Dr. Skeptic wrote:Mercury's rotation is locked in a 3:2 rotation to Earth. Coincidence?
Chris Peterson wrote:I assume you mean it's in a 3:2 resonance with the Sun, not the Earth. And it's no coincidence; tidal locking need not be 1:1.
Mercury's rotational period is 58.7 days, orbital period 88 days.Dr. Skeptic wrote:Nope, with the Earth. It's either gravitational or magnetic tidal lock or a very strange coincidence. Wikipedia can explain it better that I can.
Every 176 days it completes 3 rotations and 2 orbits.
3:2 spin-orbit resonance.
http://en.wikipedia.org/wiki/Mercury_(p ... _resonance