15 facts about Ganymede
Ganymede is a huge moon by solar system standards. It is larger than Pluto and Mercury. Apparently, it was observed with the naked eye in ancient time ...
Deimos is a smaller and more distant Martian moon. Its diameter is only 12.4 km, although it is difficult to talk about the diameter in the case of such a non-spherical celestial body as this satellite. It does not have many distinctive surface features, but there are a few craters on it. It probably entered the orbit of Mars from the outer Solar System, but there is no confirmed theory of its origin.
It was not discovered accidentally, the astronomer conducted observations precisely to find the planet's natural satellites.
Due to its small size, it is not a spherical object.
It moves in an almost circular orbit that is systematically expanding. So unlike Phobos, which will most likely fall to the surface of Mars, Deimos will one day escape into space.
These craters are less visible than on the other moon because they are filled with regolith (rock dust).
They were named after two writers who claimed that Mars had two moons before this was proven.
They are located close to each other in the northern hemisphere, right near the prime meridian.
