Would Would the Vacuum of Space Really Do to Us?

We have seen it in movies and TV shows, someone gets shut in an airlock. Then the outer doors open and they are sucked forcefully out into the vast openness of space. As the body is flying away, it freezes and the person dies.

Get ready. I’m about to go on another rant about how wrong Hollywood generally is.

First of all, let’s address being sucked into space when the airlock doors open. This simply wouldn’t happen. Once the doors opened, the air would rush out, and this would have an effect on the body. But it would only feel like a strong wind and for less than a second. Inertia is a law of physics that states that things tend to do nothing unless acted on by an outside force. The friction of the air would push your body, and you would begin to float towards the open door. However, the amount of force required to push a body out of the airlock at any reasonable speed just wouldn’t be there.

I laugh when the hero is holding on to something trying to not get sucked out into space. I mean where is all of this air coming from? Even if you were in a cargo hold that was very big, all of the air would leave in seconds.

Ok, so the door to the airlock is open and the air has rushed out. You are floating and slowly drifting towards the open door. What happens next?

Let’s assume that you don’t have any type of space suit, you are only dressed in your normal clothes. Would you instantly freeze? Would your eyes pop out of your head?


Your body is an enclosed system that holds itself together rather well. You wouldn’t freeze, well at least solid anyway. And you wouldn’t explode. Your eyes would stay inside your skull.

Another popular myth is that your blood would boil. This would happen but not throughout your body, I’ll explain that in a little bit.

Space is cold, about 2.7 Kelvin or -270 Celsius (-454.81 Fahrenheit). But without mass to conduct it, the heat of your body would leave slowly. Your body would lose heat through radiation which is very slow. So it would be impossible for your body to freeze instantly.

So what would happen?

At the same time that the air was leaving the airlock, the vacuum would suck the air out of your body as well. Your lungs would empty its entire volume in less time than it took to sneeze. Ouch! A couple experts have suggested that if you know you are about to be exposed to a vacuum to open your mouth and do your best not to hold it in. You would cause a lot of damage trying to hold back the inevitable.

The entire contents of your digestive tract would empty as well. Did you remember to bring an extra pair of shorts?

Because of the pressure difference, any exposed tissue (all tissue on the surface of your body) would begin to lose water. Water found in the cells at the surface of the tissue would boil, instantly evaporating. Some people fail to realize that when water boils it has a cooling effect. That is why you have to constantly add heat to water to keep it boiling. As the water at the surface of your tissue boils, that tissue will freeze. This will be most notable in your eyes and mouth, mainly because this is the exposed areas with the most water. The surface of your skin would also freeze, just not as dramatically.

As water continues to work its way out of your body, your body would begin to swell. The more moisture in that part of the body, the more it will swell. Blood vessels and capillaries near the surface of the tissue would burst because of the boiling blood. The blood wouldn’t boil through out your body because your body is still maintaining its own pressure. As the blood reaches the surface of tissue exposed to the vacuum that pressure is reduced and then the blood will boil. In case you are wondering there is a word for boiling blood, it’s ebullism. You are welcome.

Everything that I’ve describes so far would all happen in the first couple of seconds of being exposed to the vacuum. The ebullism would continue until there was no more water in your blood.

The next notable thing to happen is that you would pass out. This would generally happen at about fifteen seconds of being exposed to the vacuum. Fifteen seconds is the time it takes for blood to travel from the lungs to the brain.

Jim LeBlanc during vacuum testing

In 1965 at Johnson Space Flight Center in Texas, Jim LeBlanc was exposed to a nearly complete vacuum because of a leaky space suit. He passed out at fourteen seconds after exposure. It took another fifteen seconds to fill the chamber with breathable air. After he woke up he talked about the feeling of his saliva boiling on his tongue. “As I stumbled backwards, I could feel the saliva on my tongue starting to bubble just before I went unconscious and that’s the last thing I remember.”

Anoxia is the extreme state of hypoxia or lack of oxygen. As soon as your brain is exposed to blood free of oxygen, it’s nighty night.

In my research, I didn’t find a single account of the mess in LeBlanc’s pants.

So, you have passed out, that’s the end, right? No, not exactly.

After all of the trauma that you just went through, you are still alive. There is still a decent amount of water in your body. And that will take some time to work its way out. Your body could possibly survive for maybe another ninety seconds or more.

Back again to 1965, a study was done by NASA on chimps to learn more about how vacuums. Several Chimps were exposed to a near vacuum state for three and a half minutes. In most cases, the chimps were revived with no cognitive defects. After only a few hours, those chimps were moving around and acting normal. The study did have a couple drawbacks. One chimp suffered a heart attack and another died after at the three-minute mark of exposure.

So, it is possible, yet highly unlikely, that if you were saved and removed from the vacuum in under three minutes, you could possibly survive.

Worst. Sunburn. Ever.

The last thing that I need to mention is the sun. We would have direct exposure to the sun. On earth, the atmosphere helps protect us. With out this protection, we would get nearly instantaneous sunburn. Imagine the worst sunburn you have ever received, now multiply that by a high number. That is how bad this burn would be. The sunburn itself could be bad enough to kill us even without the other bad things that I mentioned.

At the end of it all, if we were somehow unlucky enough to end up in space, we wouldn’t be in very good shape. We would end up swollen and dehydrated with the worst sunburn you have ever seen.

Oh, did I mention that you would lose about one-third of your body weight from all of the water leaving your body? So, if you have a little extra “water weight” you were having a hard time getting rid of…

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