When the U.S. football field–size, cigar-shaped object ‘Oumuamua entered our solar system last year, it didn’t just give us our first glimpse of an interstellar piece of rock. It also bolstered the plausibility of space rocks spreading life among the stars by ferrying microbes between distant star systems, according to a new study. “Life could potentially be exchanged over thousands of light-years,” says author Idan Ginsburg, a postdoc at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.
The idea, known as panspermia, has been around for centuries. Some astronomers have even speculated that life on Earth was seeded by microbes that hitched a ride on debris ejected from another life-harboring world in the solar system, perhaps on meteorites from Mars. But it seemed improbable that life could have come from interstellar space.