What happens to your blood in space?

Answer 1

In the vacuum of space, exposed liquids will evaporate very quickly, so quickly they will bubble and boil.

This rapid evaporation will cause the blood to cool down, and it will freeze solid in minutes or even seconds.

Even after it has frozen solid, the remaining blood will continue to evaporate, but much more slowly.

If it's still in your body, however, this won't happen, because your skin acts as a sort of 'space suit' partially protecting the blood from the vacuum. Your blood will begin to evaporate and make bubbles in your blood vessels, but much more slowly than if it were exposed to vacuum directly.

But your mouth will be in vacuum, and so you will notice your saliva boiling and freezing on your tongue. You will pass out from lack of oxygen long before your blood begins to boil.

Answer 2

Liquids evaporate more easily if the pressure goes down. For example, water boils easier in Denver than in L.A. since Denver is higher and the air pressure is less. The pressure in space is very, very low and so any liquid would evaporate into a gas.

However, there is a lot of ice in space; in comets, asteroids, maybe the moon, etc. This ice may have come from previous bodies, such as an ancient planet, that broke up. The ice may have come from liquid water on this planet that froze faster than it could evaporate. I'm just making this up but it sounds plausible to me.

Answer 3

In space, the lack of gravity causes bodily fluids, including blood, to shift towards the head. This can lead to an increase in blood pressure and a decrease in red blood cell count. Astronauts may experience temporary vision changes and face a higher risk of blood clot formation.

Answer 4

Air pressure exists on the planet Earth because of the gravitational attraction of the Earth, which pulls the air downward. In space, gases can just expand to the point of zero pressure.