PALO ALTO, Calif., Feb. 27 (UPI) -- The Milky Way galaxy may contain untold numbers of homeless planets wandering through space instead of orbiting a star, U.S. researchers say.
Scientists at Stanford University estimate there may be more of these so-called "nomad planets" than stars in our galaxy, with studies providing evidence two nomads exist for every typical main-sequence star in the Milky Way.
If confirmed, the wanderers could change current theories of planet formation and our understanding of the origin of life, researchers said.
"If any of these nomad planets are big enough to have thick atmosphere, they could have trapped enough heat for bacterial life to exist," study leader Louis Strigari told World-Science.net.
No one is quite sure how these bodies form.
Some nomad planets were likely ejected from solar systems but research suggests not all of them could have formed in this fashion, Strigari said.
Although the nomad planets receive no heat from a star, they might generate enough heat through internal radioactive decay and geologic activity, researchers said.