Hua Feng knew that pulsars would make up for the energy radiated by consuming their rotation energy, so their rotation would gradually slow down.

But this slowing down is so slow that the signal period can be more accurate than that of an atomic clock. The age of the pulsar can be inferred from the period, and the shorter the period, the younger the pulsar. In addition to high-speed rotation, pulsars also have an extremely strong magnetic field, electrons are emitted from the magnetic poles, and the radiation is very directional.

Since the axis of rotation of a pulsar does not coincide with its magnetic axis, the observer receives a pulse during rotation when the radiation is directed towards the observer. Pulsars are neutron stars that rotate rapidly.

Neutron stars, the cores left over from the explosion of supermassive stars to form supernovae, are very dense objects, equivalent to fitting the mass of the Sun into a sphere with a diameter of only 20 kilometers.

Neutron stars are capable of rotating hundreds of times per second, and due to their superior gravitational pull and rotational speed, neutron stars can form large "ripples" in space-time, but if their surface contains bulges or other imperfections, the "ripples" that appear in space-time will appear uneven. The surface of a neutron star is thought to be made up of a crystalline layer rich in neutron particles, a solid and hard outer layer. The atoms on the surface of a neutron star are arranged more closely than steel, and they are 10 billion times stronger than steel breakpoints.

The hard surface means that neutron stars are able to support a large number of surface uplifts – "mountains", and may be able to support some 10-centimeter-high topographic uplifts that extend several kilometers away. The study suggests that gold and other heavy metal elements may have come from the Big Bang of neutron star collisions.

A quark star is a hypothetical star. A stellar eruption leaves behind a remains, a neutron star or a black hole. But if the remains are too massive to be a black hole, and too massive to form a neutron star, a quark star is formed. Although they have not yet been observed, astronomers believe they should exist. Quark stars are actually made up of strange quark matter, so they are also called strange stars.

A black hole, a particularly dense dark object. Massive stars collapse at the end of their evolution, their matter is particularly dense, it has a closed boundary called the "event horizon", and the black hole hides a huge gravitational field, because the gravitational field is so strong that any matter, including photons (i.e., particles that make up light, with a velocity of c = 3*10^8 m/s), can only enter and cannot escape.

The creation of a black hole is similar to that of a neutron star, where the core of the star contracts rapidly under its own weight, resulting in a powerful explosion. When all the matter in the core turns into neutrons, the contraction process immediately stops and is compressed into a dense planet. But in the case of black holes, because the mass of the star's core is so large that the contraction process goes on endlessly, the neutrons themselves are crushed into powder by the attraction of the squeezing gravity itself, leaving behind a matter of unimaginably high density.

The most special thing about black holes is their "stealth", because of the curved space. Light travels in a straight line. According to the general theory of relativity, space bends under the action of a gravitational field. Figuratively understood, it seems that light was meant to go in a straight line, but the strong gravitational pull pulled it away from its original direction.

On Earth, this bending is negligible due to the small action of the gravitational field. And around a black hole, this distortion of space is very large. In this way, even if the light emitted by a star blocked by a black hole will fall into the black hole and disappear, another part of the light will pass through the curved space around the black hole and reach the Earth.

So, we can effortlessly observe the starry sky on the back side of the black hole, as if the black hole does not exist, which is the stealth of the black hole. Black holes emit dazzling light, shrink in size, and even explode. When British physicist Stephen William Hawking made this prediction in 1974, the entire scientific community was shaken. He discovered that the gravitational field around the black hole releases energy while consuming both the energy and mass of the black hole.

If a pair of positive and negative particles are created near the black hole, and one of the particles is sucked into the black hole, then the created antiparticle will be sucked into the black hole, and the positive particle will escape, since energy cannot be created out of thin air, we let the antiparticle carry negative energy, and an antiparticle being sucked into the black hole can be regarded as a positive particle carrying positive energy escaping from the black hole. Whereas, Einstein's formula E=mc^2 shows that the loss of energy leads to the loss of mass.

As the mass of the black hole gets smaller and smaller, its temperature gets higher and higher. Thus, when a black hole loses mass, its temperature and emissivity increase, and therefore its mass loss is faster. So Hawking predicted that the black hole would radiate energy at an extremely high rate until the black hole exploded.

In 1917, A. Albert Einstein used the general theory of relativity to establish a "static, infinite, unbounded" model of the universe, laying the foundation of modern cosmology.

In 1922, G.D. Friedman discovered that the universe could also be expanding and oscillating according to Einstein's field equations.

In 1927, G. Lemaître proposed a model of an expanding universe in the true sense of the word. In 1929, Hubble discovered that the redshift of a galaxy is proportional to its distance, establishing the famous Hubble's law. This discovery is a strong support for the expansion of the universe model.

In the middle of the 20th century, G. Gamov and others proposed a model of the hot Big Bang universe. The discovery of microwave background radiation in 1965 confirmed the predictions of Gamow et al. The Big Bang universe model became the standard universe model.

In 1980, Alain Guth of the United States further proposed the model of the pre-Big Bang explosion universe based on the hot Big Bang universe model, which was subsequently revised by Andre Lind.

The model consists of a brief (exponential) rapid expansion that obliterates the sky and flattens the universe, solving the event horizon problem. He proposed that at the beginning of the birth of the universe, space-time underwent a process of rapid expansion, and in the moment after the Big Bang, space-time rapidly expanded by 10^78 times in less than 10-34 seconds.

Computer Evolutionary Models in History:

In May 2014, scientists produced the most successful computer model of the evolution of the universe, simulating the birth and evolution of the universe starting with dark matter.

The computer model created this time is strikingly similar to the real universe. This computer model can be used to test theories about how the universe is structured and how it works. The results have been published in the journal Nature.

The computer model initially showed the mysterious "dark matter" scattered in the Void. Millions of years have passed, and dark matter has concentrated to plant the seeds for the creation of early galaxies. With the advent of anti-dark matter, there will be future planets and life. Black holes also have a place in the model. They inhale and exhale matter, creating a series of explosions that affect the formation of planets.

Researcher Mark Vogelsberger said the model corroborates many cosmological theories, including dark matter. "In simulations, many galaxies are very similar to galaxies in the real universe," he said. This means that our understanding of the basic workings of the universe is correct and complete. If you don't factor in dark matter, it doesn't look much like the real universe. ”

The pioneer of modern cosmology was Stephen Hawking. Stephen Hawking: "God had no place in the creation of the universe. There is no need to use "God" to press the start button for the universe. ”

Stephen Hawking advocated the use of mathematics and physics to find a unified theory, and proved that "the universe was not born by accident and does not need God", and "the mathematical model of the universe is finite and unbounded".

In his speech, Hawking said:

However, it has been discovered in the last few years that the laws of science held true even at the beginning of the universe. In that case, the universe can be self-contained and fully determined by the laws of science. The assumptions made by Hartle and I can be reformulated as follows: the boundary condition of the universe is that it has no boundaries. ”

Creation of the Universe:

At the beginning of the explosion, matter could only exist in the form of elementary particles such as neutrons, protons, electrons, photons, and neutrinos. The continuous expansion that followed the explosion caused the temperature and density to drop very quickly. As the temperature decreases and cools, atoms, nuclei, and molecules are gradually formed, and they are compounded into the usual gas. The gas gradually coalesced into nebulae, which further formed a variety of stars and galaxies that eventually formed the universe we see today.

The inflation model allows the matter and energy of the universe to be generated from nothing. The grand unification theory holds that the baryon number allows non-conservation, while the gravitational energy in the universe can be roughly negative and precisely cancels out the non-gravitational energy, with zero total energy, so it is possible for the universe to evolve from nothing.

"Nothingness" is not absolute nothingness, vacuum energy is precisely a special form of matter and energy. If it is further said that vacuum energy originates from "nothing", then this "nothing" can only be an unknown form of matter and energy. From the point of view of modern physics, a vacuum can also be considered as matter.

No matter how vast the universe is, as a finite material system, it has a history of creation, development, and demise. The inflation model holds that the forms of matter and energy in the universe are not eternal, and that "nothing" as an unknown form of matter and energy has a certain epistemological and methodological significance.

Modern cosmology is not an obscure and useless philosophical speculation, but a modern science based on astronomical observations, mathematical models, and physical experiments, which is fully capable of understanding the mysteries of the universe. Astronomers point out that the Big Bang is inevitable because the "void" is inherently unstable and can be deduced from quantum mechanics and general relativity. At the scale of quantum mechanics, space will be unstable, no longer showing smoothness and continuity, space and time will lose stability, and bubbles of space-time will be mixed, and tiny space-time bubbles can form spontaneously. Quantized space-time fluctuates, and the universe arises from the "void".

Hua Feng has his own understanding of these theoretical things, and what he has to consider at the moment is not such a macro thing, but the imminent "Doomsday Catastrophe".