What’s the highest mountain in the solar system?

While I’m in Chile climbing the mountain with the most superlatives in the world, I thought it might be interesting to consider just how superlative a mountain can get.

Most of us have climbed mountains where we’ve not been able to see the summit until we’re standing on it. A few of us have also climbed mountains where the slope has been so gentle that the horizon has remained just a few metres in front of us for much of the ascent (for me, Muztag Ata springs to mind).

But imagine climbing a...