A planet about 1.6 times the radius of Earth

By NASA's Kepler space telescope A planet about 1.6 times the radius of Earth has been found circling the sun-like star Kepler-21, one of the 100,000 stars under scrutiny by NASA's Kepler Space Telescope.The goal of the Kepler program is to find Earth-like planets orbiting at the right distances from their planet stars to support liquid water on their surfaces, water being a key ingredient for life as we know it.The new planet, known as Kepler-21b, circles just 3.7 million miles from its parent star, compared to nearly 10 times that distance for our system’s innermost planet, Mercury. Scientists estimate Kepler-21b’s temperature to be about 2,960 degrees Fahrenheit."It's far too hot for anyone like us to live on," lead researcher Steve Howell, with NASA's Ames Research Center in California, told Discovery News.At that distance, the planet completes an orbit in just 2.8 days.Kepler-21b may not be at the right distance to support life, but it's moving toward the right size."It's between five and 10 Earth masses," Howell said, adding that it's unlikely Kepler-21b is completely rocky.The number of extrasolar planets is now more than 700. The Kepler science team is working to verify another 1,200 additional candidates.The research will appear in an upcoming issue of Astrophysical Journal.