One day you will die. In seconds or in a thousand years, it doesn't matter. Your body and all of its components will cease to function and reunite with the Earth as an ordinary, lifeless material. The Earth, too, will die, engulfed in an expanding, aging Sun. The sun will burn out all its fuel, turn into a white dwarf, then burn out and die. The Milky Way will collide with Andromeda and form a giant elliptical galaxy, which will perish, losing all its stars in intergalactic space.
The corpses of these remaining stars will die as they disintegrate into their component parts. The universe will age until all matter ends up in black holes or floats in the form of free elementary particles. These black holes will evaporate and the universe will die. Everything that was will become cold nothing, forever.
How the universe will die
This ending is one of the happiest possible, "heat death", it is also the death of heat, which at least will leave us time to say goodbye. The truth is that the Universe is much older than humans, it was long before us and will be for a long time after us, and we most likely will not have to contemplate its death. Because we are insignificant. We just have to study physics and have fun, waiting for our reunion with the Earth.
Heat death, or the "big freeze," is generally viewed as the most likely future based on what things look like today. The universe is expanding and will continue to expand. As the universe develops, stars will form less and less due to the rarefaction of dust and gas. The last black holes will slowly evaporate, losing energy during Hawking radiation, perhaps over 10 (to the power of 100) years. After a while, the remaining particles will decay, and the entire universe will assume an average temperature of almost absolute zero. The universe, in its essence, will be so large and meager that the chances of finding anything in it at all will be practically zero.
Of course, all this will not happen soon. If people survive their own desire for self-destruction, the Earth's atmosphere will survive for another billion years, and the Sun for another 7-10 billion years, after which it will become a red giant, throw out its outer layers and remain a luminous core the size of the Earth, but much heavier. This is a white dwarf. Small red stars could last for another hundred trillion years, says John Baez, a physicist at the University of California, Riverside. Perhaps people will be able to move to one of the planets near a red dwarf like Proxima Centauri in order to live out their days. These timescales are beyond human comprehension - just try to imagine how long it will take to traverse the universe at its current size if you stop and count every atom along the way.
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“This picture is probably very sad,” says Baez. "People are animals that think about the future, and we like to think of life as a story with a happy ending."
Heat death of the universe or something else?
Some of the much more eventful theoretical destinies of the universe may overtake it much earlier. For example, the Big Rip. As you know, in 1998, scientists discovered that the universe was not just expanding, but expanding faster and faster. They suggested that behind the accelerated expansion is some energy that seems inherent in the vacuum of the universe - dark energy. There is a possibility that, 100 billion years from now, dark energy will cause the universe to expand so rapidly that it will rip apart galaxies, solar systems, planets and atoms before they lose energy on their own. The space between each individual point will grow indefinitely. Theoretical physicists are betting on the thermal death of the universe, but who knows how it will actually end up - observations do not prohibit other options.
There is also a chance that the vacuum of space itself will change. Perhaps the "Higgs field" that permeates the universe and gives mass to subatomic particles is not in the lowest energy configuration. Perhaps it is "metastable" in nature and is a lower energy state to which it can decay. Imagine that you spend your entire life living on a platform and think that you are on solid ground - this platform is in a metastable state. One day this platform will collapse and show the true bottom hundreds of meters below it. The laws of physics as we know it will stop working, you will fall down and die. This can happen if the universe moves from a metastable state to a more stable one - if we have been on the platform all this time. The universe will endbecause this new, lower-energy universe will not be able to support the current Standard Model, all these particles that make up matter. It is unlikely, however, that this event will occur before heat death. But it would be beautiful.
However, not all possible cosmic outcomes are associated with devastation and emptiness. Perhaps in some distant future, the energy of the vacuum of the universe will spontaneously jump up and initiate inflation at this point in space, from which completely new universes will begin to form. Alan Guth, the MIT physicist who invented the theory of cosmic inflation, foresaw this turn of events. Maybe this is how our universe was formed. Maybe an infinite number of universes have formed in this way. Perhaps there are many places beyond the reach of our own universe that will not be affected by her demise.
Perhaps dark energy is not a constant value inherent in space. Perhaps her strength will fall, which will ultimately slow down the expansion of the universe. The force of gravity will again take over and everything will collapse with a "big crunch".
There is a lot we don’t know about the universe, so any of these ideas could be correct. Any new discovery about the nature of dark energy, the Higgs boson or space-time itself can reveal a completely different fate of the Universe, in which worlds collapse or arise, infinities intertwine and time freezes. Humanity will be doomed, regardless of whether it wants it or not.
Ilya Khel