5 life cycles of the Universe: what stage are we living in?

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

Every living thing on our planet is born, matures, gets older and eventually dies. All these laws also apply outside the Earth - stars, solar systems and galaxies also perish over time.

The difference exists only in time - what for you and me seems like eternity, by the standards of the Universe, is complete nonsense. But what about the universe itself? As you know, she was born after the Big Bang 13, 8 billion years ago, but what is happening to her now? What is the life cycle of the Universe itself and why do researchers distinguish five stages of its development?

Five centuries of the universe

Astronomers believe that five stages of evolution are a convenient way to represent the incredibly long life of the universe. Agree, at a time when we know only 5% of the visible Universe (the remaining 95% is occupied by mysterious dark matter, the existence of which has yet to be proven), it is rather difficult to judge its evolution. Nevertheless, researchers are trying to understand the past and present of the Universe by combining the achievements of science and human thought of the last two centuries.

If you are lucky enough to find yourself under a clear sky in a dark place on a moonless night, then when you look up, a magnificent space landscape awaits you. With ordinary binoculars, you can see a mind-boggling skyline of stars and specks of light that overlap. Light from these stars reaches our planet overcoming huge cosmic distances and makes its way to our eyes through space-time. This is the universe of the cosmological era in which we live. It's called the stellar era, but there are four others.

There are many ways to view and discuss the past, present and future of the universe, but one of them has attracted the attention of astronomers more than others. The first book about five centuries of the Universe was published in 1999, entitled "Five Ages of the Universe: Inside the Physics of Eternity." (last updated in 2013). The authors of the book, Fred Adams and Gregory Laughlin, gave a title to each of the five centuries:

• Primitive era
• Starry era
• Degenerative era
• Era of Black Holes
• Dark era

It should be noted that not all scientists are supporters of this theory. Nonetheless, many astronomers find the five-step division a useful way to discuss such an unusually large amount of time.

Primitive era

The primitive era of the universe began a second after the Big Bang. During the first, very small period of time, space-time and the laws of physics, as the researchers believe, did not yet exist. This strange, incomprehensible interval is called the Planck era, it is believed that it lasted 1044 seconds. It is also important to take into account that many of the assumptions about the Planck era are based on a hybrid of general relativity and quantum theories, called the theory of quantum gravity.

In the first second after the Big Bang, inflation began - an incredibly rapid expansion of the universe. After a few minutes, the plasma began to cool, and subatomic particles began to form and stick together. 20 minutes after the Big Bang - in a super-hot, thermonuclear universe - atoms began to form. Cooling went on at a rapid pace until 75% hydrogen and 25% helium were left in the universe, which is similar to what is happening on the Sun today. About 380,000 years after the Big Bang, the universe cooled so much that the first stable atoms began to form and the cosmic background microwave radiation appeared, which astronomers call the cosmic microwave background radiation.

Starry era

You and I live in a stellar era - at this time, most of the matter that exists in the Universe takes the form of stars and galaxies. The first stars in the universe - we recently told you about its discovery - were huge and ended their lives in the form of supernovae, which led to the formation of many other, smaller stars. Driven by the force of gravity, they approached each other to form galaxies.

One of the axioms of the stellar era is that the larger the star, the faster it burns off its energy and then dies, usually in just a couple of million years. Smaller stars that consume energy more slowly stay active longer. Scientists predict that our Milky Way galaxy, for example, will collide and merge with the neighboring Andromeda galaxy in about 4 billion years to form a new one. By the way, our solar system can survive this merger, but it is possible that the sun will die much earlier.

The era of degeneration

This is followed by the era of degeneration (degeneration), which will begin about 1 quintillion years after the Big Bang and will last up to 1 duodecillion after it. During this period, all the remnants of stars visible today will dominate the Universe. In fact, space is full of dim light sources: white dwarfs, brown dwarfs and neutron stars. These stars are much colder and emit less light. Thus, in the era of degeneration, the universe will be deprived of light in the visible spectrum.

During this era, small brown dwarfs will hold on to most of the available hydrogen, and black holes will grow, grow, and grow, feeding on the remains of stars. When there is not enough hydrogen around, the universe will become dimmer and colder over time. Then the protons that have existed from the very beginning of the Universe will begin to die, dissolving matter. As a result, most of the subatomic particles, Hawking radiation and black holes will remain in the universe.

Hawking radiation is a hypothetical process of emission by a black hole of various elementary particles, mainly photons; named after British theoretical physicist Stephen Hawking.

The era of black holes

For a significant period of time, black holes will dominate the universe, drawing in the remnants of mass and energy. However, they will eventually evaporate, albeit very slowly.

The authors of the book believe, according to Big Think, that when the black holes finally evaporate, there will be a small flash of light - the only remaining energy in the universe. At this point, the universe will be almost history, containing only low-energy, very weak subatomic particles and photons.

Dark era

Eventually, electrons and positrons drifting through space will collide with each other, sometimes forming proitronium atoms. These structures are unstable, however, their constituent particles will eventually be destroyed. Further destruction of other low-energy particles will continue, albeit very slowly. But tonight look into the night sky full of stars and do not worry about anything - they will not go anywhere for a very long time, and our understanding of the Universe and time may change in the future.