Mystery Or Myth: How Will The Universe Really End – With A Crunch, A Rip, Or Eternal Silence?

We may receive a commission on purchases made from links.

Humans have long been curious about how the world will end and made numerous predictions. Alongside a collision with Halley's comet and a great flood encompassing the planet, many of these have proved wrong already. Meanwhile, one of Stephen Hawking's grim predictions for the end of the world consists of Earth turning into a giant fireball by 2600, and Neil deGrasse Tyson's grim prediction echoes that theory but with a longer time frame. Beyond that, there's also curiosity and debate about how the greater universe will end.

Among the scenarios are — what have been nicknamed — the Big Crunch, Big Rip, and Big Freeze. While the characteristics of each are vastly different, all of these theories build upon the physics and observations of the Big Bang. 9 billion years after that birth, an unknown force dubbed dark energy began to drive the cosmos' expansion, which remains one of the biggest mysteries about space that scientists can't explain.

Astronomers and cosmologists have tried to determine the expansion rate by (1) measuring increasing distances between stars and (2) mapping a weak glow in the cosmos that they believe originated when the universe was in its infancy. However, even that still remains a mystery, with scientists publishing findings in Astronomy & Astrophysics earlier this year that the cosmos is expanding faster than early models predicted.

Despite all of that, researchers estimate that the end of the universe may occur anywhere between 20 billion years and 1 sexagintaduillion years from now. With how astronomers really think the world will end, there's no guarantee humanity will still be around at that point (what a chilling thought). That doesn't make it any less interesting to explore how the cosmos could meet its own end, so let's dig into the possibilities.

Like it sounds, the Big Crunch involves the universe collapsing (crunching) in on itself. The basis of the theory revolves around dark energy running out. While its force is currently pushing everything away from each other, that force may flip when it fades, pulling everything inward until it implodes.

This scenario was first posed in 1922, when Russian physicist Alexander Friedmann (the pioneer of the Friedmann equations that explain the cosmos' expansion) showed that the universe's density will determine its destiny. Rather than remain in a constant state, his calculations demonstrated that the cosmos could expand or contract. He also showed that enough matter could result in gravity eventually making the expansion stop and forcing the cosmos to crash in on itself. Then, astronomers concluded in the 1960s and 1970s that enough matter exists for that to happen, creating either an infinitely dense state or a massive black hole.

Scientists have continued to study the possibility of the Big Crunch, but the most recent findings came in 2025 from Cornell University. Published in the Journal of Cosmology and Astroparticle Physics, research found that the universe will begin to contract in 11 billion years — like a rubber band snapping back — resulting in the end of the universe in 20 billion years. "The new data seem to indicate that the cosmological constant is negative, and that the universe will end in a big crunch," explained Horace White Professor of Physics Emeritus Henry Tye in a press release.

Also in the paper, the scientists note that a transition into a new universe can't be ruled out. If that's a possibility, has this cycle happened before? Perhaps the current universe isn't the first and won't be the last.

Essentially, the Big Rip scenario is opposite of the Big Crunch but potentially a little scarier. Rather than dark energy running out, it's based on the "what if" should dark energy grow stronger, as it's directly related to the cosmos expanding and could be the force behind it expanding faster than originally thought. However, that possibility is unsettling because, if dark energy grows to be stronger than gravity, it could end up tearing everything apart.

This scenario was first proposed in a paper published in Physical Review Letters in 2003. For the paper, scientists from Dartmouth College and the California Institute of Technology explored the possibility of dark energy being phantom energy. Considering the worst-case scenario, if the phantom-energy density exceeds all other matter, they hypothesize that the universe would expand so fast that everything within it would literally rip to shreds.

North Carolina State University assistant professor of physics and cosmologist Katie Mack explains this end-of-the-universe scenario (and others) in her book "The End of Everything: (Astrophysically Speaking)." Also, in a 2020 YouTube video, she talks about how phantom energy is one of the scarier possibilities for what dark energy is because that would mean it's dynamic and always changing, possibly "in a way that would make it so that there's more dark energy over time."

The result, Mack says, is that space between objects within galaxies and solar systems would increase — not just the space between galaxies themselves as currently observed. Eventually, the space would grow and the universe would stretch so much that "about an hour before the end, the Earth itself would explode, and then just tiny fractions of a second ... before the end, atoms themselves would be ripped apart." What that looks like is unknown, but it would be catastrophic.

Also referred to as "Heat Death," the Big Freeze is more of an agonizing drawn-out fade compared to the violent scenarios proposed above. It's related to the theory that the cosmos will continue expanding indefinitely and that entropy in relation to thermodynamics will grow until it reaches its maximum. As a result, there won't be any space left for usable heat or energy to exist, so mechanical motion will simply stop.

This scenario was first posed in the mid-1800s and studied for many decades, but a 1997 paper published in Reviews of Modern Physics unified and expanded the research. While two research groups surveyed the distant cosmos separately, they noticed that the supernovae they were studying appeared dimmer, indicating that they were farther away than before. That indicated the speed-up of the cosmos' expansion, leading two of the scientists to calculate a timeline for the future of the universe.

Because of dark energy-induced expansion, galaxies that we can see now will be too far away to see in a couple trillion years. About 100 trillion years later, scientists think new stars won't be able to form because the gas supply will be spread too thin and because black holes and white dwarfs will suck up any materials left. Googol years from now (that's the number one with 100 zeros after it), it's hypothesized that even entropy-maximizing black holes will evaporate via Hawking radiation. The Dark Era is predicted to begin after that, and no matter will remain in the cosmos, resulting in the Big Freeze.

With the universe estimated to be less than 14 billion years old, this timeline means that most of the cosmos' life will be dark, quiet, and vacant. Interestingly, the general consensus among scientists is that this Big Freeze is the most likely end to the universe.