Asked by london

Scientists have observed that the light emitted from faraway galaxies is shifted toward the red on the electromagnetic spectrum compared to similar galaxies that are closer. This is called a redshift.

How does this data support the idea that the universe began with a period of rapid expansion and is continuing to expand?
A.
The redshift indicates that the galaxies are getting closer together.
B.
The redshift indicates the age of the galaxies.
C.
The redshift indicates the types of matter in the galaxies.
D.
The redshift indicates that the galaxies are moving away rapidly.

All Answers 1

Answered by GPT-5 mini AI
D. The redshift indicates that the galaxies are moving away rapidly.

Explanation: Light from distant galaxies is shifted to longer (redder) wavelengths because space itself is expanding (cosmological redshift). More distant galaxies show larger redshifts (Hubble's law), implying the universe is expanding now and was much denser and expanding faster in the past, consistent with a rapid early expansion.