Dr. Ermanno F. Borra

Ermanno F. Borra is a physicist and astronomer at Université Laval in Quebec City best known for two very different contributions to observational astronomy: he is a genuine pioneer of liquid mirror telescope technology, and he is the co-author of a 2016 paper claiming to have detected periodic spectral signatures, in 234 Sun-like stars, that matched the theoretical profile of an artificial laser beacon. The claim made international headlines for a few weeks, was folded into the Breakthrough Listen search for extraterrestrial intelligence, and was ultimately shown three years later to be a natural artifact of how absorption lines are spaced in ordinary stellar spectra — not a signal from anyone.

Early life and academic career

Borra earned his PhD in physics from the University of Western Ontario before joining the physics, engineering physics and optics department at Université Laval, where he built his career as a professor of astronomy and optics. Rather than working the traditional route of large ground-based optical telescopes, Borra spent much of his career on the fringes of mainstream instrumentation, chasing cheaper and stranger ways to build big mirrors. That instinct — to look for elegant, low-cost physical tricks that most of the field had not bothered to try — recurs throughout his career, and it is visible both in his telescope work and, decades later, in his approach to the search for extraterrestrial intelligence (SETI).

Building mirrors of mercury: liquid mirror telescopes

Starting around 1982, Borra revived and modernized an old idea: instead of grinding a solid glass mirror, spin a shallow pool of liquid metal fast enough that centrifugal force pulls it into a perfect parabola, then coat the surface so it reflects like a conventional telescope mirror. Earlier attempts at liquid mirror telescopes had foundered on vibration and surface-quality problems, but Borra's team at Laval showed that a thin (roughly 2mm) layer of mercury, supported on an air bearing, could produce genuinely diffraction-limited images. Over a decade of experiments the group built rotating mercury mirrors as large as 1.5 meters, and in March 1994 Borra's 2.7-meter liquid mercury telescope, built jointly with the University of British Columbia, began astronomical observations — at the time one of the largest liquid mirror instruments ever built (UBC/Laval 2.7m Liquid Mirror Telescope, ApJ 1994).

Borra continued refining the concept for years afterward, including work showing that ionic liquids — room-temperature molten salts, rather than toxic mercury — could be coated with a thin silver film to serve the same optical purpose, opening the door to lighter, less hazardous liquid mirrors. The appeal of the whole approach was economic as much as technical: a spinning liquid mirror can be enormous and comparatively cheap, at the cost of being fixed permanently pointing straight up, which limits it to survey astronomy rather than tracking individual objects. Liquid mirror telescopes built on Borra's principles were later used for large-scale sky surveys, and the technology is a legitimate, citable branch of observational astronomy — this part of Borra's career is uncontroversial and well documented in the peer-reviewed literature (Liquid Mirror Telescopes: Present and Future, PASP).

A theoretical proposal: SETI hidden in ordinary spectra

Borra's move into the search for extraterrestrial intelligence grew directly out of his optics background rather than any prior interest in ufology. In a 2012 paper, "Searching for Extraterrestrial Intelligence Signals in Astronomical Spectra, Including Existing Data" (Astronomical Journal 144, 181), he laid out a specific, testable idea: if an advanced civilization wanted to announce its presence using a laser, it could fire extremely short pulses (on the order of picoseconds) at very precisely spaced intervals. When starlight — or a laser pulse train riding along with it — passes through a spectrograph, such periodic pulses would imprint a comb-like, periodic ripple onto the star's spectrum, detectable with a simple Fourier transform. Crucially, Borra argued that this signal could in principle be hiding in spectra astronomers had already collected for entirely unrelated purposes, meaning no new telescope time was required — only a new way of looking at old data. He followed this with a 2013 paper extending the same Fourier-analysis technique to look for periodic modulations in the spectra of entire galaxies, tied speculatively to ultra-rapid light bursts from their central black holes (ApJ 774, 142), which served as a proof of concept for the detection method itself.

This theoretical groundwork is where Borra's SETI work is at its strongest: the proposal was published in a respectable peer-reviewed venue, it made a falsifiable prediction about what an artificial signal should look like, and it suggested a genuinely low-cost way to reanalyze archival astronomical data — all hallmarks of legitimate science, whatever one thinks of the underlying premise that alien engineers would choose to broadcast this way.

The 2016 announcement: 234 candidate stars

In October 2016, Borra and his graduate student Eric Trottier published "Discovery of Peculiar Periodic Spectral Modulations in a Small Fraction of Solar-type Stars" in the Publications of the Astronomical Society of the Pacific. The pair had run their Fourier-transform search across roughly 2.5 million stellar spectra drawn from the Sloan Digital Sky Survey, and reported that 234 stars — overwhelmingly of spectral types F2 through K1, i.e., Sun-like — showed a periodic modulation with statistically unusual properties matching the profile Borra had predicted in 2012. The pair was careful, in the paper itself, to frame this as a curious anomaly rather than a confirmed detection, but they explicitly noted that the ETI hypothesis could not be ruled out and remained "worthy of further study."

The press did not stay so cautious. Coverage from Phys.org ("Either stars are strange, or there are 234 aliens trying to contact us"), Space.com, Universe Today, and ScienceAlert turned a hedged statistical anomaly into a viral story about hundreds of possible alien beacons. The story gained extra traction because Breakthrough Listen — the SETI initiative funded by Yuri Milner and backed publicly by Stephen Hawking — announced it would add several of the 234 candidate stars to its own observing queue on the Automated Planet Finder telescope at Lick Observatory, which lent the story an air of institutional seriousness even as Breakthrough Listen's own statement stressed that "extraordinary claims require extraordinary evidence."

Reception and criticism

Skepticism from professional astronomers was immediate and largely centered on three points. First, the paper had not yet completed peer review at the time it was publicized, and no independent group had attempted to replicate the signal, which several commentators flagged as premature grounds for an ETI headline (as reported by GeekWire). Second, astronomers noted the methodological red flag that Borra and Trottier had gone looking for a signal whose exact shape they had predicted four years earlier and then reported finding precisely that shape — a pattern that, absent independent confirmation, is at least as consistent with confirmation bias or a subtle systematic error in the pipeline as with a real detection. Third, re-observations of individual candidate stars using different telescopes and instruments failed to reproduce the original periodic signal, undercutting the claim that it was a stable, real feature of the starlight itself rather than an artifact specific to the original Sloan spectra or the analysis pipeline used to process them.

Borra, for his part, responded to the skepticism with notable equanimity rather than defensiveness. In a 2016 interview with Vice, he argued that "the search for extraterrestrial life is a very legitimate scientific endeavour," while acknowledging that "the ETI hypothesis is a strange one, so it's normal to be skeptical." He suggested that some critics had likely not read the paper closely, since he and Trottier had never claimed certainty — only that the anomaly deserved further observation. Snopes rated the viral "probably aliens" framing of the story as a mixture of true and false: the underlying anomaly was real and published, but the leap to "probably extraterrestrial" badly overstated what the paper itself claimed.

The Hippke rebuttal and current scientific consensus

The episode reached what most working astronomers now consider its resolution in 2019, when independent researcher Michael Hippke published "Periodic Spectral Modulations Arise from Non-random Spacing of Spectral Absorption Lines" in the same journal that had carried the original claim. Hippke showed that the periodic modulation Borra and Trottier had detected is not a signal riding on top of a star's light at all, but an inevitable mathematical consequence of how absorption lines happen to be spaced within real stellar spectra. Because that spacing is not perfectly random, a Fourier transform of the spectrum will tend to show weak periodic structure even with no noise and no artificial input whatsoever — Hippke demonstrated the same telltale modulation appearing in noise-free synthetic spectra, and even in a high signal-to-noise spectrum of our own Sun, a star that is (so far as anyone can establish) not broadcasting laser pulses at Earth. In other words, the detection method itself manufactures a false-positive signal that mimics exactly the pattern the 2012 theory paper had predicted an artificial beacon would produce — an unfortunate and instructive case of a search method being tuned closely enough to its own theoretical target that it found an illusory echo of that target hiding in the ordinary physics of starlight.

Neither Borra nor Trottier has published a rebuttal to Hippke's analysis, and the broader SETI and astronomical community now generally treats the 234-star claim as adequately explained by mundane astrophysics rather than as an open mystery. No subsequent survey has resurrected the periodic-laser-pulse search as an active line of inquiry in the way Borra had hoped it would become when he first proposed archival spectral SETI in 2012.

Legacy

Borra's case is a useful one for understanding how legitimate, peer-reviewed science can generate an extraordinary claim without any fraud, deception, or fringe motivation involved. His liquid mirror telescope work stands as a genuine and lasting technical contribution to observational astronomy, still cited in surveys and technology reviews. His SETI proposal followed a defensible scientific logic — a specific, falsifiable prediction, tested against real data, published for open scrutiny, and ultimately falsified by open scrutiny from another scientist rather than covered up or suppressed. That the process took three years and a viral news cycle before the anomaly was correctly attributed to a mathematical property of spectral lines, rather than to alien engineering, illustrates both how appealing an ETI explanation can be for an ambiguous astronomical signal and how the ordinary machinery of science — replication attempts, independent analysis, published rebuttal — eventually pulled the story back down to Earth. Borra remains an active figure in Canadian astronomy and optics, and his name persists in the SETI literature chiefly as the author of one of the more well-documented instances of a promising signal turning out, on close inspection, not to be one.