Why can the physical laws that humans have discovered on Earth be applied throughout the universe?

This article is based on answering a question from netizens: Why do physicists believe that the physical laws on Earth can still be valid when extended to the universe?

My answer is: it is not a question of whether physicists believe it or not, but the fact is there, no one can believe it or not. Physicists are just a group of people who discover and study laws. In addition to physicists, there are many other scientists who are also discovering and studying laws, such as astronomers, geologists, chemists, biologists, etc.

The people who discovered and studied the laws were not limited to the Earth. Many discoveries came from the universe. The universe is everything we know, including everything on Earth. Therefore, even what is discovered on Earth is part of the universe.

The knowledge gained by human beings from observing and exploring the earth and the universe is scientific only if it conforms to the laws of nature. If we only understand superficial phenomena and then make far-fetched assumptions, if it does not conform to the laws of nature, it is not correct knowledge. Therefore, as long as it is a true scientific discovery, it is the understanding of the laws of nature, and it can be extended to the universe.

Just to name a few examples:

1. Einstein's special theory of relativity and general theory of relativity are the most profound and accurate explanations of the laws of cosmic motion to date. The special theory of relativity demonstrates the inseparable unity and relativity of space, time and matter through the limit of the speed of light and the principle of the constancy of the speed of light; the general theory of relativity demonstrates that mass causes the curvature of space-time and the various effects formed by this by establishing the gravitational field equation.

These contents are complicated to explain, but some of the assertions are more specific.

One is the speed time dilation effect in the special theory of relativity, which talks about the relationship between speed and time, also known as the clock dilation effect, that is, the faster the speed, the slower the time passes in the reference frame, and vice versa. The formula followed is: t'=t/√[1-(v/c)^2]

Here, t' represents the time dilation effect, t is the slow clock or the clock of the observer on Earth, v is the speed of the second clock relative to the slow clock, and c is the speed of light.

Many people think that this is just imagination, because this effect can only be obvious when the speed is close to the speed of light, and the speed of human beings' travel is very slow now. Not to mention approaching the speed of light, even one percent of the speed of light cannot be reached. Therefore, this effect cannot be verified on Earth, let alone in the universe.

In fact, this effect has been verified long ago, and all verifications are accurate to Einstein's speed time dilation effect formula. For example, the GPS navigation system must use the relativistic time dilation effect formula to adjust the high-altitude satellite and ground time in order to make navigation accurate; the same adjustment is also required for interstellar probes to reach their targets.

In the field of microscopic particles, this effect can be verified even more because of their fast movement speed. Muons are a type of lepton with a mass of about 207 times that of electrons. In the laboratory, the average lifetime of muons is only 2.197μs, or 0.000002197 seconds. When cosmic rays bombard the atmosphere, a certain amount of muons will be generated, but because their lifetime is too short, they cannot theoretically reach the surface of the earth.

But in fact, scientists have detected many traces of muons on the surface of the earth. Why is this? In fact, because the speed of muons is close to the speed of light, the time dilation effect greatly prolongs their lifespan, allowing them to reach the surface of the earth and leave traces.

Another example is the space-time curvature theory of general relativity, which states that mass will cause space-time to bend. The greater the mass, the greater the curvature of space-time, and light will also travel along the curved space-time. As early as 1919, shortly after the introduction of general relativity, the famous astronomer Eddington led an expedition from Britain to faraway Africa to verify the curvature of starlight passing near the sun, a massive celestial body, by observing a solar eclipse. After calculation, the curvature was consistent with the calculation of Einstein's field equations.

Subsequently, the theoretical predictions of general relativity were confirmed one by one. For example, the discovery of black holes is an example of the curvature of space-time reaching infinite curvature; there is also the famous problem of the precession of Mercury's perihelion, which is also in line with theoretical expectations; gravitational lensing, gravitational waves, gravitational redshift, gravitational time dilation effect, etc. have been discovered and verified one after another, all proving that no matter how far away they are from us, celestial bodies in the universe are governed by this law.

2. There are 118 elements in the current chemical periodic table, of which 92 exist in nature and 26 are artificial elements. These 118 elements are applicable anywhere in the universe. Human probes have now reached all the planets in the solar system, as well as some dwarf planets and satellites. By analyzing the atmosphere and geological conditions there, it is found that they are all composed of these elements.

Although human probes cannot yet fly beyond the solar system, telescopes can already see 13.5 billion light-years away from us, that is, the universe 13.5 billion years ago, when the universe was just born. Through spectral analysis, all visible celestial bodies in the universe are also composed of the elements that have been discovered.

Why can humans obtain the composition of distant matter through observation? This is because scientists can simulate various cosmic environments in the laboratory. For example, in the hadron collider, they can obtain a high temperature of 10 trillion degrees, simulating the state of the Big Bang at one trillionth of a second. They can also obtain the spectral standards of various elements at different ambient temperatures in the laboratory, which can be applied to the observation of distant celestial bodies.

3. The evolution of the earth and life are also constrained by the cosmic environment. Anything or law discovered by humans on the earth does not exist in isolation on the earth, but is closely related to and constrained by the cosmic environment. Therefore, all disciplines currently studied, such as the structure of the earth, environmental climate, the origin and evolution of life, must be combined with the evolution of the universe.

The modern standard model of the universe holds that the universe was born 13.8 billion years ago, the solar system was born 4.6 billion years ago, the Earth was born at the same time as the solar system, and life appeared about 4 billion years ago. Life evolved from the most primitive prokaryotic single cells to today's diverse animal, plant, and microbial species. Every step of extinction and regeneration is related to changes in the Earth's environment caused by the movement of the solar system.

Therefore, all the laws discovered on Earth are part of the laws of the universe and are of course applicable to the entire universe.

Two Mistakes in Viewing Scientific Discovery

One tendency is to think that scientific discoveries are short-sighted views of human beings and cannot represent the laws of the universe. In the comments section of my articles, I often see such remarks as: using science that is only 100 years old to measure the universe is overestimating one's own capabilities; humans look at the universe like ants look at humans; something that science cannot prove does not mean it does not exist, etc.

Another tendency is that people, relying on a little common sense about eating, drinking, defecating and urinating, will use their imagination to arbitrarily denigrate scientific discoveries and theories that have been recognized by the scientific community, and propose their own shocking theories, believing that they have gained insight into the true meaning of the universe. For example, they claim to have overturned the theory of relativity, discovered "acceleration system + gravitational waves + matter waves", and are willing to sell their livers and kidneys to win the Nobel Prize, etc.

Both tendencies are anti-intellectual and anti-scientific, lacking the scientific spirit and understanding of scientific methods. Humans have only a few thousand years of recorded history, and science has only a few hundred years. Of course, our understanding of the universe is still very limited, but as long as it is science, it must be to look beyond the phenomenon to the essence, and to obtain discoveries and theories based on laws. Otherwise, it is not science, or it is pseudoscience.

After hundreds of years of discovery and exploration, mankind has accumulated a series of theories, such as the mathematics, physics and chemistry knowledge we have learned from elementary school to university; we have a complete set of methods to observe and understand the world, such as relying on telescopes and microscopes to observe the world, using qualitative and quantitative methods to analyze the world, and so on.

The scientific spirit is to recognize the achievements of human civilization and be willing to follow the theories and methods that have been verified by the scientific community through long-term practice to conduct scientific discoveries and research; the scientific method is to use established laws and axioms for logical reasoning, adopt methods recognized by the scientific community to observe, experiment and experiment, and withstand repeated testing by anyone using these methods.

The results obtained in this way are scientific results. All scientific results, especially basic science, are the understanding of natural laws. They have no national or regional restrictions and are applicable to the whole world.

However, those conclusions drawn arbitrarily based on common sense of eating, drinking, defecating and urinating and according to one's own imagination can neither be logically self-consistent with scientific theories nor verified by scientific methods recognized by the world. Therefore, the scientific community will simply ignore them and even sneer at them.

This has aroused public outrage, and some people think that the scientific community is excluding these "folk scientists". They are so angry that they want to "sell their livers and kidneys to compete for the Nobel Prize", but the Nobel Prize also only recognizes results verified by scientific theories and scientific methods. Therefore, although these people are selling their sorrow, their so-called "scientific results" will be rejected by any scientific hall. They have only one way, which is to deceive the people who have no scientific knowledge and harm the world.

Science historians call this kind of people "folk scientists". Many people may be disgusted by the term "folk scientists", thinking that folk scientists are not worthy of respect? In fact, this is a substitution of concepts. The so-called "folk scientists" do not refer to folk scientists, nor are they only found in the folk. Instead, they refer to a group of "delusional people" who attempt to overthrow a major scientific theory and create their own "great" theory based on their own delusions.

Whether they are civilians or "officials", as long as they have a scientific spirit and obtain discoveries and theoretical results in accordance with scientific laws and scientific methods, and these discoveries and results can withstand repeated verification by any scientific institution, the results obtained are scientific results, which are the discovery and utilization of natural laws.

Science is always on the road, with no end.

The current level of human civilization is still very low. According to the Kardashev index, the level of human civilization is only 0.73, not even reaching level 1. Level 2 and 3 cosmic civilizations are "god-level" civilizations that we dare not even think about. Therefore, there is still a long way to go for the development of science and technology.

There are still many things in the universe that humans have not discovered and understood, such as dark matter and dark energy. Not to mention the entire universe, even on Earth, there are still many problems that humans have not explored, waiting for science to discover and understand. Therefore, scientific discoveries and theories are universal to the entire universe, not to mention the universality of the unknown world.

Science at each stage is not the ultimate truth, and may contain inaccuracies or even errors. As research and discovery go deeper, many discoveries and theories may need to be revised or even denied, but this does not mean that current science is not science. Current science is always the most correct understanding at present, and only when a deeper understanding denies this understanding should this science be abandoned.

Just like Copernicus discovered the heliocentric theory, and later astronomy discovered a larger universe, which negated the heliocentric theory; Einstein discovered the relative view of space and time and the curvature of space and time, which negated Newton's absolute view of space and time. This does not mean that Copernicus and Newton are no longer scientists. It is their theories that have promoted the progress of the times and brought mankind to where it is today. They will always be scientific giants. But their theories can only be fixed in a certain fragment of the history of scientific development.

We should also pay attention to distinguish the saying that some people often say: Not discovering something does not mean it does not exist. This statement seems to be correct. Scientists are much smarter than us. Of course, they know that not discovering something does not mean it does not exist. But the person who said this is not expressing the meaning of the words themselves, but another article.

These people are against things that are not recognized because there is no scientific evidence, such as the belief that UFOs are alien spaceships, that human civilization has appeared many times, etc. After decades of scientific exploration, there has never been any solid evidence to prove that aliens or alien spaceships have appeared on Earth, and archaeology and genetics have long confirmed that modern humans are the only civilization on Earth, so these people say: something without evidence does not mean it does not exist.

Therefore, these people are not saying that something that has not been discovered does not mean it does not exist, but they insist on following their delusions and believe that certain things do exist that there is no evidence or have even been proven not to exist.

Science does not acknowledge the existence of things that have no evidence to prove their existence. This is based on the rigor of science, not lying when there is evidence. Since Galileo pioneered the experimental scientific method, scientific discoveries and scientific theories must be able to be repeatedly verified using scientific methods to become scientific achievements.

Scientific exploration is endless and is always on the road with no end. However, the law of science spiraling upward in the negation of negation must be distinguished from groundless nonsense. This is the correct epistemology.

In the past two days, Rao Yi's criticism of Yin Ye, CEO of BGI, has become a hot topic again. This should be a debate between rigorous science and pseudo-science. If you carefully understand the arguments and evidence, you will have a deeper understanding of science. Welcome to discuss and post your thoughts in the comment section, thank you.

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