According to the Big Bang model of cosmology, the universe has been expanding since some initial time (call it t = 0) when the temperature was infinite. At early times, the temperature T scales as t^1/2 . The current temperature is about 3K. Consider the part of space which corresponds to the currently visible universe. It is about 10^10Mpc. Consider a proton confined to this part of space. Assuming that the proton is an elementary particle, then at what temperature does the momentum uncertainty become so large that we cannot tell if there is one photon in the volume or more than one?
delta x*delta p being greater than or equal to h/4pi
The Attempt at a Solution
I could not quite figure out how to move forwards after the initial formula. There does not seem to be any values for x, p or h I can insert to gain some values.