Everything has a beginning and an end, and the universe was born in the singularity explosion and will one day go to destruction.
But the universe is too magnificent for humans. It is hard for us to imagine how such a universe will disappear. Some scientists have proposed corresponding theories, believing that the ending of the universe will either collapse or be silence, or towards the end of the vacuum decay.
cosmic heat silence theory believes that as the high temperature in the universe continues to transfer to low temperatures, the heat in the universe will eventually reach a perfect equilibrium, and no temperature difference will appear anymore. is at the limit of entropy increase .
At this time, there will be no new stars in the universe, and space will no longer expand. The stars are destroyed one after another, and the neutron stars and white dwarf stars left behind will gradually extinguish in time, and even the ghost "black hole" in the universe will slowly evaporate due to the radiation of Hawking until it disappears completely.
The lively and shining universe has become a thing of the past, and it is now monotonous and calm. has no light emitted by stars and no heat, and has only the sky and eternal darkness. The cosmic ending like
is too desperate, and collapse theory seems to be more acceptable.
We all know that the universe originated from the singularity explosion 13.8 billion years ago. After that, relying on the energy of the explosion, it continues to expand outward to resist its own gravity. The universe is like a slowly blown balloon. The energy in is the driving force for the balloon to become larger. However, unlike balloons, the universe itself has inward gravity.
As energy is consumed, one day the outward expansion force will not be able to resist the inward gravity. eventually triggers a large squeeze of , causing the universe to collapse back to the singularity.
Compared with the first two ending methods, scientists are now paying more attention to vacuum decay.
Because whether it is heat silence or collapse, it will take at least tens of billions of years to happen, but vacuum may occur at any time. Some scientists even believe that some areas of the universe have begun the process of decay disintegration.
The universe was born in the explosion. At the beginning of its birth, it experienced a series of violent phase changes. We all know that the universe has four basic forces: gravity, electromagnetic force, strong interaction force and weak interaction force , Einstein used his entire second half of his life to try to integrate these four forces into a model, but it was not successful in the end.
In fact, these four forces were unified forces at the beginning of the birth of the universe. Scientists cannot imagine or describe what this ultimate force in the universe looks like, but they know that the force of has not existed for a long time.
As the universe gradually expands and cools down, gravity first separates from the unified force, with strong interaction forces following closely behind, and the other two forces gradually independent. Scientists can simulate the environment of the early universe through the collision of particles in current particle accelerators.
At this extremely high energy, can even combine electromagnetic force and weak interaction force into one , or reduce their separation process. After the separation of the four major forces of
, the universe developed stably and slowly, forming atomic nucleus and atom one after another. Finally, the atoms combine to form molecules, and then the stars are born and destroyed again, and cycle after cycle. Compared with the initial subtleties of the universe, the 13.8 billion years after the universe seem boring.
However, the stability of the universe seems to be just an illusion. In the initial period, every "phase change" of the universe erased the original order, established new forces and appeared new particles, replacing the original everything. We cannot be sure that this thing will not happen again, because scientists found that the vacuum is actually not stable.
Vacuum is not really empty.In the definition of physics, as long as the gaseous space with a pressure far less than 105 Pa can be called a vacuum. There is really no space without any matter in the universe. Even if all entities are removed, there are still non-matter particles such as electromagnetic wave and photon in the space. After they are removed, there is still some energy left in the space. We call "vacuum energy".
To understand the stability of the universe, we must understand the meaning of "phase change": phase change refers to the rapid and violent transformation of objects. For example, water turns from liquid to gas, or condenses into ice crystals, these processes are phase transitions. The last phase transition of the universe is when the electromagnetic force splits from a weak nuclear force.
The best way to detect the stability of the universe is to judge the mass of Higgs boson . The source of mass of Higgs boson is the basis for the formation of electron nuclear quarks. means that other particles form inertia in the Higgs boson field, and then they can have mass and build the world, and Higgs bosons are everywhere.
Quantum physics believes that the larger the mass of a particle, the more unstable it is, because large-mass particles are prone to decay into hydrogen particles. Therefore, if the mass of the Higgs boson is very small, will exist for a long time, and vice versa will decay into other matter.
Scientists observed that the Higgs boson is now between stability and instability, that is, " metastable ," It is now stable, but once some situations change, it will decay rapidly, and causes phase change in the universe.
Once the phase transition begins, it will expand to the surroundings at the speed of light. The laws of physics in which the phase transition have been completely different. It is no longer the universe we know, . The existence of the world and human beings rely on the stable natural law . After this principle is broken, everything will disappear.
This kind of disaster is different from an asteroid hitting the earth or the sun is extinguished, because both of the first two can escape to other galaxies on a spacecraft, and the vacuum decay has nowhere to escape.
However, this theory is based on the fact that the basic structure of the universe is particles. If the basic structure of the universe is a slight trembling string , everything will be completely different.
In the new study, researchers believe that under string theory , non-local effects can be used to eliminate the phase transition of the universe in the bud to avoid uncontrollable expansion. non-local effects sound a bit like quantum entanglement , referring to a string in space-time and time, which can instantly affect other strings, no matter how far they are.
Under string theory, once a phase-changing bubble appears in space-time, the non-local effect will make the edges of the bubble smooth, causing the bubble to burst and dissipate on the microscopic scale.
That is to say, even if a phase change suddenly begins in a certain place in the universe, this effect of string theory will prevent it from threatening the entire universe. However, even if the phase change really begins and string theory is wrong, we don’t have to worry.
Because the universe is so big, as long as we are far enough, may wait for humans to become extinct and decay will not reach the solar system.
