Multiple Choice
Why is the cosmic microwave background (CMB) so cold,if the early universe was so hot?
A) Enough time has passed for matter in the universe to release enough heat to cool down.
B) The CMB constantly interacts with atoms, which effectively cools down the photons.
C) The expansion of the universe has redshifted those photons to an effectively cooler temperature.
D) The Big Bang was initially hot but the CMB was released from cold material much later on.
Correct Answer:
Verified
Correct Answer:
Verified
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