In the popular imagination, a scientist is methodical and rational, working tirelessly and single-mindedly, ignoring repeated failure, all in pursuit of the truth. That’s about as far away from what most people think of when they hear “aliens”: Hollywood, pulp sci-fi novels, and crackpot conspiracy theorists. Which is why 2016 was a pretty strange year, with these worlds colliding in the pages of peer-reviewed journals and the hallways of some of the world’s highest institutions of astronomical study.
In October, two Canadian researchers studied archival data and found rapid bursts of light coming from a group of 234 stars across the sky. Because the researchers couldn’t attribute the bursts to any natural phenomenon, they concluded it might be aliens—that amount of energy could, in theory, indicate something like a radio beacon produced by a sufficiently advanced civilization.
“We have to follow a scientific approach, not an emotional one,” one researcher told New Scientist. “But intuitively—my emotion speaks now—I strongly suspect that it’s an ETI [extra-terrestrial intelligence] signal.”
In August, a Russian telescope recorded a very strong radio signal—not unlike AM or FM, but of a different frequency—emanating from the star HD 164595 some 94 light years away. The signal stuck out to researchers because HD 164595 is a sun-like star, and in recent years, scientists have found that these sorts of stars often have Earth-like planets around them. “[The signal’s] strength is great enough that it was clearly made by a civilization with capabilities beyond those of humankind,” one scientist working on deciphering the signal told CNN.
And, finally, all year there’s been a steady trickle of stories on the continued mystery of Tabby’s star. In Oct. 2015, researchers at Yale University found in archival data a star that exhibited a pattern of dimming that could not be explained by any natural phenomenon. This year, the more data scientists collected, the stranger the star got. A leading theory—yet to be disproved—is that a much more advanced alien civilization has built a mega-structure around the star to sap its energy.
It won’t surprise you to hear that all this news was met with deep skepticism among astronomers. After all, extraordinary claims require extraordinary evidence. But even so, it’s striking that so many serious scientists are suddenly ascribing new phenomena to aliens.
Our telescopes have gone full IMAX
“There’s plenty of historical precedent for [alien theories]” says Seth Shostak, director of the SETI Institute. “When radio astronomy really gathered steam in the 1960s, some of the interpretations of phenomena such as quasars and pulsars involved aliens too. They’re often a favorite explanation for phenomena that are, at first, not understood.”
Today, years of investment in astronomy and imaging technology are starting to pay off—and that means a lot of new phenomena that need explaining.
We now have telescopes up in space, far from our planet’s light-polluted atmosphere, that can zoom in on a tiny part of the sky and record images in great detail. (The Kepler space observatory, for example, trails the Earth’s orbit around the sun, keeping a distance of tens of millions of miles away from our planet.) We also have groups of telescopes spread across the globe that can continuously monitor one section of the sky for, say, moving objects.
“It’s like we’ve gone from looking down a drinking straw while using older generations of telescope to using a full-picture IMAX camera with the newer telescopes,” says Steve Croft, a radio astronomer at the Berkeley SETI Research Center.
We’re now collecting a staggering amount of data: the area of sky surveyed, the number of times it can be surveyed, and the amount of different regions of the electromagnetic spectrum that can be surveyed are all going up. Meanwhile, as the number of instruments and the data they gather has gone up, so has the number of astronomers working in the field. The American Astronomical Society has gone from 3,700 members in 1980 to more than 8,000 today; the International Astronomical Union has grown from 4,500 to 12,400 in the same time frame. And everyone’s collaborating more these days. “You rarely see a single author paper any more,” says Croft.
That’s because we’re getting better at storing, sorting, and sharing all that data. “The barrier to entry is lower for those who want to do science with these huge data archives,” says Croft. There are now services like the Sloan Digital Sky Survey (SDSS) that allow astronomers around the world to poke and dissect past data using new techniques.
For instance, the rapid bursts of light reported in October, were, in fact, not observed in that month. The report was based on archival data gathered before 2011, that Ermanno Borra and Eric Trottier of Université Laval got through SDSS and then analyzed for strange observations.
But 2016 is special for one more reason. In January, researchers started spending the $100 million that Russian billionaire Yuri Milner set aside for his Breakthrough Listen project. The 10-year grant allows researchers to buy time on radio telescopes specifically to search for ETI signals and to expand the range of frequencies they can listen to. The grant should allow researchers to study 10 times more of the sky than previous searches focused on ETI.
“The investment in Breakthrough Listen has put us more in the public eye,” says Croft, a beneficiary of the fund. “It raised the public consciousness of the project from people sitting in tin-foil hats to making it a legitimate scientific pursuit.”
Croft is being modest. Ever since we invented radio, the search for extraterrestrial life has been a legitimate scientific inquiry. The reason some laugh at the pursuit is because the odds of success have always been very low. It’s also why governments haven’t dedicated serious money towards it. What’s changed in the last few years is those odds of success have improved. It’s humbling: new discoveries consistently show our solar system is not particularly unique in having planets that could harbor life as we know it.
“We are possibly at a threshold of our search for extraterrestrial life,” says Croft. “We have all this cosmic real estate that we are aware of. There are likely billions of planets in our own galaxy that are potentially habitable. So it’s a valid scientific question to ask: are any of those inhabited? Are they giving any signals that we may be able to detect?”
I don’t know… therefore aliens
And, yet, for all the alien news in 2016, we’re still far from being sure we’ve found any. With lower barriers to entry for researchers, it’s even more important that those who use available data do so carefully.
“You need to understand the instrument, the archive, and the data you are looking at,” says Croft. “There are subtleties in the data that we have seen that you haven’t taken into account.”
The Borra and Trottier research, for example, has been criticized for misinterpreting what the archival data really show. It’s likely their claim will fall through the cracks of peer review, when other experts in the field analyze it as they try to get it into a scientific journal. “It’s not a bad idea to look for a signal, it’s just that they didn’t do their homework,” Peter Plavchan of Missouri State University told the New Scientist.
The mystery of the strong radio signal from star HD 164595 has already been resolved. Instead of emanating from the star, the most likely source of the signal was a military satellite orbiting the Earth.
“In the years ahead, you can expect more news about aliens,” says Croft. “Hopefully, it’s news that is vetted and convincing.”
Those who are invested in the ETI search do think they have some idea of what a real alien signal would look like. In astronomer Carl Sagan’s 1985 novel Contact, an ETI astronomer discovers a signal that forms a series of pulses containing prime numbers: 1, 3, 5, 7, 11 and so on until 101. Croft concurs with Sagan’s speculation. “If a sufficiently advanced civilization out there wants to make its presence known, the signal would be artificial in, say, a narrow range of frequencies or a series of pulses with a mathematical code in it, that is obviously not produced naturally,” he says.
That doesn’t fully account for the other critique often lobbed at alien hunters: their searches involve signals that humans themselves can produce and recognize—like radio signals hiding communiqués in coded math. Isn’t it more likely that aliens would produce signals that we have no framework to recognize or record? That may well be, but researchers have good reason to scour the skies for signals we Earthlings can produce.
“In part, it’s still like looking for keys under the street light. You could’ve lost them in the park, but you look where it’s easiest to look for first,” says Croft. “Our search is motivated based on human technology. We use radios and lasers, so we understand how to detect them and thus for now we’re looking for alien signals in those ranges.”
Radios are a particular favorite among ET researchers, because, unlike light or X-rays, radio signals are not easily absorbed by objects in the way and thus can travel unimpeded for thousands and thousands of light years.
There is a long history of imagining what meeting aliens would be like: from Voltaire depicting giants visiting the Earth to impart knowledge to us lowly humans in his 1752 short story Micromegas to the 2016 movie Arrival where aliens come to simply observe us. What will happen when we actually find an alien civilization is anybody’s guess, but if we survive the first encounter, Croft thinks meeting the next civilizations would not seem extraordinary.
“It would be like what happened with exoplanet discoveries,” says Croft. “Alien civilization number 1 is going to be very interesting, but numbers 2, 3, 10, then 1,000 will normalize things.”
And ETI hunters aren’t cowed by the possibility that years and years of searching might still yield no alien contact—after all, failure is just as much a part of science as success. “We keep improving technology and widening our searches even further. But if we still don’t get anything, the implication of that is pretty interesting too,” says Croft. “It tells us that, while we’ve learned that we live on a pretty average planet going around an average star in an average part of an average galaxy, we might still be very unusual. That would be a profound finding.”