Scientists use Allen Telescope Array to search for radio signals in the TRAPPIST-1 star system

Scientists from the SETI Institute and partners at Penn State University used the Allen Telescope Array (ATA) to search for signs of extraterrestrial technology in the TRAPPIST-1 star system.

The team spent 28 hours analyzing the system, looking for radio signals that could indicate alien technology. This project marks the longest single-target search for TRAPPIST-1 radio signals. Although they found no evidence of the existence of extraterrestrial technology, their work provided valuable data and introduced a new way to search for signals in the future.

An article describing the research is accepted for publication in the Astronomical Journal and is available online as a preprint. on the arXiv server.

“This research shows that we are getting closer to detecting radio signals similar to those we send into space,” said Penn State University graduate student Nick Tusay.

“Most research assumes some intent, like beacons, because our receivers have a sensitivity limit to a minimum transmit power beyond anything we unintentionally send. But, with better equipment, like the next Square Kilometer Array (SKA), we may soon be able to detect signals from an alien civilization communicating with its spacecraft.

The project focused on a phenomenon called planet-planet occultations (PPOs). PPOs occur when one planet moves in front of another. If intelligent life exists in this star system, radio signals sent between planets could leak and be detected from Earth.

Using the enhanced ATA, the team analyzed a wide range of frequencies, looking for narrow-band signals, considered possible signs of extraterrestrial technology. The team filtered millions of potential signals, narrowing down to around 11,000 candidates for detailed analysis. The team detected 2,264 of these signals during the planned PPO windows. However, none of the signals were of non-human origin.

The ATA’s new capabilities, which include advanced software to filter signals, helped the team separate possible extraterrestrial signals from Earth-based ones. They believe that refining these methods and focusing on events like PPOs could help increase the chances of detecting extraterrestrial signals in the future.

“This project included work completed by undergraduate students as part of the 2023 SETI Institute Research Experience for Undergraduates (REU) program,” said Dr. Sofia Sheikh, SETI researcher at the SETI Institute. “The students looked for signals from artificial orbiters around Mars to test whether the system could correctly detect the signals. It was an exciting way to involve students in cutting-edge SETI research.”

The TRAPPIST-1 system is a small, cool star located about 41 light years from Earth. It has seven rocky planets, some of which are in the habitable zone, where conditions could allow liquid water to exist, an essential ingredient for life as we know it. This makes TRAPPIST-1 a prime target for the search for life beyond Earth.

The team did not find any extraterrestrial signals this time, but they will continue to improve their search techniques and explore other star systems. Future research with larger, more powerful telescopes could help scientists detect even weaker signals and expand our understanding of the universe.