Question: Is there a certain speed when your body can't take it?

Sam Geen answered on 17 Jun 2013:

Nope! The thing that harms us is acceleration – this is how fast you change speed. Imagine sitting in a car travelling on a motorway – you only feel something when the car changes direction or slows down or speeds up. So you can travel at whatever speed you like as long as you don’t accelerate too fast. The problem in space is that if you travel too fast you can hit particles that will do a lot of damage if you hit them at a high enough speed – and the same is true in the Earth’s atmosphere, which is why spaceships get very hot when they come back into the Earth’s atmosphere – all the atoms bump into them as they fall and heat them up.