Can humans survive cosmic radiation?
If the amount of radiation is low enough, yes. But realize that it’s cumulative. Over time, radiation will do irreparable damage to human DNA, and will cause it to malfunction. Humans evolved in a low cosmic radiation environment, so they don’t have many natural defenses or repair mechanisms for this sort of damage.
Yes, they can, and we do. Cosmic Radiation is not the same as Solar Radiation or Solar storms, which you may be thinking of. In cosmology, the cosmic microwave background radiation is a form of electromagnetic radiation discovered in 1965 that fills the entire universe. The cosmic microwave background radiation and the cosmological red shift are together regarded as the best available evidence for the Big Bang (BB) theory.