Cosmologists not only think about the birth of the universe, but also about
its death. The latest theory about the end of it all is called the Big Rip.
In this scenario, around 22 billion years in the future, dark energy, which
turns gravity into a repulsive force, tears everything apart. From the
account in Science News: “A half hour before the end, Earth itself would
fall apart. Finally, one ten-thousandth of a femtosecond before the Big
Rip, molecules and atoms would break up…” [Note: a femtosecond is
one-thousandth of one-trillionth of a second.] Something more to worry
about.