When astronomers began discovering exoplanets — worlds orbiting other stars — they expected those solar systems to follow the local model. But that's not how things turned out. Planet after planet that was spotted in the earlier days of the search, when all we could detect were very large planets circling very bright stars, were not lined up the way they were supposed to be. Instead, these Jupiter-like gas giants hang at a cock-eyed angle, and sometimes rotate backwards or orbit in the opposite direction of the star's own spin.
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Finally, astronomers studying a star known as Kepler-30 have found something that looks reassuringly familiar: one, two, three exoplanets, orbiting in a plane, just like we do. And as reported in the current issue of Nature, it's not only the discovery itself that's cool, it's the way the researchers went about making it.
Exoplanets are typically discovered in one of two ways — and neither involving simply pointing a telescope in the right direction and looking. At solar distances, the planets are just too tiny and often too washed-out by the light of their suns to be spotted visually. Instead, astronomers look for wobbles in the star itself, indicating that something nearby is tugging on it gravitationally. More recently — especially since the 2009 launch of the Kepler Space Telescope — they have relied on the slight dimming in luminosity that occurs as a planet passes in front of its star, blocking a bit of its light. Even that wasn't terribly easy with Kepler-30, a relatively faint star 10,000 light-years distant. Says Joshua Winn, a co-author of the Nature paper and a professor of astrophysics at MIT: "We don't have a [good] picture of this star."
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Courtesy--TIME
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