Mondo Knows Facts
The Moon formed from a giant planetary impact
A Mars-sized body struck the young Earth and threw debris into orbit In the leading model, a body nicknamed Theia hit Earth about 4.5 billion years ago, and the ejected material gathered into the Moon within perhaps a century. That explains why the Moon has a small iron core and little volatile material. Its rocks share almost the same oxygen isotope mix as Earth's, which still puzzles modellers. It sits in Mondo's space collection, one of 200 facts that each trace back to the reference below.
Where this comes from
Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.
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More facts like this
Most heavy elements were forged in starsCalcium in your bones and iron in your blood were made inside supernovaeThe Moon is slowing Earth's spinTidal friction lengthens the day by a couple of milliseconds a centuryTotality never lasts longer than about seven and a half minutesThe Moon's shadow is small, so you have to travel into its pathThe lunar night falls to about minus 173 CelsiusWith no air to hold heat, the surface swings hundreds of degrees a dayArtemis targets the Moon's south poleWater ice in permanently shadowed craters could make fuel and airThe Moon is slowly drifting away from EarthLuni-solar tidal friction pushes the Moon outward by roughly four centimetres each year
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Tags: moon, impact, origins
The Moon formed from a giant planetary impact: the short answers
- Where does this come from, and can I check it?
- A Mars-sized body struck the young Earth and threw debris into orbit. The figure is taken from NASA Science, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
- Is this really a space fact?
- Yes. It sits on the Space shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
- What else can I read about it?
- The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.