Scientists Just Detected a Long-Lost Planet 'Hiding' Inside Earth | NYGazet

When a Mars-sized meteorite slammed into Earth billions of years ago, the impact completely reset any and all chemical processes on Earth, leaving nothing from before. Or so we thought.

If proto-Earth had all its parts and chemistry replaced to become the Earth we know today, can the two still be considered the same planet? That’s the planetary version of Theseus’s Paradox, an old philosophical puzzle about identity and perception. ... [3522 chars]