Why the moon is tidally locked with the earth? What is the reason for the tidal locking of the moon with the earth? What causes tidal locking?

  • 8
    $\begingroup$ Have you read through a resource like wikipeida? en.wikipedia.org/wiki/Tidal_locking $\endgroup$
    – James K
    Sep 1, 2022 at 8:09
  • 3
    $\begingroup$ -1, this is literally a case of googling the first sentence of the question and reading any of the articles on the first page. $\endgroup$
    – user438383
    Sep 2, 2022 at 7:28
  • $\begingroup$ Consider the time involved since formation, how much rotation it would have to lose every day for 4.5 billion years and the fact it was molten light rock exploded off from our planet chaotically rather than a captured body. $\endgroup$ Sep 2, 2022 at 19:08
  • $\begingroup$ I’m voting to close this question because there is no effort done by OP whatsoever. $\endgroup$ Sep 3, 2022 at 2:04
  • 5
    $\begingroup$ I’m voting to close this question because there's no evidence that OP has done any research. $\endgroup$
    – Jim421616
    Sep 3, 2022 at 6:43

1 Answer 1


The far side of the Moon feels less pull from the Earth than the near side. The Moon travels along the path of its center of mass. This means the mass further feels less gravitational pull from the Earth plus it is pulled outwards by centrifugal force (because it is going "too fast" for an orbit at its distance). The mass closer to the Earth feels a greater gravitation force. Plus it is going too slow for a closer orbit.

The result is the Moon is pulled out of round into an oblate spheroid. When it was spinning, this warping and pulling of the rock or flow of fluid caused heat and as the rotation energy was converted to heat the rotation slowed. Basically it "ground to a halt". The minimum energy configuration is the rotationally locked situation.

Guessing now, I would think it is permanently a bit lopsided with mass concentrated a little on the Earth side. There are orbital gravity surveys that would show this. In fact if memory serves, one of Robert Forward's rotating gravity gradiometers was flown on a satellite that orbited the Moon.


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