Thursday, December 20, 2007

Re-Entry and Vacuum-Exposure data

Did some research today, and thought you might all find it mildly interesting. Most of this is widely known in general terms, but the exact numeric specifics were knew to me...
  • An astronaut was once accidentally exposed to hard vacuum. After 14 seconds they passed out. They were repressurized and lived, with minimal injuries.
  • Had he not exhaled in the first couple seconds of exposure, he could have sustained major internal injuries. Your lungs can rupture, which propels molecules of air through your various internal tissues. This is ugly. Emptying your lungs faster than the pressure can tear them prevents this "Explosive Decompression".
  • It takes 90 seconds for your blood to start "boiling" from hard-vacuum depressurization. Boiling is a misleading term. The water in your tissues turn to vapor because the boiling point is below room temperature in total vacuum. Rather than cooking, you radiate off you heat rapidly and can actually freeze. Your tissues bloat, and some bruising occurs, especially in the eyes. It is extremely unlikely that blood will leak out your eyes like you see in film.
  • In outerspace, at high earth orbit, the side of you that's in the sun will reach 248F (120C) .At the same time, the parts of you in the shade could get as cold as -148F (-100C).
  • For comparison, the coldest parts of antarctica have a mean temperature in the winter season of -94F (-70C).
  • Adrift between the solar systems, you'd end up a the rather cold temp of 2.7 Kalvin (thats -234 Celsius) which means you're kept above absolute zero as a result of background cosmic radiation. Getting that cold would take a very long time, as your atomic motion would have to slow and the heat radiate out.
  • Re-entry subjects you to a temperature of a little over 1400 Celsius.
  • By comparison, lava flows are around 1200 Celsius, and Stratovolcano domes are around 900 Celsius.
  • I was unable to find data that indicates how long it takes a human to re-enter the atmosphere, or how long they'd be at the pinnacle of 1400 degrees.
I should list my sources. Either I am an evil supergenius who flung people and thermometers into outerspace today, or I consulted these websites:
http://www.damninteresting.com/?p=741
http://www.livescience.com/mysteries/061201_space_temperature.html
http://science.howstuffworks.com/question540.htm
http://www.antarcticconnection.com/antarctic/weather/index.shtml
http://volcano.und.edu/vwdocs/frequent_questions/grp8/question1548.html
(and a few others I forgot to bookmark)

1 comment:

rbbergstrom said...
This comment has been removed by the author.