As humans began to explore outer space in the latter half of the 20th century, radio waves proved a powerful tool. Scientists could send out radio waves to communicate with satellites, rockets and other spacecraft, and use radio telescopes to take in radio waves emitted by objects throughout the universe.
However, sometimes radio telescopes would pick up the artificial radio signals from telecommunications. This interference threatened sensitive astronomy observations, causing inaccurate data and even damaging equipment. While this interference frustrated scientists, it also sparked an idea.
During the Cold War, a new field emerged at the intersection of radio astronomy and radio communications. It put forward the idea that astronomers could search for radio communications from possibly existing extraterrestrial civilizations. Astronomy usually dealt with observing the universe’s natural phenomena. But this new field made the detection of technologically, or artificially produced radio waves, the object of a natural science.
This field has continued today and is now called the search for extraterrestrial intelligence, or SETI. SETI encompasses all that scientists do to search for intelligent life beyond Earth. It includes one of the original uses of radio telescopes: to study signals from across the galaxy in hopes of detecting intelligent messages.
When the idea behind SETI was first proposed and pursued in the 1960s, only two countries, the U.S. and the USSR, had the technical capability for it. As the only space powers at the time, they were the key actors affected by radio frequency interference.
As a historian of science, I’ve worked to make sense of what happened throughout the history of Soviet SETI during the space race by analyzing a range of primary sources. SETI captured the scientific imagination of many prominent Soviet astronomers in the 1960s and early 1970s.
Astronomers have not yet confirmed any detection of radio signals – or any other kinds of signs – from extraterrestrial civilizations. But many scientists are still searching, even as their bold ideas run into obstacles. Some evidence suggests humans might be the only intelligent life in the universe.
Soviet SETI: The golden age of radio astronomy
SETI is intertwined with the profound changes brought by radio astronomy. Up until the second part of the 20th century, scientists could see astronomical objects and phenomena only in optical or visible light. Optical light is the same kind of light that the human eye is sensitive to.
After World War II, scientists figured out that they could peacefully use radar antennas, developed for use in that war, to detect radio signals coming from objects out in the universe. Deciphering these signals allowed researchers to study astronomical objects in the universe. They learned, for example, about the most abundant element: hydrogen.
In the former Soviet Union, the prominent radio astronomy pioneer Iosif…
