NASA Confirms First Earth-Sized Planet in a Sun-like Star's Habitable Zone
VOA News December 06, 2011
NASA’s Kepler space telescope has confirmed the discovery of the first so-called super-Earth planet ever found orbiting a Sun-like star from a habitable distance.
NASA says the mysterious new super-Earth is 2.4 times the size of the Earth and has comfortable 22-degree Celsius surface temperatures. The planet’s year - the time it takes to make a single solar orbit - is 290 days, which scientists say is comparable to our 365-day year. The star the planet circles is slightly smaller and slightly cooler than our Sun.
A star's habitable zone is the region where it is possible for liquid water to exist on the surface of a planet orbiting there. Liquid water is considered essential for life to exist. Astronomers say it is not clear if the newly discovered super-Earth has a predominantly rocky, gaseous or liquid composition, or even if it has an atmosphere.
Super-Earths are alien planets with a mass greater than the Earth’s, but lower than an enormous gas-giant, such as monstrous Jupiter, which dominates our solar system. However, just because a planet is called a super-Earth does not mean it has Earth-like characteristics, such as flowing liquid water, a temperate climate, an oxygen-rich atmosphere, or perhaps life.
NASA says the landmark super-Earth find is the first such confirmation made by the planet-hunting Kepler observatory, which so far has detected more than 1,000 new planet candidates. Ten of those candidates are near the size of the Earth and they orbit within the habitable zone of their host star. The candidates require follow-up observations to verify they are actual planets.
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