Science Questions

What happens if you're exposed to the vacuum of space?

Sat, 11th Aug 2012

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Ahmed Youssef asked:

Hello, excellent show...i'm an addict.


I have a theoretical question about being exposed to outer space. if a person were to be instantly exposed to outer space, perhaps something like an astronaut opening his/her space suit while floating outside there vehicle, would the person explode first due to the lack of air pressure, or freeze first because of the lack of heat?






Dominic -   Thatís an interesting one because if you read books, what the books will often tell you is that the person will explode in the vacuum of space.  I've been thinking about this for a little while, and I'm not actually sure I quite believe that, because something you will often hear in the news is that aircrafts have depressurised at altitude.  There was a case over Australia a few years ago where a plane developed a hole when it was flying at about 40,000 ft.  and the pressure up there is only about 20% of the pressure on the surface of the Earth.  So thatís about 80% of going to the vacuum of space and everyone on the aircraft survived.  People routinely survive aircraft depressurisations. Itís quite unpleasant, but you donít explode.  So, my guess will be that you will pass out quite quickly unless you have a source of oxygen.  The air will obviously sucked out of your lungs and oxygen from your bloodstream will start to leach out into your lungs.  You'll get something very similar to bends, like divers get, and it will all be very unpleasant.  But as long as you quickly restored pressure, I think you might survive.



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the Qi answer ... RD, Sun, 12th Aug 2012

I dont know but I was just reading on Science Daily that they are thinking of treating produce with vaccuum chambers instead of chemicals to destroy bugs and things. cheryl j, Mon, 13th Aug 2012

Human skin is a pretty tough barrier, so your body won't explode.
The human body has a very high thermal inertia, so even though the skin will cool due to increased evaporation into the vacuum, your core body temperature will remain warm for some time (after all, vacuum is an excellent insulator).

Death will come by asphyxiation, with brain damage after about 4 minutes.

If you expel the air from your lungs just before exposure to vacuum, there should be minimal damage to the throat, and you would be capable of resuming breathing if air pressure were restored.

Another (comparatively minor) risk is severe sunburn - without earth's atmosphere to shield us, there would be extreme levels of ultraviolet light, and even X-Rays, if you faced the sun. evan_au, Tue, 14th Aug 2012

But what about the orifices : Qi's Stephen Fry alleges a simultaneous vomit-defecate-urinate combo when entering a vacuum.

RD, Tue, 14th Aug 2012

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