Physicists say that the universe is expanding. However, they hotly debate (OK, pun intended as a foreshadowing device) if the rate of expansion is sufficient to overcome gravity—called escape velocity. It may seem like an arcane topic, but the consequences are dire either way. If the rate of expansion is too low, then it will get slower and slower until expansion stops entirely, then finally, begin collapsing again in a Big Crunch. That’s bad enough. But the other possible fate of the universe is even worse.