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Analysis Space Is Cold Discussion

2piix
Topic
05:20:24 PM Sep 29th 2012
This analysis is hugely flawed. You don't need to transfer heat to change temperatures. Remember Boyle's law: temperature is proportional to heat AND pressure. If you are in a bubble of gas, and the gas suddenly disperses into space, it will get very cold very quickly.
robert
Topic
05:23:48 AM Sep 18th 2012
Removed final paragraph "It may help to consider what heat actually is: a measure of the molecular excitement in matter. There's generally not much energy to cause excitement in empty space, but also not much matter to be not-excited, or "cold". There's simply nothing in a vacuum which has a temperature, high or low, and therefore nothing which would immediately freeze you. With this in mind, we approach an approximate truth: vacuum is not a thing (it is, in fact, the opposite of "thing") and, since only things can have temperature, space is not cold and, really, cannot be cold."

The statement heat is 'measure of the molecular excitement in matter' is an example of Lies to Children. Heat isn't an intrinsic property of an object at all; it's energy transferred without doing useful work. You can't look at a one-metre pure iron cube at 300K and say how much heat it contains, because it would depend on the entire past history of the cube.

In thermodynamics, the temperature of a system is defined as inversely proportional to the the derivative of entropy with respect energy (how fast entropy, disorder, goes up when a system has more energy). It turns out this implies all the usual properties of temperature.

However, it also means things don't have to be made of matter to have a temperature. The microwave background radiation has a temperature, though it is made of microwaves, not matter, and so too does the vacuum itself.
FlipC
Topic
03:42:28 AM Jul 6th 2012
To be pedantic there are only two methods of heat transfer - conduction and radiation. Our bodies transmit heat to the air mostly via conduction which is then carried away via convection. Convection is not in itself a method of heat transfer it's a property of conduction in a fluid.
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