Mondo Knows Facts
The Moon is tidally locked so it always shows the same face to Earth
Matching rotational and orbital periods hide the lunar far side from view
Gravitational friction over billions of years slowed the Moon's rotation until its orbital period matched its rotational period. Because it takes 27.3 days to rotate once on its axis and 27.3 days to orbit Earth, the same side of the Moon perpetually faces Earth observers.
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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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Tags: moon, tidal locking, orbit
The Moon is tidally locked so it always shows the same face to Earth: the short answers
- Where does this come from, and can I check it?
- Matching rotational and orbital periods hide the lunar far side from view. 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 1,090 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.