Aaron Bell Links Meteorite NWA 12774 to Lost World
A rare meteorite from the Sahara Desert may preserve the first definitive evidence of a long-lost world from the early solar system. Northwest Africa 12774, a roughly one-pound rock found in 2019, led Aaron Bell and his team to a pressure clue that does not fit a small asteroid.
Bell, a geoscientist at the University of Colorado Boulder, said: "The materials that formed the angrite parent body are fundamentally different from the ingredients of Earth and Mars". He also said: "These meteorites preserved evidence of a completely different pathway through which early planets developed."
Northwest Africa 12774 and angrites
The rock is classified as an angrite, a rare type of meteorite that ranks among the oldest volcanic rocks in the solar system. Scientists say only 68 of more than 80,000 meteorites recovered on Earth are known angrites, and they formed alongside the young sun more than 4.5 billion years ago. That rarity gives Northwest Africa 12774 unusual weight in the debate over how rocky bodies formed early on.
Scientists had long assumed angrites came from a relatively small asteroid. The new study challenges that idea by tying the rock to a much larger parent body. The meteorite itself contains very little silica compared with Earth, Mars, and most other rocky worlds, which already set it apart from familiar planetary material.
17.5 kilobars in the Sahara rock
While analyzing Northwest Africa 12774, Bell and colleagues identified crystals of clinopyroxene that were exceptionally rich in aluminum. The team found the mineral required at least 17.5 kilobars of pressure to form, more than 17 times the pressure at the bottom of the Mariana Trench.
That pressure estimate is the sharpest reason scientists say the parent body could not have been a small asteroid. The study says those extreme conditions required a much larger body, one that may have rivaled the moon in size and existed just a few million years after the solar system formed 4.5 billion years ago.
What the crystals preserved
The crystals inside the space rock kept sharp edges and chemical patterns that scientists expect would have been erased if they had spent long periods deep inside a hot planetary interior. That preservation matters because it lets researchers read the rock as a record of formation, not just as debris that has been altered beyond recognition.
For readers following this field, the practical change is in the model itself: Northwest Africa 12774 pushes angrites away from the old small-asteroid explanation and toward a separate early planetary pathway. Bell’s team is not describing a finished planet, but a body large enough to leave a pressure signature in minerals that survived to reach the Sahara.
The next step for this line of research is the study’s own interpretation: more work on angrites and similar meteorites will test whether Northwest Africa 12774 really represents a distinct and separate evolutionary path in the early solar system.
