Take the 2-minute tour ×
Astronomy Stack Exchange is a question and answer site for astronomers and astrophysicists. It's 100% free, no registration required.

According to this Wikipedia page, the top five highest mountains on Mars (and the highest on Venus) are all taller than Mount Everest (and Mauna Kea as measured from the ocean floor).

Does a planet's mass or gravity affect the height of it's mountains? Is there an upper limit that a mountain can reach given the mass or gravity of a planet?

share|improve this question
1  
Good question and there is a good answer in part here physics.stackexchange.com/questions/47159/… –  user8 Nov 13 '13 at 11:54
    
An interesting / relevant aside: arxiv.org/abs/1004.1091 –  Moriarty Nov 14 '13 at 0:22
    
@UV-D: The question is good, and the answer you are pointing at is also good. However, the latter is given for a different question. There is just a bare minimum of useful information there on the matter. –  Alexey Bobrick Nov 14 '13 at 15:48
add comment

3 Answers

In addition to the answer quoted by @UV-D, gravity affects the height of mountains composed of loose material (e.g. sand, volcanic ash). In a pile of loose material, the height is determined by the angle of repose, i.e. the steepest angle at which material will stay in place rather than roll down the sides of the mountain. This angle depends on gravity.

share|improve this answer
1  
Nice point, though: 1) Would be great to see at least some quantitative discussion, 2) Mountains tend to be tectonic, not sandy in nature –  Alexey Bobrick Nov 14 '13 at 15:49
    
I agree with @AlexeyBobrick, I don't think this actually answers my question. It's unlikely that there will be a mountain of loose material that rivals the height of the solar system's highest mountains. Can you link to any evidence that gravity affects the height of actual mountains? –  Fezter Nov 14 '13 at 23:11
add comment

Yes, gravity definitely affects the maximum heigh of mountains.

Think on a solid bar of steel. It sticks straight because of the electronic forces. But when you make it larger and larger gravity makes it bend: gravity starts being considerable, but still smaller than electronic forces.

If you make the bar larger, there will be a moment in which the weight of the whole bar will be larger than the short-range electronic force: your bar will break purely due to gravity.

Exactly the same happens to mountains made of solid rock (as opposed to sedimentary ones quoted by Hobbes). There is a point,k depending on the strenght of planetary gravity, where it takes over short-range electronic forces, making the mountain collapse.

This is exactly the force that "rounds up" the planets, as opposed to the non-spherical asteroids.

share|improve this answer
add comment

The mountains actually form as a result of the tectonic plates' movement at the earth mantle. Suggesting that a new mountain would be formed tomorrow, during the tectonic activity rock from the mantle and above moves upwards, only the tip of the newly formed mountain would consist of sediments like sand or soil.

So, I don't think that the gravity or mass of a planet affects the mountains' height.

Plus, Earth is the only known planet to be affected by plate tectonics. So, the 'birth' mechanisms must be a lot different and cannot be compared with the ones' acting on our planet.

share|improve this answer
    
"Earth is the only known planet to be affected by plate tectonics" - do you have a reference for this? –  Alexey Bobrick Nov 20 '13 at 19:16
    
Trust me I'm a geologist! wwnorton.com/college/geo/egeo2/content/ch02/article_2.htm –  Nikos Nov 21 '13 at 18:27
    
Sounds trustable! Though, it is not clear, why wouldn't gravity affect either mountains as we know them on the Earth (Earth-like planets), or mountain-like structures on other types of planets. –  Alexey Bobrick Nov 21 '13 at 19:38
    
I wanted to make clear that earth's mountains are not the same as other planets' mountains, thus they can't be compared. –  Nikos Nov 22 '13 at 20:19
    
It does not matter which the birth mechanisms are in order to assert if there is a maximum size. While I agree with you in that mountaingenesys mechanisms are very different on a techtonic planet like Earth than in a non-techtonic one like Mars, basic Physics are the same. For planets with same radious, that one with bigger gravity will be more round, that is, mountains will have smaller maximum possible (note possible does not mean actual) height. –  Envite Nov 24 '13 at 13:32
show 1 more comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.