# Topographical prominence decides a mountain

Date:18 August 2017 Tags:

What makes a mountain a mountain? Two words: topographical prominence.

Mountains. What are they? You think you might know the answer, but it’s actually surprisingly confusing. So Tom Scott investigates the deceptively simple question you thought you learned in the first grade – what is a mountain?

#### Calculating topographical prominence

The answer lies in a metric called topographical prominence. The idea works on a hypothetical scenario where the sea rises to the peak you’re standing on. You then measure how many meters it takes for the water to drop before you can walk to the next peak, and that number tells you if what you’re standing on is indeed a mountain. Some climbing groups say only 300 meters means you’re standing a separate mountain, others argue that 500 meters should be the correct distance.

As Scott notes, this measuring system is one of those times when nature doesn’t easily fit in a checked box. If you’re still hazy on the concept, the website Peaklist has a good run down of areas with unusually well-defined prominence.