thanks to one of my frequent readers I will add short post to tidal forces because I forgot very important thing: Roche limit.
Roche limit is distance from object (star, planet). If satellite (moon) crosses this distance it will be eventually ripped apart (by tidal forces). Important is that for every satellite it is different because every satellite, like man-made has different properties. It is very complicated to know exact Roche limit for anything because there is lot of stuff you must count in.
On first picture there is planet orbiting sun in save distance and no great tidal forces are disturbing it.
On second planet is coming closer to Roche limit and its shape is disturbed because red side is much closer.
When planet crosses limit is starts to be ripped apart. Stuff nearer (red) starts to fly faster and that is end to our planet.