<p>The twin earth are orbiting a sun-like star called Kepler-20 in the Milky-way at a distance of about 1000 light years from the solar system. One light year is just under 10 trillion kilometre, which is the distance light travels in one year.<br /><br />One of these planets, Kepler-20f had a radius almost identical to that of the earth’s, but the other one, Kepler-20e, was little smaller than the earth, they reported in Nature on Tuesday.<br /><br />The bulk compositions of the two planets are similar to the earth with 32 per cent iron core and 68 per cent silicate mantle – the second ground layer of a planet after core – by mass. The scientists predict that Kepler-20f could be a planet in which there may be thick water vapour in the environment surrounding a rocky interior.<br /><br />With a radius 0.87 times that of the earth, Kepler-20e, on the other hand, is an entirely rocky planet and unlikely to have any trace of water in any form as it is too close to the star, whose surface temperature is more than 5000 degrees Celsius.<br /><br />Kepler-20e circles the star in 6.1 days whereas the orbital period for Kepler-20f is 19.6 days. “Its little too warm to harbour life there. Also we could not find any carbon, which along with liquid water is necessary for life,” lead author Francois Fressin at Harvard-Smithsonian Centre for Astrophysics at Cambridge, Massachusetts told Deccan Herald over phone.<br /><br />The star, Kepler-20 is known to host three larger transiting planets and with the addition of the latest two, it turns out to be a five-member alien planetary system, which resembles the solar system to a large extent. <br /><br />Stunning discovery<br /><br />Francois and his colleagues from American and Danish institutes made the stunning discovery by analysing a large volume of data collected by National Aeronautics and Space Administration's Kepler spacecraft, which watched Kepler-20, for 670 days.<br /><br />NASA’s Kepler telescope, launched in March 2009, hunts extra-solar planets and located 28 such planets excluding the latest duo, which are the smallest exo-planets discovered so far. <br /><br />The space telescope scrutinizes over 150,000 stars for tiny periodic dips in brightness that might mean orbiting planets are passing in front of the stars, blocking part of their light from reaching the telescope. But complimentary observations from ground-based telescopes are necessary to confirm the true planetary nature of these candidate.<br /><br />Since the discovery of the first extrasolar giant planets orbiting Sun-like stars around two decades ago, steady improvements in observational capabilities have led to detection of many Earth-like planets.</p>
<p>The twin earth are orbiting a sun-like star called Kepler-20 in the Milky-way at a distance of about 1000 light years from the solar system. One light year is just under 10 trillion kilometre, which is the distance light travels in one year.<br /><br />One of these planets, Kepler-20f had a radius almost identical to that of the earth’s, but the other one, Kepler-20e, was little smaller than the earth, they reported in Nature on Tuesday.<br /><br />The bulk compositions of the two planets are similar to the earth with 32 per cent iron core and 68 per cent silicate mantle – the second ground layer of a planet after core – by mass. The scientists predict that Kepler-20f could be a planet in which there may be thick water vapour in the environment surrounding a rocky interior.<br /><br />With a radius 0.87 times that of the earth, Kepler-20e, on the other hand, is an entirely rocky planet and unlikely to have any trace of water in any form as it is too close to the star, whose surface temperature is more than 5000 degrees Celsius.<br /><br />Kepler-20e circles the star in 6.1 days whereas the orbital period for Kepler-20f is 19.6 days. “Its little too warm to harbour life there. Also we could not find any carbon, which along with liquid water is necessary for life,” lead author Francois Fressin at Harvard-Smithsonian Centre for Astrophysics at Cambridge, Massachusetts told Deccan Herald over phone.<br /><br />The star, Kepler-20 is known to host three larger transiting planets and with the addition of the latest two, it turns out to be a five-member alien planetary system, which resembles the solar system to a large extent. <br /><br />Stunning discovery<br /><br />Francois and his colleagues from American and Danish institutes made the stunning discovery by analysing a large volume of data collected by National Aeronautics and Space Administration's Kepler spacecraft, which watched Kepler-20, for 670 days.<br /><br />NASA’s Kepler telescope, launched in March 2009, hunts extra-solar planets and located 28 such planets excluding the latest duo, which are the smallest exo-planets discovered so far. <br /><br />The space telescope scrutinizes over 150,000 stars for tiny periodic dips in brightness that might mean orbiting planets are passing in front of the stars, blocking part of their light from reaching the telescope. But complimentary observations from ground-based telescopes are necessary to confirm the true planetary nature of these candidate.<br /><br />Since the discovery of the first extrasolar giant planets orbiting Sun-like stars around two decades ago, steady improvements in observational capabilities have led to detection of many Earth-like planets.</p>
