For many centuries, humanity has dreamed of establishing contact with an extraterrestrial civilization. But, perhaps, only one person managed to prove to the world that the search for extraterrestrial intelligence is a serious scientific direction, and not a kind of mania. His name was Carl Sagan, and he wrote and sent the aliens a real letter. Even two.
Pioneer means first
In 1972-1973, two research vehicles, Pioneer 10 and Pioneer 11, were sent to Jupiter and Saturn. Their main task was to photograph the gas giants from more or less close range. Both "Pioneers" successfully completed their mission and set off to drift into distant space.
Along with the Voyager-1 launched a little later, the Pioneers became the first man-made vehicles to leave the solar system and find themselves in deep space. This was all planned.
That is why the "Pioneers" were chosen by the famous astronomer and popularizer of science Carl Sagan to carry aluminum tablets - messages to distant worlds with brief information about people and the Earth.
If a distant alien intelligence ever "captures" any of the devices, even after a million years, it will be able to decipher the pictograms invented by Sagan.
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The plates depict the ship itself (for scale), as well as the figures of a man and a woman. A diagram of the solar system and a diagram of the location of the Sun relative to the nearest 14 pulsars and the center of the Galaxy are engraved next to them (a pulsar is a neutron star that is a source of some kind of radiation, usually radio or light).
The coordinates of the Sun relative to the pulsars are unchanged, like the position of other stars, which means that the aliens will be able to orient themselves. Also, on the plates, a hydrogen atom is schematically depicted, the radiation wavelength of which is taken as a unit of measurement (in them, for example, a woman's height is indicated).
Carl Sagan died in 1996, long before the Pioneers left the solar system, but he knew perfectly well that he would not live to see contact, if one ever happened. He just tried to look into the very, very distant future.
How to become an astronomer
Sagan was born in Brooklyn in 1934 to an immigrant from Russia who married a girl from New York. The family lived in poverty, especially against the backdrop of the Great Depression.
Karl's parents were ordinary people with no education, but his father wanted his son to grow up different. He took little Karl to the Natural History Museum, to the planetarium, and in 1939 the whole family visited the World's Fair in New York.
And soon after the war, the boy got his hands on the issue of the famous almanac Astounding Science Fiction, which, coupled with the general hysteria of that time associated with UFOs, determined the worldview of the future scientist. Carl Sagan wanted to become an astrophysicist.
And he became one, and brilliant. University of Chicago, Astronomical Society, PhD and dissertation on "Physical Planetary Exploration" - by 1960, the newly minted Ph. D. in physics was considered one of the country's leading young astrophysicists and showed great promise.
He worked at the University of California, at the Smithsonian Astrophysical Observatory in Cambridge, lectured at Harvard, Cornell University, was a consultant at NASA (including in preparing astronauts for flights to the moon).
During his work, Sagan made a number of astronomical and astrophysical discoveries - for example, he discovered high-temperature regions on Venus, explored Titan and Europa (the moons of Saturn and Jupiter). But he was known primarily for his research in the field of alien intelligence. And he became the only scientist whose research on this topic was recognized by the world scientific community.
Where do aliens live
The question of alien intelligence bothered Sagan since childhood. He was fond of science fiction (and in 1984 he wrote the science fiction novel Contact, which was included in the golden fund of American fiction), loved comics, and was passionately interested in the UFO mania of the 1950s. When astronomers Thomas Pearson and Jill Tarter founded the SETI Institute in the mid-1980s, the main purpose of which was contact with alien races, Carl Sagan, along with another popularizer of alien intelligence, Frank Drake, became one of its leading figures. In fact, he himself was at the origins of the SETI program back in the 1970s.
It was Sagan who managed to punch through NASA for funding and permission to install two aluminum, gold-anodized plates on the Pioneer probes.
A few years later, in 1977, Sagan headed a commission that prepared yet another plate, which went to the infinity of space on the Voyager series research vehicle. Moreover, this message was a plate in a different sense of the word.
The sounds of the Earth are recorded on it. Most of it is music (from Bach and Beethoven to Chuck Berry and Georgian choral singing), the smaller part is just human voices and various noises, sirens, hammering, birdsong and animal cries.
At the same time, the plate contains in coded form 116 drawings and photographs reflecting life on Earth and the structure of the solar system. On the outside of the case, in addition to repeating the image from the Pioneer plates, there is a diagram of a device that allows you to extract information from the plate.
Between the sending of the plaques and records, in 1974, Carl Sagan and Frank Drake made another attempt to contact distant space by sending a radio signal there. It is now known as the Arecibo message (by the name of the source radio telescope).
The signal-message lasting 169 seconds was encoded information about human civilization - numbers in the binary system, atomic numbers of basic elements, information about human DNA, humanity as a whole, the solar system and the telescope itself.
The constellation Hercules (globular star cluster M13) was chosen as the direction of the radio signal. Sagan was well aware that the signal would travel to its destination for about 25 thousand years, and if it was received by aliens, successfully decoded and answered, it would take another 25 thousand years in the opposite direction. Nevertheless, he pinned more hopes on this method of communication than on the plates, which he described in detail in the novel "Contact".
By the way, this was the second attempt to send a radio signal into space. The words "peace", "Lenin" and "USSR" were sent in 1962 from the Yevpatoria center for deep space communications. Subsequently, many messages were sent to other worlds, but it is Sagan's message that remains the most famous and informative.
Another life
Carl Sagan is an amazing combination of serious research scientist, science fiction dreamer and popularizing star. He gave exciting lectures, understandable even to an unprepared person, knew how to captivate anyone with his ideas and enthusiasm.
His work was a huge success. The book “Dragons of Eden. Reasoning on the Evolution of the Human Brain won the prestigious Pulitzer Prize in 1978 and topped the New York Times bestseller list for several weeks, which is incredible for a non-fiction publication.
Sagan was interested in absolutely everything - astronomy and anthropology, psychology and biology, problems of artificial intelligence and the development of computer networks.
There was no branch in science that he did not pay attention to in his books, lectures, stories. The most important thing in Sagan was unconditional faith in humanity, its limitless possibilities and its inexhaustible resources.
In honor of Sagan, an asteroid is named, the landing point of the first rover, a number of awards in various branches of science and even a special number characterizing the number of stars in the observable Universe (approximately equal to 70 x 1021). The 1997 film, based on the novel Contact, won the Hugo Award for Best Science Fiction Movie.
But the main monument to Karl Sagan is four plates flying somewhere in endless space. They will fly for millions of years more and may ever reach their destination. And then the mission of Carl Sagan will be completed.
Tim SKOREYKO