(GIZMODO) — A first-of-its-kind space rock filled with pristine material from the formation of the Earth itself has returned to the inner solar system, after billions of years in the cosmic boondocks. And it could help us piece together our planet’s origin story.
Four and a half billion years ago, chunks of the same material that formed Earth and the other rocky planets are thought to have been flung into the Oort cloud, a ring of icy debris encircling the outermost edge of the solar system. Untouched, they’ve been preserved for eons in the deep freeze of space. Now, astronomers have spotted one of these fossils nearby, marking the very first observation of a rocky object from the Oort cloud.
“This is super exciting, because it could be a piece of what formed the Earth” Olivier Hainaut—an astronomer at the European Southern Observatory and co-author on the new Science Advances study describing the discovery—told Gizmodo.
“You don’t at all expect to find a rocky asteroid on an Oort cloud orbit. That’s wrong.”
The object, dubbed PANSTARRS, was spotted in 2014 by Pan-STARRS1, a Hawaiian telescope used to identify rogue comets and asteroids in our planet’s backyard. The telescope routinely surveys the entire sky and turns up thousands of uninteresting hunks of debris. But as soon as PANSTARRS’ orbit had been calculated, Hainaut and his colleagues realized they had found something exceptional.