Three Ways To Destroy The Universe

The Universe’s Inevitable Demise

One day, the universe will cease to exist. But what are the reasons behind this? How will it happen? Will the universe be dead forever? How do we know all this? To answer these questions, we must first understand that the universe is expanding. Moreover, the rate of its expansion is accelerating due to a strange phenomenon that scientists believe permeates the universe: dark energy.

Understanding Dark Energy

Until 1998, we thought that the universe must work a bit like a ball that you throw into the sky. The ball moves up, but at some point, it has to come down again. However, the expansion of the universe is actually speeding up. This is akin to throwing a ball up and watching it fly away faster and faster. The source of this acceleration is unknown, but we refer to it as “dark energy”. Albert Einstein first conceived of this concept, later dismissing it as foolish. However, modern astrophysicists have deemed it plausible. Despite this, our understanding of dark energy remains largely theoretical, and its properties are still unknown. Various theories about dark energy lead us to three possible scenarios for the end of the universe: the Big Rip, Heat Death or Big Freeze, and the Big Crunch and Big Bounce.

The Big Rip Scenario

Since its birth, the universe has been expanding, creating new spaces everywhere equally. The space between galaxies expands, causing them to move apart. The space inside galaxies also expands, but gravity is strong enough to keep them together. In the Big Rip scenario, the expansion accelerates to a point where space expands so fast that gravity can’t compensate for this effect anymore. The result is a Big Rip. Large structures like galaxies are torn apart first, followed by black holes, stars, and planets. Eventually, space would expand faster than the speed of light, causing atoms to disband. Once space is expanding faster than light, no particle in the universe can interact with any other particle. The universe would dissolve into countless lonely particles that won’t be able to touch anything else in a strange, timeless universe.

Heat Death or Big Freeze Scenario

The difference between the Big Rip and heat death is that in a heat death scenario, matter stays intact and is converted over an incredibly long but finite period of time into radiation, while the universe expands forever. This process is driven by entropy, the tendency of every system to move towards the state of highest entropy. As the universe expands, matter slowly decays and spreads out. After many generations of stars, all the gas clouds necessary to form stars will be exhausted, and the universe will turn dark. The remaining suns will die, and black holes will slowly degenerate and evaporate over trillions of years due to what’s known as Hawking radiation. When this process is complete, only a dilute gas of photons and light particles remains, until even this decays. All activity in the universe ceases at this point; entropy is at its maximum and the universe is dead forever. However, theoretically, after an incredibly long amount of time, there might be a spontaneous entropy decrease as a result of something called “quantum tunneling”, leading to a new Big Bang.

Big Crunch and Big Bounce Scenario

This is the most uplifting scenario. If there is less dark energy than we think or it decreases over time, gravity will become the dominating force in the universe. In a few trillion years, the rate of expansion of the universe will slow down and stop. After that, it reverses. Galaxies will race at each other, merging as the universe becomes smaller and smaller. A smaller universe also means a hotter universe, so temperatures rise everywhere all at once. One hundred thousand years before the Big Crunch, background radiation would be hotter than the surfaces of most stars, which means that they would be cooked from the outside. Minutes before the Big Crunch happens, atom cores are ripped apart, before supermassive black holes devour everything. Finally, all black holes would merge into a supermassive mega-black hole that contains the entire mass of the universe, and in the last moment before the Big Crunch, it would devour the universe, including itself. The Big Bounce theory states that this has happened a lot of times and that the universe goes through an infinite cycle of expansion and contraction.

Conclusion

So what will actually happen to the universe in the end? At the moment, heat death seems the most likely, but we at Kurzgesagt hope that this “dead forever” stuff is wrong and the universe will start over and over again. We don’t know for sure either way, so let’s just assume the most uplifting theory is true.