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.
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.
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.
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.
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.
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.
Create an interactive timeline that outlines the key events and stages of the universe’s potential demise. Use online tools like Tiki-Toki or Prezi to make your timeline visually engaging. Include descriptions and images for each stage, such as the Big Rip, Heat Death, and Big Crunch. This will help you understand the sequence and impact of each scenario.
Participate in a classroom debate where you are assigned one of the three scenarios: Big Rip, Heat Death, or Big Crunch. Research your assigned scenario in detail and prepare arguments to support why it is the most plausible outcome. This activity will enhance your critical thinking and public speaking skills while deepening your understanding of dark energy and the universe’s expansion.
Use a balloon and markers to model the expansion of the universe. Draw galaxies on the surface of the balloon, then slowly inflate it to observe how the galaxies move apart. This hands-on activity will help you visualize how the universe’s expansion affects the distance between galaxies and understand the concept of dark energy.
Conduct a research project on dark energy, exploring its discovery, properties, and the role it plays in the universe’s expansion. Present your findings in a detailed report or a multimedia presentation. This project will allow you to delve deeper into the mysterious force driving the universe’s acceleration and its implications for the future.
Write a short story or a creative essay imagining life in the final moments of one of the universe’s end scenarios. Describe the environment, the experiences of any remaining life forms, and the emotional impact of the universe’s demise. This activity will encourage you to think creatively and empathetically about the scientific concepts discussed in the article.
inevitable – certain to happen; unavoidable – It was inevitable that she would forget about the meeting with the busy schedule she had.
universe – all existing matter and space considered as a whole; the cosmos – Scientists are still studying the vastness of the universe to uncover its mysteries.
reasons – a cause, explanation, or justification for an action or event – She listed several reasons why she couldn’t attend the party.
dead – no longer alive; lifeless – The flowers in the garden were dead after the severe frost.
forever – for all future time; for always – They promised to love each other forever.
dark energy – a theoretical form of energy that is thought to permeate all of space and accelerate the expansion of the universe – Dark energy is believed to be responsible for the current acceleration in the expansion of the universe.
expanding – growing larger or spreading out – The company’s success led to the expanding of their operations worldwide.
acceleration – the rate at which an object changes its velocity over time – The car’s acceleration was impressive as it went from 0 to 60 mph in just a few seconds.
theories – a supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained – The theory of relativity revolutionized the field of physics.
scenarios – possible situations or sequences of events – The team discussed various scenarios before deciding on the best course of action.
