Question

Which discovery by astronomer Vera Rubin helped prove the existence of dark matter? Galaxies exist outside of the Milky Way. The expansion of the universe is accelerating. Galaxies spin faster than they should, based on their visible matter. Gas giants form farther from the Sun, where temperatures are cooler.

Answer 1

Galaxies spin faster than they should, based on their visible matter.

Answer 2

Answer: option c- Galaxies spin faster than they should based on visible matter.

Astronomer Vera Rubin discovered that the observed galaxies are moving with expected speeds. From Newton's law, it is expected that objects closer to the center of the galaxy move faster than the objects towards the edge. This can be seen in our solar system as well. The inner planets revolve round the sun faster than the outer planets. But, in the galaxies being observed, the edge of the galaxy is moving faster than estimated and almost equal to the region closer to center. This led to the discovery of dark matter eventually. This could only be explained by the presence of dark matter.