[Nateman]

Mercury was once believed to be tidally locked with the Sun. Tough call for something 71 light years away.

In order to be warm enough for life you have to be relatively close for a red dwarf star. Problem with that is that it close enough to be burned with occasional solar flares.

[21twelve]

The tides on earth are pretty important to marine life, and perhaps the entire ecosystem as it flushes out the crap that accumulates.