Beneath Deep Space

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This is a universe full of wonders. Among them, the biggest miracle is that it gave birth to life and produced intelligent life that can observe and think about the universe. To get to this point, many prerequisites are needed, such as the large-scale structure of the universe, the existence of galaxies, stars, planets, chemical reactions, the origin of life, etc. These are incredibly unlikely coincidences.

The essence of the universe is physics (this sentence is questionable), and its operation is governed by the laws of physics. Many physical laws contain a large number of physical constants, and the values ​​of these constants determine the final shape of our universe. It can be said that all coincidences and miracles in the universe are due to the values ​​of these constants falling within some very small ranges. If the values ​​of these constants change even slightly, our universe will be completely different. Not only will there be no life, but galaxies and stars will not appear.

Therefore, people often call such a universe a fine-tuned universe or a universe on the knife-edge.

Let's take a look at the outrageous requirements for the accuracy range of physical constants to reach the current state of the universe.

1. The gravitational constant appears in many physical laws from Newton's law of universal gravitation to general relativity, and is crucial to the macroscopic structure of the universe. The value of this constant should be familiar to everyone: 6.67 X 10^-11.

If the gravitational constant is 10^-36 smaller than its current value, stars will not exist stably. Its own gravity cannot compete with the radiation pressure from core fusion, and it will collapse in an instant.

If the universal gravitational constant is 10^-40 larger than the current value, under the influence of too strong gravity, the universe will be filled with black holes and there will be no more stars.

10^-36 is a number too small for the human brain to understand. The following example may help you understand it. If you connected 10^36 grains of sand with a diameter of 0.1 mm, its length would be 114 times the diameter of the observable universe (93 billion light-years). At such an unimaginable length, if you remove a grain of sand, the entire universe collapses.

In addition, there are other parameters that play an important role in the current state of the universe. Some of them are physical constants, and some are the result of the interaction of multiple constants.

2. The efficiency of stellar nuclear fusion is 0.007, which means that when hydrogen is fused into helium, 0.7% of the mass is converted into energy. This parameter is determined by several other physical constants, including the magnitude of the strong interaction. If the value of this parameter is 0.006, then complex chemical elements will not be able to exist, and complex chemical reactions on which life activities depend will not occur. If the value of this parameter is 0.008, then all hydrogen will be consumed quickly after the Big Bang. However, not all physicists agree with this view. They believe that as long as the increase in the strong interaction does not exceed 50%, hydrogen can exist stably for a long time.

3. The density parameter of the universe is the ratio of the density of matter in the universe to the critical density. This value is approximately equal to 1. If the matter density of the universe is too high and the dark energy is not enough to drive the expansion of the universe, then the universe will shrink rapidly before the Big Bang. On the contrary, if the density of matter in the universe is too small, it cannot provide enough gravity to form stars.

4. The cosmological constant describes the ratio of dark energy density to the key energy density of the universe. The magnitude of this constant is 10^-122. This minuscule value determines that it can only function on a scale of 1 billion light-years. If it weren't so small, stars and galaxies wouldn't be able to form.

5. The third lowest energy state of the carbon 12 atom is 7.656 MeV. If this value is lower than 7.596MeV or higher than 7.716MeV, the star will not produce enough carbon to support carbon-based life. Similarly, to create the oxygen element needed to meet the needs of life on earth, our requirement for the size range of the strong interaction force is 0.5%, while the requirement for the size range of the electromagnetic force is 4%. Of course, you can ignore this if you believe that other elements, such as silicon, can also support life.

There are many such examples, such as the fine structure constant, the dimensions of the universe, etc., so I won’t go into details here. However, it cannot be ignored that the final state of the universe today is the result of all these factors. They must both fall within the specified range. So, the probability that we get the universe today is the product of all the small probabilities. You can probably imagine what a big prize we won.

Whether from a scientific or philosophical perspective, a precisely regulated universe is an unavoidable problem. So why do we get a universe that seems to be designed just for us?

The first thing we must consider is that physics is not developed enough to answer all the questions in the universe. Constants of physics that currently appear to be independent of each other may be related to each other at a deeper level. In the future we may find that the probability of the current state of the universe is much greater than the above calculation.

Here's a look at various attempts to explain a precisely tuned universe.

1. Intelligent design

One answer that readily comes to mind is that the universe was designed by higher intelligent beings, whether gods or aliens beyond our comprehension. The purpose of designing such a universe is to breed life in it, or as an experiment to see how long it takes for the germs of life to spread throughout the universe. If we extend this idea further, we can even assume that our universe is just a virtual world of a computer system.

Opponents of this view point out that it would be too inefficient to create such a huge and incredibly long universe just to feed a few creatures on an inconspicuous little blue star (after all, we have not yet discovered the reliability of extraterrestrial life) evidence). In fact, this does not effectively overturn the idea of ​​intelligent design, because the first bacteria in the petri dish may also raise the same question.

However, the extent to which this answer solves your problem depends on the level of your faith. If you think that an all-powerful God is the ultimate answer to all questions, and the existence and origin of this God cannot be questioned, then you don’t need to think any further. On the contrary, if you want to continue to use scientific research methods to think about the existence of intelligent designers, you will find yourself falling into an infinite loop: intelligent creatures that can design the universe must be more advanced than the universe itself. Incomprehensible.

2. Anthropic principle

Supporters of the anthropic principle believe: "If the universe had not been precisely adjusted to its current state, humans would not exist, and we would not be able to observe and think about the universe."

There are many versions of the anthropic principle. Among them, the weak anthropic principle holds that the possible values ​​of parameters in physics and cosmology are not completely equivalent, and the universe prefers those values ​​that allow carbon-based life to evolve.

The strong anthropic principle goes a step further and holds that the universe must have properties that allow certain stages of life to develop. The ultimate anthropic principle holds that information processing processes containing intelligence will definitely appear in the universe, and once they appear, they will not perish. Opponents of the anthropic principle argue that the idea is neither testable nor falsifiable and that it reverses the relationship between cause and effect. Humans evolved to adapt to the universe, not the universe to adapt to humans. Hawking also believes that our universe is not as special as the anthropic principle describes.

3. Multiverse theory Among the many explanations, the multiverse theory is probably the most closely related to physics. This view holds that all values ​​of physical constants are possible and must exist. It's just that they exist in different universes. The universe we live in happened to get the existing constant value, so it finally got the current state of the universe, and intelligent life that can observe and think about the universe appeared. Other universes have obtained different constant values, so they may collapse quickly after the Big Bang and return to the singularity, without forming galaxies or stars; in some universes, stars may burn into ashes as soon as they are ignited and cannot evolve. life.

There are many different versions of the multiverse hypothesis in current physics. The only hypotheses that can be used to explain a finely tuned universe are probably versions based on string theory or M-theory. For details, please refer to What is the relationship between string theory and parallel universes? However, neither string theory nor multiverse theory is currently proven. Likewise, a precisely tuned universe is an unanswered question.

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Let’s make a complaint, the subscriptions have been really bad these days. Is it possible that all those who read the book are college entrance examination addicts?