What Would Happen to Your Body in Space?

With Virgin Galactic’s maiden voyage now only weeks away, you may find yourself thinking more than usual about space and specifically about you in space. Fortunately for the passengers heading up with Richard Branson they won’t actually be in space, so much as in a space shuttle that will be flying through space. In other words, they aren’t going to be exposed directly to the vacuum of space which is a good thing as well seeing as that would actually be incredibly bad for them and have devastating consequences. If you were to jump out of a space rocket with no space suit on, things would get pretty ugly pretty quickly. Here’s what would happen…


If you’ve ever seen the ending to Total Recall (the original), then you’ll probably remember scenes of Arnold Schwarzenegger having his eyes gratuitously pulled out of his skull. It’s a pretty disturbing scene on its own, but what makes it all the more unsettling is that it’s actually quite accurate. That is to say, that if you were to jump out of a rocket into space this is almost exactly what would happen to you. Ouch.

The reason for this is pressure. Because space is completely devoid of air, of particles, or of anything else (hence the name space), this means that there is very low pressure around you when you’re out there (in the film Mars is the same because it has no atmosphere). This is a bad thing because of something called ‘equalisation’ – which describes the natural tendency for particles to ‘spread out’ evenly to fill a space. That’s why you can’t build a ‘tower’ of water – it will always spread out to fill the space. It’s also why air will fill a balloon evenly rather than ‘clumping’ in particular places.

More relevant is that this equalisation is also what causes wind: air particles from a high pressure area rush to fill the area with low pressure creating movement and kinetic energy. The greater the difference in pressure between two areas, the greater the pull and force will be.

Normally your body has a higher pressure than the air around you, but fortunately that difference isn’t enough to cause any major problems. When you’re in space however, the suction from the vacuum around you will be so strong that it will actually dry you out immediately of all your fluids and even start to stretch your body and damage your softer tissue. Before you had a chance to suffocate you would be immediately freeze dried and pulled apart. The air though would be the first thing to go – immediately your lungs would be emptied causing you to pretty much black out and your bowels would follow shortly as well. Nice.


My choice of words there (‘freeze dried’) might have given you a clue as to the other thing that would happen to your body: which is that it would get pretty chilly.

As you can imagine, space is pretty cold. The reason for this is that heat requires a medium to travel through. While you rarely think of it this way, heat is actually caused by tiny movements in the surrounding particles – the heat excites the atoms in whatever it is heating and this then causes them to vibrate and eventually break away turning into steam.

Because there is no air in space, there is nothing to vibrate and so you don’t feel much heat. In fact, the temperature of space would be absolute zero. Absolute zero meaning the completely absence of any kinetic energy surrounding you and thus the absolute absence of heat. It would be, but actually it is precisely three Celsius above absolute zero (three kelvin) due to the background cosmic radiation (science fans will know that this is the ‘afterglow of creation’ – the wake of the big bang).

Interestingly this incredibly low temperature allows for something called ‘cold welding’ to occur. In other words, when two objects touch each other they bond together (as they do when you try to lick a frozen lamppost). Thus you would probably find your mouth sticking together, your limbs sticking to your body, and generally your skin welding to itself. Meanwhile your tears would instantly freeze and your saliva – which would hurt seeing as those liquids would be getting sucked out of you at the same time as painful ice crystals.

Fortunately you wouldn’t notice any of this because the freezing would occur more slowly than the sucking. You’d be dead before you were frozen. Few.


It might seem weird that in space there’s less between you and the sun, and yet you’re much colder. If that’s confusing then don’t worry – you will still feel the effects of the sun. Rather than the heat though, what you will feel is the light and the ultraviolet light responsible for causing skin cancer. On Earth we have a magnetic atmosphere with the ability to block many of these rays – no such luck in space.

Likewise you’d also be bombarded with radiation from other stars, from various ancient explosions that have occurred all over the place over the millennia and more. These are high-travelling particles known as ‘cosmic rays’. In the Fantastic Four comics they give Mr Fantastic and his family their extraordinary powers. In real life though they’re much more likely to burn your skin to a cinder and increase your risk of suffering from all kinds of diseases.

In fact, cosmic rays are also an issue for astronauts even when they’re safely inside their space suits. This is an issue that space missions have to contend with but again if you were left floating naked in space you’d hardly have time to worry about cosmic radiation due to the other problems.

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Adam Sinicki

Adam Sinicki is a full time writer who spends most of his time in the coffee shops of London. Adam has a BSc in psychology and is an amateur bodybuilder with a couple of competition wins to his name. His other interests are self improvement, general health, transhumanism and brain training. As well as writing for websites and magazines, he also runs his own sites and has published several books and apps on these topics.

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