1
vote
3answers
179 views

black body and cosmic microwave background radiation

Why is the sprectum of the cosmic microwave background radiation (or seems to be) that of a black body?
1
vote
0answers
67 views

Cosmic radiation cutoff at LOW energies?

The energy spectrum of the cosmic radiation (not CMB) is limited to both sides. I know about the GZK-cutoff at high energies. Basically the interaction probability for photons of energies above 10^20 ...