I’m on a Star Trek kick and one question is starting to bother me (not related to the show, just space travel in general):
Upon occasion, the crew sees space junk drifting by. All well and good, but what would happen to a DEAD body if it was jettisoned out into space? Would it decompose? How? Would it burn up? Why?
Please fight my ignorance. Thank you. Live long and prosper. 
Decomposition should not occur, as the organisms responsible for that tend to require moisture and oxygen. If the body has merely been jettisoned unceremoniously out the airlock, there’s probably a good chance that over time the moisture in the corpse will sublimate out, leaving behind a mummy.
I would expect that micrometeor collisions would cause a similar degree of pitting and scuffing as would be suffered by space junk, but this would likely take a significant amount of time.
Burning up would, of course, occur only if the corpse was to plunge through an atmosphere to the surface of a planet.
If the body got a respectful burial at space, a la Spock in The Wrath of Khan, with a coffin and shroud, it should remain in pristine condition pretty much indefinitely.
Disclaimer: I am not an expert in, well, pretty much anything, nor do I play one on TV. Take these as WAGs, based on a small amount of knowledge as to that happens to dead bodies on Earth, and why.
Yes, but in the meantime, the body is relatively watertight and the gut flora population will explode following death and rot the corpse from the inside. Until it bursts open from gas pressure, after which it will begin to dehydrate rapidly.
The only thing I could add is that if the body were jettisoned in solar space, rather than in between stars, the body would bear the full brunt of that stars light, which might cook it.
Yes. Anaerobic bacteria, as you might guess from their name, don’t like oxygen and your gut is full of them, just waiting for their chance to putrefy you. Let’s use 2001’s Frank Poole, all sealed up in a space suit, as an example. I’m not sure the claim that the temperature in space is close to absolute zero has any meaning in a vacuum, but let’s move him closer to the sun than Jupiter so he stays warm. After a few months you unzip his suit and you will find an intense stink and that the suit contains a pool of Frank.
You can test this closer to home. If your Uncle Floyd’s widow paid for a well-sealed coffin, have him exhumed. Depending on the quality of the seal and how long Floyd’s been buried, you probably don’t want to do this.
Okay, to keep peace with Aunt Flora, toss a roadkill squirrel into a garbage bag, seal it up real well, and watch as the bag inflates. Rather than open it, toss it in a garbage can and bring it out front. And don’t throw anything heavy or sharp on it.
Well, while we’re in pure WAG territory, I’m figuring, just how much thermal mass does a human body have? Sooner, or not much later, the body will cool to a few degrees above absolute zero, the temperature of space, and that pretty much locks down terrestrial microbes. Yes their initial decomposition metabolism makes some heat, but the corpse is likely to lose it rapidly. I don’t think that we’re likely to have the spores of extreme thermophiles in our gut.
I guess to keep things neat you’d want to aspirate the abdominal cavity then, huh?
About how long would it take for those gut flora to reach critical pressure? Let’s not assume any particular proximity to the sun.
If it’s in orbit anywhere near Earth, we can expect its average temperature to stabilize at around Earth’s global average; say, around 4 degrees C or so.
Lose it to what, if there are no atoms around to siphon off the energy?
Radiation. Warm bodies emit largely in the infrared, which carries off energy with it.
Yeah, you’ll only get down to 3 Kelvins in the depths of the great inter-cluster voids.
And if you’re way the fuck out there, you’re probably better off dead, anyway.
Thanks. I knew I was [del]wrong[/del] not entirely right, but hadn’t figured out where.
Will it really stay that way in a vacuum? I’d think it would lose a considerable percentage of its moisture in a day or so.
Good point. Absolutely NOTHING to do with your time.
Well, the process approximates freeze drying which is frequently used nowadays to prepare specimens for taxidermy. I’m having trouble pinning down details, but apparently large specimens take several weeks to dry out.
This doesn’t sound right to me. The earth produces some heat due to to radioactive decay of things that radioactivly decay. Also sunlight reaching the earth is trapped there, you’ve no doubt read about this in the papers.
Joe Blow on the other hand would, I imagine, rapidly cool to whatever the average temp of space is at a 93 million mile remove from the sun. Would the heat produced by the various internal flora be enough to keep the core warm? It seems a bit of a long shot to me.
We need a volunteer.
Does it need to dry out? Seems to me it only need to get cold fairly quickly. As the body cools the microbes should work slower and slower.
Whew! I guess this means no one will convince an aging Arthur C. Clarke to include a resurrected Frank Poole in a 2001 sequel. Tragedy averted!
Early stages would involve ebullism (volatilisation of body fluids) bloating the body to about twice it’s normal size. This is somewhat slowed due to the containment pressure of blood vessels, and mitigated by the elastic and porous nature of tissue. Damage is likely to be accompanied by haemorrhaging from the lungs, eyes and mouth. Besides radiation, evaporative cooling would also be significant from these surfaces, potentially creating a temporary frost layer.