There is a theory that gravity could pull galaxies back together, causing a reverse big bang.Which observation makes this theory less likely than the idea that the universe may continue to expand?

An accelerating expansion means that galaxies are moving apart faster over time, rather than slowing down under gravity and eventually coming back together. This observation therefore makes a reverse big bang less likely and supports the possibility that the universe will continue expanding. The correct choice is C, “The expansion of the universe is accelerating.”

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