubble spectra also revealed no chemical fingerprints in GJ 1214b's atmosphere, but the data were so precise they could rule out cloud-free compositions of water vapor, methane, nitrogen, carbon monoxide, or carbon dioxide for the first time. 

"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," said Knutson. "We'd really like to determine the size at which these planets transition from looking like mini-gas giants to something more like a water world or a rocky, scaled-up version of the Earth. Both of these observations are fundamentally trying to answer that question." 

This is an illustration of the hypothetical appearance of the exoplanet GJ 1214b, which is known as a "super-Earth" type planet because it is slightly more than six Earth masses. Spectroscopic observations with NASA's Hubble Space Telescope provide evidence of high clouds blanketing the planet. These clouds hide any information about the composition and behavior of the world's lower atmosphere and surface. The composition of the clouds is unknown. GJ1214b is located 40 light-years from Earth, in the constellation Ophiuchus. 

For a little more insight into the project see this：http://hubblesite.org/newscenter/archive/releases/2014/06/