The end of the Universe: 3 plausible theories of a global apocalypse

The universe, according to scientists, has not always existed: it appeared sometime in the distant past and, therefore, may disappear sometime in the future. How will this happen? There are many theories about this, but the NEWS.am Tech editors have chosen the 3 most plausible of them.

Birth of the Universe: Big Bang

The current understanding of the origin of the Universe is based on the Big Bang theory, which is supported by a huge amount of observational data. According to this theory, the universe began approximately 13.8 billion years ago: all matter, energy, space and time were concentrated at one point, known as a singularity. The Universe then underwent a rapid and violent expansion known as the Big Bang, during which space itself began to expand and cool.

In the earliest times of the universe, conditions were too extreme for atoms to form. Back then, the Universe was filled with a hot, dense soup of subatomic particles such as protons, neutrons and electrons. As the Universe expanded and cooled, these particles began to combine to form the first nuclei of hydrogen and helium, and later, about 380,000 years after the Big Bang, the first atoms appeared.

As the Universe continued to expand and evolve, gravity began to pull matter into “clumps,” eventually leading to the formation of galaxies, stars, and planets. This process of cosmic evolution continued over billions of years, shaping the structure and composition of the Universe as we see it today.

The End of the Universe: The Big Rip Theory

The Big Rip theory is one of the hypothetical scenarios for the disappearance of the Universe. According to the authors of the theory, the expansion of the Universe continues at a tremendous speed, and someday it will lead to the fact that the entire Universe will be torn apart and completely destroyed. Galaxies, stars, planets and even atoms - everything will cease to exist.

The Big Rip theory is based on the idea that the expansion of the universe is not just continuing, but is accelerating thanks to a mysterious force called dark energy. Dark energy is thought to permeate all space, causing galaxies to move away from each other at increasing speeds, counteracting the force of gravity.

The timing of the Big Rip scenario, according to scientists, depends on the properties of dark energy and the rate of cosmic expansion. Some models suggest that the Big Rip could occur billions or even trillions of years from now. However, the exact timing and overall likelihood of a Big Rip remains the subject of ongoing research and debate.

Alternate Ending: The Big Freeze Theory

The Big Freeze theory is closely related to the Big Rip theory. According to it, if the Universe continues to expand, sooner or later it will reach a state of maximum entropy - a state of thermodynamic equilibrium: all the energy will be distributed evenly and there will be no useful energy left, and then the Universe will become cold and dark, and the maintenance of life or any other physical processes it will no longer be possible.

According to this theory, as the Universe expands, the energy density of space decreases. Stars burn out, galaxies move apart, matter becomes increasingly dispersed, and the universe becomes colder and darker as the energy available for heat and light decreases.

So, in the distant future, the temperature in the Universe will approach absolute zero, and the Universe will turn into a vast expanse of cold, dark space with almost zero activity. By this time, all stars will have exhausted their nuclear fuel, and no new stars will form. Black holes will evaporate due to Hawking radiation, leaving behind only elementary particles and radiation.

Reversed Expansion: The Big Crunch Theory

The Big Crunch theory is another hypothetical scenario for the fate of the Universe. Unlike the Big Rip theory, which suggests that the Universe will expand indefinitely, the Big Crunch theory suggests that the expansion of the Universe will eventually reverse - and begin a period of contraction.

According to the Big Crunch theory, the gravitational attraction between all matter in the Universe will eventually overcome the external momentum of the original Big Bang, causing the Universe to begin to contract, and galaxies, stars and other cosmic structures will begin to move closer together over time.

As the compression continues, the Universe will become denser and hotter, eventually leading to the emergence of a cosmic singularity - a point of infinite density and temperature - similar to the initial state of the Universe during the Big Bang.

The timing of the Big Crunch scenario, according to supporters of the theory, depends on various factors, including the amount and distribution of matter and energy in the Universe, as well as the rate of cosmic expansion. Some models suggest that the Universe may undergo several cycles of expansion and contraction, with each cycle ending in a Big Crunch followed by another Big Bang.