4.5-billion-year-old traces of ‘proto-Earth’ discovered could rewrite our planet’s origin story

MIT scientists have discovered ancient rock samples from Greenland, Canada, and Hawaii exhibiting a rare potassium-40 deficit. This chemical signature suggests these rocks are remnants of "proto-Earth," predating the giant impact that formed the Moon. The findings challenge previous assumptions about the early Earth's complete remelting and offer a glimpse into the solar system's initial chemistry.