Hacker News Reader

Comment by OnlineCourage | Hacker News Reader

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.

View on HN

> 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

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.

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.

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.

Also Mars has less gravity than Earth. This helps.

Also erosion on Mars is probably lesser than on Earth.

Reply on news.ycombinator.com