Tidal locking isn't always 1:1. Mercury, the lone tidally locked planet in our Solar System, is locked at a 3:2 resonance. For simple thermodynamic reasons one

Tidal locking isn't always 1:1. Mercury, the lone tidally locked planet in our Solar System, is locked at a 3:2 resonance. For simple thermodynamic reasons one would expect that in most cases the planets locked at an "offset" ratio are far more likely to be habitable than the ones locked at 1:1. This happens when there are outlying large planets that disrupt the orbit: http://en.wikipedia.org/wiki/Mercury_%28planet%29#Spin.E2.80.93orbit_resonance http://en.wikipedia.org/wiki/Mercury_%28planet%29#Spin.E2.80...