A NASA veteran’s multi-year survey of over 1,300 Sun-like stars has discovered several mysterious fast pulses of light that defy traditional cosmological explanations.
Part of a new SETI (Search for Extraterrestrial Intelligence) approach that scans the cosmos for signs of technologically advanced non-human intelligences employing light pulses instead of radio signals to communicate, called ‘optical SETI’, the detections could unveil previously misunderstood natural phenomena or may represent actual extraterrestrial communications.
Scanning for Pulses of Light: The Latest Approach to Finding Extraterrestrials
Since the 1960s, SETI scientists like Frank Drake, the author of the Drake Equation used to estimate the number of extraterrestrial civilizations, have scanned the cosmos for signs of extraterrestrial intelligence in the form of radio signals, including scanning the TRAPPIST-1 exoplanet system. Some tantalizing possibilities have emerged, including the infamous “WOW” signal discovered in 1977, although that detection was most likely resolved as a natural occurrence in 2024. As a result, none of these efforts have detected definitive evidence of non-human radio communication.
More recently, scientists have proposed innovative new methods to look for extraterrestrials communicating with one another. Examples include scanning for alien communications using gravitational waves, looking for galactic-level radio communications by alien supercivilizations, and hunting for light pulses caused by extraterrestrials communicating with lasers called optical SETI.
In a recently published study, veteran NASA scientist Richard H. Stanton detailed a multi-year optical SETI effort aimed specifically at Sun-like stars that revealed some unusual results. According to Stanton, whose impressive resume includes NASA’s Voyager missions and working as the Engineering Manager of the Gravity Recovery And Climate Experiment (GRACE) mission, several potential explanations exist for his unexpected findings, including the possibility of extraterrestrial communication.
Findings Leave Scientists Scratching Their Heads
Since retiring, Stanton has been using the 76.2-cm (30-inch) telescope at the Shay Meadow Observatory in Big Bear, California, to look for signs of extraterrestrials trying to communicate, or as a propulsion system to power light sail spacecraft. Unlike other optical SETI projects that hunt for light signals in varying spectra, Stanton’s study employed a multi-channel photometer that he designed and the immense patience of a NASA veteran to study the light from stars for these signals.
“My approach is to stare at a single star for roughly 1 hour using photon counting to sample the star’s light at what is considered a very high time-resolution for astronomy (100 microsecond samples),” Stanton explained. “The resulting time series are then searched for pulses and optical tones.”
“I’m not sure if anyone else is doing this with a significant time commitment,” he added.
Stanton said that patience finally paid off on May 14, 2023, when his equipment detected an unexpected “signal” while observing the Sun-like star HD 89389. During his one-hour survey, the scientists spotted two fast, identical pulses of light separated by 4.4 seconds. After double-checking previous surveys of the F-type star in the constellation Ursa Major, Stanton confirmed the pulses of light had not been previously detected.
“I am not aware of any discovery of similar pulses,” he writes.
What Makes These Pulses of Light Unique…and Possibly Alien
To eliminate potentially false signals, the NASA veteran compared his readings against signals produced by sources known to occasionally confuse astronomical instruments. After some detailed analysis, he was able to rule out lightning, meteors, airplanes, satellites, system noise, and other atmospheric phenomena as the source of the light pulses.
Next, Stanton looked for similar “overlooked” detections in previous historical observation data. As hoped, he found a nearly identical pair of light pulses detected on September 30th, 2019, around the Sun-like star HD 217014. Roughly the same size, age, and mass as our sun, the star is also the site of the first exoplanet detected by humans in 1995.
Stanton discussed another event that occurred on January 18th of this year, after the paper was submitted for publication. According to the scientist, all three events occurred in pairs, with all pairs of pulses of light separated by between 1.2 and 4.4 seconds. Stanton says that in over 1,500 hours of searching, “no single pulse resembling these has ever been detected.”
A deeper analysis of the 2023 detection also revealed an interesting pattern that Stanton found difficult to explain with natural phenomena. When the pulses of light were detected, the star got brighter, fainter, and brighter again before returning to its previous ambient light level, “all in about 0.2 seconds.” Stanton says this variation is much too strong to be caused by the typical false signal culprits, such as random noise or atmospheric turbulence.
“How do you make a star, over a million kilometers across, partially disappear in a tenth of a second?” he asks. “The source of this variation can’t be as far away as the star itself.”
A follow-up analysis of photography data captured during the event confirmed that nothing else was detected moving near the star at the time of the detection. Separately, when Stanton took a closer look at the fine structure found within the star’s light between pulses, he found a repeating pattern at exactly the 4.4-second mark of the second pulse that seemingly defies conventional explanations.
“No one knows how to explain this behavior,” he writes.
Still Can’t Say if “Extraterrestrials Are Involved”
In the study’s conclusion, the NASA veteran discusses several potential explanations for the light pulses and the problems associated with each.
For example, the 2019 detection was originally written off as a false signal caused by birds, a determination Stanton was able to refute with new data and analysis. The scientist suggests that a shockwave in Earth’s atmosphere could also explain the detections. However, he calls that possibility unlikely, “since shockwaves would have had to occur with perfect timing to coincide with all three optical pulses.”
Stanton also discusses other possible explanations, including starlight diffraction by a distant object in the solar system, partial eclipses caused by satellites or asteroids, edge refraction, and gravitational waves. Still, Stanton says that none of these explanations are satisfying “at this point” and suggests that more study of all three known events is required to further limit the possibilities.
“We don’t know what kind of object could produce these pulses or how far away it is. We don’t know if the two-pulse signal is produced by something passing between us and the star or if it is generated by something that modulates the star’s light without moving across the field. Until we learn more, we can’t even say whether or not extraterrestrials are involved!”
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.