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I seem to remember reading somewhere recently - and, annoyingly, I can't find it so have no idea whether it was a "reputable" source - that gravity itself impos

I seem to remember reading somewhere recently - and, annoyingly, I can't find it so have no idea whether it was a "reputable" source - that gravity itself imposes a hard limit on the maximum height of mountains. I guess it makes sense given that the larger a mass in space is, the more gravity forces it into a spherical configuration. Still, happy to be told I'm wrong.

OnlineCourage 7y ago
Probably not correct since the earth is pear shaped not spherical, and the size of mountains are quite small relative to the earth's curvature. However from the article erosion of mountains seems to be impacted by water, limiting height, so on a smaller similar planet by material and water composition it would stand to reason that force of water given the same mass would be less so perhaps mountains would erode more slowly relative to continental drift and therefore be higher.
- perl4ever 7y ago
  I was reading about extraterrestrial mountains once, and what I retained was that there aren't any mountains on other planets/moons that are really amazingly higher than earth. By which I would infer that water erosion probably isn't the overwhelming limiting factor.
  - webnrrd2k 7y ago
    Umm... not true. "The highest mountain on Mars is also the highest mountain and volcano in the entire solar system. It is called Olympus Mons and is 16 miles (24 kilometers) high which makes it about three times higher than Mt. Everest" My knowlege is old, but iirc I think the reason for Martian mountains being (potentially) higher than earth is the the rock is physically stronger due to lower water content. On earth, the water that eventually makes its way into rocks reduces it's strength, but, on Mars, the relative lack of water makes the rocks physically stronger.
    - ekianjo 7y ago
      Also erosion on Mars is probably lesser than on Earth.
    - dreamcompiler 7y ago
      Also Mars has less gravity than Earth. This helps.
    - perl4ever 7y ago
      1. You're telling me what I mean by "really amazingly higher"? Well, you don't get to do that. In my opinion, the scarp/cliff around Olympus Mons doesn't count, and disregarding that, it's less than 40% higher than from Mauna Kea/Loa to the seafloor. Frankly, a mountain would have to be well over double earth's highest base-to-peak to be "really amazing" to me. Ten times would really be "really amazing". 2. There's a Wikipedia page on the subject of tallest mountains in the solar system and it says the current leader is (probably) Rheasilvia on Vesta.
- guessmyname 7y ago
  > Probably not correct since the earth is pear shaped not spherical […] What!? What kind of pears are you eating? Do you mean “Egg Shaped”? EDIT: I think I found the answer myself [1]; @OnlineCourage is probably referring to Seckel or Comice pears. All my life I have eaten either Concorde, Barlett or Bosc pears, but I just remembered that I also found Asian pears in many Chinese supermarkets. OP’s comment freaked out a little bit thinking they see Earth as a Concorde pear. [1] https://i.imgur.com/Hd5NK9T.png https://i.imgur.com/Hd5NK9T.png
hyperpallium 7y ago
Yes, mountains and continents sink into the mantle due to their weight. Although I can't access the paywalled article, I believe they show it's related to "channel steepness", which is caused by river erosion - perhaps implying mountains could be higher where there are no rivers?
- dasil003 7y ago
  You mean where there is no rain? I’m not sure if there are any terrestrial mountains that don’t get significant precipitation on geological time scales because the topography of mountains themselves causes precipitation of moisture passing over them.
  - xvedejas 7y ago
    Mountains in the rain shadow of other mountains? Or under an ice cap?
    - mannykannot 7y ago
      Ice itself is a potent eroder of mountains, but with regard to aridity, both the northern Himalayas and parts of the Chilean/Argentinian Andes are in arid regions - though not arid enough for them to be ice-free, at least for now.

OnlineCourage 7y ago

Probably not correct since the earth is pear shaped not spherical, and the size of mountains are quite small relative to the earth's curvature. However from the article erosion of mountains seems to be impacted by water, limiting height, so on a smaller similar planet by material and water composition it would stand to reason that force of water given the same mass would be less so perhaps mountains would erode more slowly relative to continental drift and therefore be higher.

perl4ever 7y ago
I was reading about extraterrestrial mountains once, and what I retained was that there aren't any mountains on other planets/moons that are really amazingly higher than earth. By which I would infer that water erosion probably isn't the overwhelming limiting factor.
- webnrrd2k 7y ago
  Umm... not true. "The highest mountain on Mars is also the highest mountain and volcano in the entire solar system. It is called Olympus Mons and is 16 miles (24 kilometers) high which makes it about three times higher than Mt. Everest" My knowlege is old, but iirc I think the reason for Martian mountains being (potentially) higher than earth is the the rock is physically stronger due to lower water content. On earth, the water that eventually makes its way into rocks reduces it's strength, but, on Mars, the relative lack of water makes the rocks physically stronger.
  - ekianjo 7y ago
    Also erosion on Mars is probably lesser than on Earth.
  - dreamcompiler 7y ago
    Also Mars has less gravity than Earth. This helps.
  - perl4ever 7y ago
    1. You're telling me what I mean by "really amazingly higher"? Well, you don't get to do that. In my opinion, the scarp/cliff around Olympus Mons doesn't count, and disregarding that, it's less than 40% higher than from Mauna Kea/Loa to the seafloor. Frankly, a mountain would have to be well over double earth's highest base-to-peak to be "really amazing" to me. Ten times would really be "really amazing". 2. There's a Wikipedia page on the subject of tallest mountains in the solar system and it says the current leader is (probably) Rheasilvia on Vesta.
guessmyname 7y ago
> Probably not correct since the earth is pear shaped not spherical […] What!? What kind of pears are you eating? Do you mean “Egg Shaped”? EDIT: I think I found the answer myself [1]; @OnlineCourage is probably referring to Seckel or Comice pears. All my life I have eaten either Concorde, Barlett or Bosc pears, but I just remembered that I also found Asian pears in many Chinese supermarkets. OP’s comment freaked out a little bit thinking they see Earth as a Concorde pear. [1] https://i.imgur.com/Hd5NK9T.png https://i.imgur.com/Hd5NK9T.png

hyperpallium 7y ago

Yes, mountains and continents sink into the mantle due to their weight. Although I can't access the paywalled article, I believe they show it's related to "channel steepness", which is caused by river erosion - perhaps implying mountains could be higher where there are no rivers?

dasil003 7y ago
You mean where there is no rain? I’m not sure if there are any terrestrial mountains that don’t get significant precipitation on geological time scales because the topography of mountains themselves causes precipitation of moisture passing over them.
- xvedejas 7y ago
  Mountains in the rain shadow of other mountains? Or under an ice cap?
  - mannykannot 7y ago
    Ice itself is a potent eroder of mountains, but with regard to aridity, both the northern Himalayas and parts of the Chilean/Argentinian Andes are in arid regions - though not arid enough for them to be ice-free, at least for now.