Question
Scientists know the universe is expanding because of the blue shift of distant galaxies. red shift of the brightest galaxies. blue shift of the brightest galaxies. red shift of distant galaxies.
Answer
3.7
(253 Votes)
Arabella
Veteran · Tutor for 9 years
Answer
Red shift of distant galaxies.
Explanation
## Step 1: The question asks us to identify the reason why scientists know the universe is expanding. ## Step 2: We know from the Doppler Effect that the light from galaxies moving away from us is shifted towards the red end of the spectrum. This is known as redshift. ## Step 3: Looking at the options, we can see that the correct answer should involve redshift and distant galaxies.