Researchers have introduced a new approach utilizing the Allen Telescope Array to investigate potential radio communications from planets in the TRAPPIST-1 star system.
This innovative method enables astronomers to pinpoint exoplanets that align with Earth, facilitating the detection of radio signals akin to those utilized for communication with Mars rovers. Scientists from Penn State and the SETI Institute dedicated 28 hours to examine the TRAPPIST-1 star system for indications of alien technology using the Allen Telescope Array (ATA). This effort represents the most extensive search for radio signals specifically targeting TRAPPIST-1. Although the researchers did not uncover any evidence of extraterrestrial technology, they have laid the groundwork for future signal detection methodologies.
A paper detailing this research has been accepted for publication in the Astronomical Journal and is currently available online as a preprint.
“This research demonstrates that we are advancing our technologies and techniques towards the possibility of detecting radio signals akin to those we emit into space,” stated Nick Tusay, a graduate student research fellow at Penn State and the paper’s primary author. “Most searches presume a strong signal, much like a beacon intended to reach far-off planets, given that our receivers can only capture signals above a certain power level that we don’t unintentionally emit. However, with improved equipment, such as the forthcoming Square Kilometer Array, we could soon identify communications from an alien civilization speaking to its spacecraft.”
The research concentrated on a phenomenon referred to as planet-planet occultations (PPOs), which occur when one planet transits in front of another from our viewpoint on Earth. Should intelligent life exist in that star system, radio waves transmitted between planets might escape and be detectable from our planet.
The upgraded ATA — a series of radio antennas committed to searching for extraterrestrial technology located at the Hat Creek Observatory in the Cascade Mountains, roughly 300 miles north of San Francisco — swept through a broad spectrum of frequencies to identify narrowband signals, which could indicate the presence of alien technology. The team sifted through millions of potential signals, ultimately narrowing the pool down to about 11,000 candidates for thorough examination. During predicted PPO events, 2,264 signals were detected, but none were determined to be of non-human origin.
The advanced capabilities of the ATA, which include sophisticated software designed to filter signals, enabled the team to distinguish potential alien signals from those generated on Earth. The researchers are optimistic that refining these methods and concentrating on occurrences like PPOs will heighten the opportunity for detecting alien signals in future endeavors.
“This project also involved undergraduate students participating in the 2023 SETI Institute Research Experience for Undergraduates program,” explained Sofia Sheikh, a SETI researcher at the SETI Institute who completed her doctorate at Penn State. “The students analyzed signals from human-made orbiters around Mars to ensure the system’s accuracy in detecting signals. It was a thrilling way to engage students in groundbreaking SETI research.”
The TRAPPIST-1 system contains a dim, cool star located approximately 41 light years away from Earth and features seven rocky planets, some situated within the habitable zone, where conditions may be suitable for liquid water—an essential element for life as we understand it. This characteristic makes TRAPPIST-1 a prime candidate in the search for life beyond Earth.
“Given TRAPPIST-1’s relative proximity to Earth and the well-established orbits of its planets, it serves as an excellent natural laboratory for testing these techniques,” Tusay noted. “The methods and algorithms we devised for this project could eventually be applied to other star systems, enhancing our prospects of identifying interplanetary communications beyond our solar system, if they indeed exist.”
While the team did not find any extraterrestrial signals in this instance, they remain committed to enhancing their search techniques and exploring additional star systems. Future investigations with advanced, powerful telescopes may allow scientists to detect fainter signals and broaden our understanding of the universe, according to the team.
Beyond Tusay and Sheikh, the research team consists of Jason T. Wright from Penn State, Evan L. Sneed from the University of California, Riverside, Wael Farah, Andrew Siemion, and David R. DeBoer from the University of California, Berkeley, alongside Alexander W. Pollak and Luigi F. Cruz from the SETI Institute. The research received primary funding from grants awarded by the U.S. National Science Foundation, supplemented by support from the Penn State Extraterrestrial Intelligence Center and the Penn State Center for Exoplanets and Habitable Worlds, both funded by Penn State and the Penn State Eberly College of Science.
