How long can a person survive in the vacuum of space?

Space, beyond the atmosphere and gravitational confines of Earth, has always fascinated humans. Since the dawn of our species, man has gazed upon the countless shining trinkets scattered amongst the deep black canvas of the Universe and pondered upon their existence and meaning. Understandably, many religious and superstitious beliefs about our planet’s canopy have sprung up all across history as we tried to make sense of what awaited us in the “great beyond”.

Now it is accessible to us, even if it is for scientists or the rich. It is difficult to meet someone who hasn’t got the desire to go up there, and float in the vast expanse of vacuum. However, Space is as oppressive as it is attractive. One can’t survive for long there without the help of a space suit. There are a number of things that make your life in space very short; from the absence of oxygen to the high-speed projectiles wandering up there.

Since there is no oxygen, which we need the most to survive, a person would lose consciousness in as little as 15 seconds. If he was to be brought back into the standard environment within two minutes or so, he can be saved.

The lack of atmosphere also means the lack of air pressure Space. The pressure is what keeps our blood and other body fluids in a liquid state, and in its absence they would ‘boil’. It would result in a rapid loss of energy, and the fluids would freeze before the evaporation. This can happen in a period of 30 seconds to 1 minute. Also, the tissues of our skin and the internal organs like heart and lungs would expand because of the boiling fluids and the expanding air. However, the tight structure of the skin would prevent itself from tearing apart. Due to the freezing of blood, its circulation would stop within a minute as well.

Notwithstanding all of the threats above, Space is crowded with various celestial particles that move at high velocities due to lack of any form of air resistance, with no apparent destination. Some are controlled by gravitational forces and orbiting certain celestial bodies. Any of them can collide with you causing fatal damage to you. Space is also filled with various types of harmful radiations emitted by the Sun and other stars. These can cause very serious damage to the body.

Then there is the temperature. The temperature in space shows an extreme range of difference which can be withstood by no human. It can range from minus 100 degree Celsius to 120 degree Celsius. All of these situations taken into account, a person can survive barely a minute or two in outer space without any kind of protective gear.

Most of these conclusions, apart from that about cosmic objects and radiation, come from studies on animals, especially dogs and chimpanzees. Experiments proved that chimpanzees can survive longer in space than dogs. Also, a few human accidents have also contributed to these findings.

So, in short, if you were suddenly thrown out to the stars you would swell, get frostbite from the cold and burns from the radiation, fall unconscious in 15 seconds because of the lack of oxygenated blood, and die within a couple of minutes due to your organs not receiving oxygen. Basically it comes down to suffocating, with a few skin anomalies thrown in for good measure.