In this universe, one can consider four different regimes of space in which distances between objects might be changing as a result of the general expansion of the universe: (1) distances between different parts of Earth, (2) distances between planets in the solar system, (3) distances between stars in the Milky Way Galaxy, and (4) distances between superclusters of galaxies. In which of these regimes are the distances changing because of the universal expansion?
A) 4 and 3
B) 4, 3, 2, and 1
C) 4, 3, and 2
D) 4 only

Question

Quizplus · Accepted Answer

The universal expansion primarily affects the largest scales of the universe, such as the distances between superclusters of galaxies. Gravitational forces within galaxies, solar systems, and certainly on the scale of planets like Earth, are strong enough to overcome the effects of universal expansion, keeping these objects bound together.

In This Universe, One Can Consider Four Different Regimes of Space