关于Gravity（严重剧透，非看勿入）

搬运：imdb的faq
What would have happened if the cabin door was opened and Stone didn't have her helmet on?
She would eventually have succumbed to the rapid loss of oxygen and temperature change if the door had stayed open. As can be seen earlier when Stone and Kowalski return to their ship, the crew inside has been frozen solid due to prolonged exposure to space temperature. However, contrary to what most movies depict, a human body exposed to the vacuum of space does not blow apart or immediately flash-freeze to death.
Lots of experiments on Earth and in space and simulations with altitude chambers have given scientist a very good idea of what would happen if a person suddenly gets exposed to space without a pressurized suit. As paradoxical as it seems, the body wouldn't freeze immediately, despite a temperature well below -200 degree Celsius (-328 degree Fahrenheit). The reason is that there is no gas in space vacuum that can carry sound or absorb the heat; most body heat would disperse as radiation, which takes a while longer. So freezing to death within seconds as seen in Sunshine would not occur.
The absence of pressure would cause the gasses in our lungs and gastrointestinal tract to expand rapidly, which is why critical damage can be postponed by exhaling before the exposure. Normal air pressure on Earth keeps liquids such as water in liquid form; vacuum causes the water in the skin and muscles to vaporize and expand, causing small superficial arteries to burst and several body parts to swell. However, the human skin is resilient and will be able to withstand the internal pressure build-up, at least when one is exposed from normal pressure to a vacuum (normally a drop in pressure of 1 atmosphere). The extreme bloating from Total Recall, the excessive skin-tearing and hemorrhaging from Event Horizon or violent explosive decompression á la Outland would not happen either under such circumstances. Decompression with explosive effects would only occur with pressure drops of several atmospheres (as seen in License to Kill).
Another gas affected inside the body would be the considerable amount of nitrogen dissolved in the blood. The loss of pressure outside the body causes this gas to expand as well, and form bubbles inside the blood vessels and tissues. This occurs most often in the joints, and causes decompression sickness, also known as 'the bends' or caisson disease, which can be painful, but is rarely lethal.
Thus, exposure to space vacuum does not cause an instant death due to all the blood vessels in the head bursting all at once, as was suggested in Mission to Mars. As unbelievable as it sounds, the first 10 seconds or so in space would be uncomfortable, but you could still manage to work with full mental capacity, and attempt to take countermeasures; there is still enough oxygen in the blood to keep the brain working, as long as the blood remains circulating. After those 10 seconds, oxygen gradually stops entering the brain (hypoxia), the skin turns blue from oxygen deprivation (cyanosis) and the person would begin to lose consciousness. So the crew of the ship would have passed out long before they had felt the effects of the freezing.
Convulsions would occur due to lack of oxygen in the brain, but the heart will continue to beat for a while. All negative effects up until that point are generally reversible. It is not until an estimated one-and-a-half minutes that the vacuum would start to affect systemic blood flow, the heart stops, and freezing becomes a serious problem. If a person gets back into a pressurized enviroment with plenty of oxygen within that time frame, resuscitation is a very likely outcome with only minor injuries.
So, the depiction of the opening of the door was quite realistic; had it really occurred, Stone would probably have lost consciousness after about 10 seconds; but within the shown time-frame of re-closing the door and rapid re-pressurization, she would have awoken quickly with no ill effects expected.
Actual NASA space medicine documents confirm that an individual can/could survive up to 1 minute in a vacuum. This came up during the filming of 2001: A Space Odyssey, when Dave re-enters the emergency airlock.
As has been been said, that's all moot, since, in the film, it's a hallucination, but it is a convincing one.
(Source: http://www.damninteresting.com/outer-space-exposure/)

NASA文件证实人在真空中可存活1分钟，暴露10秒后会失去知觉。
所以克鲁尼手脚快的话女主角应该死不了。