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Name: Dana F.
Status: other
Age: 40s
Location: N/A
Country: N/A
Date: 4/29/2004


Question:
I am curious about the temperature of space between galaxies. Would it be close to, near or at 0 degrees K? >If there is no energy to heat, it should be.


Replies:
Intergalactic temperature at some point in space primarily depends upon how much radiation a probe at that location, because radiation (as opposed to convection, or conducting) is the major mechanism for transferring energy in "outer space". The amount of energy (the number and energy of individual photons) the probe absorbs and converts into heat depends of course on the absorbance/reflectivity of the probe's surface, but assume that the probe is 100% efficient in absorbing incoming photons of all energies. Then, the incident energy is the energy of the various photons times the number of photons of that given energy. If the probe is not near any other stars, galaxies, etc. that give off a lot of photons, you are correct, the temperature of the probe will by near 0 kelvins. The energy density falls decreases as R^-2 the inverse square of the distance from the photon source (assuming there are no other absorbing inter-galactic clouds and the like). If the probe is near a photon source, and the other assumptions above apply, the temperature of the probe will be higher.

Vince Calder



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