"Ping-Pong" Planets Can Bounce From Star to Star
Worlds would switch stars for millenia before being ejected, models hint.
Scientists had previously theorized that gravitational interactions among multiple planets orbiting a star can sometimes cause a world to get ejected from its system, leaving the rogue planet to wander alone.
(Related: "Earth-Size 'Lone Wolf' Planets May Host Life.")
Now a complex set of computer simulations shows that certain types of binary star systems might not let go of wayward worlds so easily.
Instead, when a planet gets tossed out by its binary parent, the world can bounce over to the stellar companion. The hapless planet then begins to orbit wildly, only to end up being tossed back to the original star.
(Watch animations of planets bouncing between binary stars.)
This gravitational bouncing can go on for as long as a million years,