NASA Discover New Earth Like Planet - Kepler-22b
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It may have a radius
It may have a radius about 2.4 times that of our home planet, but NASA scientists have confirmed that Kepler-22b — depicted in the artist's conception up top — is the first planet we've ever confirmed orbits within the so-called "habitable zone" of a Sun-like star, making it the most Earth-like planet we've yet discovered.
In astronomy, the habitable zone (also known as the Goldilocks zone") is the region surrounding a star in which an orbiting planet could maintain liquid water (and, by extension, life) on its surface. And as the "Goldilocks" moniker implies, whether or not a planet resides inside a habitable zone has everything to do with whether the planet is a little too cold, a little too hot, or just right, temperature-wise.
Take Kepler-21b, for example, whose discovery was announced last week by the National Optical Astronomy Observatory. Kepler-21b is even closer to the size of Earth than Kepler-22b, but it orbits far too close to its sun to sustain any form of life we're familiar with; as this conception of K-21b by artist Ron Miller clearly illustrates, surface temperatures on the planet are estimated to reach as much as 3000-degrees Fahrenheit — that's hot enough to melt iron, not to mention any hope of us ever calling K-21b "Earth 2.0."
But Kepler-22b is a different story. Sure, the planet orbits about 15% closer to its star than Earth does to the Sun, but its star is also significantly cooler, dimmer, and smaller than ours. And while scientists have yet to determine K-22b's composition — be it rocky, gaseous or liquid — they estimate that surface temperatures on K-22b average a very Earth-like 72-degrees Fahrenheit.
"This is a major milestone on the road to finding Earth's twin," said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington. "Kepler's results continue to demonstrate the importance of NASA's science missions, which aim to answer some of the biggest questions about our place in the universe."
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در تاریخ 1403/07/08 منتشر شده
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