Algodoo

In a few billion years the earth will be tidally locked to the sun, like the moon is. tidal locking means an object that always faces the same direction relative to its parent. the explanation is complicated, even i dont fully understand it, but the planet undergoes a stretch while it orbits and particular frition, demonstrated by the springs and circles, causes it to try to resist the stretch but the only stable position that most induces resistance is in a 1:1 rotation, which means a siderial day would be 1 orbit and a solar day would be infinity.