A rare angrite meteorite known as NWA 12774, discovered in the Sahara Desert, may be a remnant of a long-lost protoplanet from the early solar system. Unlike most meteorites, angrites are among the oldest basaltic rocks, dating back 4.56 billion years, and have a unique chemical composition. Researchers at the University of Colorado Boulder analyzed the mineral structure of NWA 12774 and found high-aluminum clinopyroxene crystals, which form only under high pressure—indicating it originated deep within a large planetary body.

Using thermodynamic modeling, the team determined the crystals required at least 17.5 kilobars of pressure to form—far more than small asteroids could generate. This suggests the meteorite came from a parent body with a radius of at least 1,000 kilometers, possibly as large as Mars. The well-preserved, sharp crystal edges also imply the fragment came from shallow depths, meaning the protoplanet likely broke apart early in the solar system’s history.

While definitive proof is impossible, the findings open the possibility that many undiscovered protoplanets once existed. These ancient meteorites act as time capsules, preserving geochemical records of planetary formation processes we are only beginning to understand.