Is the search for extraterrestrial civilizations a subject of scientific research if the object itself has not yet been found? And is contact with them so important if we are still unlikely to be able to apply the knowledge of a civilization that is millions of years ahead of us? Astronomers Vladimir Surdin and Lev Gindilis talk about methods of searching for brothers in mind in Alexander Gordon’s “Night Air”.
Working materials
Participants:Gindilis Lev Mironovich - Candidate of Physical and Mathematical Sciences, radio astronomer, senior researcher at the State Astronomical Institute named after. P. K. Sternberg (MSU), head of the SETI Scientific and Cultural Center of the Russian Academy of Cosmonautics named after. K. E. Tsiolkovsky
Surdin Vladimir Georgievich - astronomer, candidate of physical and mathematical sciences, senior researcher at the State Astronomical Institute named after. P. K. Sternberg (MSU), Deputy Chairman of the section “Search for Extraterrestrial Civilizations” of the Scientific Council for Astronomy of the Russian Academy of Sciences
Discussion plan:
1. Is the search for extraterrestrial civilizations a subject of scientific research? Can science exist without a subject of research? After all, not a single extraterrestrial civilization has been discovered yet. (There is no science about extraterrestrial civilizations yet. There is a science about methods of searching for extraterrestrial civilizations.)
What traces can be used to search for the CC? (Stories about “contacts” and UFOs, archaeological traces of visits, traces of space activity - there is nothing convincing yet.)
Is it really that important to establish contact with them? After all, we will not be able to apply the knowledge of a civilization that is millions of years ahead of us.
What impact will contact have on our civilization? Panic? Enslavement? Public indifference?
2. History of the search for extraterrestrial civilizations:
Background (before 1959)
Era of Sturm und Drang (1959–1980)
Crisis of the genre: from CETI to SETI
Transition to siege tactics
3. How the situation has changed over the past 40 years.
At the end of the Cold War, funding decreased;
Biologists have expanded the “boundaries of life”;
Astronomers have found planetary systems;
Radio astronomers have found organic matter in interstellar space;
Fossil microorganisms in meteorites?
Electronics engineers have created million-channel receivers.
4. Is the probability of success high: Drake’s formula:
If the search has not yielded results so far, is there a high probability of success in the future?
Is it possible to estimate the number of potential “brothers in mind”?
“Cosmic haystack”: still SETI - Terra incognita
In what range is it better to search?
5. In what language can the dialogue take place?
Pictograms of Drake and Pioneer
Voyager Gold Record
Constructed languages: Volapuk, Esperanto, Interlingua, Linkos
6. Let everyone know about us!
We have been transmitting into space for a long time
Can you hear us far away?
1974, Arecibo - message to the globular cluster M 13 - 1999, Evpatoria - Cosmoc Call
2002 Moscow - Children's SETI
7. Project SETI-Home: anyone can participate in the search for extraterrestrial civilizations via the Internet. Hundreds of thousands of people around the world are already actively doing this.
Possible questions for discussion:
Is there any danger for earthly civilization from contact with extraterrestrial intelligence?
Are there rules of conduct for those who first make contact with aliens? Can they speak on behalf of all earthlings?
Are they obligated to disclose the fact of contact or have the right to hide it for their own purposes?
Which countries are most actively involved in the search for extraterrestrial civilizations?
What is more important - the search process or the very fact of discovering extraterrestrial civilizations?
Video and audio
Electronic slides in JPG format, size 800 x 600, an episode from the movie “Contact”; recordings of space radio signals.
Materials for the program:
From the article by V. G. Surdin “Are there other civilizations?”
Scientists made many wonderful discoveries in the past twentieth century: the theory of relativity and quantum mechanics, nuclear reactions and superconductivity, DNA and quarks, neutron stars and black holes... You can’t list it all. But one, long-awaited and eagerly awaited discovery that could change our world has not yet taken place: we still have not been able to detect space brothers in mind. This search has been going on for more than 40 years, but the result is still negative. Every year, humanity increasingly feels its loneliness in the Universe and asks itself more and more serious questions: “Is life often born in the Universe? Does the development of life always lead to the emergence of intelligence? Does intelligent life necessarily strive to develop technology? Is a technically advanced civilization capable of surviving for a long time? How safe is it for us to search for brothers in mind?
These and many other important questions will remain unanswered until we establish contact with other intelligent beings, until we exchange knowledge about the Universe, life, mind and society with them.
The first attempts to make contact with extraterrestrial intelligence were made in 1960 by American radio astronomer Francis Drake and his colleagues in the OZMA Project. They pointed a radio telescope with a diameter of 26 m at the stars Tau Ceti and Epsilon Eridani, expecting that these stars, close to us and very similar to the Sun, could have planets similar to Earth, inhabited by technologically advanced creatures. If these creatures had the same equipment as Drake, then it would be possible to maintain radio contact with them. However, it was not possible to receive any messages from space at that time.
The OZMA Project was followed by other, much larger experiments. Radio astronomers in the USA, USSR, England, Australia and other countries pointed their sensitive antennas at hundreds of nearby and distant stars, star clusters and even other galaxies. At first this work was called CETI (Communication with ExtraTerrestrial Intelligents = Communication with Extraterrestrial Civilizations).
Later they began to use a more cautious name - SETI (Search for ExtraTerrestrial Intelligents = Search for Extraterrestrial Civilizations). It was meant that before establishing radio contact with brothers in mind, it was necessary to find at least some traces of their activities in space. But the main problem, of course, was not the name of the work, but how to carry it out. Each time, starting an experiment, the scientist had to decide what object to point the antenna at, what wavelength to tune the receiver to, and how to distinguish a reasonable signal from cosmic “noise.”
The first problem was usually solved simply: they pointed antennas at the nearest stars similar to the Sun, in the hope that there were planets similar to Earth near them. The second problem turned out to be more difficult. When we “catch” a radio station, we turn the receiver’s tuning knob and “wander” across the entire wavelength range. A powerful station can be heard immediately, but to find a weak transmitter, you need to slowly move from wave to wave, carefully listening to the rustling noise; this takes a lot of time. The signal expected from space is so weak that simply turning the receiver knob you will not find it; That’s why astronomical radios don’t even have such a knob. Each receiver is constantly tuned to one wavelength.
In the 1960s and 70s, scientists tried to guess at what wavelength we could expect transmission from space. A very popular idea was to look for a signal at a wavelength of 21 cm, since it is at this wavelength that interstellar hydrogen emits, filling the entire Galaxy. It is clear that every radio astronomer on any planet should know this wave and have an appropriate receiver. Now this search strategy looks naive. Just imagine: thousands of radio astronomers across the Galaxy sit at their receivers and wait for signals, and the transmission is carried out ... only by interstellar hydrogen.
Therefore, when a technical opportunity arose, radio astronomers changed their search strategy. Firstly, they began not only to receive, but also to transmit signals into space: the first radiogram was sent on November 16, 1974 from the Arecibo Observatory in the direction of the globular star cluster M 13. It contains about a million stars similar to the Sun, so it is likely that our message will be accepted by someone; but not soon - the signal will get there only after 25 thousand years.
The second important innovation relates to radio reception technology. Instead of “turning the tuning knob,” they are now creating special radio receivers that record the signal on several channels at once. In everyday life, we also use similar receivers with a fixed setting. But our receiver can remember from 3 to 30 stations and at the same time receives only one of them at a time. And special multi-channel radio telescope receivers during SETI experiments simultaneously listen to millions (!) of channels, covering almost the entire range of the cosmic airwaves.
True, the problem still remains unresolved: in the direction of which stars (or not stars?) the radio antenna should be pointed. The best solution is to listen to all corners of the Galaxy, but this requires a lot of time. In 1992, the American space agency NASA launched the most ambitious program to search for extraterrestrial civilizations, designed for 10 years. This project was called SERENDIP (SERENDIP = Search for Extraterrestrial Radio Emission from Nearby Developed Intelligent Populations, which means “search for extraterrestrial radio emission from neighboring developed civilizations”). As it takes place, the world's largest radio telescopes listen across the sky in hopes of finding something unusual.
It is curious that the word “Serendip” itself came to us from an ancient Persian fairy tale, which tells the story of three noble young men from the island of Serendip (as the island of Ceylon was called in the old days), who once went in search of an unknown beauty. The young men traveled all over the world for a long time and had incredible adventures. While wandering, they discovered so many amazing and unexpected things that they even forgot why they set off. Nowadays, this fairy tale has become popular, and its readers even invented a new English word “serendipity”, denoting a person’s lucky ability to easily make unexpected discoveries.
By giving the new project the name SERENDIP, scientists meant that equipping large radio telescopes with new “smart” equipment, even if it does not lead to the detection of intelligent signals, will still allow the discovery of interesting cosmic phenomena. This is what actually happens. Bye. But who can guarantee that tomorrow or even tonight we will not hear a reasonable signal from space?
From the article: V. G. Surdina “Drake’s Formula”
Discovering and studying extraterrestrial life forms is a biologist's dream.
Just as our Solar system “in one copy” could not provide astronomers with sufficient grounds for constructing a general theory of the origin of planetary systems, the unique terrestrial biosphere does not provide biologists with sufficient information for constructing a theory of the origin of life. Any information about extraterrestrial life would be invaluable.
The easiest way to obtain this information, as it now appears, is to establish contact with intelligent inhabitants of other worlds and exchange scientific information with them. How realistic is this? Forty years ago, American radio astronomer Francis Drake proposed a simple formula for estimating the number of intelligent communities in our Galaxy that are ready to make contact with us:
N = N * P1 * P2 * P3 * P4 * t / T,
Where n is the number of civilizations in the Galaxy ready for radio contact; N is the number of stars in the Galaxy; P1 - the proportion of stars with planetary systems; P2 is the proportion of planetary systems in which life arose; P3 - the proportion of biospheres in which life has reached the level of intelligence; P4 - the proportion of intelligent communities that reach the technical level of our civilization (or higher) and want to establish contact; t is the average time of existence of technical civilization; T is the age of the Galaxy. It is clear that the ratio t/T is the proportion of civilizations ready for contact that exist in the same era as us (in the event that civilizations arise and die at arbitrary moments in time evenly throughout the history of the Galaxy). Thus, Drake's formula divided a very complex problem into a number of simpler ones, a partial solution of which is available to specialists of different profiles. So far, we know with relative accuracy only three factors in this formula: the age of the Galaxy T ~ 10^10 years, the number of stars in it N ~ 10^11 and the frequency of formation of planetary systems P1 ~ 0.1. Each reader is free to evaluate the remaining factors in his own way; The author of this article has the following opinion on this matter: P2 ~ 1, P3 ~ 0.1, P4 ~ 1, t ~ 100 years. Substituting these values into Drake's formula, we see that several civilizations in the Galaxy are now ready for contact with us. Therefore, it makes sense to make an effort and finally establish this contact.
From the article: L. M. Gindilis, A. S. Satarinov “SETI: 90s”
Research and experiments in the search for extraterrestrial civilizations, which began in the 60s, continue in our time, despite the difficulties and problems that arise.
By the mid-80s, about 50 experiments were conducted around the world to search for signals from extraterrestrial civilizations (ECs). These studies were mainly carried out in the USA and the USSR. Individual experiments were carried out in France, Germany, the Netherlands, Canada, Australia and Japan. What is the current situation? The USA still holds the leading role. In Europe, including Russia, practically no searches are being carried out, although some projects in this area are being developed. But the countries of the southern hemisphere - Australia and Argentina - have intensified their efforts.
FOUR PROJECTS IN THE USA. In the USA, several programs are being carried out to search for CC signals in the radio range. The largest of these are the High Resolution Microwave Sky Survey (HRMS), SERENDIP, META/BETA and the Ohio Observatory program. They are all based on a similar ideology. Narrowband (monochromatic) signals with a bandwidth of several hertz or even a fraction of a hertz are sought. Such signals make it possible to obtain a higher signal-to-noise ratio and, therefore, for a given transmitter power, provide a greater detection range than for broadband signals (or, for a given range, get by with a more modest power). In addition, “narrowband” can be considered as a criterion for the artificiality of the signal, since we do not know natural radiation sources with similar parameters.
This ideology is not the only one possible. N. S. Karadashev, for example, substantiated the opposite concept of searching for broadband signals from supercivilizations. Given the level of our modern knowledge about CC, both concepts have the right to exist and can complement each other. In the USSR, the concept of searching for narrowband signals was actively supported and developed by V. S. Troitsky. Back in 1964, V. A. Kotelnikov substantiated the need to create multi-channel receivers containing up to a million spectral channels to search for such signals. Many years later, this idea was implemented in the USA, where unique megachannel receivers were developed specifically for SETI tasks. However, they can also be used for some applied tasks. So these receivers were used in the search for the Mars Observer spacecraft when radio contact with it was lost in August 1993.
Microwave imaging with high spectral resolution. On October 12, 1992, on the day of the 500th anniversary of the discovery of America, work began on the HRMS (High-Resolution Microwave Servey) project in the USA. American scientists have been preparing for this work for many years. They presented the first outlines of their plans at the All-Union Symposium on the Search for Intelligent Life in the Universe, which was held in Tallinn in 1981, and where American scientists were invited. The project is funded by NASA and consists of two parts - “targeted search” (i.e. searching for signals from specific objects) and “sky survey”. The targeted search examines 1000 sun-like stars located within a radius of 100 light-years. years from the Sun.
The second part of the project - the sky survey - is led by M. Klein and S. Gulkis from the Jet Propulsion Laboratory (JPL). Here the task is to study the entire sky. The review was planned to take approximately 6 years. In this case, research should be completed by the beginning of the next millennium. The review methodology is as follows. First, using the 34-m antenna, a strip of sky 1.4 degrees wide and 30 degrees long is quickly scanned. Then the computer sorts the received data and selects the most “suspicious” ones from all recorded sources. These sources are now studied in more detail (in slow scanning mode). This allows you to cut off false sources associated with various interferences. The remaining sources are entered into a special catalog for detailed study using large radio telescopes.
A “by-product” of these observations was to become radio astronomical maps of the Galaxy. And at that moment, when, it would seem, all the stages of scientific and engineering research associated with the creation of unique equipment were left behind, suddenly a message came that Congress had stopped funding this project. It is difficult to say what caused this decision. It is possible that the cessation of the Cold War, on the one hand, and the decline in the scientific potential of the former USSR, on the other, played a significant role here. During the years of confrontation, the two superpowers sought to maintain parity in the most important areas and not allow their partner to gain a significant lead. Now there is no need for this.
To the credit of the project leaders, it should be noted that they did not lose heart and made vigorous efforts to find sponsors. As a result, part of the project, namely targeted search, was able to be revived in the new Phoenix project, which is financed exclusively by donations from individuals and companies. To continue the program, funding of $3 million per year is required.
SERENDIP. Another program currently running in the United States is called SERENDIP. This is a program at the University of California, Berkeley. It is designed to receive signals from civilizations with a level of development close to ours (Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations, abbreviated SERENDIP.)
SERENDIP is a companion search program; it is carried out simultaneously with the implementation of the main astrophysical (or applied) task. That is, the output data of the receiving equipment on which routine radio astronomy observations are carried out is analyzed. This allows, without distracting radio telescopes from performing basic radio astronomical observations, while at the same time searching for CC signals.
By the end of 1994, about 30% of the celestial sphere was surveyed using the SERENDIP-III system (virtually the entire area accessible to observations with the Arecibo radio telescope). Over the entire duration of the program, about 400 “suspicious” sources were detected. However, unfortunately, the data is not enough to confidently attribute them to extraterrestrial artificial origin.
It is planned to further increase the spectral channels to 120 million (SERENDIP-IV). This system is planned to be used in Arecibo for observations in the 21 cm range. Meanwhile, the project also encountered financial difficulties, since the US Congress refused to allocate the necessary funds (about 12 million dollars). To support this unique project, the Friends of Serendip Society was created, headquartered at the University of California at Berkeley, headed by the famous writer and futurist Arthur C. Clarke.
Ohio Project. Another major program is being conducted at the University of Ohio in the USA using the Kraus radio telescope. The telescope has a knife-edge design and is therefore very convenient for complete views of the sky. It was used to conduct the 1st SETI sky survey in the 21 cm line. If we take all stars of spectral classes F, G, K within a radius of 1000 light. years from the Sun, then at any given time some three of them will be in the “field of view” (in the diagram) of the radio telescope. Since the sender of the signals and the receiver move relative to each other in space, due to the Doppler effect, the frequency of radio emission at the receiving point differs from the frequency at the emission point. Since the sender and receiver know nothing about each other in advance, their relative speed is unknown. Consequently, the frequency shift at the observation point is also unknown.
R. Dixon proposed a very ingenious idea: guided by the principle of anticryptography, each of the communication partners adjusts the signal frequency to some common frequency standard. According to Dixon, such a standard is taken to be a source stationary relative to the center of the Galaxy. In accordance with this, the Ohio survey was carried out at the frequency of the hydrogen radio line, corrected to the center of the Galaxy.
Observations under the SETI program began in December 1973. During these observations, a special SETI flag was raised over the observatory. During the observations, several interesting sources were discovered, including hydrogen clouds emitting in a very narrow frequency band. But a particularly interesting signal was recorded in August 1977. It was called the “Wow!” signal. This is approximately how one can translate into Russian the exclamation that the excited operator recorded on the recorder tape near this signal. A very strong signal, many times greater than the noise level, was observed in only a few spectral channels. Its characteristics pointed to a clearly extraterrestrial origin; its source was located near the ecliptic plane. The signal was observed for a very short time, and then disappeared and did not appear again. It was never possible to identify him. Maybe this was the CC signal?!
Project META/BETA. Finally, another program using multi-channel receivers (Mega-channel ExtraTerrestrial Assay, abbreviated META) is conducted by Harvard University in the USA in collaboration with the Planetary Society.
For 5 years, from 1986 to 1990, the sky region was surveyed in declination from -30° to +60°. At the same time, at a wave of 21 cm the area was blocked three times, and at a wave of 10.5 cm - twice. About 40 “suspicious” signals were detected, of which 8 can be considered the most reliable.
SEARCHING FOR SIGNALS IN THE SOUTHERN SKY. Australia. Experiments to search for TC radio signals began in Australia in the 60s and then continued in the 70s and 80s. The 64-m radio telescope at Parkes and antennas at NASA's Tidbinbilla station were used. Since no signals were detected, this negative result was used by the authors to estimate the upper limit on the time of existence of civilizations in the communication phase. Under some (rather arbitrary) assumptions, an estimate of 100 million years was obtained. That is, it is assumed that if the lifetime of civilizations (more precisely, the duration of the communication phase) was more than 108 years, then the signals would most likely be detected. (If, of course, CCs generally send signals in this range!)
Argentina. Since the early 90s, Argentine scientists have been actively involved in the search for CC signals. On October 12, 1990, the META-II project experiment began (see above). The META equipment is installed on the 30-m radio telescope of the Argentine Radio Astronomy Institute. Observations are carried out daily, 12 hours a day. It is intended to cover the entire southern sky.
This involves a repeated survey of certain areas of the sky, as well as observations of some nearby stars. If over 5 years of work under the META-I program about 10 “suspicious” signals were registered, then over 2 years of work under the META-II program - approximately the same number. Their sources are grouped towards the Galactic plane. However, the nature of the “suspicious” signals could not be established.
SEARCHING FOR SIGNALS IN THE OPTICAL AND INFRARED RANGES. Although most efforts have been focused on searching for signals in the radio range, during the 70s and 80s several experiments were carried out to search for laser signals in the optical range. The main advantage of an optical channel compared to a radio channel is its higher throughput, which makes it possible to transmit a huge amount of information in a relatively short time, as well as a much higher directivity of the transmitting beam.
When observed from Earth, the laser signal will produce a narrow spectral line in the spectrum of the star near which the CC laser transmitter is located. Consequently, the task comes down to the search for “laser stars” with ultra-narrow emission lines. This is what the experiments mentioned above boiled down to.
A particularly impressive search program for “laser stars” was carried out in the 70s and 80s at the Special Astrophysical Observatory under the leadership of V. F. Shvartsman. A special complex of MANIA equipment was developed, which makes it possible to detect ultra-fast, up to 10^-7 s, temporal variations in the light flux and ultra-narrow, up to 10^-6 angstem emission lines. The complex is designed to search for black holes, neutron stars and “star lasers”. That is, this is an example of a companion program when the search for CC signals is carried out in parallel with the solution of astrophysical problems.
The search objects also included two “Arkhipov stars”. According to the hypothesis of A.V. Arkhipov, developed extraterrestrial civilizations, having a power of 10^25 W, spend about 10^19 W for internal communication needs (i.e. the same share of the total power as we spend on Earth), using the range 100 - 1000 MHz. For "environmental safety" reasons, they place their radio transmitters at a distance of 1000 AU. from their sun. When observed from Earth, such radio transmitters can be detected near the nearest stars (located no further than 20 pc). They will be observed as radio sources with a flux of the order of 1 Jy, located at an angular distance of about 1 arcminute from nearby sun-like stars. After analyzing a catalog of nearby stars and a catalog of radio sources at a frequency of 408 MHz, Arkhipov found four cases of a radio source falling into a given neighborhood of stars of spectral classes F8 - K0. The probability of a random projection, according to his estimate, is 2 x 10^-4. Such objects, according to Arkhipov, may be of interest to the SETI program. Two of Arkhipov's four objects are in the southern sky. They were included in the Argentine program.
SETI IN RUSSIA. By the beginning of the 90s, experiments to search for CC signals in the USSR were practically stopped. The exception is the amateur project “Aelita”, carried out at the Orlyonok RDC (formerly the All-Russian Pioneer Camp of the Komsomol Central Committee). It includes two programs “Overview” and “Zodiac”. At the Special Astrophysical Observatory of the Russian Academy of Sciences, work continues on the search for laser signals, but the “center of gravity” of this research has been moved to Argentina.
FUTURE PROJECTS. Along with the use of existing radio telescopes, new SETI projects are being developed, the implementation of which will only become possible in the near or more distant future.
One of these projects - “Cyclops” - was developed back in the 70s by Stanford University in the USA together with NASA under the leadership of B. Oliver. The antenna of a radio telescope with an electrically controlled beam consists of a large number (from 1000 to 10,000) of mirrors with a diameter of 100 m each. All of them are combined with each other and form a single system, equivalent to a solid antenna with a diameter of 5000 m. The system is 10^12 times more efficient than the Ozma project. But its cost is very high (comparable to the Apollo project for landing a man on the Moon). Therefore, although the project was developed in the early 70s, it has not yet been implemented.
The possibilities of using some existing and under construction radio telescopes seem more realistic. This is how the construction of the giant radio telescope GMRT ends in India. It consists of 30 antennas with a diameter of 45 m and its collecting area will be comparable to the Arecibo radio telescope.
In France, the Large Radio Telescope in Nance is being reconstructed, one of the reasons for which is the possibility of adapting it for SETI tasks. The radio telescope is planned to be used for the HRMS targeted search program (approximately 200 days per year for the last decade). In Italy, work is underway to create a multichannel spectrometer, which is planned to be used for SETI sky survey in the 408 MHz range.
R. Dixon (USA) is developing an omnidirectional detection system for SETI tasks, in which a large number of small antennas are connected using computers into a common system for continuous monitoring of the entire sky. To some extent, it can be considered a development of the “Review” system proposed by V. S. Troitsky in 1981 in Tallinn.
The capabilities of ground-based radio telescopes are limited. One of the limiting factors is the absorption of radio waves in the Earth's atmosphere, as well as noise caused by the atmosphere's own radiation. Another limitation is related to the design of radio telescopes - on Earth it is impossible to create an accurate reflecting surface of very large sizes due to the deformations that the structure experiences under the influence of gravity, as well as from wind loads. For centimeter-wave radio telescopes, the maximum size is on the order of several hundred meters. All these restrictions do not exist in outer space. Therefore, the use of space radio telescopes (SRT) for SETI tasks is very promising.
Additional opportunities arise when using SRT as part of a ground-space radio interferometer. As is known, the larger the interferometer base (the distance between its constituent antennas), the higher the angular resolution of the system. For ground-based interferometers, the base is limited by the size of the globe. If one or more radio telescopes are placed in outer space, then the size of the base can be much larger than the size of the Earth.
At the Astrospace Center of the Physical Institute named after. P. N. Lebedev under the leadership of academician. N. S. Kardashev developed the RADIOASTRON project, which provides for the launch of the SRT into orbit with a distance from the Earth (at apogee) of 100 thousand km. Working in tandem with ground-based radio telescopes, it forms a radio interferometer, the resolution of which will be 10.-6 arc seconds!
A radio image with this angular resolution will make it possible to detect structures 100 - 1000 km in size from a distance of several parsecs. And structures such as Dyson spheres can be detected from distances greater than the size of the Galaxy. The possibility of building a radio telescope on the far side of the Moon, protected from terrestrial radio interference, is also being discussed. But, as far as we know, there are no specific developments yet. This is probably already a 21st century project.
HUMANIZATION OF SETI. When characterizing the state of SETI in the 90s, one cannot remain silent about the tendency to humanize SETI. On the one hand, the 90s were marked by major technical achievements, the development of research and experiments, which were mentioned above, on the other hand, there was a desire to go beyond technical and natural science issues. In Russia, this trend was expressed in the creation of the SETI Scientific and Cultural Center at the Academy of Cosmonautics named after. K. E. Tsiolkovsky.
In the West, it manifested itself in the development of a number of educational programs based on the ideas of SETI, and in the broader issues of reports at scientific sessions of SETI. In this regard, the International Interdisciplinary SETI Seminar, held in Finland in March 1993, should also be noted. Finally, on the initiative of J. Billengham, it was decided to hold an international conference “SETI and Society” in France in 1995, at which it is expected to consider historical, sociological, political, psychological, philosophical, religious and other aspects of SETI. All this suggests that SETI is beginning to be recognized as a general scientific and general cultural problem.
Bibliography
SETI Newsletter. 2000–2002
Extraterrestrial civilizations. The problem of interstellar communication/Ed. S. A. Kaplan. M.: Nauka, 1969.
Gindilis L. M. SETI in Russia: the last decades of the twentieth century // Earth and the Universe. 2000. N 5 and N 6.
Gindilis L. M. SETI: Search for extraterrestrial intelligence. M.: Fizmatlit, 2002.
Efremov Yu. N., Gindilis L. M. SETI and the progress of astronomy // Astrophysics at the turn of the century. M.: Janus-K, 2001.
Kardashev N. S. Cosmology and SETI problems // Earth and the Universe. 2002. N 4.
Kardashev N. S. Hidden mass and the search for extraterrestrial civilizations // Astrophysics at the turn of the century. M.: Janus-K, 2001.
The problem of searching for extraterrestrial civilizations. M.: Nauka, 1981.
The problem of searching for life in the Universe. M.: Nauka, 1986.
Sullivan W. We are not alone. M.: Mir, 1967.
Surdin V.G. Life in the Universe. Panspermia hypothesis. Drake's formula. What is SERENDIP?/Astronomy. M.: Avanta+, 1997–2002.
Shklovsky I. S. Universe, life, mind. M.: Nauka, 1962, ... 1987.
SETI Newsletter. 1993–2000
Sagan S. The Cosmic Connection. An Extraterrestrial Perspective. New York: Anchor Press, 1973.
Sagan S. et al. Murmurs of Earth: The Voyager Interstellar Records. New York: Random House, 1978.
Sagan S. Pale Blue Dot: A Vision of the Human Future in Space. New York: Random House, 1994.
SETI on the threshold of the 21st century. Proceedings of the Moscow Conference 2002/www.astronet.ru:8101/db/msg/1177541.
Broadcast 09/17/2002
Timing: 00:50.
“We know that there are hundreds of billions of planets like Earth. We also know that there are all kinds of complex organic molecules in the Galaxy. That is, everything that we think is necessary for the emergence of life is there.
So I think the odds are pretty high that there is life somewhere else in the galaxy." (Andrew Simion, director of the SETI Research Center at the University of California, Berkeley).
Where can we look for our “brothers in mind” in the vast expanses of the Universe? A unique woman tried to answer this question 55 years ago. SETI (Search for Extraterrestrial Intelligence) program.
The search for the homeland of the little green men, about whom ufologists talked so much, began with the Ozma project, launched in 1960 by astrophysicist Frank Drake. Drake's team began listening to space with the 25-meter Green Bank radio telescope in the direction of nearby sun-like stars: Tau Ceti and Epsilon Eridani.
The project ended without results, but in 1971 NASA joined the search for signals, proposing the Cyclops plan. It involved the use of one and a half thousand radio telescopes and was supposed to cost almost ten billion dollars. Two decades of hard work did not bring any discoveries, and in 1993 the project was mothballed.
In subsequent years, SETI was supported by modest private grants and donations. Unexpectedly, in the 55th year of the program's existence, Russian businessman Yuri Milner announced the allocation of one hundred million dollars for a ten-year search for intelligent life in the Universe. One of the project's scientific consultants will be world-famous physicist Stephen Hawking.
IN THE WOODS OF "KEPLER"
In 1988, a strong hurricane toppled the Green Bank radio telescope, and twelve years later the largest fully rotating and ultra-sensitive radio telescope of the US National Radio Astronomy Observatory arose in its place.
The 100-meter antenna of the 77,000-ton structure is capable of receiving up to a gigabyte of data per second. Radio astronomers decided to search at wider frequencies, trying to receive more signals. Each day, one of 86 exoplanets will be scanned, selected from 1,235 planetary systems discovered by NASA's Kepler Space Telescope.
“Using large radio and optical telescopes, we will look for electromagnetic or light radiation that may come from technology built by some highly advanced intelligence living on a planet that orbits one of the stars in the Galaxy,” said Andrew Simion, director of the research center. SETI University of California at Berkeley.
Another participant in the SETI project was the radio astronomy observatory in Arecibo (Puerto Rico).
In 1974, from its 305-meter “dish”, located in the crater of an extinct volcano and suspended on three 110-meter towers, an “interstellar telegram” was sent in the direction of the globular star cluster M13.
Such a destination at a distance of 25,100 light years was not chosen by chance, because such clusters of stars are the oldest in our Galaxy, which means they can contain highly developed civilizations.
The Arecibo Message contained the position of the solar system, an image of a person and chemical formulas. True, taking into account the colossal distance, our distant descendants will receive the answer only after 52,166 years.
Arecibo scientists selected planets with temperatures from 0 to 100 degrees Celsius, lying in the conventional planetary “belt of life.”
Subsequent observations of this outstanding tandem of radio telescopes did not bring anything new, showing the deep conditionality of the planetary field of life. Indeed, even in our solar system, the “Goldilocks zone” (as Western astronomers call the “belt of life”) includes Venus, Mars, and the Moon...
Nevertheless, the very principle of preliminary selection of potential objects for observation using space telescopes has given rise to a new round of SETI research.
THEY WILL ANSWER... UNTIL 2025
Exactly 20 years ago, American SETI enthusiasts, dissatisfied with meager funding from the Capitol, NASA and the Pentagon, decided to create their own research center, supported by private donations and grants from charitable foundations.
This is how the non-profit SETI Institute in Mountain View (California) was born. At the same time, the permanent director of the SETI research center for 35 years (!) until 2012 was the famous astronomer Jill Tarter.
Those who have read the wonderful novel “Contact” by the outstanding astronomer and popularizer of science Carl Sagan will probably remember astrophysicist Ellie Arroway, who devoted her life to the search for intelligent radio signals from space. In the film of the same name, Jodie Foster brilliantly embodied her selfless service to science.
Meanwhile, behind the image of Dr. Arroway it was Dr. Tarter, whom Sagan knew well. Professor Tarter is considered the largest astrobiologist and at one time was even named among the hundred most influential people on the planet by Times magazine.
Having retired, Professor Tarter is doing his best to find a minimum of a couple of million dollars for the more or less stable operation of the institute and research center. According to her, the cessation of government funding for SETI will inevitably lead to US losses in the field of radio astronomy research technologies.
It was Tarter who was at the origins of the large-scale Phoenix project, which included the study of thousands of nearby sun-like bodies in the radio range of 1,200-3,000 MHz. This project used extremely sensitive instruments, capable in principle of detecting the radiation of a conventional airfield radar at a distance of hundreds of light years.
Over two decades, the SETI Research Center has scanned thousands of stars using a modest annual budget of $5 million for such an institution.
In current work and future research, the new leadership of the SETI Institute intends to focus on cooperation with the NASA team servicing the Kepler telescope. At the same time, Dr. Tarter believes that the vast experience of the SETI Center staff will help detect “alien signals” even before Kepler and other space telescopes find a habitable planet in the “life zone.”
Alas! So far, the only and rather controversial result can be considered a signal received on January 5, 2012 in the direction of the exoplanet KOI 817.
WORKING PROJECT MILLIONS
In 1999, the amazing “millions of Internet users project - SETI@home” was launched at the radio astronomy laboratory at the University of California at Berkeley. The basis of this unusual mission was to recruit millions of Internet users who wanted to participate in the search for signals from alien intelligence.
SETI enthusiasts should download special programs from the World Wide Web that work in screensaver mode. These programs process packets of radio signals received by radio telescopes during the current SETI mission.
Currently, the team of green men search engines has already been replenished with several million users from more than two hundred countries. They have already spent more than a billion dollars in electricity alone, although this is imperceptible to each participant in the project. To date, this is the most ambitious scientific project in the history of the Internet!
And although the SETI@home project has not yet discovered a single intelligent signal, it is precisely this that Milner’s team wants to connect to, which, in addition to Stephen Hawking, has already been supported by Jill Tarter, radio physicist Dan Wertheimer, who heads the project at Arecibo, and leading astronomer at the SETI Institute Seth Szostak .
The latter confidently predicts that if the Allen Telescope's most expensive system of 350 antennas were deployed, it would "stumble upon a signal before 2025."
Oleg ARSENOV
The study of extraterrestrial civilizations must be preceded by the establishment of one form or another of communication with them. Currently, there are several directions for searching for traces of the activity of extraterrestrial civilizations.
Firstly, the search for traces of astro-engineering activities of extraterrestrial civilizations. This direction is based on the assumption that technically advanced civilizations must sooner or later move on to transforming the surrounding outer space (creating artificial satellites, artificial biosphere, etc.), in particular to intercept a significant part of the star’s energy. As calculations show, the radiation of the main part of such astro-engineering structures should be concentrated in the infrared region of the spectrum. Therefore, the task of detecting such extraterrestrial civilizations should begin with a search for local sources of infrared radiation or stars with an anomalous excess of infrared radiation. Such studies are currently underway. As a result, several dozen infrared sources were discovered, but so far there is no reason to connect any of them with an extraterrestrial civilization.
Secondly, the search for traces of visits by extraterrestrial civilizations on Earth. This direction is based on the assumption that the activity of extraterrestrial civilizations could manifest itself in the historical past in the form of a visit to Earth, and such a visit could not but leave traces in the monuments of the material or spiritual culture of various peoples. Thus, the problem of extraterrestrial civilizations comes closer to the history of culture, archeology, where there are also many “blank spots”, riddles, secrets and problems. On this path there are many opportunities for various kinds of sensations - stunning “discoveries”, quasi-scientific myths about the cosmic origins of individual cultures (or their elements); Thus, the story of the astronauts is the name given to the legends about the ascension of saints to heaven. The so far inexplicable construction of large stone structures also does not prove their cosmic origin. For example, speculation of this kind around giant stone idols on Easter Island was dispelled by T. Heyerdahl: the descendants of the ancient population of this island showed him how it was done not only without the intervention of astronauts, but also without any technology. In the same row is the hypothesis that the Tunguska meteorite was not a meteorite or a comet, but an alien spaceship. These kinds of hypotheses and assumptions need to be examined most carefully.
Thirdly, the search for signals from extraterrestrial civilizations. This problem is currently formulated primarily as the problem of searching for artificial signals in the radio and optical (for example, a highly directed laser beam) ranges. The most likely is radio communication. Therefore, the most important task is to select the optimal wave range for such communication. The analysis shows that the most likely artificial signals are at waves λ ≡ 21 cm (hydrogen radio line), λ ≡ 18 cm (OH radio line), λ ≡ 1.35 cm (water vapor radio line) or at waves combined from the fundamental frequency with which -or a mathematical constant (π, e, etc.).
A serious approach to searching for signals from extraterrestrial civilizations requires the creation of a permanent service covering the entire celestial sphere. Moreover, such a service must be quite universal - designed to receive signals of various types (pulse, narrowband and broadband).
The first work on searching for signals from extraterrestrial civilizations was carried out in the USA in 1960. The radio emission of nearby stars (τ Ceti and ε Eridani) at a wavelength of 21 cm was studied. Subsequently (70-80s), such studies were also carried out in the USSR. The research yielded encouraging results. Thus, in 1977 in the USA (Observatory of the University of Ohio), during a survey of the sky at a wavelength of 21 cm, a narrow-band signal was recorded, the characteristics of which indicated its extraterrestrial and, probably, artificial origin. However, this signal could not be detected again, and the question of its nature remained open. Since 1972, searches in the optical range have been carried out at orbital stations. Projects for the construction of multi-mirror telescopes on Earth and the Moon, giant space radio telescopes, etc. were discussed.
Searching for signals from extraterrestrial civilizations is one aspect of contact with them. But there is another one - a message to such civilizations about our earthly civilization. Therefore, along with the search for signals from space civilizations, attempts were made to send a message to extraterrestrial civilizations. In 1974, from the radio astronomical observatory in Arecibo (Puerto Rico) towards the globular cluster M-31, located at a distance of 24 thousand light years from Earth, a radio message was sent containing coded text about life and civilization on Earth. Information messages were also repeatedly placed on spacecraft, the trajectories of which provided them with exit beyond the solar system. Of course, there is very little chance that these messages will ever reach their goal, but we have to start somewhere. It is important that humanity is not only seriously thinking about contacts with intelligent beings from other worlds, but is already turning out to be able to establish such contacts, even in the simplest form.
In the last decade, the opinion has increasingly prevailed among scientists and philosophers that Humanity is alone, if not in the entire Universe, then at least in our Galaxy. This opinion entails the most important ideological conclusions about the meaning and value of earthly civilization and its achievements. It is quite possible that our planet Earth is the highest “color” of the development of the entire or at least a huge part of the Universe; all the main results, the results of the self-development of the World and Nature are concentrated in humanity. This means that we, people, humanity, are to a huge extent responsible - not only for our planet, but also for the development of the Universe as a whole!
In 1960 Cornell University astronomer Frank Drake laid the foundation for an experiment called SETI (Search for Extra-Terrestrial Intelligence), in which scientists around the world search for signals from extraterrestrial civilizations. Initially, Drake began monitoring radio signals coming from the stars Tau Ceti and Epsilon Eridani, which were considered the most likely candidates for the presence of Earth-like planets. Within two months, the antennas were installed in the direction of two neighboring stars, his receiver was tuned to a frequency of 1420 MHz. So far, no signals of extraterrestrial origin have been detected. Drake also created his famous formula, the Drake equation, to calculate the number of civilizations in the galaxy with which contact is possible.
Around the same time, physicists Cocconi and Morrison published an article in the journal Nature, where they noted the great potential in using radio waves in the search for extraterrestrial civilizations.
Physicist Enrico Fermi formulated a thesis (Fermi's paradox) in response to the rather high estimate of the chances of interplanetary contact according to the Drake equation: if there are so many alien civilizations, why does humanity not observe any traces of these civilizations? The hypothesis of the uniqueness of the Earth, which is put forward by some physicists and astronomers, tries to explain this paradox. They argue that all forms of life must be carbon-based like ours.
Currently, Frank Drake is the director of the Center for the Study of Life in the Universe and is engaged in the search for optical signals of extraterrestrial origin, as well as the development of radio telescope projects for SETI. In particular, his proposals are used in the design of the Allen Composite Radio Telescope (named after Paul Allen, the founder of Microsoft) in California, one of the most famous projects in the search for extraterrestrial intelligence.
The first 42 antennas of the telescope were launched in 2007, and in total it is planned to build an array of 350 antennas to search for extraterrestrial civilizations.
The USSR also showed interest in the search for extraterrestrial intelligent life forms in the early 1960s. A group of enthusiasts was assembled at the Sternberg State Astronomical Institute to work on searching for signals from space. This idea was supported by outstanding physicists. At that time, the Americans did not enter the name of their SETI project, so the Russian program had the interesting name “Project Au”. Russian specialists managed to do a lot during this time: in addition to active discussion of the problem, they explored the distant depths of space. And today, technology makes it possible to view the Universe in the entire range of radio emissions, recording the emission spectra of distant stars.
In 1962, the first radio message was sent into space; it contained three words “Peace, Lenin, USSR.” In 1774, the Americans sent their signal from the Arecibo radio telescope. Three subsequent messages were sent from the radar telescope in Evpatoria in 1999, 2001 and 2003 by the Institute of Radio Engineering and Electronics. They contained digital and analogue information (texts and music) and headed towards several solar-type stars.
It is assumed that these messages will take at least 30 years to arrive and the same amount of time to return. Some experts believe that all of this is an attempt to find a civilization similar to ours. But perhaps there are other civilizations that are millions of years older than ours, and they communicate with each other using “dark matter.” There is an assumption that the presence of this particular matter explains the “silence” of the Universe. The Physics Institute of the Academy of Sciences has compiled a list of the hundred closest star systems to Earth, having analyzed the entire array of stars discovered by mankind. Of these, approximately 58 may be SETI objects.
In 2006, the US Planetary Society, as part of the SETI project, introduced a new powerful telescope to search for extraterrestrial civilizations. By this time, many years of experience in the field of radio research had been accumulated and it was decided to focus efforts on searching and recording light rather than radio signals from space. Visible light can easily travel through space, and a focused bright beam like a laser can be several times brighter than the Sun, allowing it to be detected from cosmic distances. Light signals, unlike radio waves, are unidirectional, which makes it possible to identify their source. Extraterrestrial civilizations, according to the American community, can use light signals to communicate with Earth with the same success as radio signals.
The telescope was installed at the Massachusetts Observatory and cost more than $400,000, much less than the cost of a conventional research telescope. Interest in the SETI project has grown, and many hopes are pinned on it.
Since 1995, within the framework of the SETI project, the distributed computing project SETI@home began its work. It involves the participation of volunteers who must provide free resources from their home computers to process signals collected from space.
Now, by registering on the project website, a participant can even improve the code of programs used to decipher and process the digital signal from the Allen telescopes. Specialists with programming skills can study the processed data in a collective search for possible signals of artificial origin.
At the annual conference in California, which took place in 2010, a prize was awarded for the dissemination of worthy ideas in this area. It was received by astronomer Jill Tarter, who wished that all earthlings would have the opportunity to become active participants in the search for extraterrestrial civilizations. In the same year, in honor of the 50th anniversary of the project to search for intelligent life in the Universe, residents of Great Britain had the opportunity to send messages to extraterrestrial civilizations. All citizens over 16 years of age who wished to send this message filled out a form on the Penguin website of no more than 40 words. The first several thousand messages were sent into space using a radio telescope, and the authors of the most interesting messages received a book by theoretical physicist Paul Davis, “An Ominous Silence: Are We Alone in the Universe?”, dedicated to the SETI project. The advertisements varied in content, including humorous ones, for example, “An attractive life form, wondering if it is alone in the Universe, wants to meet other life forms for a serious relationship. You need to have a good sense of humor."
This was stated by David Messerschmitt from the University of California at Berkeley. He disclosed this statement in his work, which should change the approach to the search for extraterrestrial civilizations.
The most common statement that radio is the best and final form of communication is not the ultimate truth, and this is not surprising, because we ourselves have been using this technology only recently (even by earthly standards). However, without a more convenient alternative for searching for other civilizations, it is necessary to optimize and improve this process as much as possible, Messerschmitt believes.
According to the researcher, the first step is to get rid of the problem of excessive load in the case of listening and sending a signal not to a specific area, but in all directions. In his opinion, the best optimization strategy should adhere to the principle that the transmission power should be strictly limited. Since the transfer itself requires a huge amount of time, there is no point in chasing a high transfer speed.
There are other options, but each of them has its own disadvantages. For example, for economical signal transmission, you can use the polarization of electromagnetic waves and various types of multiplexing, however, despite the fact that this will save energy, another problem arises - focusing on contact with civilizations that have already mastered this technology (so, if, the level technology of an extraterrestrial civilization will be the same as ours in the 1960s, then they will not be able to receive the signal). On the other hand, this minus cannot be called big, but it is unpleasant - calmly. And therefore, optimization in this vector is quite doubtful.
The researcher suggests using methods that are not popular for SETI. Messerschmitt notes that by using the widest possible range, the average energy cost should be much more economical than a fixed-frequency broadcast approach (as SETI does). That is, if computer centers think the same way, then it is necessary to search for more broadband signals with lower power and information transmission speed.
In addition, the author of the work believes that the SETI approach to search strategy is fundamentally wrong. The main problem lies in the fact that the so-called “truth check” takes a lot of energy for a long repeating signal - they try to distinguish a real signal from a false one by long-term “listening” to a specific sector. At one time, a similar problem was encountered in 1977, when the so-called “Wow!” signal was recorded. This signal was received by the Big Ear radio telescope, but to verify its origin, it was the “truth check” method that was used and the signal was not confirmed and intercepted again. It would seem that listening should take place on an ongoing basis, but neither then nor now is such a strategy used.
If we follow the thought of David Messerschmitt and assume that the digital center transmitting the signal saved energy, then register the “Wow!” signal. researchers could not for a very simple reason - there was no need to repeat the signal more often than, for example, once every few years.
Avoiding such failures, according to the researcher, can be quite simple - for this you need to systematically and for a long time examine each sector of the sky, moving away from the strategy of not systematically “listening” to different parts and maintaining a database of all signals supposedly of artificial origin.
Note that SETI (Search for Extraterrestrial Intelligence) is the general name for projects and activities to search for extraterrestrial civilizations and possible contact with them. The beginning of the project dates back to 1959. There is an opinion that the SETI project could pose serious dangers. It is assumed that a highly developed alien civilization may use radio signals as an information weapon or a means of its own propagation
