Four-and-a-half billion years ago, a massive world—possibly as big as the moon or even Mars—orbited our sun before crashing into another celestial body and shattering into rubble. Now, in a paper published in the journal Earth and Planetary Science Letters, scientists report the first definitive evidence that this lost planetary embryo (protoplanet) existed. Its unique geological makeup challenges long-held assumptions about how planets evolve.
“It’s incredible to think there was once a world this large,” said Aaron Bell, an assistant research professor in the Department of Earth Science at the University of Colorado Boulder. “We only know it existed because a few fragments of it happened to land on Earth. These meteorites preserved evidence of a completely different pathway through which early planets developed.”
What gave away the lost world’s secret was a piece of its debris uncovered on Earth in the Sahara Desert, known as the Northwest Africa (NWA) 12,774 angrite meteorite.





