In order to get in touch with aliens, scientists have even built huge and complex devices to try to send and receive information from extraterrestrials.

However, after many efforts, people still have not found the aliens. Some claims of alien sightings are only legends and are difficult to conclusively prove.

Also worth mentioning is the flying saucer. Many people have seen it. It is also guessed that it is a spaceship piloted by aliens, but this is just a conjecture.

Scientists have analyzed that there are certainly many planets like the earth in the universe, and it is indeed very likely that some planets with a similar environment to the earth will have aliens, but because our aerospace and communication technologies have not yet developed enough, we must redouble our efforts to find them.

In order to search for extraterrestrial life, on May 24, 1999, a company called "Encounter 2001" launched a series of radio signals in the direction of four sun-like stars 50-70 light-years away with the help of a 70-meter-diameter radio telescope in Yevpatoria, Ukraine, on the Crimean peninsula, which was the first conscious interstellar broadcast in 25 years.

As early as November 16, 1974, American radio astronomer Drake used the 305-meter-diameter radio telescope in Arecibo to send a signal to the globular cluster M13 24,000 light-years away. However, the message was only 3 minutes long and consisted of 1,679 bytes, including the Earth's position in the solar system, human appearance and DNA data, the atomic composition of five chemical elements, and the graphics of a radio telescope.

In contrast, the signal sent this time is richer than Drake's, and it is more likely to be picked up by extraterrestrial life. Transmitted at a frequency of 5,010 kilohertz, 100,000 times stronger than a television broadcast, and 400,000 bits long, the signal consists of a series of pages containing detailed information about the Earth and human beings, basic symbols, logical descriptions of numbers and geometry, atoms, planets and DNA, etc., and is repeated three times in three hours.

Of course, both messages are sent in the same binary mathematical language, because it is the only language that makes it possible for us to communicate with the hypothetical extraterrestrial life in the universe. Scientists believe that any extraterrestrial life with some mathematical knowledge will have the ability to decipher these binary codes and thus understand their contents. If he/she/it can really intercept and record these signals, then it will understand the general state of the earth, the solar system, the human body, human culture and technology.

On the other hand, in the absence of sufficiently powerful computers, scientists have also built SETI@home systems to prevent the signals of extraterrestrial life collected by radio telescopes from being helped by computer users around the globe to prevent them from slipping away.

In addition, the "Encounter 2001" company, which is a joint venture of a number of well-known international companies in the fields of aerospace, information and biochemistry, is also tasked with another important task: the launch of a small spacecraft at the end of 2001.

The ship will remain adrift in the universe until one day it is intercepted by extraterrestrial life. It will carry more human information and can send hundreds of thousands of volunteer participants' photographs, handwritten messages and hair specimens into space. Among them, the hair specimen has undergone special treatment to preserve the human DNA information contained in it.

The countdown to the world's largest radio telescope array (SKA), planned and built by scientists from 20 countries around the world, including China, Australia, France, Germany, and Italy, has begun. It is reported that the SKA project consists of 3,000 smaller antennas with a diameter of about 15 meters. According to the plan, the construction of the SKA project will start in 2016, the first phase of construction will be completed by the end of 2020, and the entire project will be completed in 2024.

When put into service, SKA will be 50 times more sensitive than the world's most advanced space exploration equipment, 100 times more resolution, and 10,000 times faster than the world's most advanced space exploration equipment. Therefore, in the future, it can better help scientists to listen to aliens, and human exploration of the universe will definitely lead to more exciting discoveries.

To this end, they began to train specialized personnel in a planned way.

The University of Washington announced in September 1998 that it would launch a National Science Foundation funded graduate education program aimed at training doctoral students studying extraterrestrial life, the first of its kind in cosmic life.

This major may seem interesting, but it's not that easy to learn. Students must first understand how life on Earth formed, which involves astronomy, atmospheric science, oceanography, and microbiology.

"We want to study life in the Earth's environment, so we have to study the formation of Earth's craters, sea ice and underground basalts, because these are excellent environments for the formation of microorganisms, and they are likely to be similar to those on other planets," said James Strey, a microbiologist who led the project. "In addition to this, students are studying a large number of organisms that are less well known on Earth.

The University of Washington is not alone in giving students a taste of extraterrestrial life, and NASA's new Institute of Cosmic Life Sciences will provide the same opportunity. NASA scientists are talking to professors from five universities about the collaboration.

In the field of UFO research, there are four types of contact that are generally accepted as ways to describe the relationship between UFOs and humans:

Type 1 Contact: "Refers to a witness seeing a UFO within a certain distance, but no further contact has occurred." "Of the four types of exposures, this type of exposure has the highest incidence. We often see similar programs and reports, such and such as the spotting of UFOs, the sighting of UFOs by such and such people, the pictures or videos of UFOs taken by such and such people, and so on.

Type 2 exposure: "Refers to the effects of UFOs on the environment, such as making cars inactive, leaving burn marks or imprints on the ground, and physical and physiological effects on plants and humans." "The 1994 incident at Duxi Forest Farm in Guiyang, Guizhou Province was summed up as this type of contact.

Category 3 Contact: "Refers to humanoid organisms that appear in the vicinity of UFOs and have face-to-face contact with humans on Earth, including handshakes, conversations, sexual encounters, and abduction of humans." This is also the most questioned type, after all, there are very few people who experience this kind of contact, and their contact process is often recorded through post-event descriptions, and it is difficult to leave any solid evidence.

However, in general, when recording after the fact, the person concerned often needs to undergo hypnosis to recreate the process of contact with extraterrestrial life. For those who admit the science of hypnosis, this kind of evidence can still be admissible, at least not as an intentional codification by the experiencer.

The fourth type of contact: "refers to the contact of the heart." Humans don't see UFOs or humanoids directly, but they pass on some special messages through human psychic mediums. Witnesses see human-like creatures in the vicinity of UFOs, but they do not make further contact with the witnesses. The information provided here is also in the form of secondary information, but it seems to be more convincing than the third type of contact.

It was also thought that UFOs might be related to a natural phenomenon called "sprite flashes".

Colin Price, a geophysicist at Tel Aviv University in Israel, said: "The lightning spikes produced during thunderstorms 'set the electric field above you, prompting it to produce a light known as sprite flashes.'"

We know that only one special type of lightning can cause flashes of light at high altitudes. "Researchers have found this flash at an altitude of 35 to 80 miles above the ground, far more than the 7 to 10 miles above the ground where lightning often occurs. Although previous studies have shown that flashes of light often move forward or spin quickly, flashes can also appear in the form of rapidly rolling balls of electricity.

Israeli scientists have suggested that some of the mysterious UFO phenomena may be related to a puzzling natural phenomenon, "elf flashes", which are flashes triggered by thunderstorms high in the atmosphere.

One of the more typical incidents is Area 51, the Great Pyramid, and the UFO crash.

Area 51 is where the alien bodies and planes of the Nation M are stored and studied, including the alien spacecraft that crashed in Roswell and the bodies of the aliens. Some even say that this is an officially approved landing base for alien spacecraft.

Science cannot explain how the Egyptian "Great Pyramids" were built, and cannot give a rational explanation for how they were arranged and designed so perfectly. Some believe that aliens must have played a major role in the construction of these magnificent structures thousands of years ago.

On July 8, 1947, the Daily News in Roseville, New Mexico, USA, published a sensational news: "The Air Force found a downed flying saucer in Roseville. The news was immediately picked up by the New York Times and other major newspapers, and radio waves spread around the world. This news caused an uproar among the American public like a bombshell*.

People rushed from far and wide to New Mexico in the southern part of the United States. On a pasture 20 kilometres from Roswell, the swarm of people was blocked by rows of iron bars and groups of heavily armed soldiers...... Corresponding to the Roswell alien UFO crash. In addition, on the 8th, in a wasteland five kilometers west of the Bledsoe farm, which was strewn with metal debris, Grady L., a civil engineer who lived in Socorro, found the remains of a metal saucer, about nine meters in diameter, which had cracked open and several bodies scattered on the ground inside and outside the saucer.

The corpses were very small, measuring only 100 to 130 centimeters in length, weighing only 18 kilograms, with no hair, large heads, large eyes, small mouths, and wearing tight-fitting gray uniforms......

For this confusing past, Hua Feng didn't know if it was a harbinger of a possible interstellar war in the future.