Mars have several mountains above 10 km, with the highest being around 22 km (full list for Solar System here). Same for Io, Jupiter's moon. In contrast, the Earth has no mountain higher than 10.2 km (Manua Kea and Manua Loa, when considered from the bottom of the ocean, more comparable with mars and Io), with the Everest being 8.8 km above sea level.

Is there any restriction in terms of the geological nature of Earth, or perhaps due to the atmosphere (e.g. water cycle/erosion), or closeness to the Sun (Mercury and Venus have even smaller mountains), that doesn't allow for higher mountains on Earth? Or is it perhaps just a matter of age? (in the sense that future tectonic movements will lead to higher mountains, without a particular limit)

More generally, is there any physical limit about how high mountains on this planet can ever be?

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    $\begingroup$ This is indeed a duplicate of that question. The article referenced in the top answer (which is the correct answer) even discusses how tall mountains made out of granite might get on other planets / moons. $\endgroup$ – David Hammen Dec 20 '19 at 15:45

The reason mountains are higher on Mars than on Earth is the lower gravity on Mars, which is only one third of Earth gravity. Mountains are very heavy things, and on Earth the forces that build them have to fight against gravity, which is constantly trying to drag them down. For the same reason, small asteroids are usually not spherical, because they don't have enough gravity to even out the bumps, but when they get to about the size of Ceres, which is 500 miles in diameter, they do. Ceres is spherical. Mountains like Mauna Kea which have a large part under water don't count, because although mountains are heavy things they still have buoyancy and the sea is taking part of their weight. Venus has slightly less gravity than Earth, but because of the enormous heat is also more plastic, so this would mitigate against the building of very high mountains.


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