With new technologies come new opportunities. And that is especially true in astronomy—with every new advanced telescope, we have the potential to see (or in some cases, listen) farther and more clearly than ever before. That is certainly the case for the new Square Kilometer Array (SKA), which is currently undergoing a multiyear rollout phase. Despite that drawn-out process, astronomers are already excited about its potential, and a new book chapter from Dr. Chenoa Tremblay and her co-authors details how this new technology could be used to answer one of the most fundamental questions: Are we alone?
The Search for Extraterrestrial Intelligence (SETI) has always been constrained by its resources. This constraint required researchers to focus mainly on tight signals such as the narrow band between hydrogen and hydroxyl. Early SETI pioneers justified this by claiming that such a narrow beacon would be a clear signal of intent. However, it also meant that they were able to find only signals that were intentionally sent in our direction. And the likelihood of that happening is minuscule compared with the chances that there were advanced civilizations that did not feel the need to reach out to us.
Enter the SKA. Its design, which spans two continents (Australia and Africa), allows it to scan an absolutely gigantic amount of the sky. Critically, this will enable it to pick up "leakage" radiation. The authors calculated that one hour of observational time on the SKA itself would be enough to pick up signals from the equivalent of a modern-day mobile phone network similar to what we currently have on Earth from an exoplanet 4 light-years away.
That is a massive step change in our ability to detect unintentional emissions. But actually getting the time to do so is a huge part of the challenge. Telescope time on world-leading instruments like the SKA is notoriously difficult to get. So SETI researchers came up with a productive solution—they will simply piggyback off the data the SKA is already collecting for other surveys, such as watching supernovae or bright radio galaxies.
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