Multiple Choice
When the cosmic microwave background was produced,it was a blackbody with a temperature of 4,000 K.Today,we observe it to have a temperature of 2.7 K.By approximately what factor has the Universe expanded between those two time periods?
A) 300
B) 1,000
C) 3,000
D) 7,000
Correct Answer:
Verified
Correct Answer:
Verified
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