The universe may end sooner than we thought, but don't worry, we still have 33 billion years

The end is almost, at least in cosmic terms.

The universe began with an event we call the Big Bang, about 13.8 billion years ago. Humanity has been able to understand much of what has happened since then and where the Universe is moving, but we do not know exactly how it will end. A new study suggests that space may leave much earlier than many others expected: in just 33 billion years.

It all comes down to a mysterious component of the universe called dark energy. This hypothetical substance is responsible for the current accelerated expansion of the cosmos, but depending on its true nature, it can lead to a radically different future for everything in the Universe.

The universe can expand forever and become colder and colder, eventually reaching thermal death. If this scenario is correct, the universe will exist for a huge number of years (although perhaps not as much as we originally thought). But what if the universe doesn't expand forever? Well, then it can collapse back into Big Crunch.

This idea has existed for a long time, but the discovery of the accelerated expansion of the universe made many believe that it is less likely. Initially, the Big Crunch scenario saw the universe expand, just like ours. After many billions of years, it slows down until everything starts to converge again. Now the Universe looks as if it is filled with dark energy acting as a cosmological constant of space-time. This means that the more space-time, the more dark energy. In this scenario, you never slow down the universe.

We don't know what dark energy is. Most observations believe that this is consistent with the cosmological constant within a certain error, but this may not be the case. Recently, some observational data have shown that dark energy can change. If it's not a constant, everything may be different in the future.

The scenario for the nature of this different dark energy was evaluated in a new article that is currently awaiting review. Its authors find its nature mixed: partly a cosmological constant, and partly the energy of axions, a possible particle that makes up an equally mysterious and hypothetical dark matter. Interestingly, their model of the cosmological constant is negative. Thus, despite the current accelerated expansion, the Universe will eventually change its course.

According to their model, the universe will end in 33.3 billion years in the future, so we have enough time to go before we experience the midpoint of this hypothetical scenario.

There are other ways to make the universe end. Dark energy can be more than a cosmological constant and a space-time break (Big Rip), the Big Bang and Big Crunch will be components of an infinite repeating cycle (Big Bounce), and my personal favorite, false vacuum decay, where a random quantum effect can return the end of everything without warning.