In the field of telescopes, humanity continues to progress in a concrete way: increasingly efficient, they allow scientists to observe the universe with increased precision and range. The Square Kilometer Array (SKA) project, currently being deployed over several years, perfectly illustrates this evolution. Researchers are already enthusiastic about its potential, particularly regarding the answer to a fundamental question: are we alone in the universe?
The various research projects for extraterrestrial intelligence have long been limited by technical and material constraints. Historically, scientists focused on very specific radio signals, particularly in a narrow band of frequencies associated with hydrogen and hydroxyl. This approach was based on the idea that any civilization seeking to communicate would send an intentional and easily identifiable signal. A way of sorting which nevertheless considerably reduces the chances of detection.
Indeed, this strategy only makes it possible to capture signals deliberately directed towards Earth. However, it is much more likely that advanced civilizations will not send targeted messages, or that they will not seek contact at all. A large part of the potential signals, particularly those arising from ordinary technological activities, therefore completely escaped traditional methods.
The SKA could change the situation, explains the specialist site Universe Today. Spread between Africa and Australia, this network of radio telescopes will cover an immense portion of the sky. It will be able to detect weak and unintentional radio emissions, comparable to “leaks” produced by our own technologies. According to the researchers, one hour of observation would be enough to capture signals equivalent to those of a terrestrial mobile telephone network coming from a planet located four light years away.
One step beyond
This capability marks a major advance in the detection of unintentional signals. However, obtaining observation time on such a coveted instrument remains difficult. To get around this problem, the researchers came up with an effective solution: exploit the data collected by the SKA for other scientific projects, such as the study of supernovas or radio galaxies (whose emitted energy comes mainly from radio waves).
This approach relies on the duplication and parallel analysis of data, without disrupting the telescope’s main missions. The detected signals can also be compared to other astronomical databases, such as those from the Gaia mission, in order to identify promising sources. But this method poses a major challenge: data processing.
Radio telescopes generate enormous volumes of information, the analysis of which requires considerable computing power. Without sufficient resources, some interesting signals could be ignored or deleted, because their long-term storage is expensive.
Another major obstacle lies in interference from terrestrial origin: signals produced by planes, satellites or other human technologies can easily be confused with extraterrestrial broadcasts. To solve this problem, researchers are relying on artificial intelligence to filter out these noises, as well as a technique called very long baseline interferometry, which allows signals received by very distant antennas to be compared.
