Scientists Found a Piece of a Lost Planet in the Sahara Desert

A 4.5-billion-year-old meteorite recovered from the Sahara Desert in 2019 may be a fragment of a planet that no longer exists — one that formed and was destroyed before Earth was fully assembled. A new study published in the journal Earth and Planetary Science Letters concludes that the space rock, known as NWA 12774, likely originated in the deep interior of a massive protoplanet at least the size of Earth's moon and possibly approaching the size of Mars, shattered during the violent collisions of the early solar system.

The finding is significant because no physical evidence of this kind of large early world has ever been recovered before. Most of what scientists know about the first few million years of planetary formation comes from computer models and astronomical observations. This meteorite appears to be a physical remnant of that history.

A Rock Unlike Almost Any Other

NWA 12774 is an angrite, one of the rarest categories of meteorites on Earth. Of the roughly 80,000 meteorites ever cataloged, only 68 are angrites. These rocks contain almost no silica, the mineral that makes up the bulk of every terrestrial planet in our solar system. Because silica is so common and angrites have so little of it, scientists long assumed angrites came from small asteroids rather than full-sized worlds.