When I was a child I can remember wishing I could be an astronaut and go to outerspace, but as far back as I could remember I've always heard the myth/fact that if you go out in space without a space suit on you will explode?

I was wondering if this is even plausible to test, i'm not sure what kind of methods you could pursue to prove this but I always wondered if this was an old wives tale or not...

Thank you
Justin Engleka
Idaho

It's been tested... the cosmonauts of Soyuz 11 died when the spaceship depressurized prior to re-entry.

Your body may swell a little, but it does not burst. After you pass out from lack of oxygen, your blood pressure continues to fall and your blood starts to boil. Cause of death is either thrombosis, or cardiac arrest.

I seem to remember a scientific discussion about this a number of years ago and the consensus was that even if you were suddenly thrown out of an airlock in space you wouldn't explode. Most scientists thought that you would freeze so fast because of the temperature that even the swelling would be minimal.

You won't explode; you won't freeze, and your blood won't boil. The primary cause of death when being launched into space without a suit would most likely be asphyxiation, as any air in your lungs would quickly escape.

i never thought that when my astronmy teacher told me this that it would every be helpful to anyone, but at 0psi which is space you die within a minute in the frist 15 seconds you go deaf and blind as your ear drums implode and you corena pops, then your blood boils and capialers pop giving you broses all over your body and finily the nitigin in your orgins comes out literaly riping your orgins to peces, and space being -430 degrees i think you would freeze to death within the minute so does that answer your questio.

quote:

i never thought that when my astronmy teacher told me this that it would every be helpful to anyone, but at 0psi which is space you die within a minute in the frist 15 seconds you go deaf and blind as your ear drums implode and you corena pops, then your blood boils and capialers pop giving you broses all over your body and finily the nitigin in your orgins comes out literaly riping your orgins to peces, and space being -430 degrees i think you would freeze to death within the minute so does that answer your questio.

You must not have read my post; none of that happens as rapidly as you say it will. You will most likely suffocate to death before any of those things happen.

greatnt:

With all due respect, as blood pressure drops it "boils". That's the term the medical field generally uses for the gases coming out solution. They don't mean physical boiling like putting a pot of water on the stove. It's just a more severe case of "the bends".

The brain can survive (in general terms, conditions vary) for several minutes without oxygen, but after the gas bubbles form in sizeable amounts, especially in the heart's arteries and the lung's arteries, resuscitation is no longer possible -- the ateries can no longer carry blood to the lungs, the heart and the brain.

In space, this "no going back" time is usually estimated to be between 90-120 seconds... before this, administering oxygen to the victim is believed to be able to resuscitate.

The official cause of death on Soyuz 11 was "pulmonary embolism".

(Sorry, I said thrombosis, but meant embolism earlier)

quote:

With all due respect, as blood pressure drops it "boils".

That is true; however, it doesn't occur as quickly as one would think it would. It isn't quite the same conditions as a SCUBA diver rising too quickly and nitrogen bubbles forming in the blood; that's a direct result of overpressurization of gas into the blood at great depths.

I should have made myself clearer; you won't experience "the bends" immediately upon depressurization. You certainly won't explode, and you certainly won't be ripped to shreds.

It is exitus letalis, people! You will not breathe, because you will be dead at the time you usually need to have a breath. Without air pressure, ANY liquid boils, since boiling is turning to gas.
I guess, your eyes will explode, then you will start losing your blood through your eye-holes, ears, nose and mouth. Then, you will get frozen all over. It will take a second or two. The reason why you cannot freeze immediately is like that: your body's temperature is about 36,6 degrees. Absolutely cold temperature is about 273 degrees. But there is no conductor for your warm in the vacuum, and you will lose it because you will radiate it, like a little star. But you're not a star, so it takes parts of a second.

No you don't explode, your eyes to not stick out of your head, you don't instantly turn into an ice sculpture or melt nor will you instantly die from radioation.

There are no ways MB could test this without useing a living creature as far as I can see, which would be unethical if not illegal. Besides, they wouldn't need to. If you want to know anything about Space myths the first place to look is with NASA, they can tell you exactly what would happen to a human exposed to vacume/space since they've been studying that for 50+ years and (I believe) have access to some of the papers from 'experiments' the Nazis carried out during the 1940's.

Try using find, I wrote a long post on space related/exposure myths a while back-although I'm not sure if that post/thread is still around.

when i id my teacher told me about he's actually a proffesor so unless any of you are the for most experts on the matter of being in space with out a suit i really don't think you should be saying i'm wrong. what i told you is accatelly true you all seem to think that the movie event horizon was based on fact in that justin would survie only a few seconds in space with only minor problems but in reality he would be dead apon entering space as it's -430 dgrees. you can't surive in space for any length of time even seconds.

quote:

Originally posted by lander600:
when i id my teacher told me about he's actually a proffesor so unless any of you are the for most experts on the matter of being in space with out a suit i really don't think you should be saying i'm wrong. what i told you is accatelly true you all seem to think that the movie event horizon was based on fact in that justin would survie only a few seconds in space with only minor problems but in reality he would be dead apon entering space as it's -430 dgrees. you can't surive in space for any length of time even seconds.

Wrong, totally wrong.

As I said, if you want answers to a question that is related to space the FIRST and best place to look is with NASA. These guys and Girls are the experts in the field, they know what they are talking about since they have been doing this for 50 years.

They also have PhD's.

The question has been answered by them online here; http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970603.html

To quote directly from the articles first paragraph;

"How long can a human live unprotected in space?

If you don't try to hold your breath, exposure to space for half a minute or so is unlikely to produce permanent injury. Holding your breath is likely to damage your lungs, something scuba divers have to watch out for when ascending, and you'll have eardrum trouble if your Eustachian tubes are badly plugged up, but theory predicts -- and animal experiments confirm -- that otherwise, exposure to vacuum causes no immediate injury. You do not explode. Your blood does not boil. You do not freeze. You do not instantly lose consciousness."

However, the NASA Ask An Astrophysicist site does qualify their answer with "unless you go into deep shock", and then offers

For more information and references, see http://www.sff.net/people/geoffrey.landis/vacuum.html

which quotes from NASA SP-3006, Bioastronautics Data Book:

"Heart rate may rise initially, but will fall rapidly thereafter. Arterial blood pressure will also fall over a period of 30 to 60 seconds, while venous pressure rises due to distention of the venous system by gas and vapor. Venous pressure will meet or exceed arterial pressure within one minute. There will be virtually no effective circulation of blood."

The two comments renforce each other, 30 seconds or less for the average healthy human who isn't attemting to hold their breath you can survive-although you'll pass out after 14 seconds. 30-60 seconds You'll have problems, even if you get picked up. Longer than 60 seconds you've got serious problems, pray.

I guess when someone asks 'can you survive in space without a space suit?' or any variation on that, the first thing to do ask is ask 'Survive for how long?'

Sorry cybermortis, I was only referring to the "boiling" issue, wasn't trying to refute any of your other post(s). I agree with the main Goddard page that says the blood pressure probably will not drop enough so the blood actually vapourizes, but the "gas and vapour" distending the venous system that is mentioned is from the release of gases from the blood, that the medical field seems to like referring to as "boiling" in popular literature.

It's like discussing "sample sizes" between a statistician and a geologist. The terms mean different things to different people.

I think you and I (and NASA) can all agree the blood does not change from liquid to vapour. But the evidence seems to indicate that the dissolved gases will come out of solution. Maybe we should start a petition to find a new name for this?

quote:

I think you and I (and NASA) can all agree the blood does not change from liquid to vapour. But the evidence seems to indicate that the dissolved gases will come out of solution. Maybe we should start a petition to find a new name for this?

There is already a name for gas coming out of the blood at low(er) pressures. Its called 'The Bends', can happen to deep sea divers if they come up from low depths to quickly.

(And I know you were not attempting to refute what I said roof. I just thought it was worth noting that our respective posts did not contridict each other. It can be easy to miss-read things, so felt making it a little clearer might help someone who was trying to make sense of the whole thing)

Quite frankly, the Goddard page is wrong. The medical term for it is "ebullism" -- look it up. It begins to happen at 47mm pressure (about 61,000 feet altitude), when the boiling point of water is reduced to body temperature. In a vacuum, you are in the same situation that you'd be in a freeze drier. Sure, it's not a "rolling boil", and there's certainly no explosion, but your blood is boiling (changing from liquid to gas) in the capillaries in your skin. Symptoms include swelling of the skin, reduced blood circulation and breathing, bubbles in the membranes of the mouth and eyes, intense pain, hemorrhaging, and death.

Perhaps a more accurate commonplace term would be "outgassing" instead of "boiling". As your blood (and skin) outgasses, your body temperature falls (an inherent consequence of evaporation) and the blood thickens. The thickened blood ultimately clots and kills you (pulmonary embolism). You're left as a freeze-dried corpse.

The facts are simple. In a vaccuum, water in a liquid state is not stable, and human skin is not an impermeable membrane. Excluding plasma and other exotic states, water has two stable states in a vacuum: solid and gas. Ice sublimes in a vacuum rather than going through a liquid phase. Your body is not in a stable state, and the laws of physics *will* remedy this problem. Very painfully.

quote:

Quite frankly, the Goddard page is wrong..

"Since the earliest days of America’s Manned Spaceflight program, one of the foremost concerns has been that of decompressions beyond Earth’s atmosphere. Early experiments in the 1800s on laboratory animals revealed the catastrophic consequences of decompression to near-vacuum: hypoxia, decompression sickness (DCS), arterial gas embolism (AGE) and ebullism, a ‘boiling away’ of water vapor from the body, generally considered (at the time) to be almost immediately fatal. While the conditions necessary for ebullism are present at an altitude of roughly 63,000 feet (referred to as the Armstrong Line), variations in the body’s temperature and pressure can allow this to occur as low as 55,000 feet; thus, the ‘line’ is perhaps better thought of as a band."

But,

"If the external pressure drops to zero, at a blood pressure of 75 Torr the boiling point of water is 46 degrees Celsius (115 F). This is well above body temperature of 37 C (98.6 F). Blood won't boil, because the elastic pressure of the blood vessels keeps it it a pressure high enough that the body temperature is below the boiling point-- at least, until the heart stops beating"

Notice in the first quote "boiling away" is put in quotes, and is qualified "from the body"? Until blood pressure drops below 47 torr, ebullism is confined to interstitial fluids.

First quote is from Tamarack R. Czarnik, MD and is referenced therein... the second quote is again from Geoffrey A. Landis, whom NASA doesn't seem willing to refute.

That'd be fine if only the skin was a water-impermeable membrane. It's not. Neither are capillaries -- not to mention that they rupture readily. If you su ck hard enough for long enough, you can literally su ck blood through the skin. I know this from firsthand experience (playful hic key competition back in hs/college... don't ask.) This is just from a relatively weak partial vacuum created by the mouth, nothing like a hard vacuum.

Perhaps the aorta and other major vessels will resist rupture, and perhaps they won't leak when the pressure differential is increased, but capillaries most certainly will, and the skin will most certainly let it out. Even Landis states, right after you left off, "To be more pedantic, blood pressure varies depending on where in the body it is measured, so the above statement should be understood as a generalization". True indeed. The venous pressure is lower than the measured arterial pressure.

However, Landis's page is way, way off on a lot of things. Take this for example:

quote:

But in a practical sense, space doesn't really have a temperature-- you can't measure a temperature on a vacuum, something that isn't there. The residual molecules that do exist aren't enough to have much of any effect. Space isn't "cold," it isn't "hot", it really isn't anything.

What space is, though, is a very good insulator. (In fact, vacuum is the secret behind thermos bottles.) Astronauts tend to have more problem with overheating than keeping warm.

If you were exposed to space without a spacesuit, your skin would most feel slightly cool, due to water evaporating off you skin, leading to a small amount of evaporative cooling. But you wouldn't freeze solid!

First off, while space doesn't "have a temperature", and there's no convection there, there is *most certainly* thermal radiation. The body is constantly losing a tremendous amount of energy to thermal radiation, thanks to Stefan-Boltzmann law. That is, to say, the emissivity times 5.670400e-8 times the temperature in kelvins to the fourth power, i.e., for something at 37C with an emissivity of .85, ~445W, about the energy of a household stove burner on medium heat. To put it another way, that's over 9,000 food calories per day. The only reason we're not constantly freezing is that we're also constantly *receiving* radiated infrared at just a little cooler temperature than us. In space, if you're shielded from the sun, you're mostly exchanging heat with the cosmic microwave background, just over absolute zero. I.e., you're losing heat at an almost unthinkable rate, far faster than your body can restore it. Let's say you've got a net loss of 300 watts. The specific heat capacity of the body is about 3.5kJ/kg*C, so a 60kg astronaut has a specific heat of 210kJ/C, or 58.33 Wh/C. Mild hypothermia would occur in minutes. Death from hypothermia (body temp around 32C) would occur in an hour.

But that's not the real problem.

Skin gives up water readily; cover yourself in a desiccant on your skin if you disagree Skin is water and gas permeable. In a vacuum, this means very rapid dessication through evaporation. Rapid evaporation of moisture means rapid cooling. With the rupture of capillaries, there's an extra source of moisture loss. I can do the math on this if you want, but I assure you, it's much faster. And this ignores the huge surface area that is the lungs, which is *designed* to exchange gasses between your blood and the outside world

Back to his commentary about blood pressure. His own page contradicts what he just states and his calculations. Remember what he wrote about blood pressure, using normal blood pressure values? From near the top:

"Arterial blood pressure will also fall over a period of 30 to 60 seconds, while venous pressure rises due to distention of the venous system by gas and vapor. Venous pressure will meet or exceed arterial pressure within one minute. There will be virtually no effective circulation of blood. After an initial rush of gas from the lungs during decompression, gas and water vapor will continue to flow outward through the airways. This continual evaporation of water will cool the mouth and nose to near-freezing temperatures; the remainder of the body will also become cooled, but more slowly."

In short, everything he writes later is completely contradicted by his very first reference. Blood pressure in a vacuum is *not* 75 torr, gas and vapor *does* form in the bloodstream, there is virtually no effective circulation of blood (so the heart's capability to keep pressure up is gone), and the body rapidly cools.

The facts are simple: your blood *does* boil, and your body rapidly cools. However, it's not some dramatic rolling boil -- it's more appropriately seen as outgassing. Death occurs when the blood gets thin enough that clots form.

Karen:

Thanks for putting such effort into smacking me upside the head.

My typing rarely keeps up with my mind. I know that NASA experiments (and accidents) show that blood pressure will fall. I also know that even in full atmosphere, the blood pressure actually at the capillaries can be as low as 15 torr at the venous end.

Hence NASA's contention/observation that vapour and gas forms venously.

I was only trying to point out (poorly, obviously) that the ebullism (at least in regards to large veins and arteries) isn't instantaneous -- the pressure needs to drop.

I gave Landis the benefit of the doubt, and assumed his "blood won't boil" argument based on 75 torr, was meant to mean "won't instantaneously boil on exposure to vacuum" since, as you pointed out, he'd already quoted NASA as saying the pressure will fall and gas will form.

And, although your points about radiative effects are well meant, it's somewhat pointless to point out you'll start to suffer hypothermia in minutes and die within an hour, when the window for cardiac arrest/pulmonary embolism is 90 seconds to 2 minutes.