100 Billion Alien Planets In The Milky Way? One Study Thinks So
There may be over 100 billion alien planets in the Milky Way galaxy, according to one study.
Space.com reports that researchers studied a similar system called Kepler-32, which is about 915 light years away from Earth. Like Earth, the planets in this solar system orbit close to a star. However, its star is considered an M dwarf, which is smaller and cooler than the Earth's sun.
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"I usually try not to call things 'Rosetta stones,' but this is as close to a Rosetta stone as anything I've seen," said study co-author John Johnson. "It's like unlocking a language that we're trying to understand - the language of planet formation."
The Kepler Telescope discovered the five planets in Kepler-32 because the instrument can detect the dips in brightness that occur when the planets cross the front of the M dwarf. The researchers then calculated the odds that an M-dwarf system was properly oriented so it could be detected by the telescope. They then determined approximately how many of these systems the Kepler could detect in order to come up with their estimate of 100 billion alien planets.
"It's a staggering number, if you think about it," said study lead author Jonathan Swift in a statement. "Basically there's one of these planets per star."
This estimate of 100 billion alien planets may actually be low, as the study only looked at planets that orbit close to M dwarf stars. Taking into account those that orbit far away from M dwarf stars or those that do not orbit around those types of stars at all, the actual number of alien planets could be closer to 200 billion.
As we previously reported, a Kepler Space Telescope has discovered over 2,300 planets since March 2009. Researchers believe that they are close to discovering the first "alien Earth" planet with similar properties to our home.
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