[ot] blood in space

[wighair]

i saw some film in which blood was floating round in zero g in big red squishy spheres. fair enough, nice effect. However, this got me thinking about blood in space and the different colours blood goes depending on the amount of oxygen in it (ie. red arteries, blue veins). So, as there is no oxygen in space, if you got wounded in space and the blood splattered outside your suite what would happen?

red spheres?

blue spheres?

crusty brown lumps? - I heard that in a vacuum the thing that kills you first is the moisture leaving from mouth/nose/bum etc.

Does anyone know what that correct answer is?

 

[Desdichado]

I don't know the answer, but would they movie have been Star Trek VI by any chance?

 

[Marius Delphus]

Okay, my Outer Space Physics and Human Biology are a little rusty, so anyone who knows better should feel free to step in any time.

First, let's talk about zero-g, or "microgravity" as it's referred to while in orbit. Liquids exposed to microgravity environments do tend to collect in spheroid shapes and float around, as film showing astronauts having fun with their Tang (or whatever ) proves. We don't fully understand the ramifications of spending extended periods in microgravity, but we have a number of good guesses.

http://spacelink.nasa.gov/products/Space.Food.and.Nutrition/microgravity.html (the text, not the pic)
http://www.space.edu/projects/book/chapter31.html

Second, blood takes its color from the oxygen incorporated into it; the level of atmospheric oxygen doesn't change the color of blood. Blood changes color to "crusty brown" as it *dries.*

http://www.madsci.org/posts/archives/dec96/839903302.An.r.html
http://www.seps.org/oracle/oracle.archive/Life_Science.Anatomy/2001.02/000981693349.24712.html

Third, the primary hazard to an exposed human body in outer space is the zero atmospheric pressure ("hard vacuum"), after which follows the ultra-cold {EDIT - extreme} temperature and, if the unfortunate soul somehow survives *those* two hazards, there's often a hefty dose of hard radiation to deal with.

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970603.html

So to answer the question we leave aside the fact that a spacesuited character in hard vacuum is facing a serious and quickly lethal emergency if the suit is punctured (venting the suit's air and pressure into space) and the character is bleeding (venting blood into space).

So the color of the blood will vary between dark red, venous blood and bright red, arterial blood depending on what's been punctured. Assuming our poor victim is in a hard vacuum + microgravity environment, the blood will most likely spray forth from the suit (remember, blood is under pressure) and collect in large droplets. If we now assume our hapless astronaut is in the cold of outer space, I'm inclined to guess the droplets will freeze rather quickly, but that may {EDIT - does} depend on how much radiant heat is available from the nearest star.

 

[Emiricol]

depends on whether the cells died before freezing or after. If after, it could still be oxygenated, and thus red.

Also, dying in space would really really suck, because first the blood boils - all that pressure in a zero-pressure environment... (*shudder*)

 

[BlackRazor]

Deep space blood

I would go for little red frozed sphere.

Outter space temperature is nearly absolute zero and the first thig that get damaged in an unplanified EVA is your lung because the air in them is violently sucked out.

If skin is exposed, it freeze almost instantly and blister like craked parchment because of the exploding skin cells (since the water in your cells take more volume frozen than when liquid, the cellular membrane break,killing the cell)

Realisticly, exposure to deep space is simply lethal. If you want to make a good roleplaying moment out of it however, look at the movie named Event Horizon. One of the scene have a poor fellow go for a walk in space without a suit and you can see a fairly good rendition of the damage a body could suffer from a lethal dose of the void.

- The void, where star sing...

 

[Emiricol]

Ouch

 

[Brisk-sg]

Third, the primary hazard to an exposed human body in outer space is the zero atmospheric pressure ("hard vacuum"), after which follows the ultra-cold temperature and, if the unfortunate soul somehow survives *those* two hazards, there's often a hefty dose of hard radiation to deal with.

I just want to point out that space has no temperature, and the temperature of objects in that space will very based on proximity to energy sources such as the sun.

Contrary to popular belief, liquid (such as blood) will often change states (evaporate into gaseous form) if lost into space, assuming proximity to sun equivalent to earth's orbit to the sun. If in deep space or the shadow of a planet, it would freeze.

So if the blood was lost in space, with a line of sight to a sun it would likely evaporate due to the large water content.

-Josh

 

[Marius Delphus]

Thanks for the clarification Brisk {EDIT - and Meepo}! This is the reason these boards are great even for off-topic questions... almost guaranteed to hit someone more knowledgeable.

 

[MeepoTheMighty]

I just want to point out that space has no temperature, and the temperature of objects in that space will very based on proximity to energy sources such as the sun.

Contrary to popular belief, liquid (such as blood) will often change states (evaporate into gaseous form) if lost into space, assuming proximity to sun equivalent to earth's orbit to the sun. If in deep space or the shadow of a planet, it would freeze.

So if the blood was lost in space, with a line of sight to a sun it would likely evaporate due to the large water content.

-Josh

That's not entirely true, space has a temperature of around 2.7 K due to background microwave radiation. Still, you're correct, the main factor to be concerned about would be the proximity of other sources of heat.

Nasa has an interesting page on the human body in space:
http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970603.html

 

[Kamard]

The Straight Dope just talked about this the other day, though it was in regards to urine freezing in the presence of "space".