Astronomers discover three habitable planets just 40 light years away [View all]

[G_j]

http://www.extremetech.com/extreme/227385-trappist-1-a-star-with-three-very-habitable-planets-just-40-light-years-away

By Graham Templeton on May 2, 2016 at 11:00 am

Scientists from MIT, University of Liege, and elsewhere, have found not one, not two, but three planets orbiting a single star, all of which seem to be habitable by a variety of measures. The team is calling them the best candidates yet found for life outside our solar system, and since they’re only 40 light years from Earth, they ought to be perfectly positioned for detailed further investigation. If you’re betting on which system out there is most likely to produce evidence of alien life, this one might be a good one to remember: 2MASS J23062928-0502285, also known as TRAPPIST-1.

The star is a so-called brown dwarf star, or a star that isn’t massive enough to exert the level of gravity needed to jump-start hydrogen fusion at its core. This means two things: It’s very cold (sometimes referred to as an ultra-cool dwarf star) and it doesn’t put out very much visible light. A regular star is, of course, a big lightbulb in the dark, meaning that when you stare right into it with a telescope, it tends to blind you; this is one of the main reasons it took so long to actually see exoplanets. Eventually, astronomers built customized planet-hunters meant specifically to stare into suns, and quickly found hundreds, then thousands of exoplanets. These sightings are known as “transits,” where the orbiting planet moves between the target star and the telescope, dimming the star for as long as the planet remains in the way.

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