Slowly, Hua Feng also had some understanding of the weapons of mass destruction that the earth currently possessed.

NASA recently announced that the extraterrestrial life exploration project has made great progress, and among the more than 2,000 terrestrial planets discovered so far, some planets have traces of life, which means that human beings are expected to discover extraterrestrial life in the next 20 years, and extraterrestrial intelligent life (commonly known as "aliens") may be found within 30 years.

In fact, the search for extraterrestrial intelligent life has long been out of the realm of science fiction and has become a serious scientific exploration. As early as 1960, American astronomer Frank Drake began the "Ozma Project" for the first time in human history to purposefully and organically search for extraterrestrial intelligent life in the Milky Way. Since then, various programs to monitor signals of extraterrestrial intelligent life have never stopped.

In addition to taking a "passive monitoring" approach to finding extraterrestrial intelligent life, scientists are also trying to proactively contact them. To carry out this activity, the first thing that will undoubtedly be encountered is the problem of "language".

Scientists have long speculated that the language of mathematics may be the common language of every civilization. Carl Sagan, an American astronomer and popular science writer, said in his monograph "Cosmic Connections" that no matter how different the technological civilizations in the universe are, they have a common language - the language of mathematics.

Zhou Haizhong, a Chinese mathematician and linguist, also pointed out that mathematical language has the characteristics of scientificity, accuracy, conciseness, abstraction and universality, and is an ideal tool for cosmic communication.

As a result, the language of mathematics has become the medium of choice for human beings to connect with intelligent life outside the earth. Scientists at the Extraterrestrial Civilization Search Institute in California, USA, are planning to compile all the contents of Wikipedia into mathematical language information and send it to space 20 light-years away through radio telescopes, hoping that extraterrestrial intelligent life can receive this information and learn about Earth's civilization. In addition, scientists are also trying to get in touch with extraterrestrial intelligent life by means of images, music, and sending physical objects.

British physicist Stephen Hawking is also convinced of the existence of extraterrestrial intelligent life. But he warns that humanity reaching out to them could lead to disaster.

For example, the American astronomer Seth Shostak recently said that we should strive to take the initiative to establish friendly relations with them, and at the same time speed up the pace of searching for them, and the process of searching for them is more meaningful than the results obtained.

The search for extraterrestrial intelligent life is not only a process for human beings to explore the unknown world, but also a process for human beings to understand the universe and life. If extraterrestrial intelligent life were found, it would be one of the most significant discoveries in the history of science. But is humanity ready to accept a "neighbor" from the other side of the universe?

The term "weapons of mass destruction" first appeared in 1937, when Germany carried out strategic bombing against non-military targets during the Spanish Civil War. During the Cold War, "weapons of mass destruction" referred to nuclear weapons. Because nuclear weapons are more powerful than biological or chemical weapons, some argue that weapons of mass destruction should include only nuclear weapons.

UN Security Council Resolution 687 in 1991 referred to nuclear, biological and chemical weapons as weapons of mass destruction for the first time, and referred to three related international treaties: the Nuclear Non-Proliferation Treaty (NPT), the Chemical Weapons Convention (CWC), and the Biological Weapons Convention (BTWC). Weapons of mass destruction are not practical, because once used, the opponent will also retaliate with similar weapons, and the scale of damage is large enough to destroy the entire human civilization.

The term "weapons of mass destruction" first appeared in 1937, but today weapons of mass destruction generally refer to only the following three types (collectively known as NBC):

The emergence of nuclear weapons is the result of major scientific and technological developments around the 40s of the 20 th century. At the beginning of 1939, the German chemist O. Hahn and the physical chemist F. Strassmann published a paper on the fission phenomenon of uranium nuclei.

Within a few weeks, scientists in many countries verified the discovery and further suggested that it was possible to create conditions for this fission reaction to proceed autonomously, thus opening up a broad prospect of using this new energy source to create wealth for mankind.

However, like many new scientific and technological discoveries in history, the development of nuclear energy was first used for military purposes, that is, to create powerful ***, and its process was influenced and constrained by the social and political conditions of the time. From 1939 onwards, due to the expansion of the war of aggression by fascist Germany,

It is becoming increasingly difficult to carry out scientific research in many countries in Europe. In early September of the same year, the Danish physicist N.H.D. Bohr and his collaborator J.A. Wheeler theorized the process of nuclear fission reaction and pointed out that the best element that can cause this reaction is the isotope uranium-235. Just as this instructive study was published, Britain and France declared war on Germany.

In the summer of 1940, German troops occupied France. Part of the scientists led by the French physicist J.-F. Joliot-Curie were forced to emigrate. Britain had made plans to conduct research in this field, but due to the impact of the war and the shortage of manpower and material resources, it could only adopt the method of cooperation with the United States, and sent a team of scientists headed by physicist J. Chadwick to the United States to participate in the research work led by theoretical physicist J. R. Oppenheimer.

The two bombs dropped by the United States on Japan were in the form of nuclear bombs with parachutes, using airplanes as delivery vehicles. Later, with the development of weapons technology, a variety of nuclear weapons systems have been formed, including ballistic nuclear, cruise nuclear, air defense nuclear, anti-nuclear, anti-submarine nuclear rockets, deep-water nuclear, nuclear aerial bombs, nuclear artillery shells, nuclear weapons, and so on.

Among them, ballistic nuclear weapons equipped with multiple warheads** and cruise nuclear weapons with various launch modes are the main nuclear weapons equipped by the United States and the Soviet Union.

Nuclear weapons are usually divided into two categories according to their operational use, namely, strategic nuclear weapons used to attack the enemy's strategic targets and defend one's own strategic points, and tactical nuclear weapons mainly used to strike at the enemy's combat strength on the battlefield. The USSR also had "operational-tactical nuclear weapons".

The classification of nuclear weapons is not very strict because of geographical conditions and socio-political factors. Since the end of the 70s, official documents of the United States have rarely used "tactical nuclear weapons", and in their place there are "theater nuclear weapons" and "non-strategic nuclear weapons", and medium- and long-range nuclear weapons are also classified in this category. The nuclear weapons that have been produced and equipped with troops, according to the design of nuclear warheads, mainly belong to two types: *** and ***.

As for the number of nuclear weapons, no accurate figures have been published, and estimates by the relevant research institutions are inconsistent. According to a comprehensive analysis of data in recent years, by the mid-80s, the United States and the Soviet Union had a total of about 50,000 nuclear warheads, accounting for more than 95 percent of the world's total. Its equivalent amount, totaling about 12 billion tons.

During World War II, the United States dropped a total of about 2 million tons in Germany and Japan, which is only equivalent to the equivalent of 2 ** carried by American B-52 bombers.

This rough comparison illustrates the enormity of the stockpiles of nuclear weapons. Comparing the number and yield of offensive strategic nuclear weapons (including intercontinental nuclear weapons**, ballistic nuclear launched by submarines**, cruise nuclear** and strategic bombers) between the United States and the Soviet Union, the United States is less than the Soviet Union in terms of the total number of projection vehicles (land-based launchers, submarine launch tubes, aircraft) and the total yield of ***, but it is more than the Soviet Union in the total number of nuclear warheads.

Considering that the damage effect of the target opposite the nuclear explosion is not a simple proportional relationship with the yield size, another estimation method is to measure the destructive capability of the nuclear warhead by the destruction area corresponding to a certain shock wave overpressure, that is, to the power of 2/3 of the nuclear warhead yield value (calculated in million tons) as its "equivalent million ton yield" value (there are also different situations such as the characteristics of the target and its distribution and the scale of the nuclear attack, and other parties that are less than 2/3 are selected), and then the total value is calculated according to the cumulative number of nuclear warheads.

According to this method, the United States and the Soviet Union compare the destructive capabilities of strategic nuclear weapons, and because the yield is less than one million tons of nuclear warheads, the United States has more than the Soviet Union, and the gap between the two countries is not very large. But since the 80s, with the development of the Soviet Union in the nuclear weapons of the split-guided multiple warheads, this gap has also widened. And the ability to destroy point (hard) targets (see point targets), the accuracy of nuclear weapon projection plays a more important role, since the United States has always been ahead in this regard, it is still in an advantage.

In addition to the United States, the Soviet Union, the United Kingdom, France and China, which already possessed nuclear weapons, India conducted a nuclear test in 1974. It is generally believed that a country that has mastered the necessary nuclear technology and has a certain industrial base and economic strength is also entirely possible to produce ***.

Due to the increase in the accuracy of the means of delivering nuclear weapons, since the 60s, the development of nuclear weapons, first of all, the weight and size of the nuclear warhead have been greatly reduced, but a certain power has been maintained, that is, the specific power (the ratio of power to weight) has increased significantly.

For example, the United States dropped a total weight of about 1.32 tons of "Trident" I. submersible ground in Nagasaki, with a total weight of about 1.32 tons, and a total of 8 sub-guided warheads, each with a power of 100,000 tons, which is about 135 times higher than that dropped by Nagasaki.

Thermonuclear weapons, which are more powerful, are more powerful than they are more powerful. However, it is generally believed that this area of development may be close to the limits of objective reality. Since the 70s, the development of nuclear weapons systems has focused more on improving the survivability and accuracy of weapons, such as the United States' "Peacekeeper/MX" intercontinental**, "Pygmy" small intercontinental**, "Trident" II. submarine**, and the Soviet Union's SS-24 and SS-25 intercontinental**, all of which have been greatly improved and improved in these aspects.