The picture I referred to had multiple impact craters. None of these had any sharp edges. They all look like a soap bubble popped. A large meteorite hitting the ground is a violent impact event. The picture also has an extensive canyon all of which is rounded. This is an airless world so what created the canyon and subsequently, what rounded off its edges if there is little or no erosion factor?
The simple action of heating and cooling as it revolves and orbits the local star would probably cause sections to break off. There should be at least some jaggedness to stop this looking so uniform and computer generated.
Everything slopes. There are no overhangs. It is simply a 2d surface deformed into a 3d surface by adding height or depth. Where are the outcrops or overhangs?
Actually, you are misunderstanding how failure in materials occur.
Solids that make up celestial bodies are made up of solidified mixtures of minerals. They were all liquid once and then solidified by radiating heat into space. Since the bodies have very little to no gas phases surrounding them, heat loss due to anything other than radiation is negligible.
When liquid mineral mixtures solidify on their own, solid nuclei start to form at a critical temperature and after they reach a critical radius, they start to grow. They are now called grains of a solid material. These grains grow until they touch each other and when there is no more liquid left, we have a solid body made up of grains connecting at what we call grain boundaries. Grains are made up of either a single crystal or crystallites which join at sub grain boundaries.
These crystals are not perfect crystals, they have lattice mismatches, dislocations, vacancies where an atom is missing where there was supposed to be one...
After solidification, temperature changes cause these grains to expand and contract as defined by their thermal expansion coefficients. Since there are sub grain boundaries, micro cracks start to appear along these and after a number of cycles, the grains break into smaller pieces.
As the celestial body is exposed to such extreme temperature changes (there is no gas to insulate them against the vacuum of space, if they are getting direct radiation from the star, they heat up extremely quickly, then once they are in the shadow of something, they cool extremely rapidly too), the grain boundaries will break much earlier than a large crack to propagate enough to break off a huge chunk of rock, which will happen much more rarely.
So the science on the subject says, unless you have something with really pure, huge single crystals with nearly perfect microstructure, which would be extremely rare to occur on its own, you'll get rounded edges on bodies without atmospheres.
So everything will slope, as the particles breaking off will settle at the skirts of whatever they are breaking off of. The canyons on non atmospheric bodies are fault lines on the crust. They are due to tectonic activity. Edges are rounded rapidly because of the mechanism I explained in the beginning.
Overhangs require special circumstances too, the most common of which is some mineral to be chemically etched away while some other mineral on top of it survives, which requires some liquid solvent present. Another way to form overhangs is to freeze water, put soil on top, pack it tight and melt the ice, which not only requires an atmosphere but also water and also life because soil is organic material left from dead things.
So... Celestial bodies of ED are scientifically accurate.
Oh, I have some more to add that I have forgotten. The sand which forms by grains breaking through their lattice faults result in a kind of sand which is not found on places with atmospheres, such as earth. This sand usually has extremely sharp edges and is highly abrasive, unlike the mostly silica based sand of our world, which is constantly rounded and polished by movement by water.
In conclusion, atmospheric planets with flowing liquid chemicals (such as water) will usually have sharp edged canyons with rounded sand, non atmospheric ones will usually have rounded canyon edges with extremely sharp sand. Such is life.
