Planetary systems

Planetary systems

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  NASA craft's planet-hunting days may be numbered

  NASA's planet-hunting Kepler telescope is broken, potentially jeopardizing the search for other worlds where life could exist outside our solar system 

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  Comet posing beside crescent moon in cool photo op

  Now's your chance to see the comet that passed within 100 million miles of Earth last week. Twilight on Tuesday will provide the best photo op for the ... 

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  Comet making closest approach ever of Earth

  A recently discovered comet is closer than it's ever been to Earth, and stargazers in the Northern Hemisphere finally get to see it. 

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  Smallest planet yet found outside solar system

  Astronomers searching for planets outside our solar system have discovered the tiniest one yet — one that's about the size of our moon. But hunters ... 

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  Study: Billions of Earth-size planets in Milky Way

  Our Milky Way is home to at least 17 billion planets that are similar in size to Earth, a new estimate suggests. That's more than two Earth-size ...