TIL because of its slow rotation one "day" on mercury equals 59 earth days. It orbits the Sun in a 3:2 spin–orbit resonance, rotating on its axis exactly three times for every two revolutions around the Sun meaning a day lasts twice as long as its year.

https://en.wikipedia.org/wiki/Mercury_(planet)

https://www.reddit.com/r/todayilearned/comments/15kek36/til_because_of_its_slow_rotation_one_day_on/