There are surface features on Mars that we can observe with remote sensing data. There are many shorelines seen in a way. Despite its subtle atmosphere or storms, these surface features remain. How do surface shapes on Mars still exist?
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1$\begingroup$ you just answered the questions yourself, there's nothing to erode it $\endgroup$– TopcodeDec 9, 2020 at 19:55
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$\begingroup$ @Topcode "Despite its subtle atmosphere or storms..." is not a priori nothing, this is a reasonable question to which an informative answer has been posted. $\endgroup$– uhohDec 9, 2020 at 21:17
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1$\begingroup$ I suggest to change the title of the question such that it is more specific. $\endgroup$– Everyday AstronautDec 10, 2020 at 19:29
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1 Answer
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The surface features on Mars are still present because of their resistance to erosion, the magnitude of erosive forces and geological inactivity on Mars: no active volcanoes, no plate tectonics and negligible seismic activity to cause land forms to move or to disrupt the surface of Mars.
Erosion is,
the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location.
On Earth the main causes of erosion are:
- Wind
- Flowing water
- Water waves
- Glaciers
- Snow and rain
- Animals
- Human activity
- Plants
As far as we know, there are no significant life forms on Mars, animals or plants, so that removes that form of erosion.
Human activity on Mars is due to the actions of rovers on Mars. The wheels of the rovers cause very little disturbance to the surface as do minor drilling or digging activities to test surface rocks or regolith. The actions of rovers, and thus humans so far, cause negligible erosion on Mars.
Features interpreted as glaciers on Mars,
are largely restricted to latitudes polewards of around 30° latitude.
Any erosion caused by current glaciers on Mars is not enough to cause major changes to surface features.
Snow falls on Mars under specific unusual conditions. When it does fall it doesn't last long as it evaporates or sublimes. Consequently, snow is not a erosive medium on Mars. Similarly, rain does not fall on Mars.
There are no major sources of flowing water (streams) or standing water on Mars to form waves, so there is no erosion on Mars caused by such sources. There are however, seasonal seeps in specific locations on Mars that can cause minor seasonal flows of water on Mars.
This leaves wind and yes it does cause some erosion, but because the atmosphere on Mars is thin, winds on Mars are less powerful than on Earth and thus less erosive than on Earth.
