It’s true that E.T. tried to call home, and for decades now NASA, SETI and others have been sending out, and searching for radio waves as a way to detect intelligent life “out there.” However, new research suggests that we may be going about the search for alien life in the wrong way.
Rather than sending and/or scanning for radio signals several scientists and astronomers believe that instead, we should be looking for alien “superstructures.”
The approach is to scan the galaxies for evidence of alien artifacts — massive engineering works that an advanced society has constructed somewhere in space.
What’s the advantage over radio signals? One, looking for alien mega-structures eliminates the requirement that the aliens have chosen to get in touch by transmiting radio signals our way. Maybe they’d want to send signals our way, but then again maybe they’d rather lay low. If you’re not sure you’re the neighborhood’s top-dog society, you may not want to be broadcasting your location all over the galaxy. Silence could have survival value.
Furthermore, detecting an actual deliberate radio signal sent by an alien race, requires that the signal reach your telescope at the very moment that you’re pointing it in their direction. This is SETI’s well-known “synchronicity” problem, and it’s been likened to firing a bullet and expecting that it will intercept, head-on, another bullet shot by someone else thousands of feet away – a very improbable prospect. In nearly every radio SETI experiment, the amount of time spent listening at any given frequency is a scant few minutes, before moving down the dial to the next frequency. The universe has been around for nearly ten thousand trillion minutes, so SETI efforts are a bit like stepping into the backyard hoping you’re just in time to catch a raccoon stealing the cat food.
Space Artifacts Stand the Test of Time
On the other hand, large space artifacts may be lurking in orbits just waiting for our discovery. China’s Great Wall and the Egyptian pyramids are earthly constructions that have existed for centuries. Finding them doesn’t demand much synchronicity.
But is this simply a mind exercise, or have scientists ever found any evidence of such alien artifacts?
In 2015, astronomer Tabetha Boyajian and her colleagues reported on a star 1,400 light-years away that occasionally dimmed. Actually, it dimmed a lot, and this wasn’t normal stellar behavior.
One explanation was that the star was surrounded by a Dyson sphere. The idea, proposed years ago by physicist Freeman Dyson, is that really advanced aliens could construct a gargantuan, spherical swarm of solar panels in orbit beyond their own planet — sort of the way you might cup your hands around a candle to collect the heat. The swarm would gather enough starlight to energize the aliens’ souped-up lifestyles, and could sometimes get in the way of light from the star, causing it to intermittently dim as seen from afar.
That explanation for Tabby’s star seems less likely today. Astronomical measurements show that it gets redder when it dims, suggesting that it’s surrounded by naturally produced dust, not a gargantuan group of light collectors.
But, with all due respect to Larry Niven, it’s reasonable to believe that such massive “Ringworlds” could exist somewhere. In the past, astronomers looked for clues to such massive engineering projects by trawling star catalogs for systems that show an excess of infrared light — produced by the warm backside of the panels. Another approach is to comb through data from the European Space Agency’s Gaia space telescope to find stars whose light is fainter than expected, simply because their shine is partially, and constantly, blocked by a bunch of panels.
Recently, University of Chicago physicist Daniel Hooper offered a new idea for searching for high-tech alien artifacts. He notes that the universe is expanding, and galaxies are growing ever farther apart. So forward-thinking alien societies might want to grab stars from nearby galaxies while they can and park them in their cosmic neighborhoods as a hedge against future energy scarcity. This is akin to storing gasoline if you’re worried about a developing shortage. If collections of corralled stars do exist, they’d be easy to spot in the course of mainstream astronomy research.
Looking for that special extraterrestrial text, or Instagram post has a long history, and the search for alien signals will no doubt continue. But a successful search for an ancient alien mega-structure may just win someone a Nobel Prize!