If I have two containers filled with very hot water(~210F) with one in outer space and one on earth, which one has a higher rate of cooling initially? Imagine the containers are single wall metal containers that are able to withstand any pressure.
Intuitively I would assume the one in space would cool faster because the average temperature of space is 3K. However a vacuum flask is an extremely good insulator since the only way heat can transfer is through radiation. Space is an even more extreme vacuum then any flask so would that mean that it "insulates" even better?
If allowed to come to thermal equilibrium, the space container would certainly lose more energy overall, but is the rate affected by the temperature difference a la Newton's Law of Cooling or does it lose energy at the same rate no matter what?