From the Tampa Tribune:
Planets found without stars
Are these planets without orbits? Astronomers have found 10 potential planets as massive as Jupiter wandering through a slice of the Milky Way galaxy, following either very wide orbits or no orbit at all. Scientists think they are more common than the stars.
These mysterious bodies, apparently gaseous balls like the largest planets in our solar system, may help scientists understand how planets form.
"They're finding evidence for a lot of pretty big planets," said Alan Boss of the Carnegie Institution of Washington, who wasn't involved in the research.
If they orbit stars, their sheer number suggests every star in the galaxy has one or two of them, "which is astounding" because that's five or 10 times the number of stars scientists had thought harbored such gas-giant planets, he said.
And if instead they are wandering free, that "would be really stunning" because it's hard to explain how they formed, he said.
If that's the case, it would give a boost to some theories that say planets can be thrown out of orbit during formation, said Lisa Kaltenegger of the Harvard-Smithsonian Center for Astrophysics.
Other scientists have reported free-wandering objects in star-forming regions of the cosmos, but the newfound objects appear to be different, said one author of the new study, physicist David Bennett of the University of Notre Dame.
Bennett and colleagues report the finding in today's issue of the journal Nature. They didn't observe the objects directly. Instead, they used the fact that massive objects bend the light of distant stars with their gravity, just as a lens does. So they looked extensively for such "microlensing" events.
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