( CNN ) -- NASA 's Kepler space telescope has already made a discovery , and its science operations are n't even officially under way yet . The planet used in the test is a giant gas planet about the size of Jupiter that orbits a star called HAT P-7 . NASA scientists who put the telescope through a 10-day test after its March 6 launch said this week that Kepler is working well . Its ability to detect minute changes in light has enabled scientists to determine that a planet orbiting a distant star has an atmosphere , shows only one side to its sun and is so hot it glows . Kepler 's ability to take measurements that precise at such a great distance `` proves we can find Earth-size planets , '' William Borucki , Kepler 's principal science investigator told reporters at a recent briefing . The powerful scope is looking at thousands of stars in its vision field in the Milky Way on a 3½-year mission to find planets the size of Earth and to determine how common these planets are . The planet used in the test , a giant gas planet about the size of Jupiter , orbits a star called HAT P-7 in just 2.2 days and is 26 times closer than Earth is to the sun , according to NASA . It is called an exoplanet because it orbits a star outside the solar system . Kepler detected the planet 's atmosphere , demonstrating the telescope 's capabilities and giving astronomers what NASA says is `` only a taste of things to come . '' `` It learned that this planet is like 4,000 degrees Fahrenheit . That is so hot . And it 's 4,000 degrees Fahrenheit just on one side only . The other side would be closer to 1,000 degrees Fahrenheit , `` said Sara Seager , a professor at Massachusetts Institute of Technology and a Kepler science team member . `` This particular planet showed an unusual change in brightness , '' she said . `` As the planet is orbiting the star , it goes through phases just as the moon goes through phases as seen from Earth . '' `` Kepler learned something new about an old planet , '' she said . `` The new discovery was that planet is extremely hot , very , very hot . And it 's very , very hot on one side , compared to the other . '' Borucki compared it to `` an element in your toaster or stove . ''
Kepler orbiting observatory beginning mission to find planets the size of Earth . Comment: