What hypothesis outlines the idea that the universe will expand and then contract over time?

The Oscillating Universe Hypothesis articulates a cyclical model of the universe, suggesting that it undergoes a continuous process of expansion followed by contraction. According to this hypothesis, after the universe expands to a certain point, gravitational forces will cause it to collapse back in on itself, leading to a "big crunch." This cycle of expansion and contraction could theoretically repeat infinitely, hence the term "oscillating."

This idea contrasts with other hypotheses such as the Big Bang Theory, which primarily explains the origin of the universe rather than its cyclic nature. The Infinite Universe Theory posits that the universe has no boundaries and is always expanding, while the Static Universe Hypothesis suggests that the universe is unchanging over long periods, which does not align with the concept of expansion and contraction. Thus, the Oscillating Universe Hypothesis is distinguished by its emphasis on the repetitive cycle of expansion and contraction, making it the correct choice in this context.