Extraterrestrial Memes In Search Of A Second Earth 100 Billion Earth Like Planets In Milky Way Say Astronomers

APRIL 05, 2013 - SPACE - There could be more than 100 billion Earth-like planets in our galaxy that could be home to life, according to new estimates by astronomers. Researchers have developed a new method for finding planets that orbit their stars in the so-called "habitable zone" - the right distance to be able to support life. Currently these planets are difficult to spot as they tend to be comparatively tiny when compared to the star they orbit and until now most Earth-sized alien worlds to be found in other solar systems have been so close to their stars that no life could ever survive. More than 800 exoplanets - worlds orbiting stars other than our own - have been spotted since 1995 Photo: APScientists at the University of Auckland, however, claim that by combining data from a Nasa space telescope that is currently searching the heavens for other planets with a ground based technique called gravitational microlensing, it will be possible to identify smaller Earth-like planets in the right orbit. They estimate there could be as many as 100 billion of these planets in the Milky Way, our own galaxy. With roughly 300 billion stars in our galaxy, this figure may not be as unlikely as it first seems, they say. Dr Phil Yock, from the department of physics at the University of Auckland, said they would combine measurements taken by Nasa's Kepler Space Telescope and the microlensing technique, which uses robotic telescopes to detect tiny deflections in the light coming from stars as a small planet orbits them. He said: "Kepler finds Earth-sized planets that are quite close to parent stars, and it estimates that there are 17 billion such planets in the Milky Way. These planets are generally hotter than Earth. "Our proposal is to measure the number of Earth-mass planets orbiting stars at distances typically twice the Sun-Earth distance. Our planets will therefore be cooler than the Earth. "By interpolating between the Kepler and microlensing observation results, we should get a good estimate of the number of Earthlike, habitable planets in the Galaxy. "We anticipate a number in the order of 100 billion. Of course, it will be a long way from measuring this number to actually finding inhabited planets, but it will be a step along the way." Scientists have so far discovered around 860 planets outside our solar system, also called exoplanets, but that number is rapidly increasing. Last month astronomers found an Earth-like planet orbiting a red dwarf star just 13 light years away - making it our closest potentially habitable neighbour outside our own solar system. Nasa's Kepler telescope has found around roughly 110 new planets, many of them many times larger than the Earth. Detecting smaller planets with the telescope is much harder as they are often lost in the glare of the star. Instead Dr Yock has outlined a new technique for spotting Earth-like planets in the journal Monthly Notices of the Royal Astronomical Society. He is working with Japanese scientists to spot tiny deflections in the light coming from a distant star caused by the gravity of an Earth sized planet. They hope to use a network of telescopes that are now being deployed by the Las Cumbres Observatory Global Telescope Network, with three being stationed in Chile, three in South Africa, three in Australia, one in Hawaii and one in Texas. Data from these telescopes will be combined with others around the world before then being put alongside the Kepler measurements to identify those stars that may have small planets orbiting at the right distance to support life. - TELEGRAPH.

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