What happens to a human in open space?

When she's not daydreaming about flying through space, she's daydreaming about bats. With no air and almost zero pressure, the human body isn't going to last long without some form of protection. The first thing you would notice is the lack of air. You wouldn't lose consciousness straight away; it might take up to 15 seconds as your body uses up the remaining oxygen reserves from your bloodstream, and -- if you don't hold your breath -- you could perhaps survive for as long as two minutes without permanent injury. If you do hold your breath, the loss of external pressure would cause the gas inside your lungs to expand, which will rupture the lungs and release air into the circulatory system. The first thing to do if you ever find yourself suddenly expelled into the vacuum of space is exhale. After about 10 seconds or so, your skin and the tissue underneath will begin to swell as the water in your body starts to vaporise in the absence of atmospheric pressure. You won't balloon to the point of exploding, though, since human skin is strong enough to keep from bursting; and, if you're brought back to atmospheric pressure, your skin and tissue will return to normal. Because you will be exposed to unfiltered cosmic radiation, you can expect some nasty sunburn, and you'll probably also get a case of decompression sickness. You would not, however, freeze straight away, despite the extremely cold temperatures; heat does not leave the body quickly enough for you to freeze before you suffocate, due to the lack of both convection and conduction. If you do die in space, your body will not decompose in the normal way, since there is no oxygen. If you were near a source of heat, your body would mummify; if you were not, it would freeze. If your body was sealed in a space suit, it would decompose, but only for as long as the oxygen lasted. Whichever the condition, though, your body would last for a very, very long time without air to facilitate weathering and degradation. Your corpse could drift in the vast expanse of space for millions of years.

What would happen to a human body, suddenly pushed out to space? Imagine for example that someone is ejected from the ISS. Without any kind of protection. What would happen to that human body in the seconds/minutes after being in space?

When we go to space, what sort of effects do our bodies experience? Space is a very severe environment. On the ISS, or spacecraft that have flown into space, the force of gravity is much weaker than on the earth. As a result, many people show symptoms of "space sickness," such as headaches, nausea, and vomiting. In the low gravity of space, the information received from the vestibular organs changes. If you stay for a few days in space, your brain adjusts its interpretation of the vestibular information, so the space sickness goes away. When you go to space, gravity weakens and thus fluids are no longer pulled down, resulting in a state where fluids accumulate in the upper body. If you stay for a while in space, the fluids in your body balance out, and facial swelling typically begins to disappear after a few weeks. If you stay for a long time in space, your muscles and bones will weaken, primarily in the legs and lower back. In outer space, with no atmosphere, radiation is more intense and has major impacts on the human body. Astronauts who stay in space, where there is almost no atmosphere, are exposed to higher energy radiation than on the earth. If a person is exposed to a lot of higher energy radiation, the risk increases that they will develop diseases such as cancer. People can experience intense stress living in cramped spaces The astronauts on the ISS come from different places, including Russia, America, Canada, Europe, and Japan, so factors such as language barriers and cultural differences may also lead to stress.

Humans in space without spacesuits would not last long. An astronaut floating without a suit in space wouldn't survive, but their demise would happen within minutes, not within seconds, and it would be a gnarly exit, with boiling bodily fluids and a nearly frozen nose and mouth. In the absence of pressure, liquid water in our bodies would boil — changing immediately from a liquid to a gas. In essence, all of your body tissues that contain water will start to expand. The formation of gas bubbles in bodily fluids, known as an ebullism, also occurs in deep-water scuba divers who surface too quickly because they go from an underwater environment of high pressure to low pressure at the water's surface. No human can survive this — death is likely in less than two minutes. The vacuum of space would also pull air out of your lungs, causing you to suffocate within minutes. The continuous boiling of water would also produce a cooling effect — the evaporation of water molecules would absorb heat energy from your body and would cause the parts near your nose and mouth to nearly freeze.