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Viewpoint presentation process
How can people speculate that there may be a big explosion? It depends on astronomical observation and research. Our sun is just one of the120 billion stars in the Milky Way. Such as our Milky Way, extrasolar galaxies and Qian Qian. From the observation, it is found that those distant galaxies are leaving us. The farther away galaxies are, the faster they fly, thus forming an expanding universe.
In this regard, people began to reflect, if we look at these galaxies in all directions, they may be emitted from the same source. Was there an unimaginable big bang at the beginning of the universe? Later, we observed the microwave background radiation that filled the universe, that is to say, the aftermath generated by BIGBANG about 65.438+0.37 billion years ago was weak but did exist. This discovery is a strong support for BIGBANG.
The Big Bang theory is a major school of modern cosmology, which can satisfactorily explain some basic problems in the universe. Although The Big Bang Theory was put forward in the 1940s, it began to sprout in the 1920s. In the 1920s, many astronomers observed that the spectral lines of many extragalactic galaxies had wavelength changes compared with the spectral lines of the same element on the earth, that is, the phenomenon of red shift.
By 1929, American astronomer Hubble summed up the law that the stars whose spectral lines are red-shifted are directly proportional to the distance from the galaxy to the earth. He pointed out in theory that if the red shift of spectral lines is the result of Doppler effect, it means that galaxies outside the river are moving away from us and retreating far away, and the farther away the galaxies are, the faster they are. This is the image of the expansion of the universe.
1932, Lemaistre put forward the modern big bang theory for the first time: the whole universe first gathered in a "primitive atom", and then the big bang happened, and the fragments scattered in all directions, forming our universe. Gamov, an American Russian astrophysicist, first integrated general relativity into the theory of the universe and put forward a cosmological model of the Big Bang: the universe started from high-temperature and high-density primitive matter, and its initial temperature exceeded several billion degrees. As the temperature continues to drop, the universe begins to expand.
The Big Bang theory is the most influential theory about the formation of the universe. It was born in the 1920s, supplemented and developed in the 1940s, but it has been unknown. In the 1940s, American astrophysicist Gamov and others formally put forward the Big Bang theory. According to this theory, the universe was in a state of extreme high temperature and high density in the distant past, which was vividly called "primitive fireball". The so-called primitive fireball is an infinitesimal point, and now the universe will continue to expand, which is infinite. It is possible that when the energy of the universe explosion reaches the limit, the universe will become a primitive flame, that is, an infinitesimal point. After the fireball explodes, the universe will begin to expand, the density of matter will gradually become thinner, and the temperature will gradually decrease until today's state. This theory can naturally explain the red shift of spectral lines of celestial bodies outside the river, and can also satisfactorily explain many astrophysical problems. It was not until 1950s that people began to pay extensive attention to this theory.
In 1960s, penzias and Wilson discovered the new powerful evidence of the Big Bang theory, and they discovered the cosmic background radiation. Later, they confirmed that the cosmic background radiation was a relic left by the Big Bang, which provided an important basis for the Big Bang theory. When measuring the radio intensity of the silver halo gas, they accidentally detected a microwave noise with a wavelength of 7.35cm. No matter where the antenna turns, this mysterious noise is continuous and stable day and night, spring, summer, autumn and winter. It is equivalent to the radiation emitted by a black body at three K degrees Celsius. Astronomers are very excited about this discovery. They have long estimated that after the big bang, there will always be something left today. With the passage of time, each stage of equilibrium should have a corresponding equivalent temperature. Therefore, penzias and Wilson won the 1978 Nobel Prize in Physics.
Hawking embodies the wisdom and perseverance of science in the 20th century. He gave a clear explanation of the evolution of the universe from10 to 43 seconds after the origin of the universe. The origin of the universe: at first it was a singularity smaller than an atom, and later it was the Big Bang. BIGBANG's energy forms some elementary particles, which gradually form various substances in the universe under the action of energy. At this point, the Big Bang model has become the most convincing theory of the universe. However, so far, the Big Bang theory still lacks the support of a large number of experiments, and we still don't know the picture before and after the universe began to explode.
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Theoretical viewpoint
The main idea of the Big Bang theory is that our universe once had an evolutionary history from hot to cold. During this period, the cosmic system is not static, but constantly expanding, which makes the density of matter evolve from dense to sparse. This process from hot to cold, from dense to thin, is like a huge explosion. According to BIGBANG's cosmology, the whole process of BIGBANG was in the early universe, and the temperature was extremely high, above 1000 billion degrees. The density of matter is also quite large, and the whole universe system is in equilibrium. There are only some elementary particles in the universe, such as neutrons, protons, electrons, photons and neutrinos. But because the whole system is expanding, the temperature drops rapidly. When the temperature drops to about1000 billion degrees, neutrons begin to lose the condition of free existence, and they either decay or combine with protons to form heavy hydrogen, helium and other elements. It was from this period that chemical elements began to form. When the temperature further drops to 6.5438+0 million degrees, the early process of forming chemical elements ends (see the theory of element synthesis). The substances in the universe are mainly protons, electrons, photons and some lighter nuclei. When the temperature drops to several thousand degrees, the radiation decreases, and the universe is mainly gaseous. Gas gradually condenses into gas clouds, and then further forms various star systems, becoming the universe we see today.
Since Gamov established the concept of the Big Bang in 1948, cosmologists have outlined such a cosmic history for us through decades of efforts:
At the beginning of the Big Bang, about 654.38+03.7 billion years ago, it was very small, with extremely high density and extremely high temperature.
Before the big bang, the universe appeared from the quantum background in 10~43 seconds.
Before the big bang 10~35 seconds, the same field was decomposed into strong, weak electric power and gravity.
/kloc-protons and neutrons formed in 0/0 trillion seconds before the Big Bang 10 ~ 5 seconds.
After the Big Bang, it was 0.0 1 sec 1000 billion degrees, mainly photons, electrons and neutrinos. Proton neutrons only accounted for a part of 1 billion, and were in thermal equilibrium. The system expanded rapidly and the temperature and density decreased continuously.
0. 1 s after the big bang, and after 30 billion degrees, the neutron-proton ratio decreased from 1.0 to 0.6 1.
After the Big Bang, after 1 second, 1000 billion degrees, neutrinos escaped outward, and the positive and negative electrons annihilated, so the nuclear force was not enough to bind neutrons and protons.
Three billion degrees after BIGBANG 13.8 seconds, deuterium and helium stable nuclei (chemical elements) were formed.
35 minutes after the big bang, at 300 million degrees, the nuclear process stopped and neutral atoms could not be formed.
300,000 years after BIGBANG, at 3,000 degrees, neutral atoms were formed by chemical combination, and the universe was mainly composed of gaseous substances, which gradually condensed into high-density gas clouds under the action of self-gravity until stars and star systems.
According to Hubble constant, it can also be inferred that the universe started from a singularity about 654.38+0.5 billion years ago.
Wenger Beaumont said: "When the explosion1100 seconds, the temperature is 1000 billion degrees Celsius, and the universe is in the simplest state of thermal balance. Photons produced by pure energy are mixed with positive and negative electrons, and even phantom neutrinos are soaked in this hot soup (which is what we call basic particle thick soup). The ratio of photons to protons is 10 1. After the explosion 1 s, the temperature dropped to 1000 billion degrees Celsius, and neutrinos began to get out of thermal balance. Three minutes is an epoch-making time. The temperature dropped to 65.438+0 billion degrees Celsius, and the annihilation of positive and negative electrons was completed. The universe is mainly composed of light, positive and negative neutrinos, and nuclear particles account for only a small share, in which the ratio of hydrogen to helium is 73∶27. The other is the extra electrons that are as rare as nuclear particles in annihilation. After 700,000 years, nothing happened until the temperature dropped to 3,000 degrees Celsius, and the free electrons gradually became their own masters, forming hydrogen and helium with the nucleus, so the matter broke away from the thermal balance of radiation and the universe became transparent.
Big bang model
A widely accepted theory of cosmic evolution. The main idea is that the universe was created by a "big bang" from a state of extremely high temperature and density. It happened at least 654.38 billion years ago. This model is based on two assumptions: the first is Einstein's general theory of relativity, which can correctly describe the gravitational effect of cosmic matter; The second is the so-called cosmological principle, that is, what the observer sees in the universe has nothing to do with the direction or position of observation. This principle only applies to the large scale of the universe, which also means that the universe is boundless. So the BIGBANG source does not occur at a certain point in space, but at the same time in the whole space. With these two hypotheses, we can calculate the history of the universe from a certain time (called Planck time), but before that, what physical laws are at work is still unclear. Since then, the universe has expanded rapidly, and the density and temperature have decreased from the initial extremely high state. Then, some processes that show proton decay also make the number of matter far exceed that of antimatter, as we see today. Many elementary particles may also appear at this stage. After a few seconds, the temperature of the universe drops, forming some nuclei. This theory also predicts that a certain number of nuclides such as hydrogen, helium and lithium can be formed, and the abundance is consistent with that seen today. After about 6.5438+million years, the universe cooled further and began to form atoms, while the radiation full of the universe spread freely in space. This kind of radiation is called cosmic microwave background radiation, which has been confirmed by observation. In addition to primitive matter and radiation, the Big Bang theory also predicts that the universe should be full of neutrinos, which are massless or uncharged elementary particles. Now scientists are trying to find this substance.
The Big Bang model can uniformly explain the following observations:
(1) Theory holds that all stars were born after the temperature dropped, so the age of any celestial body should be shorter than the period when the temperature dropped to today, that is, less than 20 billion years. The measurement of the ages of various celestial bodies proves this.
(b) It is observed that the spectral lines of celestial bodies outside the river have a systematic red shift, which is roughly proportional to the distance. If it is explained by Doppler effect, then the red shift is a reflection of the expansion of the universe.
(c) Helium is quite abundant in various celestial bodies, most of which is 30%. The mechanism of stellar nuclear reaction is not enough to explain why there is so much helium. According to the big bang theory, the early temperature was very high and the efficiency of producing helium was also very high, which can explain this fact.
(d) According to the expansion speed of the universe and the abundance of helium, temperature of the universe in various historical periods can be calculated concretely.
According to the Big Bang theory, the universe was born at a tiny point 65.438+037 billion years ago. From this tiny point, space-time, mass and energy were born, which made small particles of matter gather into mass matter and eventually formed galaxies, stars and planets. Before the Big Bang, there was no matter, no energy and even no life in the universe.
However, the big bang theory can't answer what the universe was like before the big bang, or what was the cause of the big bang? According to the big bang theory, the universe has no beginning. It is just a cyclical process, from the Big Bang to the black hole, which is the process of the creation and destruction of the universe and its rebirth.
This is just an idea, not a perfect theory.
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quarrel
Although the big bang theory is not mature, it is still the mainstream theory of the formation of the universe. The point is that there is some evidence to support the big bang theory. More traditional evidence is as follows:
(a) redshift
From any direction of the earth, distant galaxies are moving away from us, so it can be inferred that the universe is expanding, and the farther away galaxies are, the faster they leave.
Hubble's law
Hubble's law is about the relationship between the speed and distance between galaxies. It still explains the motion and expansion of the universe.
V=H×D
Where v (km/s) is the departure speed; H(Km/sec/Mpc) is Hubble constant, which is 50; D(Mpc) is the distance between galaxies. 1MPC = 3.26 million light years.
(c) abundant hydrogen and helium.
The model predicts that hydrogen accounts for 25% and helium accounts for 75%, which has been confirmed by experiments.
(d) rich in trace elements.
For these trace elements, the estimated abundance in the model is the same as the measured abundance.
(e)3K cosmic background radiation
According to the big bang theory, the universe cooled due to expansion, and there should be radiation embers in today's universe. At 1965, the background radiation of 3K was measured.
(f) Tracking background radiation inhomogeneity
It is proved that the initial state of the universe is uneven, which is the reason why the present universe and the present galaxies and clusters of galaxies are produced.
(g) New evidence of the Big Bang theory
In the British journal Nature from June 5 to February 2000, scientists said that they had found new evidence that could be used to confirm the Big Bang theory.
For a long time, there has been a theory that the universe was originally a point with great mass, small volume and extremely high temperature, and then this point exploded, and with the expansion of its volume, the temperature kept decreasing. Today, there are still cosmic rays called "cosmic background radiation" in the universe at the beginning of BIGBANG.
After analyzing the light absorbed from quasars by distant gas clouds in the universe billions of years ago, scientists found that its temperature was indeed higher than that of the universe today. They found that the background temperature was about 263 degrees below zero. 89 degrees Celsius, which is higher than the measured temperature of -273.33 degrees Celsius in temperature of the universe.
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The voice of anti-big bang theorists
On May 22nd, 2004, New Scientist published an open letter to the scientific community signed by 34 scientists and engineers. We translated it in order to let readers know the arguments of people in The Big Bang Theory. After this open letter was posted online, it was signed by 185 scientists (now more than 400):
Nowadays, the Big Bang theory is increasingly based on some assumptions and things that have never been observed empirically: inflation, dark matter and dark energy are some of the most shocking examples. Without these things, we will find that there is a direct contradiction between the actual astronomical observation and the prediction of the Big Bang theory. This practice of constantly resorting to new assumptions to bridge the gap between theory and reality is impossible to accept in any other field of physics. This at least reflects that this theory of unknown origin has serious problems in its effectiveness.
However, without these far-fetched factors, the Big Bang theory could not survive. Without the assumption of inflation, the Big Bang theory cannot explain the uniform and isotropic cosmic background radiation found in actual observation. Because in that case, it can't explain why the distant places in the universe have the same temperature and emit the same amount of microwave radiation. If there is no so-called dark matter, which is incompatible with all the substances we have tried to observe on the earth for more than 20 years, then the prediction of the Big Bang theory is completely contradictory to the actual density of matter in the universe. The density of inflation is 20 times that of nuclear fusion, which may be the theoretical explanation of the source of lighter elements in the big bang theory. Without dark energy, the age of the universe calculated according to the big bang theory is only 8 billion years, even several billion years younger than the age of many stars in our galaxy.
More importantly, the Big Bang theory has never been verified by any quantitative prediction. Defenders of this theory claim that its success is all due to its ability to cater to the actual observation results afterwards, and it is constantly adding adjustable parameters, just as Ptolemy's geocentric theory always needs to prove itself with this round and even rounds. In fact, the big bang theory is not the only way to understand the history of the universe. Both "plasma cosmology" and "steady-state cosmology model theory" are hypotheses about such an evolving universe. They believe that the universe has neither a beginning nor an end. These models, as well as other viewpoints, can also explain the basic phenomena of the universe, such as the proportion of lighter elements in the universe, the background radiation of the universe, and the red shift of spectral lines in distant galaxies with increasing distance. Some of their predictions have even been verified by actual observations, which has never been done by the Big Bang theory. Supporters of the Big Bang believe that these theories cannot explain all the observed astronomical phenomena. But this is not surprising, because their development is seriously lacking in financial support. In fact, until today, such problems and alternative theories cannot be freely debated and tested. Most seminars go with the flow, and researchers are not allowed to exchange views completely and openly. Richard. Richard feynman once said that' science is a culture of doubt', but in today's cosmology field, doubts and objections are not tolerated, and young scholars dare not express any negative thoughts on the standard model of the Big Bang. Scholars who doubt the Big Bang theory will lose their funding if they speak out their doubts. Even the actual observation results should be screened according to whether the standards can support the Big Bang theory. In this way, all substandard data, such as the red shift of spectral lines, the ratio of lithium to helium in the universe and the distribution of galaxies, are ignored or even distorted. This reflects an inflated dogmatism, which is totally incompatible with the spirit of free scientific research. Nowadays, in the field of cosmology research, almost all the funds and experimental resources are allocated to projects with the big bang theory as the topic. The sources of scientific research funds are limited, and all the review committees responsible for the allocation of funds are controlled by supporters of the big bang theory. The result is that the big bang theory has a comprehensive leading position in this field, which has nothing to do with the scientific effectiveness of the theory. Only subsidizing the subjects subordinate to the big bang theory obliterates a basic principle of scientific method: that is, the theory must be constantly tested by actual observation. This restriction makes it impossible to conduct any discussion and research. In order to cure this stubborn disease, we call on the institutions that fund cosmology research to reserve a considerable part of their funds for research topics of alternative theories and empirical observations that are contrary to the Big Bang theory. In order to avoid unfair allocation of funds, the jury responsible for the allocation of funds can be composed of astronomers and physicists in non-cosmology fields. The fair allocation of funds to the research projects aimed at verifying the Big Bang theory and its replacement theory will enable us to find the most credible model about the historical evolution of the universe in a scientific way.
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Defects of the big bang theory
According to the big bang theory, galaxies and all other stars and planets were born in the so-called singularity. This singularity concentrates all the most primitive matter in the universe. Scientists evaluate the physical parameters of this singularity as follows: the temperature is 10 3 1 K, and the hidden energy density is 10 98 erg/cm3 (for comparison, the highest temperature in a star is10.8 k, while the material density of a neutron star is10.658 k).
It is hard for us to imagine what the universe was like during the singularity period. Nowadays, the popular theory of cosmic superstructure holds that micro black holes formed after the Big Bang are all over the universe. These black holes are not as big as atomic nuclei, but their mass is equivalent to that of an asteroid. Not long ago, it was reported that NASA planned to launch a high-power X-ray telescope "GLAST" in 2007. According to astrophysicists' calculations, the telescope is sensitive enough to detect the fluctuations of miniature black holes. The theory of cosmic superstructure will be finally confirmed by experiments.
The biggest flaw of the "Big Bang" theory is that it can't answer where this strange point came from before the Big Bang. The Big Bang theory has existed for more than 100 years, but surprisingly, the development of this theory will inevitably lead people's understanding of the birth and demise of the universe to creationism. Not surprisingly, Pope Joao Pavel II has long said in his letter that contemporary cosmology coincides with the discourse in the Bible.
Electromagnetic Universe Imagination —— A New Universe Theory
In recent years, our ideas about the electromagnetic universe have answered many questions. The basic ideas of electromagnetic universe theory are embodied in the following three main aspects: first, the universe will exist forever; Second, all substances in the universe exchange energy in various frequency ranges-from ultra-low frequency to ultra-high frequency; Third, all activities in the universe are cyclical (planets are born in black holes and then condense into black holes) and follow the conservation laws (energy, charge and matter).
The basic view of the electromagnetic universe theory is that the universe is a ring system, in which many galaxies are connected by the cosmic magnetic field, and the spiral ring cosmic magnetic field controls all the galaxy flows. Each galaxy group is separated by a black hole belt, which is the place where galaxies are bred and produced. Some scientists call it the "production room" of galaxies.
According to the theory of electromagnetic universe, black holes create two types of galaxies, one is the material world composed of negative electrons and protons, and the other is the so-called antimatter world composed of positrons and antiprotons. It is the huge material and charge difference between these two worlds that forms the energy that gives life and development to the universe.
Galaxies are born in the presence of cosmic magnetic field, and the movement of matter between star systems and galaxies forms a powerful current in the universe. Just like the discharge phenomenon in thunderstorm days in the earth's atmosphere, the discharge phenomenon in black holes has made many galaxies born and died. If the discharge phenomenon on the earth is instantaneous, then the discharge phenomenon of black holes will last for billions of years and ultimately determine what kind of world will be formed around us.
According to the theory of electromagnetic universe, BIGBANG is actually the birth process of galaxies. Because there are countless galaxies in the universe, it can be speculated that the Big Bang happens all the time, that is to say, the birth and death of galaxies in the universe happen every second. The explosion of the atomic bomb is such an example.
During the Cold War, every time an atomic bomb was tested and exploded, the sensing instruments installed by Americans on satellites would observe the explosion. Atomic bomb explosions are always accompanied by neutron radiation. To scientists' surprise, the instrument will record uninterrupted neutron radiation after each explosion. Later, astronomers' research showed that explosions have been happening in every region of the universe.
The advent of the electromagnetic universe theory will make the Big Bang theory forgotten by people with the passage of time. Because matter and energy are always transforming each other, time is just a tool to record from one event to another. In fact, time is eternal, and the cycle of life has no beginning or end.
A new theory of the universe: The Big Bang is happening.
According to a report by the British Broadcasting Corporation (BBC) on April 25, 2002, a physicist at Princeton University in the United States put forward a new theory of the universe based on astronomical observations, that is, the universe is still expanding at an accelerated speed, saying that the Big Bang has been happening again and again in the past and in the future, and our present universe is just one of a series of big explosions. Although the process of the Big Bang is extremely long (more than one trillion years), through the observation of gravity waves predicted by this theory,
The universe is still expanding. It is reported that in the past five years, a strange phenomenon has attracted people's attention.
Run in the opposite direction
Radiation wave generated by Big Bang: Since Big Bang 65.438+03.7 billion years ago, stars and galaxies began to fly outward respectively. Theoretically, interdependent gravity should slow down the expansion, but this is not the case. In fact, the expansion is still accelerating. There is some force in the universe that pulls stars away from galaxies. Cosmologists don't know what this force is, but they can establish mathematical formulas to describe this phenomenon.
Steinhardt of Princeton University is one of the proponents of the new theory of the universe. He said that these formulas predict that the universe has no beginning or end, and BIGBANG will never stop and happen again and again.
Explosion period
He said: "Our pictures show that the Big Bang was not the beginning of time, but only the latest in a series of explosion cycles. In these cycles, the universe experiences heating, expansion, cooling, stagnation, emptiness, and then expands again. " According to this theory, the universe will continue to expand for about one trillion years. At this time, the mysterious anti-gravity characteristics calculated by the formula changed, and there was another big explosion in a corner of the universe, and everything started again.
confirm
You don't have to wait a trillion years to verify whether steinhardt's statement is correct. Right or wrong can be decided soon. Every big bang will produce gravity waves, which will spread all over the universe. Scientists are building a new generation of instruments on earth and in space to detect these gravity waves. The first detection result will appear in a few years, which will confirm or deny the saying that the universe has no beginning and no end.