Patt Morrison For January 13, 2012

100 billion planets and counting in the Milky Way, according to new survey

NASA's Kepler Mission Discovers A World Orbiting Two Stars

NASA/NASA via Getty Images

In this digital illustration released on September 15, 2011 by NASA, the newly-discovered gaseous planet Kepler-16b orbits it's two stars.

The Earth really is a tiny grain of sand on a cosmic beach, according to a new survey that indicates 100 billion planets exist in the Milky Way galaxy alone.

The approximation is based on a study headed by lead astronomer Arnaud Cassan at the Institute of Astrophysics in Paris. Dr. Cassan and his colleagues examined 100 billion stars up to 25,000 light years from Earth and by their calculation most of the stars have at least one planet orbiting them. “One can point at almost any random star and say there are planets orbiting that star,” said astronomer Uffe Grae Jorgensen, who was a member of Dr. Cassan’s team as reported by the Wall Street Journal. Researchers say 100 billion planets is the most conservative estimate and that most of these planets are larger than Earth, but that none of the alien planets identified so far appear suitable for carbon-based life. The most unique discovery associated with the survey is that millions of these planets may circle two stars, a circumstance previously considered to be virtually non-existent.


How might we benefit from studying billions of other planets? How important is this type of research in terms of practicality? How does the realization that Earth is a minuscule speck of dust impact the way humans contemplate our existence in the universe?


Kilash Sahu, inaugural researcher on the study and staff astronomer at the Space Telescope Science Institute (STSCI)

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