Mt Everest is just under 5.5miles high. Olympus Mons on Mars is 16 miles high. Why aren’t there much larger mountains on Earth? What’s the highest a mountain can go on Earth?
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Also, its not just gravity. Another factor has to do with how we measure elevation on Mars. Earth’s zero elevation is sea level. Mars has no sea level. In order to have a scientific reference, Mars’s zero elevation datum was chosen to be the elevation where the atmospheric pressure on Mars was at the triple point of water. That is where the atmospheric pressure is 610Pa. By comparison, Earth’s atmospheric pressure as sea level is 101,000Pa. Mars’s lowest elevation is 4.4 miles below Martian zero elevation, not nearly as as far below the zero elevation as earth’s oceans. When you start your yardsticks at different spots, you get different measurements.
Gravity limits how tall a mountain can be before it’s too tall and heavy to support itself. Mars has a much lower gravity.
Similar to jelly – you can fill a jelly mould that’s huge and deep, and tip it out. But it will collapse under its own weight and spread out to a certain level….you could add more jelly on top, but it will just do the same thing and push down and spread outwards.
Same with mountains…only less jelly, more rock.
The size of mountains on a planet is influenced by several factors, including the planet’s gravity, crust composition, tectonic activity, and erosion processes. Here’s a breakdown regarding Earth and Mars:
1. Gravity: Earth’s gravity is stronger than that of Mars. A higher gravitational force will tend to pull tall structures (like mountains) down, limiting their maximum height. In contrast, Mars, with its weaker gravity, allows for taller structures to exist.
2. Plate Tectonics: Earth’s crust is broken into tectonic plates that move around on the semi-fluid asthenosphere below. Mountains on Earth, especially the tallest ones like Everest, are formed by the collision of these plates. Once mountains reach a certain height, the crust can begin to flow outwards, and the gravitational forces pushing downwards can prevent the mountain from growing taller.
3. Erosion: Earth has a dynamic climate with rain, wind, snow, and ice, all of which contribute to the erosion of mountains. Over time, these processes wear down the mountains, limiting their height. Mars, on the other hand, has a much thinner atmosphere and lacks the liquid water that’s so abundant on Earth, so erosion from these processes is significantly reduced.
4. Crust Composition: The crustal composition can influence a mountain’s height. For instance, the presence of certain rock types can support taller structures, while others might not.
5. Isostasy: This is the concept of Earth’s crust “floating” on the semi-fluid mantle below. When mountains form, the crust is pushed downwards into the mantle to compensate. Over time, this can limit the height of the mountain.
As for the maximum height a mountain can reach on Earth, it’s a complex issue and depends on various factors, including the ones listed above. One hypothesis, known as the “theoretical maximum height,” suggests a limit of around 10 km (or about 6.2 miles) due to the principles of isostasy and the material properties of the Earth’s crust. However, this is a rough estimate and could change with new discoveries or insights….
Most mountains on earth are made via tectonic processes. Olympus mons is essentially a hot spot volcano that erupted in the same place for a long time because there are no plate tectonics on mars. Hot spots on earth also remain stationary, but the tectonic plates drift over them so there isn’t enough time for any single vent of the hotspot to create such a large pile of lava. The Hawaiian islands are a great example of this, the Hawaiian spot has been making large shield volcanos (like Olympus Mons) for at least 50my and perhaps a lot longer than that. Each vent is only active for a short period of time, it forms a large mountain akin to Mauna Kea before the plate drags the mountain away to be worn away by weather and waves. Then a new vent opens, and makes the next volcano. If there was no plate tectonics on earth, it’s possible we could have several large volcanos a lot closer in size to Olympus Mons. Gravity and erosion rates are limiting factors to height as well, but the main difference is the tectonic settings of the two planets.
Ugh these are all incorrect, or misunderstandings. The reason they aren’t tens of km high is because of EROSION. That can be influenced by gravity, but it’s primarily freeze thaw, rain, earthquakes, and the rock not having the sheer strength for chunks of rock to fall off. The taller a mountain gets your angles increase and thus it’s more susceptible to being eroded.
Isn’t Mt Everest growing like 2cm every year so eventually it’ll be that tall?
The earth’s continents float on something called the Mantle which is layer of superheated, compressed, and rather malleable rock (not really liquid but not fully solid). When any part of a continent gets too heavy, like from mountain building, it displaces more of the mantle dipping into under it’s weight. Additionally the earth’s natural atmosphere (air blowing sand), hydrosphere (water movement), and biosphere (tree roots for example) all have the ability to erode rock in our around mountain ranges.
A fun thing of note is that Mars has a dead volcano that is over twice as tall as our tallest mountains. The atmosphere is many times less dense, there is no liquid water, and no known plant/animal life to break it down. But, there is not thought to be plate tectonics taking place on mars which suggests it lacks a mantle for the continents to float on.
We do.
Mount Everest is around 12 miles high. It’s just that the lower half is hidden by the ocean, which Mars doesn’t have.
This might be a bit late to the party, but at Uni we were told about the glacial buzzsaw theory, which is probably my favourite name of any theory!
Basically as mountains get higher the top gets colder. Beyond the freeze thaw cycle a permanent glacier just grind the tops down. So mountains could be higher but in geological time they get eroded faster the higher and colder they go.
This theory however does have its critics: https://en.m.wikipedia.org/wiki/Glacial_buzzsaw
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