Ancient Space Rock Rewrites Solar System’s Origin Story

This small 50-gram rock, named "Northwest Africa 12264", was purchased by researcher Ben Hoefnagels in August 2018 from a merchant in Agadir, Morocco, reveals The Meteoritical Society, an international organization dedicated to the promotion of research and education in planetary sciences. A recent study, published in the journal Nature Communications Earth & Environment, shows that this space rock could have formed 4,564 million years ago, a period when the presence of basalts was noted in the inner solar system and in planetary crusts.

"Our results are consistent with observations of exoplanetary disks that imply rapid formation of planetesimals at radial distances," the study explains. Historically, it was thought that the rocky planets closest to the Sun, namely Mercury, Venus, Earth, and Mars, were the first to form. But according to the study, the composition of the NWA 12264 meteorite, originating from more distant regions in the asteroid belt, reveals that it was born at the same time as the planets closest to the Sun and that the formation of the solar system did not follow any proximity model.

This discovery challenges all previous theories. "Surprisingly, NWA 12264 provides the first direct evidence of an olivine-rich mantle of a body formed in the outer solar system. This finding reinforces the idea that differentiated rocky planets, those with a core, mantle, and crust, also formed in the outer solar system, and not just in the inner regions, as previously thought," the researchers explain.