how some fish species can live at insane depths of the ocean, while the best nuclear submarines can only go a couple thousand feet before being crushed.

Question

Soft bodied fish like the snail fish can apparently live at depths deeper than 25,000 feet… yet somehow, despite modern engineering marvels, and the availability of the strongest materials available to man, we can barely create underwater vehicles that dive to the same depths — and even the ones that do, are far from safe. How do these submarines get crushed and these soft bodied fish survive?

In: 2

Answer 1

Because those fish evolved at that depth and their bodies are at the same pressure as the water at the depth. It’s not really about the pressure, it’s about the *difference* in pressures.Submarines carry humans, and since humans did NOT evolve at the depth, our bodies cannot withstand that pressure, so we need a pressure vessel that can protect us. This means the vessel has to withstand the enormous pressure *difference* between the inside, which is the same pressure as sea level because that’s where the people are, and the ambient pressure outside which dramatically increases as you descend.