I wrote about Earth already here (for the medium article click here). Let’s talk about our most familiar neighbour, Mars. If you just want the answer, that’s at the end of the post. If you want a bit of background information to make sense of it, keep reading.
Firstly, what is the largest mountain known on Mars? Olympus Mons, aka Mount Olympus.
How tall is it? It’s estimated to be 25 kilometres high (around 16 miles). MUCH taller than anything here on Earth. And way too far away for you to climb, so don’t get any ideas… yet.
It’s height is thanks to the lower gravity on Mars. It’s actually a shield volcano. This is a volcano that has built up from years of steady lava flow.
In the picture above you can see the edges of the volcano/mountain, and in the middle is the crater where lava would have come out aeons ago. We have these on Earth as well, and there’s significant debate on whether certain volcanoes should take the title of tallest mountain. But Everest still maintains that title.
Anyway, I digress. Mars is no longer volcanically active, so Olympus Mons is stuck for the time being. But hypothetically, if mountains were to continue growing on Mars, what height could they get to before they start collapsing?
In my last article about Earth mountain heights, I discussed the limitations placed on mountains due to gravity and pressure. If you already know this you can skip ahead. The higher the mountain is, the more it weighs and thus creates higher pressure exerted by gravity on the base of the mountain. The gravity of the planet and the pressure limit of those rocks determine what the maximum height can be. This is because when rocks are compressed past their limit they start to liquefy. This then causes sinking and shifting of the mountain until the pressure is reduced enough for the rocks to solidify again. Capisce?
If you’re any good at maths you can use the same equation used to calculate Earth’s maximum mountain height and work it out for Mars. We don’t know exactly what composition of rocks makes up Mount Olympus (though this could change in the future with our exploration rovers), so I used the same estimate as for Earth rocks. Mars’ gravity is roughly 38% that of Earth’s. The answer I got for Mars’ maximum mountain height was approximately 26km. But there’s a lot of room for error here because there are so many variables and uncertainties.
NASA has calculated Mount Olympus height to roughly 25kms tall, so that’s pretty close, but again could vary. We also know that it can’t get any higher due to the lack of lava flow. There’s no activity on Mars in terms of plate tectonics and there’s no other active volcanoes. So mountains on Mars are stuck at their height, probably shrinking actually due to erosion. I guess we’ll never know what would happen to Mount Olympus if it got bigger. I could theorise that perhaps it wouldn’t reach that limit due to lava channels underneath automatically shifting away loose or pressure-liquified rock.
Here’s a video that might help explain how to calculate mountain height limitations:
Originally published at http://haveyoueverwondered123.wordpress.com on March 6, 2022.
