NASA's Kepler mission has found two Earth-sized plaents that are orbiting a "sun-like" star outside our solar system. NASA officials have named the planets Kepler-20e and Kepler-2of and note that they are too close to their star to be called "habitable zones" because of a likely lack of liquid water due to extremely hot temperatures.
According to NASA the planets are thought to be rocky with Kepler-2oe slightly smaller than Venus and .87 times the radius of earth. Kepler-20f on the other hand is 1.03 times the radius of earth.
The two planets reside in a five-planet system named Kepler-20 which is located 1,000 light-years away from Earth in the constellation Lyra.
NASA also revealed that Kepler-20e orbits its parent star every 6.1 days while Kepler-20f takes a longer 19.6 days. The short orbital periods would mean the planets are very hot with Kepler-20f likely reaching temperatures of 800 degrees Fahrenheit and Kepler-20e reaching even higher temperatures of 1,400 degrees Fahrenheit.
The other three planets (Kepler-20b, Kepler-20c and Kepler-20d) are larger than earth but smaller then Neptune and orbit around their star every 3.7, 10.9 and 77.6 days.
According to NASA official Michele Johnson:
The system has an unexpected arrangement. In our solar system, small, rocky worlds orbit close to the sun and large, gaseous worlds orbit farther out. In comparison, the planets of Kepler-20 are organized in alternating size: large, small, large, small and large.