Written speculation about life beyond the confines of Earth dates back thousands of years, to the time of the Greek philosophers Epicurus and Democritus. Unrecorded curiosity about this question undoubtedly goes back much further still. Remarkably, today's generation seems about to get an answer from the study of exoplanets – planets orbiting other stars than the Sun. The early results are upending many assumptions from that long history.Two months ago, our research team at the University of Cambridge and the University of Liège in Belgium reported that a nearby star, called TRAPPIST-1A, is orbited by seven planets similar in size and mass to Earth. All seven planets are temperate, meaning that under the right atmospheric and geologic conditions, they could sustain liquid water. Three of the planets show particular potential for habitability, receiving about as much energy from their star as the Earth receives from the Sun.Our discovery received ecstatic and gratifying news coverage around the world. In many ways, though, the TRAPPIST-1 system is an odd place to look for life. The central star is just 1/12th the mass of the Sun and scarcely bigger than the planet Jupiter. It gives off just 0.05 percent as much light as the Sun. TRAPPIST-1A belongs to a class that we call ultra-cool dwarfs, the very smallest stars that exist.Continue reading on Motherboard.
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