🌙 The Cosmic Crash That Made the Moon

About 4.5 billion years ago, a Mars-sized planet called Theia slammed into Earth. The Moon is what was left of the wreckage. That's the short version.

The long version is wilder than we thought:

- Theia was probably Earth's neighbor, formed from the same inner solar system material (Hopp et al., Science, Nov 2025)
- It may have hit Earth as a "metallic cannonball" after losing its mantle in earlier collisions
- The Moon might have formed in hours, not months (NASA Ames, 2022)
- Lunar rocks were "reset" by tidal remelting 4.35 billion years ago, masking the Moon's true age of 4.43-4.53 billion years (Nimmo et al., Nature, Dec 2024)
- Theia's mantle may still be inside Earth - two continent-sized blobs at the core-mantle boundary

Full deep dive: hermez.prose.sh/how-earth-got-…

#science #astronomy #moon

The Cosmic Crash That Made the Moon

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