Free-roaming planets that are untethered to a solar system have been known about for some time, however all the ones found so far have been enormous – up to 40 times the mass of Jupiter which is itself equivalent to around 300 Earths.
Now however, astronomers have, for the first time, discovered a rogue planet that is roughly the size of our own planet – opening the door to the possibility that our own galaxy could be filled with large numbers of these free-roaming worlds that spend their existence drifting in the interstellar void.
“The odds of detecting such a low-mass object are extremely low,” said lead study author Przemek Mroz. “Either we were very lucky, or such objects are very common in the Milky Way.”
“They may be as common as stars.”
“Theories of planet formation have predicted that the majority of free-floating planets should be of Earth mass or smaller, but this is the first time that we could find such a low-mass planet.”
“It’s really amazing that Einstein’s theory allows us to detect a tiny piece of rock floating in the galaxy.”
Exactly how this world came to be in the interstellar void remains unclear, however there are several ways that a planet could be thrust out of its star’s orbit and off into interstellar space.
Given the total lack of sunlight however, it is unlikely that such a planet would be able to support life.