Do we need to rethink the way we search for intelligent alien life?

Our search for extraterrestrial signals has always focused on radio, but a new study suggests that aliens may be communicating with Earth via pulsing starlight.

A new study suggests aliens may be trying to make contact with Earth – not through radio broadcasts or UFO flybys, but by the flickering of distant cosmic lights.

A small group of stars – just 234 out of the 2.5 million catalogued by the Sloan Digital Sky Survey (SDSS) – are acting strangely. Astronomers have observed these stars exhibiting what’s called “spectral modulation.” In other words, they’re subtly changing color in repeating patterns. Two scientists, both from Laval University in Quebec, suggest that these modulations may have been intentionally created by extraterrestrials.

While many in the astronomical community doubt these “signals” were really created by aliens, the theory may expose an oversight in our search for intelligent life elsewhere in the universe. We build vast arrays of radio telescopes in hopes of 'hearing' an alien voice, but what if our interstellar visitors choose to show rather than tell? Our ears, so to speak, have long been open to the possibility of extraterrestrial life – is it time we opened our eyes?

In humanity’s ceaseless quest to understand what lies beyond our planet, radio has proven to be an essential tool. Quasars, the oldest and most distant objects in the observable universe, were first discovered by radio surveys in the late 1950s. Early pioneers of the technology, such as Nikola Tesla and Guglielmo Marconi, believed they could make contact with Martian creatures through radio signals.

Even today, the search for extraterrestrial life relies heavily on radio. That’s because radio waves can flow through most matter, and scientists have some degree of control over their path.

“Some surveys have used lasers and other forms of optical light to communicate, but matter tends to get in the way,” Jeffrey Coughlin, a SETI Institute consultant for NASA’s Kepler Mission, tells The Christian Science Monitor in a phone interview. “There’s not much that can slow down radio waves.”

“If there’s another civilization out there that’s at all like us,” he adds, “radio is the best way we know to communicate.”

But the Laval University study, authored by astrophysicists Ermanno Borra and Eric Trottier, suggests a different type of communication. It interprets optical anomalies, detected by the SDSS, as alien billboards.

“We consider the possibility, predicted in a previous published paper, that the signals are caused by light pulses generated by Extraterrestrial Intelligence [ETI] to make us aware of their existence,” the study reads. “We find that the detected signals have exactly the shape of an ETI signal predicted in the previous publication and are therefore in agreement with this hypothesis.”

Drs. Borra and Trottier have acknowledged that the signals could also be caused by “highly peculiar chemical compositions” in a small number of stars, and have called for additional research into the matter. Even still, they have dismissed the chemical theory as “unlikely.”

But as the adage goes, extraordinary claims require extraordinary evidence. And according to Dr. Coughlin, Borra and Trottier haven’t yet met that burden. While working on the Kepler exoplanet mission, Coughlin encountered similar “oddball” cases.

“But we always find astrophysical explanations for them,” Coughlin says. “There’s no such thing as a perfectly invariable star.”

When gamma-ray bursts were first imaged in 1997, Coughlin notes, many people believed they were alien signals. But the astronomer is quick to distinguish his skepticism from dismissal: paired with radio surveys, optical signals can still be quite telling.

“I think it’s good to look,” Coughlin says, “but if you’re going to have a dedicated survey, radio is definitely the way to go.”