Are humans the first civilization in the universe? Four scientific theories about aliens tell you the truth

This topic has been popular on the Internet for a long time, and it has never been explained clearly. Because so far, not to mention extraterrestrial civilization, even a hair of extraterrestrial life has not been found.

But this does not mean that extraterrestrial civilizations do not exist. Most scientists believe that Earth is not the only civilization in the universe, but it has not been discovered by humans yet, or because the universe is too big and civilizations are rare, it is difficult to encounter them. Why is this so? This requires the explanation of four theories about aliens.

In the middle of the last century, the scientific community was very enthusiastic about the discussion of "aliens", from which four theories related to aliens were derived. According to the time of their proposal, they are the Fermi paradox, the Drake equation, the Dyson sphere, the Kardashev hierarchy, etc. Now let's learn about these four theories together.

Fermi Paradox

The Fermi Paradox, also known as the Fermi Paradox, was proposed by Enrique Fermi, a famous American physicist and Nobel Prize winner in 1950. It is a scientific paradox about aliens and interstellar travel, which explains the contradiction between the overestimation of extraterrestrial civilizations and the lack of relevant evidence.

The core idea of ​​the Fermi Paradox is: since the universe is so big and has a history of 13.8 billion years, there should be many civilizations and even advanced civilizations, but where are they? After the paradox was proposed, it aroused a warm response from the scientific community. Many scientists participated in the discussion and put forward their opinions. The subjects involved are becoming more and more extensive, covering astronomy, biology, ecology and philosophy, forming an interdisciplinary debate and research.

Discussions on the Fermi Paradox have roughly formed the following questions and answers:

1. The universe is very large. There are about 400 billion stars in the Milky Way alone. There may be more than one trillion galaxies in the observable universe, with at least 100 trillion stars. The Earth is just a relatively typical ordinary planet with only one 330,000th of the mass of the sun. It is not special in the universe. Therefore, there should be a considerable number of civilizations in the Milky Way alone. Even if there is only one civilization, the Earth, in the Milky Way, with an average of one civilization in one galaxy, there are trillions of civilizations in the entire universe.

2. There may be two reasons why we cannot find extraterrestrial civilizations now: one is that civilization is too rare and difficult to encounter; the other is that our understanding of life and civilization is misunderstanding. Perhaps other civilizations in the universe are completely different from what we imagined, so even if we meet, we will not know each other.

3. Since there are many uncertain risks and disasters in the universe, such as gamma-ray bursts, which will regularly or irregularly clear out more than 90% of the civilizations in the universe, thus limiting the survival time of civilizations, or it is difficult to develop a civilization capable of interstellar travel. Therefore, although many civilizations may have been born in the 13.8 billion years since the birth of the universe, these civilizations rarely exist at the same time in a certain period of time, making them difficult to encounter.

4. From the history of life and civilization on Earth, the Earth is more than 4 billion years old. Although life has existed for 3 to 4 billion years, tangible life has only existed for 500 million years. Among countless creatures, only humans have evolved to be intelligent and have created civilization. It can be seen that even if there is a planet with similar conditions to Earth, the probability of civilization appearing is extremely small.

Drake Equation

The Drake Equation, also known as the Drake Formula, is a theory proposed by American astronomer Frank Drake in 1960. It is actually a theory that attempts to answer the Fermi Paradox. The core of this theory is to propose a formula to calculate the number of extraterrestrial civilizations that humans may come into contact with. Astronomer and science fiction writer Carl Morgan also participated in the research and discussion of the equation.

There are two expressions for this equation. Formula 1 is: N=Ng×Fp×Ne×Fl×Fi×Fc×FL; Formula 2 is: N=R*×Fp×Ne×Fl×Fi×Fc×L.

The letters in Formula 1 represent the following meanings: N is the number of stars in the Milky Way that may communicate with us; Ng is the number of stars in the Milky Way; Fp is the proportion of stars with planets; Ne is the number of Earth-like planets in each planetary system; Fl is the proportion of habitable planets; Fi is the probability of evolving highly intelligent life forms; Fc is the probability that highly intelligent life forms can communicate; FL is the proportion of the duration of scientific and technological texts in the life cycle of a planet.

The difference between Formula 2 and Formula 1 is that R* replaces Ng and L replaces FL. R* represents the average rate of star formation in the Milky Way; L represents the lifespan of technological civilization.

The Drake equation may not seem complicated, but it is difficult to solve. This is because the biggest uncertainty in the equation is the lifespan of technological civilization. For example, human technological civilization has only lasted for a few hundred years, and the time for communication with the extraterrestrial world is only over 100 years. If this time is taken as technological civilization, it is only a little over 4/100 million of the age of the Earth. How long will the lifespan of technology be in the future? Whether it will be hundreds of years or thousands of years, or immortality, is still unknown.

What we know is that scientific and technological civilization has only been around for a few hundred years, and human survival is already fraught with dangers, with natural and man-made disasters constantly occurring. In particular, the destruction of the environment has led to an increasingly serious greenhouse effect. Many scientists have exclaimed that if humans do not control and reverse it, this century may lead to a major extinction disaster.

Moreover, from the perspective of human history, every now and then, a few poisonous vegetables and anti-human and anti-social scums will seize power and instigate humans to slaughter each other. In this way, with the upgrading of scientific and technological civilization, the possibility of civilization self-destruction is getting greater and greater. For example, the shadow of nuclear war is always hanging over people's heads. Who knows when human civilization will end?

It is impossible to predict how long human civilization can last. If the technological civilization of the universe is destroyed in a very short time, how can civilizations possibly know and meet each other?

Some items in the formula can be determined, such as the number of stars in the Milky Way or the rate at which stars are formed in the Milky Way; but some items have not yet been determined, such as the conditions for habitable planets, the probability of evolving civilized life, the probability of developing interstellar communication, etc. Therefore, it is impossible to accurately calculate the number of civilizations in the Milky Way and the universe, and we can only make a rough estimate.

A more optimistic estimate is that there may be 1 million planets with civilizations in the Milky Way, a medium estimate is that there are 100,000 civilizations, and a minimum estimate is that there is only one civilization, Earth.

Even if there are 1 million civilizations in the Milky Way, a simple calculation shows that the average distance is about 680 light years, and it takes 1,360 years for light to travel back and forth. If human technological civilization is very short, it will be over before the radio waves for mutual communication are received. If there is only one civilization on Earth in the Milky Way, then the connection between civilizations is even slimmer.

Dyson Sphere Theory

The Dyson Sphere Theory is a theory proposed by Freeman Dyson, a famous American physicist and mathematician and former deputy of Einstein. He believes that if human civilization continues long enough, one day the energy required will reach the total output of the sun. Except for the sun itself, this huge energy cannot be obtained anywhere else in the solar system. Therefore, it is necessary to build a device around the sun to collect all the sun's energy.

His idea was published in the journal Science in 1959 as a paper titled "Search for Artificial Stellar Infrared Radiation Sources". The core content is to artificially create a huge spherical shell device to wrap around the sun. The radius of this device is about 150 million kilometers, which is the same as the distance from the sun to the earth's orbit. In this way, the inner wall can collect all the solar radiation energy and convert it into energy needed for human technological development and interstellar migration through nuclear fusion devices.

This spherical shell device is called a Dyson sphere. The Dyson sphere can not only perform nuclear fusion energy conversion, but also build and install living facilities for humans on it. In the future, humans will live on the Dyson sphere.

This is an unimaginably huge project. After calculation, it is not enough to dismantle all the planets and celestial bodies of all sizes in the solar system. It is also necessary to transform the most abundant hydrogen and helium elements in the solar system into heavy metals through nuclear fusion, so as to barely build a shell about 20 centimeters thick and about 600 kilograms per square meter.

The Dyson sphere theory has been favored by many scientists, who have joined the research and developed many types of Dyson sphere solutions, including Dyson shell, Dyson cloud, Dyson bubble, Dyson net, etc. These methods all wrap the sun, but the wrapping methods are different, some are fully enclosed, and some are enclosed with gaps.

The Dyson Shell is actually the mainstream Dyson Sphere mentioned above. This Dyson Sphere is difficult to resist the pull of gravity and rotation speed, but the Dyson Cloud can solve this problem. The so-called Dyson Cloud is to build a huge number of independent structures around the sun. Each structure consists of solar energy collecting satellites and space settlements. There will be many of these devices, just like the white clouds around the earth, surrounding the sun.

The advantages of this type of structure are that the size is not fixed, the structural method is highly selective, and it can be built one by one over a long period of time, eventually forming a Dyson cloud surrounding the sun, while the energy collection and transmission is wireless. The disadvantage of the Dyson cloud is that the complex orbital patterns may affect each other, increase instability and mutual blocking of sunlight eclipses, affect efficiency, and cannot fully collect solar energy.

The concept of a Dyson bubble is similar to that of a Dyson cloud, which is also composed of many independent structures and can also be built in stages over a long period of time. Unlike a Dyson cloud, it uses a huge solar sail to collect the sun. The solar sail can offset the gravitational pull of the sun by receiving the pressure of sunlight. It is distributed at different distances along the sun's path. The solar sail is attached to a solar-collecting satellite, which collects the sun independently and motionlessly.

The difficulty of this technology is that the density of the light sail is required to reach 0.78 grams per square meter, while humans can only achieve 3 grams per square meter now. The advantage of this technology is that it consumes very little material. The total mass of the entire Dyson bubble that wraps the sun is about 2.17*10^20 kilograms, which is enough to dismantle an asteroid Pallas with a diameter of 560 kilometers.

Although the Dyson Sphere Theory is just a thought experiment, many scientists believe that it is likely to be the inevitable path for human civilization to upgrade to Class II. In addition, many scientists have demonstrated that this path may be possible in the next 100 years and that it is feasible.

The Dyson sphere theory has also become a basis for the scientific community to search for aliens. Because if the Dyson sphere will inevitably cause the brightness of stars to drop significantly, as long as such a star is found, it can prove that there is a high-level civilization in the universe. Therefore, since the middle of the last century, people have used radio telescopes to scan hundreds of millions of stars in an attempt to find evidence of the existence of Dyson spheres in the Milky Way.

There have been several surprising discoveries, and scientists believed that they had found phenomena similar to the Dyson sphere, but these were later denied, and to this day no evidence of the definite existence of the Dyson sphere has been found.

Kardashev Scale

The Kardashev scale refers to a theory created by Soviet astronomer Nikolai Kardashev in 1964. This theory envisions dividing cosmic civilizations into three levels, namely, first-level civilization is the mother star civilization, second-level civilization is the star civilization, and third-level civilization is the galaxy civilization.

The measure of civilization level is energy consumption, and mainly refers to the energy consumed for interstellar communication or interstellar activities. Kardashev believes that the energy consumption standards of civilization levels are different according to the planets, planetary systems, and galaxies where different civilizations are located, and are determined according to their actual conditions.

Taking human civilization on Earth as an example, the mother star civilization of the first-class civilization refers to the Earth civilization. A civilization that reaches this level can fully control all the resources and energy of the Earth and respond to all disasters on Earth; its activity range is within the solar system and can reach planets near the Earth; its energy consumption reaches the total energy radiated by the sun to the Earth, that is, one 2.2 billionth of the total solar radiation, which is about 1.75*10^17 joules/second.

The stellar civilization referred to as second-class civilization refers to solar civilization. A civilization that reaches this level can fully control all resources and energy of the sun and the solar system and respond to all disasters from the solar system; its activity range can reach every corner of the solar system and the surrounding star systems; its energy consumption reaches the total radiation of the sun, which is about 3.86*10^26 joules/second.

The galactic civilization mentioned in the third-class civilization refers to the Milky Way civilization. A civilization that reaches this level can fully control all resources and energy in the Milky Way and can cope with all disasters from the galaxy. At this time, except for the dissipation of consciousness and the Big Bang, humans are almost immortal, and their range of activities can reach galaxy clusters and even wider interstellar space. The energy consumption reaches the total radiation of the Milky Way, which is about 4*10^37 joules/second.

After calculations and analyses of current human energy usage, some scientists believe that human civilization has only reached level 0.73. To reach level 1 civilization, energy utilization needs to increase by thousands of times, which will take 200 years of effort. To reach level 2 civilization, energy utilization needs to increase by hundreds of billions of times, which will take another 5,000 years of effort.

This is also the reason why a Dyson sphere must be built to achieve a second-class civilization. No other energy source can meet this demand.

The third-level civilization is considered a god-level civilization, which is completely unimaginable to humans today, so it is unknown how long it will take. Some scientists predict that it may take more than 100 million years, or even longer, to achieve continuous efforts. The prerequisite for achieving a high-level civilization is that the technological civilization can last long enough and will not be destroyed by various disasters.

Technological civilization is a double-edged sword. It can enhance human's ability to resist disasters, but it can also become a weapon for anti-human groups to destroy humanity. But in general, the higher the level of human civilization, the less likely it is to be destroyed by disasters, and the greater the probability of long-term continuation.

Of course, this theory itself is just a conjecture, and many other theories about cosmic civilization have emerged later, such as dividing cosmic civilization into four or seven levels. However, the most widely recognized theory in the scientific community is Kardashev's hierarchy theory, which is widely used in the search for extraterrestrial civilizations.

So, based on these four theories, can we draw a conclusion?

Still no, we can only assume. In view of the above theory, I think the probability of the existence of extraterrestrial civilization is very high, but overall it is very rare. Due to the distance, type of civilization, duration of civilization and other reasons, it is difficult for civilizations to know each other, let alone meet each other. Perhaps humans will never encounter the so-called "aliens" in their entire existence history.

In this way, we can only assume that human civilization is the first civilization in the universe, or even the only civilization. Of course, the probability of discovering extraterrestrial civilization or "aliens" is very small, but it is not zero. In this case, there is a chance that it will be discovered suddenly tomorrow, or 1 million years later, or even longer. If it is discovered, the assumption of the only civilization will fail, but is it the first civilization? It is necessary to evaluate and verify it.

Through these four scientific theories about aliens, do you have a clearer understanding of cosmic civilization or so-called aliens? Please express your opinions in the comment section. Welcome to discuss, thank you for reading.

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