By Basant El-Faramawy
Astronomers searching for extraterrestrial intelligence have adopted a new strategy based on game theory to determine not only where but when alien civilizations might attempt contact. The approach, led by researchers at the SETI Institute, focuses on the “anti-solar point” – a specific region of space that both Earth and a hypothetical alien world could independently identify as a logical meeting place for communication.
Schelling point guides search
The method draws on the concept of a “Schelling point,” a game-theory idea describing a choice two parties would make independently without coordination. Just as two people might meet at Grand Central Station at noon in New York, the anti-solar point – the spot in the sky directly opposite the Sun from Earth’s perspective – could serve as a natural coordination target for civilizations observing each other’s planetary transits.
First observational search of anti-solar point
The research represents the first observational survey of that region. Using the Allen Telescope Array at Hat Creek Radio Observatory in Northern California, scientists conducted a pilot survey over three nights in summer 2023, collecting 32 terabytes of data across 17 hours. The survey yielded 1.9 million detections, all attributable to human-made radio interference. However, the data helped refine automated filtering for “technosignatures” – potential signs of alien technology – and established that a transmitter as powerful as the decommissioned Arecibo radar could be detected from over 124 light-years away.
Ongoing campaign covers Earth’s orbit
Researchers now plan to observe two or three nights per week for four years, covering key portions of Earth’s orbit. An automated pipeline will sift the massive data volumes for technosignatures while rejecting terrestrial interference. “The challenge in SETI isn’t simply deciding where to point a telescope,” said Sofia Sheikh, SETI Institute research scientist and co-lead author of the study. “It’s figuring out where and when another civilization might choose to transmit.”
New perspective on coordination
The paper, published in The Astronomical Journal, outlines the survey design and pilot results. The team emphasizes there is no evidence aliens are using this strategy, but the anti-solar point offers a novel framework for thinking about interstellar communication from the sender’s perspective rather than only the receiver’s.
