"There are a number of critical physiological problems that would be life-ending, likely within seconds," said Peter Wagner, a physician and physiologist at the University of California, San Diego. "Forget about the fact that you donâ€™t have a parachute. You would be instantly exposed to very, very low oxygen levels. Within three or four seconds, my guess is that you would be breathing like hell."
Loss of consciousness and death would soon follow purely from oxygen deprivation to the brain, Wagner continued. At the same time, temperatures of -70 degrees Fahrenheit (-57 degrees Celsius) -- made even colder by the chill of 500 mile-per-hour (805 kilometer-per-hour) winds -- would lead to rapid freezing, beginning with the skin, eyes and other surface tissues.
In response to such extreme stress, your nervous system would go haywire, leading to potentially fatal spikes in blood pressure and heart rate. And the sudden change in air pressure would lead to a nasty case of the bends, as if you were scuba diving and came up too fast.
Then, thereâ€™s the danger of getting slammed into the plane on the way out, not to mention the trauma of falling.
"You would probably be cut in half or something, depending on what you hit and what part of the body connected," Wagner said. "All kinds of awful imagery are possible."
Fortunately, incidents like these are extremely rare.