06 Oct 07
2 edits
Originally posted by MarsanElectromagnetic waves/particles have a certain amount of potential kinetic energy and potential temperature but those attributes only become apparent when impinging on baryonic matter, ordinary stuff like hydrogen, carbon, iron, etc. In space where there is no matter to interact with, any "temperature" is only potential, its Hv content which remains undisturbed in the absence of matter, as seen by the fact that we can see galaxies ten billion light years away and that light has interacted with a considerable amount of matter yet some of it still arrives in the vicinity of the solar system even though it (the EM radiation) has interacted with plenty of atoms between here and there. In the absence of such interaction, there is no temperature measurement possible because it does not impart energy to just vacuum. That said, there is still the fundamental nature of spacetime that allows the creation and destruction of virtual particles and that is the cause of the Casimir effect, so there is a certain pressure associated with space and that might be considered to have some kind of temperature. Other than the virtual particle scene, what is there about space that COULD have a temperature? Temperature is a measure of the movement or vibration of atoms and molecules so in that sense, you remove the atoms from consideration and you have no temperature to measure since we define temperature as a vibration of atoms and molecules. So you have to look at different attributes of space to make a case for a 'temperature' measurement. I think it would still be more like a conversion factor somewhat like saying how do you relate the weight of one kilogram of matter to the pressure in a container of the stuff. That make sense?
No. Absolutely no.
This statement betrays a fundamental misunderstanding of the principles being discussed.
So in a total vacuum with zero matter, baryonic matter, how would you go about measuring temperature anyway? What technique would you use to do that? Two crossed laser beams? The Casimir effect? If you used what is normally used to detect the Casimir effect, two plates close together similar to a capacitor except you take pains to make sure there are no electrical effects, you are introducing ordinary matter which HAS a real temperature and so likely to disturb your measurement of your proported vacuum temperature so how do you propose to measure that attribute?
07 Oct 07
Originally posted by FabianFnasStick an iron pipe outside the spaceship. Stick your head outside and put your tongue on the pipe. If your tongue sticks to the pipe....it's cold. If it doesn't stick .....it isn't cold. It's simple relativity stuff.
What is the temperature of vacuum?
Let's say we want to measure the temperature of the space between the Earth and the Moon. Let's consider it is vacuum there. You go there and stick out a thermometer in the outside of the rocket.
Then, what do you measure? Of course the temp of the thermometer itself, not the actual space.
Has vacuum a temperature ...[text shortened]... No matter, no temperature?
So has vacuum a temperature, and if so, how do you measure it?
Granny.
07 Oct 07
Originally posted by smw6869Oh you are soooo low tech... there is actually a special device for this measurement using a similar process to what you just described, but is much safer for the astronauts.
Stick an iron pipe outside the spaceship. Stick your head outside and put your tongue on the pipe. If your tongue sticks to the pipe....it's cold. If it doesn't stick .....it isn't cold. It's simple relativity stuff.
Granny.
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