If we could have turned a receiver toward the heavens in hopes of observing the cosmic microwave radiation 4.5 billion years ago,at the time the solar nebula was forming,what would we have found?
A) We would have seen nothing since the CMB had not yet been created.
B) We would have seen the same blackbody curve we see now, with a peak intensity at a wavelength of about 1 mm.
C) We would have seen a blackbody curve of the same shape we see now but with a peak intensity at a wavelength shorter than 1 mm.
D) We would have seen a blackbody curve of the same shape we see now but with a peak intensity at a wavelength longer than 1 mm.

Question

Quizplus · Accepted Answer

The cosmic microwave background (CMB) radiation was created about 13.8 billion years ago, shortly after the Big Bang. Over time, as the universe expanded, the CMB has redshifted, causing its peak wavelength to increase. 4.5 billion years ago, the universe was younger, and the CMB would have had a shorter peak wavelength than it does today.

If We Could Have Turned a Receiver Toward the Heavens