A meteorite picked up in the Sahara may be a shard of a vanished world. New analysis of NWA 12774 suggests the rock formed deep inside a large planetary body, giving scientists what they describe as the first direct evidence of an ancient planetary embryo destroyed around 4.5 billion years ago.
The Sahara meteorite matters because angrites, the rare meteorite family that includes NWA 12774, were long treated as leftovers from small asteroids. This sample points to something much bigger – a body that may have been Moon-sized and, in the most extreme reading, close to Mars in scale. That pushes the early Solar System closer to a violent smash-up than the tidy assembly line many diagrams still like to suggest.
What NWA 12774 shows
Researchers publishing in Earth and Planetary Science Letters focused on the meteorite’s clinopyroxene crystals. Their chemistry, especially the unusually high aluminium content, is the giveaway: that kind of structure forms only under extreme pressure deep inside a sizable planetary body.
The pressure estimates are the headline number here. The minerals appear to have crystallised at no less than 17.5 kilobar – a brutal environment compared with about 1 kilobar at the bottom of the Mariana Trench. In other words, this was not a shallow rock on a tiny asteroid drifting quietly through space.
- Meteorite: NWA 12774
- Meteorite class: angrite
- Estimated parent-body radius: more than 1,800 kilometres
- Formation pressure: at least 17.5 kilobar
A bigger parent body than expected
The inferred size of the parent body is the real plot twist. A radius above 1,800 kilometres puts it in the same conversation as the Moon, not the modest asteroids that have usually been blamed for angrite origins. That forces a rethink of how differentiated bodies formed, cooled, and got torn apart in the Solar System’s early chaos.
It also fits a broader pattern seen in planetary science over the past decade: meteorites are increasingly behaving like forensic evidence from worlds that no longer exist. The Solar System did not begin with neat lanes and polite growth. It was crowded, violent, and bad at keeping planets intact.
Why this changes the angrite story
Aaron Bell of the University of Colorado Boulder and co-authors argue that the chemistry of these rocks reflects an evolutionary path different from Earth’s and Mars’s. That is a strong hint that multiple large planetary bodies formed early, survived briefly, and then got pulverised during the era of heavy collisions and accretion.
The open question now is how many other meteorite groups are hiding the same kind of origin story. If one Sahara find can rewrite the ancestry of angrites, the next frontier is obvious: finding how many other ”small rocks” are actually the remains of lost planets.