Our galaxy is thought to be teeming with billions of "nomad" planets. These worlds are interstellar orphans, with no stellar parent to call home. Some were likely gravitationally flung from their parent star at an early age, while others may have evolved on their lonesome, clumping from small clouds of interstellar gas and dust.
If there are so many orphaned worlds drifting alone, how often might they be snatched by the gravitational tug of a star that happens to be drifting in the same direction?
Surprisingly, say astronomers from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and Peking University in China, it may happen more often than astrophysicists ever dreamed.
"Stars trade planets just like baseball teams trade players," said CfA's Hagai Perets in an April 17 press release.
In a Feb. 24 Discovery News article, space correspondent Irene Klotz detailed research based on the microlensing of nomad planets and the estimate that there may be as many as 100,000 of these interstellar orphans per star in our galaxy.