Final answer:
The Doppler effect indicates that the universe is expanding, which is a key support for the Big Bang theory. This expansion is observable as the red shift of light from distant galaxies.
Step-by-step explanation:
The Doppler effect supports the Big Bang theory by showing that the universe is expanding. This is evidenced by the red shift observed in the light from distant galaxies, which indicates they are moving away from us. Edwin Hubble's discoveries in the 1920s demonstrated that these galaxies had a red shift in their hydrogen spectra that is proportional to their distance from the Milky Way, leading to the conclusion that the universe is not only expanding but also much larger than previously thought.
Thus, the correct answer to the student's question is that the Doppler effect supports the Big Bang theory by showing that the universe is expanding (option 1). Neither the size of the universe, the location of the Earth at the center of the universe, the formation of planets by accretion, nor the rate of passage of time relative to an object's velocity is directly addressed by the Doppler effect in this context.