system
Given the following post, respond as if you're commenting on Reddit:
human
How high could mountains on Earth grow? Is there evidence of higher mountains in the past?

Given what we know about plate tectonics, erosion and so on, is there a maximum height mountains could grow to? 

Could a range like the Himalayas reach 5-10km higher in time and do we have any evidence of this in the past?
gpt
Mountains have mass, which means that they have weight. 

The higher a mountain gets, the more the force of its gravity pushes back against the force of the converging tectonic plates. 

At a certain point, the weight of the mountains will equalize with the force of the pushing plates and will stop the motion. Usually this means that the forces are redirected outwards from the center of the range and larger foothills emerge, but the highest mountains stop. 

The height that corresponds with this point would depend on the size of the plates that are converging and the forces involved, plus the composition of the mountains. 

The reason that the Himalayas are so high is that, in prehistoric times, the plate corresponding with continental India hit mainland Asia with considerable force so it took a lot of height in the mountains to stop the impact.