There Are Way More Rogue Planets Than We Thought
The galaxy is wild. Our solar system, with its surprising abundance of living creatures and nonstop radiation and asteroid showers, is a placid, private garden compared to the rest of it.
In particular, there are perhaps trillions of rogue planets (planetary bodies ranging from little rocky Earth-sized guys to super-Jupiter gas giants) in the Milky Way, including a surprisingly large fleet of the things right near the galactic core.
This is unusual, since the typical way we detect exoplanets is by marking their repeated procession across a star. But rogue planets, by definition, don’t orbit stars. So the way astronomers find them is a little different, requiring use of gravitational microlensing.
Gizmodo breaks it down:
Data gathered by NASA’s now-retired Kepler Space Telescope has revealed a small population of free-floating planets near the Galactic Bulge. The new finding raises hope that a pair of upcoming missions will result in further detections of unbound planets, which drift through space separated from their home stars….
It’s impossible to know what the conditions are like on these presumed rogue exoplanets, but [astronomer Iain] McDonald said they could be “cold, icy wastelands,” and, if similar in size to Earth, their surfaces would “closely resemble bodies in the outer Solar System, like Pluto.”
The new paper suggests the presence of a large population of Earth-sized rogue planets in the Milky Way. It’s becoming clear that free-floating planets are common. McDonald said his team is currently working to come up with a more precise estimate for how many of them might exist.
Did you catch that part about how McDonald’s team made this discovery using a now-retired telescope? Yeah. Apparently the new telescope projects coming online are both more powerful and (in particular) better equipped to detect gravitational lensing effects, and therefore more likely to detect rogue planets in the future.
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