Part of the show Stars, Cosmology and the Beginning of the Universe
Tanna in Montana, US asked:
Is it true that someone's head would explode if you went out into space without a helmet on?
If you go into space, there is essentially no pressure. The pressure of any gases you have in your head at the time would expand and potentially split it apart. However, I've never done the sums to see if it could break apart bone. Your body fluids would also boil instantly and evaporate.