Science questions after watching Sunshine film...

[Mr Whippy]

1st, the cold of space. They froze pretty quickly when they were out in the vacuum of space. I agree it's very cold, but much like 150degC jam and 150degC pastry, the thermal capacity is a big consideration shirley?
It's around absolute zero, but there is very little matter around for heat transfer from you to occur. So why would you freeze up? I just assumed that the worst part would be decompression blowing your lungs out, but after that would you be pretty happy to float around nice and warm because no matter is rubbing past your skin to steal the energy?


2nd, air, no air, eeek! Well, we say no air, but at the very end, in that HUGE chamber with the bomb, it looks like a good 400m x 400m x 400m, with maybe 50m to the roof, so a HUGE volume of air... then the actual bomb setting off chamber looks fairly big... so shirley before they lose the O2 because their garden gets burnt, that HUGE volume in the bomb chamber/room would be enough to keep a few humans going for months and months alone with no scrubbing of air.
Lets assume we have the volume of 500m x 500m x 500m... subtract the interior, 400m x 400m x 400m... multiply to get litres of air ~ 60 billion litres of air.
A human male adult breathes maybe 15 l per minute, so 4 billion minutes, or 2.8 million days... even if my numbers are out by a magnitude of 10 or 100x, there still wouldn't have been an issue as far as I can tell
BUT, does the air do weird things before it's all used up? Ie, re-mix with more CO2 and so the oxygen is spread out more so even with TONS of it left you can't breathe and survive because it's so spread out?!


Can anyone help clarify as I was pondering these a bit...!?

Cheers

Dave

[nonuts]

It's a story, happy to help

(I agree though some bits don't add up)

[Vipers]

Mr Whippy] said:

A human male adult breathes maybe 15 l per minute, so 4 billion minutes, or 2.8 million days... even if my numbers are out by a magnitude of 10 or 100x, there still wouldn't have been an issue as far as I can tell Cheers Dave

Its not the breathing rate, its the amount of oxygen we consume, at rest its about 0.5 litres per minute, for you who are involved in diving, this amount is not affect by pressure if you are in a compression chamber, on SCUBA of course, you breath out all you breath in, ie 15 lpm. So whilst you may need 15 lpm to convey the air to your lungs, your body only consumes 0.5 litres, (In a chamber, or in this case, a space ship), and produce roughly the same amount of CO2.

Provided you scrub the CO2 out of the atmosphere, that would take care of that, as they do in subs, also they have oxygen generators, how they work I have absolutely no idea.

Edited by Vipers on Tuesday 1st December 12:52

[Hugo a Gogo]

he wouldn't freeze like that so quickly in space, but he would pass out quickly from lack of oxygen

http://en.wikipedia.org/wiki/Space_exposure

(yes, I watched it too and thought it was wrong )

edit: a better sciencey-link about decompression etc

http://www.geoffreylandis.com/vacuum.html

Edited by Hugo a Gogo on Tuesday 1st December 13:19

[Vipers]

Hugo a Gogo said:

he wouldn't freeze like that so quickly in space, but he would pass out quickly from lack of oxygen

http://en.wikipedia.org/wiki/Space_exposure

(yes, I watched it too and thought it was wrong )

The inert nitrogen in the body would come out of solution, as in a diver getting a bend. That coupled with zero oxygen, would result in a quick death, no point worrying about getting cold, that comes after your brown bread, so wont be there to notice it me thinks.

Edited by Vipers on Tuesday 1st December 13:19

Edited by Vipers on Tuesday 1st December 13:30

[Hugo a Gogo]

people have (or at least one person has) survived a vacuum for about 30 seconds

[Vipers]

Hugo a Gogo said:

people have (or at least one person has) survived a vacuum for about 30 seconds

So did my budgie in my hoover sorry, just came to the forethought.

Edited by Vipers on Tuesday 1st December 13:31

[Oakey]

This is a film that could have been a very good psychological thriller but halfway through introduces a superhuman being as a villain and you're worried about a few inaccuracies regarding space?

[Hugo a Gogo]

although hoovers have injured a cockatoo....

[Vipers]

Is it me, or what, cant go back to a previous page with back arrow, have to keep loading up web site???

[Hugo a Gogo]

Oakey said:

This is a film that could have been a very good psychological thriller but halfway through introduces a superhuman being as a villain and you're worried about a few inaccuracies regarding space?

he was superhuman? what film was this?

[ewenm]

Mr Whippy said:

1st, the cold of space. They froze pretty quickly when they were out in the vacuum of space. I agree it's very cold, but much like 150degC jam and 150degC pastry, the thermal capacity is a big consideration shirley?
It's around absolute zero, but there is very little matter around for heat transfer from you to occur. So why would you freeze up? I just assumed that the worst part would be decompression blowing your lungs out, but after that would you be pretty happy to float around nice and warm because no matter is rubbing past your skin to steal the energy?

Convection isn't the only way you lose heat though. The major loss in space would be radiation - your body would radiate heat in the form of infra-red and with no infra-red to absorb from the environment you'd get cold pretty quickly.

[Hugo a Gogo]

ewenm said:

Mr Whippy said:

1st, the cold of space. They froze pretty quickly when they were out in the vacuum of space. I agree it's very cold, but much like 150degC jam and 150degC pastry, the thermal capacity is a big consideration shirley?
It's around absolute zero, but there is very little matter around for heat transfer from you to occur. So why would you freeze up? I just assumed that the worst part would be decompression blowing your lungs out, but after that would you be pretty happy to float around nice and warm because no matter is rubbing past your skin to steal the energy?

Convection isn't the only way you lose heat though. The major loss in space would be radiation - your body would radiate heat in the form of infra-red and with no infra-red to absorb from the environment you'd get cold pretty quickly.

'getting cold' and freezing solid in seconds are rather different things though

[Vipers]

Hugo a Gogo said:

'getting cold' and freezing solid in seconds are rather different things though

Agree, but lets not forget ZERO in the fridge is not ZERO in space, absolute ZERO is (In celcious) minus 273 degrees below ZERO in the fridge. And near absolute zero is what you have in spacek (Apparantly).

Whether or not you would freeze solid or not, I have no idea. But one way or another, us Ph'S will work it out.

[TJD2003]

It was of course a documentary according to the posts above not a made up story. I must have missed this bit of human history.

There quite happy with humans travelling all that way and restarting a star but not the fact that he froze too quick etc etc

Very bizarre, I enjoyed it and didn't notice any superhuman people only a spaceman who had been alone for 7 years in a dormant ship and gone completely nuts. I did notice the things pointed out above and a few others but thought to myself "don't dwell on it its not real"

Regards
TJ

Edited for spelling (because I'm not dyslectic just unable too due to being a badly behaved child once)

Edited by TJD2003 on Tuesday 1st December 13:47

[ewenm]

Hugo a Gogo said:

ewenm said:

Mr Whippy said:

1st, the cold of space. They froze pretty quickly when they were out in the vacuum of space. I agree it's very cold, but much like 150degC jam and 150degC pastry, the thermal capacity is a big consideration shirley?
It's around absolute zero, but there is very little matter around for heat transfer from you to occur. So why would you freeze up? I just assumed that the worst part would be decompression blowing your lungs out, but after that would you be pretty happy to float around nice and warm because no matter is rubbing past your skin to steal the energy?

Convection isn't the only way you lose heat though. The major loss in space would be radiation - your body would radiate heat in the form of infra-red and with no infra-red to absorb from the environment you'd get cold pretty quickly.

'getting cold' and freezing solid in seconds are rather different things though

Indeed, I was mostly pointing out that convection isn't the only method of heat loss and that radiation would be the one that you'd worry about. Didn't watch the program so no idea how realistic the freezing was, sounds like not very...

[Vipers]

Jet Morgan didnt have to contend with all this ste did he?

[Hugo a Gogo]

Vipers said:

Hugo a Gogo said:

'getting cold' and freezing solid in seconds are rather different things though

Agree, but lets not forget ZERO in the fridge is not ZERO in space, absolute ZERO is (In celcious) minus 273 degrees below ZERO in the fridge. And near absolute zero is what you have in spacek (Apparantly).

Whether or not you would freeze solid or not, I have no idea. But one way or another, us Ph'S will work it out.

no, in space you have a vacuum

a vacuum can't have a temperature

[Mr Whippy]

I worry about lots of things

When you are the questioning type, and a film sets a premise to start with at all scientific, then things do stand out.
If they set a scene where the science was hugely advanced, like Star Trek, then I'd be happier, but the do have issues that are very much issues today wrt space travel. Soooo, setting the scene, using half of them but ignoring others, and having them impact core storyline plots, does grate a little.

The stupid burnt man who runs around with almost 100% burns, well, it's a bit far fetched, but at least it's just in loo loo laa laa land. I'd prefer the film to have ignored the O2 issue and worries about freezing when doing the space jump, because you could have missed them out without issue. However, adding them in inaccurately as pivotal issues makes you notice them


Good links on decompression. I've never really understood the issue with nitrogen and decompression but those links help a great deal. So a jump into space would see you stay warm and floppy but dead from the bends pretty quickly!


Still not sure on the air issue. That bomb room place looks to have lots of air in it. I reckon you could kick around in there for ages (indeed why they didn't use that space to live/work in, and then just have a smaller back end to fly back to earth in, is beyond me)

Bah!

Dave

[Vipers]

Hugo a Gogo said:

Vipers said:

Hugo a Gogo said:

'getting cold' and freezing solid in seconds are rather different things though

Agree, but lets not forget ZERO in the fridge is not ZERO in space, absolute ZERO is (In celcious) minus 273 degrees below ZERO in the fridge. And near absolute zero is what you have in spacek (Apparantly).

Whether or not you would freeze solid or not, I have no idea. But one way or another, us Ph'S will work it out.

no, in space you have a vacuum

a vacuum can't have a temperature

Exactly, if you can't have a temperature, what is it then, ABSOLUTE ZERO, think about it, or not far from it.

To quote from a web site:-

The short answer is that the temperature in space is approximately 2.725 Kelvin. That means the universe is generally just shy of three degrees above absolute zero – the temperature at which molecules themselves stop.

Edited by Vipers on Tuesday 1st December 13:54