For many years, scientists have been hoping to get even a faint sound from alien life through electronic signal receiving equipment. Moreover, in space, various signals-some like the knocking of a hammer, some like the noise of an electric welding machine-are really inspiring scientists. It is the existence of these signals that makes more and more powerful telescopes be made, and it also makes people think about the question: Are we alone in the vast galaxy? Do aliens, or strictly speaking, alien life really exist? With the increase of funds and facilities, the progress of technology and the continuous expansion of space discovery, the answer to this question is getting closer and closer to us. Researchers say that in just a few years, we will be able to detect whether there is a possible civilization outside the solar system. Kent, director of the R&D department of the California Institute for Searching for Extraterrestrial Life, said. Kuhles said that the detectable area "is showing explosive growth"; He himself was "not only excited, but also admired". More than a decade ago, the exploration of extraterrestrial life was more ridicule than encouragement. At that time, the United States Congress expressed great doubts about this, and NASA also stopped the original small-scale research projects, so the research of such projects was all carried out by private institutions. But now, the interest in this field has been aroused widely, and one of the factors is the development of science and technology. Cosmologists are constantly developing new planets that revolve around other stars-a discovery that shows that there may be a large number of small galaxies similar to the sun in the vast galaxy. NASA is planning to build two telescopes, the main purpose of which is to detect the conditions of terrestrial planets outside our solar system. Another important reason why scientists have never given up looking for extraterrestrial life is the rapid progress of science and technology. With the popularization and upgrading of electronic computers and receiving equipment, people can detect and analyze weaker signals than in the past; Advances in technology give researchers the opportunity to expand their research beyond radio signals and visible light. At present, at least two ground-based telescopes are being made, and their purpose is also to detect alien life. In August this year, the leading scientists in charge of searching for extraterrestrial life will meet at Harvard University to discuss the prospects of potential new projects. Despite countless efforts, scientists are still empty-handed. However, this is an incentive in itself. Dr Kuhles said: "The Milky Way we have detected is only a small part. For example, it may be about 700 to 800 stars among billions of stars. If we can develop like Moore's Law in the computer industry, we will be able to detect far more than today's quantity within 50 years. " Dan is a researcher in the Space Science Laboratory of the University of California, Berkeley, a cosmologist and one of the pioneers in the search for extraterrestrial life. Worthimo said, 1960 American cosmologist Frank. When Drake first started receiving signals from space, he could only receive one frequency; In 1970s, the new receiver could detect 100 frequencies at the same time. Now, cosmologists can receive 65.438+68 billion frequencies at the same time, and it is doubling every year. A new "model" is being established in this field. After accumulating the main problems and required experiments in astronautics and cosmology in the past 10 years, a group of experts from the National Research Council concluded that the search for the telescope being built by the Institute of Extraterrestrial Life and the University of California, Berkeley is an encouraging project. Although this expert group has previously affirmed the project of searching for extraterrestrial life, this 200 1 document is the first time in history to recognize such private non-profit projects. In addition, influenced by Congress on 1993, NASA suspended its search plan, and has called a scientist from the Institute for Searching for Alien Life into its own Institute for Space Biology. Dr. Kuhles said that there was a time when searching for extraterrestrial life almost became an insulting word in NASA; But now, researchers in this project can compete for funds for their own projects under completely equal conditions. At present, the "Allen Telescope Array" is higher on the list of construction projects. This is a new type of radio telescope, which will be located in Hart, University of California, Berkeley. Crick Observatory covers an area of 1 hectare. Within the coverage of the antenna, scientists can receive signals from stars, galaxies, nebulae and other celestial bodies in space for 24 hours through telescopes, and can also track dark matter or other substances. In March this year, Paul Allen, the former CEO of Microsoft, announced that he would donate $654.38 million+$03.5 million to support the telescope array project. At present, Paul Allen Foundation has paid 1 1.5 million dollars to help build the first batch of 32 antennas, which are expected to be put into operation by the end of this year. The reason for the continuous construction of radio telescopes is that the United States is actively competing with the world, and plans to build a huge radio telescope array covering an area of 205 acres (83 hectares), which is expected to be put into use in 2020 after site selection. Among them, the construction of Allen telescope array is a great progress. Dr. Kuhles pointed out that the goal of the current research project is to enable the life exploration project based on radio technology to find multiple modes of signals at the same time, including very complex signals, such as signals transmitted by mobile phones. If radio signals are the main means to find other civilizations in the galaxy, researchers are still expanding various forms of optical signals as a medium of communication and contact. Paul Horowitz, a professor of physics at Harvard University, said that the invention of laser increased the possibility of exciting a powerful laser through 1 billionth of a second, and then emitting it in the opposite direction through a telescope. Herowitz said that the brightness of this laser is 5,000 times that of sunlight, which is similar to the fading probability of starlight, so "as long as you can see the stars, you can see the beam". So far, Horowitz and his colleagues at Harvard University and Princeton University have observed 65,438+05,000 stars without any results. But they are not discouraged. They are building a 72-inch (1.8m) telescope to observe a larger area at the same time. According to their plan, the telescope built by California Planetary Group with a donation of $350,000 is expected to be put into use this year. At the same time, other research institutions, such as the Rick Observatory in California, are also raising more elaborate projects. One of the key points is infrared, that is, light waves outside the visible range observed by electromagnetic spectrum. Freeman of the Institute of Advanced Studies at Princeton University was the first to study infrared rays. Dyson. As early as 1959, he put forward a hypothesis that advanced alien civilization would build orbital settlements and solar power stations, and make the planet's appearance shrouded in a "shell". This "dyson sphere" will emit a lot of infrared radiation, which becomes its unusual symbol. This theory was very attractive at that time. But soon, cosmologists found that stars like the sun-especially those with dust or gas around them-would emit too much infrared rays, similar to the dyson sphere mentioned above. Dr vashimo and his colleague Charles. Conroy has conducted infrared radiation detection on some aging stars, which have entered their twilight years and will not have planetary rings. Different from previous observations, this time they mainly collected data from ground-based and space infrared telescopes. They have completed the observation of 32 possible stars in dyson sphere. Results The observatory in Puerto Rico has proved that 20 of them have no special radio emission and light pulse, and through ordinary optical observation, 25 stars have nothing special. Other scientists are planning to look for infrared laser pulses. They believe that finding this infrared laser is also a very good choice, because cosmic dust, which usually blocks visible light, cannot stop this pulse. Expanding the coverage of a wider range of wavelengths and more transmission modes is an investment in the right direction; However, it is not correct to limit the research to a communication mode or strategy itself. Worthimo said: "It is foolish to think that we know exactly what ET is doing." Rob, former director of the NASA Institute? In an interview with 1985, Dr. Jietino said, "The earth has no special characteristics in the universe. There are10 billion galaxies in the universe. The Milky Way, where we humans live, consists of 300 billion to 500 billion stars. We cannot assert that the planet where humans live is only the solar system. " He believes that flying saucers exist. In recent years, American astronomer Drake developed Drake equation, and estimated that there should be100000 to100000 intelligent and civilized planets in this galaxy. Dr. The sand, an outer space biologist at Cornell University in the United States, estimated that there should be one million planets similar to earth civilization in the Milky Way. It is known that there should be intelligent aliens on other planets in the universe. Some of them have a longer history of wisdom and civilization than us, and technology surpasses us. For today's astronomers, the search for aliens is no longer just a story in science fiction, but an action put into practice. Send out the information of interstellar probes 1972 pioneer 10 and 1 1973 pioneer 1. Everyone carries an aluminum plate with a man and a woman painted on it, and also draws a map indicating the position of the earth in the Milky Way, so that aliens who want to contact the earth can find it according to the map. This is the first time that man has launched a spaceship to leave the solar system. 1977 Voyager 1 and No.2 each contain a video recording life on the earth and a copper CD recording various special sounds made on the earth. The earth calls to the universe, please respond when you hear it' 1974. Arecibo radio telescope, Puerto Rico, sent radio waves with the frequency of hydrogen atoms to the M 13 cluster (a cluster of 300,000 stars connected by gravity), carrying information about the earth. The news is still sailing to the cluster, and it will not arrive until 24,000 years later. Listening to the information of the alien 1992, NASA implemented a plan to search for 1000 stars similar to the sun with two precise frequencies, and to scan the sky on a large scale at millions of frequencies, looking for artificial signals that may be sent by distant civilized worlds. The vast universe, the vast starry sky, do aliens exist? Where the hell are they? I hope that in the near future, scientists from all over the world can give mankind a satisfactory answer. We can only wait and see.