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Scientists have discovered three new planets beyond our solar system. They're about 40 light-years away. Some astronomers say they may be the best places yet to look for signs of alien life. NPR's Nell Greenfieldboyce reports.
GREENFIELDBOYCE: The three new planets were found by a team looking at ultracool dwarf stars. Not ultracool as in hip, but, you know, colder.
JULIEN DE WIT: So they're not as big, bright and warm as the sun.
GREENFIELDBOYCE: Julien de Wit is an astronomer at MIT. He says until recently, planet hunters ignored these small, reddish stars. He collaborated with a team that built a prototype telescope to look for planets around them, even though some theorists thought they wouldn't find any. But they did - a trio of worlds about the same size as Earth.
DE WIT: We never found planets around such stars, so now we actually know that these stars can produce such planets.
GREENFIELDBOYCE: These planets spin differently than Earth. It looks like each one has a side that stays in perpetual darkness and another that sees constant daylight. If you stood on one of these planets and looked up, the star would look like a big red ball that never moved. The planets orbit really close to their star. It takes just a couple of days or so for them to go all the way around it. But they don't get totally roasted because the star is so cool.
DE WIT: They can still be temperate and be able to support life, at least on part of their globe.
GREENFIELDBOYCE: What's more, he says when a star is this small, it's easier for scientists to analyze a planet's atmosphere by using telescopes to look at the starlight.
DE WIT: So part of the light coming from the star will be blocked by the planet, but a tiny, tiny, tiny fraction of it is going to go through the planet atmosphere.
GREENFIELDBOYCE: That fraction of light contains clues about what the atmosphere is made of. He and his colleagues will start looking at that this week using the Hubble Space Telescope. The researchers describe the new planets in the journal Nature. Scientists have found over a thousand planets around other stars, but ones that are Earth-sized and potentially habitable are few and far between. That's one reason these three new ones are exciting.
MARC KUCHNER: They're all pretty darn interesting.
GREENFIELDBOYCE: Marc Kuchner is at NASA's Goddard Space Flight Center in Maryland. He says this solar system reminds him of another world, a planet called GJ 1214 b.
KUCHNER: It's just as good as 1214 b, and that was our benchmark.
GREENFIELDBOYCE: Scientists liked that one because it's also about the size of Earth and around a star that makes it relatively easy to study. But Hubble couldn't get a good look at its atmosphere because it's too cloudy, so now we'll have to see if the weather is better on these three new worlds. Nell Greenfieldboyce, NPR News.
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