If there is a doomsday, this is it. A major aspect of cosmology and astronomy is that the universe is expanding. “Expanding” in this sense doesn’t necessarily mean that the universe it getting bigger, but that everything is accelerating away from everything else. Everything is accelerating from everything else. EVERYTHING. Planets that make up the solar system, the rocks that make up the rocky planets and asteroids, the chemicals that make up the rocks, the atoms that make up the chemicals and the fundamental particles that make up the atoms. Everything is getting farther apart, and is moving away from everything else faster and faster every second. The Big Rip hypothesis was postulated in 2003 and relies on the value of a variable, w, to determine the time the universe has left. In an example where w=-1.5, the universe has about 22 billion years left before it starts to get ripped apart. So how long do we really have? w is probably, according to the authors, closer to -1, and if w is exactly -1 the Big Rip will never happen. So, you have at least 22 billion years, and probably far longer, to worry.