News: Milky Way Could Contain Billions Of Earth Sized Planets


The Milky Way galaxy could contain billions of Earth-sized planets orbiting stars much like our sun. Astronomers using data from NASA calculated that our galaxy holds at least 8.8 billion stars with planets much like ours.

For perspective, NBC News notes that there are more Earth-like planets in our galaxy than there are people on Earth. Study author Geoff Marcy, a longtime planet hunter with the University of California at Berkeley, added that it also means there is a chance there is life out there, in our own galaxy.

While it was operational, NASA’s Kepler Space Telescope looked at 42,000 stars, a sliver of our galaxy, to see how many planets are like Earth. From there, the astronomers extrapolated that figure to the rest of the galaxy, which is home to hundreds of billions of stars.

Based on the one in five estimate, the closest Earth-sized planet in its sun-like star’s habitable zone is likely within 70 trillion miles of Earth. Also, the 8.8 billion figure is only a start, because scientists in the study only looked at sun-like stars, which aren’t the most common.

An earlier study also showed that 15 percent of red dwarf stars, which are more common, have Earth-sized planets that are close enough to be in the habitable, or Goldilocks, zone. Putting the figures together, Marcy says that there are probably about 40 billion right-size, right place planets.



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