19 July 2023
Scientists from the University of California at Berkeley have created a new technology for searching for extraterrestrial civilizations, which increases the accuracy of checking possible radio signals from extraterrestrial intelligence in the Milky Way galaxy. The results of the work are published in The Astrophysical Journal.
Most of today's radio signals, potentially coming from extraterrestrial civilizations, are received by ground-based radio telescopes, and any radio interference (from satellites to mobile phones, microwave ovens and car engines) can create a signal simulating a pulse outside the Solar System. To avoid such inaccuracies, researchers check all suspicious signals by pointing the telescope to another place in the sky, and then return several times to the site where the signal was originally detected to confirm that it was not a one-time event. But even this does not give any guarantees that the source was not on Earth.
A new approach developed as part of the Breakthrough Listen project examines evidence that the signal actually passed through interstellar space, excluding radio interference from Earth. It also involves exploring the northern and southern firmament with the Green Bank radio telescopes in West Virginia and the MeerKAT array system in South Africa. In addition, the technology focuses on observing thousands of individual stars in the Milky Way with special attention to the center of the galaxy.
The authors also added a computer algorithm that analyzes the flicker of narrowband signals and highlights those that dim and become brighter for less than a minute, indicating that they have passed through the interstellar medium. It is clarified that the method is applicable only to signals that originate at a distance of more than 10 thousand light-years from Earth, since the signal must pass through a sufficient amount of interstellar medium to have a noticeable flicker.