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07-20-2009, 08:00 PM
On a TOS Star Trek episode, they find "NOMAD", a 500kg metal robot, which is in the depths of outerspace, and then transport it directly to the Enterprise.

Since space is almost absolute zero, the object would be just near 0 kelvin. Very veddy cold. That being so, would it be cold enough that Spock and J.T. Kirk should have worn their tutlenecks in the transport room?

RickJay
07-20-2009, 08:05 PM
On a TOS Star Trek episode, they find "NOMAD", a 500kg metal robot, which is in the depths of outerspace, and then transport it directly to the Enterprise.

Since space is almost absolute zero, the object would be just near 0 kelvin. Very veddy cold. That being so, would it be cold enough that Spock and J.T. Kirk should have worn their tutlenecks in the transport room?
Space isn't any temperature. Temperature is a property of matter.

An object in space might be very cold (assuming it was a long way from a star; if it was close to a star it might be quite warm) but it seems unlikely a single object could absord that much heat. You certainly would not want to touch it with your bare hands, but let me ask you this; would a block of dry ice in your bedroom make you cold? It's very cold, and presumably your bedroom's smaller than the Enterprise's cargo hold, but you probably wouldn't notice unless you were very close to it.

OldGuy
07-20-2009, 08:33 PM
The specific heat of iron is 0.449 J/gK. The specific heat of air at a constant volume is 0.718 J/gK so 1 gram of iron increasing in temperature by one (degree) Kelvin will lower the temperature of 1 gram of air by 0.625 Kelvins.

Now you just need to know the temperature of and quantity of the iron and of the air. The density of air at room temperature is 1.2 kg/m^3. A medium size room might be 50 m^3 so that would be 60 kg. If you had a 10 kg chunk of iron, the iron would rise one kelvin for each 0.104 drop in air temperature. So to get the air temperature to drop from 20 to 0. Th iron would have to increase in temperature by about 200 kelvins. So it would have to be about 73 degrees absolute.

This assumes the room is closed with no fresh air coming in. And of course it would be colder right next to the iron until the air temperature equilibrated.

I hope I've done this all correctly.

dracoi
07-20-2009, 08:42 PM
I don't think the air temperature would be much of a concern. Even if the deep-space object is very cold and even if it has enough heat capacity to cool the air down, it still takes time to do so. When I thaw a 20 lb turkey, it takes about 36 hours at room temperature... plenty of time go to get a sweater if the room gets chilly.

Chronos
07-20-2009, 09:11 PM
Space isn't any temperature. Temperature is a property of matter.One can nonetheless define the "temperature of space" as the temperature a thermometer would read in space once it came into equilibrium.

The Tao's Revenge
07-20-2009, 10:23 PM
Nomad was a computer, a very advanced computer with, judging from his abilities, an impressive power generator, with, due thermodynamics, waste heat production. Space may have a temperature but it's also a good insulator.

Nomad prolly kept himself pretty warm. For one thing he was launched in 2002 when digital convergence between CPUs and heating coils was taking place.

Dallas Jones
07-20-2009, 11:12 PM
There is no such thing as 'cold'. Cold is the absence of heat. You cannot produce or make 'cold', you can only remove heat.

Your home freezer isn't making cold, it is removing heat. Seems like the little motor is making it cold, but it's just removing heat.

Objects in space can recieve a great deal of heat in the form of radiation but without an insulating property, such as an atmosphere, the heat is quickly lost once the radiant source is removed. If the body is rotating away from the radiant source, the body itself can radiate the energy away again.

So an object can be blisteringly hot on the surface of one side but bitterly cold on the other. Like having your head in the oven and your ass in the freezer.

On the average, once you reach equilibrium, you should feel fine.

RaftPeople
07-20-2009, 11:23 PM
There is no such thing as 'cold'.

Ok, I've stricken 'cold' from my vocabulary.

Cold is the absence of heat.

Wait, you just said there is no such thing as 'cold'.

WarmNPrickly
07-20-2009, 11:51 PM
Chronos can correct me, but shouldn't an object floating in deep space be about 3K assuming it has had enough time to radiate it's heat?

Machine Elf
07-21-2009, 08:52 AM
Chronos can correct me, but shouldn't an object floating in deep space be about 3K assuming it has had enough time to radiate it's heat?

Provided it's not particularly close to a star, then yes, via radiative heat transfer it should come to equilibrium with the cosmic background radiation right around (IIRC) 4 Kelvins.

A textbook on the fundamentals of heat transfer will show how to calculate the radiative interaction between objects based on their geometry and separation, so you should be able to calculate an object's equilibrium temperature when near a star based on the star's temperature, size, and distance from the object.

It's worth noting that the space shuttle and ISS need to take steps to manage solar heating - IOW, they are quite a bit hotter than 4 Kelvins - and that's at 93M miles from the sun.

Quercus
07-21-2009, 08:53 AM
Chronos can correct me, but shouldn't an object floating in deep space be about 3K assuming it has had enough time to radiate it's heat?Yup, I was just about to point that out. (2.725 K to be precise, Captain [/Spock]). By 'deep space' we mean far enough away from a star to get negligible heat.

But for Nomad specifically, I think Tao's Revenge has a good point. There's probably a fair amount of waste heat generated by Nomad's internal workings, so equilibrium will be higher than 3K. Then, of course, the Enterprise's life support systems will be warming the cargo bay as the air cools, so while Kirk and company might feel a little chill standing right next to Nomad while it warms, they're not going to need insulated suits or anything.

Oglomott
07-21-2009, 10:09 AM
So, if you could transport a block of ice out into space, would it remain frozen?

dracoi
07-21-2009, 10:24 AM
So, if you could transport a block of ice out into space, would it remain frozen?

It depends on whether it is in strong sunlight or not. It would melt, then boil and gas off quite quickly if it had a heat source. Otherwise, it would be relatively stable. Comets, after all, are blocks of ice in space.

Baal Houtham
07-21-2009, 10:38 AM
Nomad was a computer, a very advanced computer with, judging from his abilities, an impressive power generator, with, due thermodynamics, waste heat production....

Nomad prolly kept himself pretty warm. For one thing he was launched in 2002 when digital convergence between CPUs and heating coils was taking place.

I'm pretty much scientifically illiterate, but...

Was Nomad designed for deep space operation? If so, he probably would have incorporated superconductivity to reduce his energy needs. Most of his mass might has stayed at space ambient.

And regarding the OPs question, if a 1100 lb chunk of metal that was heated to 595 F was plopped into my living room it would be uncomfortable to approach it. I imagine it would be more oppressive than the hottest and biggest fireplace or wood stove you've ever experienced.

Deep space is around -455 F, which is the same temperature differential from 70 F as 595 F is in the opposite direction. Would the discomfort level be similar?

I dinna know, Capt'n.

WarmNPrickly
07-21-2009, 10:45 AM
I never saw the episode, but if Nomad is in deep space, then presumably it is in some kind of sleep mode. It may not generate any more heat than a cell phone.

Gyrate
07-21-2009, 10:47 AM
I feel that the best policy here would be to avoid putting your tongue on it, just in case.

dracoi
07-21-2009, 10:58 AM
Deep space is around -455 F, which is the same temperature differential from 70 F as 595 F is in the opposite direction. Would the discomfort level be similar?

I dinna know, Capt'n.

This is why it's so important to realize that cold is not a quantifiable thing, but rather just a description for a relative lack of heat. It's a little like a sponge. Sponges don't "add dryness" to a spilled drink; the liquid moves into the sponge so that there's less left on your table.

Heat is transferred in three ways: radiation, convection and conduction. A very hot object radiates heat directly as infrared rays, but a cold one radiates less heat because there's less heat there to begin with. Cold is not radiated. Convection and conduction can carry heat into the cold object. This makes everything around it cooler, which is why we tend to think of cold as something that can be spread, but the actual mechanic is that heat goes into the cold object.

Quercus
07-21-2009, 11:04 AM
This is why it's so important to realize that cold is not a quantifiable thing, but rather just a description for a relative lack of heat. It's a little like a sponge. Sponges don't "add dryness" to a spilled drink; the liquid moves into the sponge so that there's less left on your table.

Heat is transferred in three ways: radiation, convection and conduction. A very hot object radiates heat directly as infrared rays, but a cold one radiates less heat because there's less heat there to begin with. Cold is not radiated. Convection and conduction can carry heat into the cold object. This makes everything around it cooler, which is why we tend to think of cold as something that can be spread, but the actual mechanic is that heat goes into the cold object.
What I think he's trying to say is that a very cold object in your room will basically just cool down the air near it (and air will swirl around so cold air will get mixed into the room). But a very hot object will not only heat up the air, but radiate infrared (and visible light) making you hotter directly. So the very hot object makes you more uncomfortable than the very cold object.

Mogle
07-21-2009, 11:06 AM
Deep space is around -455 F, which is the same temperature differential from 70 F as 595 F is in the opposite direction. Would the discomfort level be similar?

I doubt it, the reason a hot object is uncomfortable to approach is because it radiates heat, a cold object doesn't 'radiate cold' in the same way. The primary source of discomfort would be the object cooling the surrounding air. If you could somehow survive in a vacuum and remove all air from the room the hot object would still be unpleasant while cold one wouldn't bother you unless you touched it.

On preview: What dracoi said.

Chronos
07-21-2009, 12:22 PM
It's worth noting that the space shuttle and ISS need to take steps to manage solar heating - IOW, they are quite a bit hotter than 4 Kelvins - and that's at 93M miles from the sun.Forget about the Shuttle or the Space Station-- The Earth itself is in space, but in the vicinity of a star. We're (thankfully) a little bit warmer than a true blackbody would be, due to the greenhouse effect, but more or less, typical Earthlike temperatures are basically what you get for an object in space 1 AU away from a G-type star.

And a cold object could, in a sense, be said to be "radiating cold". All objects above absolute zero radiate light (mostly infrared, for things at Earthly temperatures). Right now, I'm radiating infrared to the walls of my cubicle, and the walls of my cubicle are radiating infrared to me. Since I'm at close to the same temperature as the walls of my cubicle, they're giving me close to as much energy as I'm giving them (of course, I'm a bit warmer, so I'm giving a little more than I'm getting, but it's pretty close). But if you chilled the walls of my cubicle down to almost absolute zero, I'd still be radiating the same amount of heat to them, but they'd be radiating almost none to me. The net effect would be that I'd lose energy pretty rapidly. True, there's not actually any "cold radiating from the walls to me", but it'd feel an awful lot like that, and it'd take a pretty sophisticated experiment to tell the difference.

And regarding the OPs question, if a 1100 lb chunk of metal that was heated to 595 F was plopped into my living room it would be uncomfortable to approach it. I imagine it would be more oppressive than the hottest and biggest fireplace or wood stove you've ever experienced.A fireplace or wood stove can get a fair bit hotter than that. Even just a standard kitchen oven can get up to about 500 F, and you could briefly reach your unprotected hand into the heart of your oven without harm, as long as you didn't touch anything. You wouldn't want to leave your hand in that oven, of course, as eventually it'd come into equilibrium with the oven, but it'd take a while.

Lemur866
07-21-2009, 12:51 PM
Right. Stick your hand in a 400 degree oven for a second and it feels hot, but no big deal. Touch the 400 degree steel oven rack and YEEEEEEAAAAAaaaAAAgHHHH!

Baal Houtham
07-21-2009, 01:00 PM
A fireplace or wood stove can get a fair bit hotter than that. Even just a standard kitchen oven can get up to about 500 F, and you could briefly reach your unprotected hand into the heart of your oven without harm, as long as you didn't touch anything.

True. I remember melting lead in an outdoor garbage drum, back in the days of rural trash burning.

When I proposed that it would be more oppressive than a wood burning stove, I was thinking that the surface area of a hot 500 Kg robot (or similar iron mass) would be substantially greater than the surface area of an iron stove. But it probably wouldn't be enough larger to compensate for the higher core temperature of the stove.

EdwardLost
07-21-2009, 01:06 PM
True, there's not actually any "cold radiating from the walls to me", but it'd feel an awful lot like that...

This is a good description. They would definitely feel a "chill" from Nomad as they walked around it. This would be the lack of radiation that they would have otherwise felt from the walls behind it.

Nomad would quickly ice up as water condensed onto it from the air. The ice layer would build up until an equilibrium was reached, with the surface of the layer at zero Celsius. Then the ice layer would slowly melt away until the metal was exposed again. Nomad would then continue warming from zero Celsius up to room temperature.

Quercus
07-21-2009, 02:17 PM

Nomad would quickly ice up as water condensed onto it from the air. The ice layer would build up until an equilibrium was reached, with the surface of the layer at zero Celsius. Then the ice layer would slowly melt away until the metal was exposed again. Nomad would then continue warming from zero Celsius up to room temperature.Excellent point. The Enterprise life-support probably keeps the air on the dry side, but there would still be lots of condensation. I'm not sure it would reach the point of an ice layer, as opposed to beads of water and ice, though.

EdwardLost
07-21-2009, 06:03 PM

It's true: a hot stove would radiate more heat than a section of room-temperature wall of equal area. It's also true that Nomad would be chilling the air, and the cool air would waft around the room. But even if, somehow, Kirk couldn't feel the cool air he would still be able to feel a cooling on his skin in the direction of Nomad because of its lack of radiant heat. I don't know if Nomad would gain heat faster from air convection or from radiation off Kirk and the walls; I suspect the latter.

DSYoungEsq
07-21-2009, 07:27 PM
I never saw the episode, but if Nomad is in deep space, then presumably it is in some kind of sleep mode. It may not generate any more heat than a cell phone.

Nomad has just gotten done eliminating the Malurian race, 4 billion strong. I don't think it did that in sleep mode. ;)

dracoi
07-22-2009, 12:09 PM
It's true: a hot stove would radiate more heat than a section of room-temperature wall of equal area. It's also true that Nomad would be chilling the air, and the cool air would waft around the room. But even if, somehow, Kirk couldn't feel the cool air he would still be able to feel a cooling on his skin in the direction of Nomad because of its lack of radiant heat. I don't know if Nomad would gain heat faster from air convection or from radiation off Kirk and the walls; I suspect the latter.

Radiation is usually pretty minimal as far as heat transfer goes. Even at oven temperatures, its amazing how much of a difference convection makes in cooking times.

Rigamarole
07-22-2009, 12:55 PM