SMRTR Science & EngineeringOct 14, 2025Interesting Engineering

Chemical fingerprints offer first evidence of 4.5-billion-year old proto-Earth

SMRTR summary

MIT researchers discovered chemical fingerprints in ancient rocks from Greenland, Canada, and Hawaii containing remnants of proto-Earth from 4.5 billion years ago. These samples show a unique potassium-40 deficit that survived the massive impact that formed Earth and the Moon, contradicting theories that this event completely erased all original planetary material. The findings provide first direct evidence that primitive Earth materials remained intact deep within our planet's interior.

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