since I have done first two planets of Solar System I would go to the Earth but I find it not so important for me 😀 so I will do the Earth´s partner, the Moon.
Our Moon is largest compared to other moons with their planets.
It has radius of 3470 km compared to Earth which has 6378 km. Moon is orbiting about 380 000 km far away while Earth orbits Sun in 150 000 000 km.
First of all. It is assumed that the Moon was created by extremely huge impact of some planet about the size of Mars which collided with Earth. From this collision Moon was born having both material from Earth and from second planet (Theia is it´s unofficial name).
This event made Earth very very hot so when Moon was cooling its closer side to us was
cooling more slowly and when material evaporated it felt on the dark side. This made Moon much thinner on the side turned to us. (Moon is locked by tidal force)
Over eons and eons stuff fell on our brother. When something collided on the thinner side it was much more common to break through thin layer of the surface so lava could bubble up. When this happened couple of times places called mares (marines) were created, this could not happen on the other side because of its thick crust.
There are lot of different structures on the surface. Dark one are marines, there are also craters and lines from old lava flow or even small canyons and places where it is thought that can be milliards of liters of water in the form of ice. Moon is not geologically active but there is still some liquid lava inside, even after 4.5 mld years.
PS: I saw the blood moon and it was amazing!
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.
sorry for not writing such long time, I was enjoying holidays for whole week. Anyway I am coming back with post about tidal force.
Tidal force is effect of gravitational force and it can be seen as for example tide.
So you have Moon which is attracting everything, even water in our oceans. Water closest to Moon is attracted with greatest force while water far away with least. As you can see on the picture there is Moon (Satellite) on the right this grants us two high tides per day.
So as is Moon orbiting it changes the place where low and high tides are.
This effect creates amazing things: rings! Planetary rings can be made by some satellite which moved too close to its planet and tidal forces were so strong that it ripped it apart, so there is higher probability that larger planet will have ring.
Tidal force also can be “seen” in effect called spaghettification which is made by black holes or other massive objects.