We, the inhabitants of Earth, may continue to grapple with the question “Are we alone in the Universe?” for a very long time—perhaps for the rest of our lives. Yet it turns out that an answer could be obtained as soon as tomorrow. Not for the entire Universe, but at least for our galaxy, the Milky Way. How? Oxford astrophysicist Brian C. Lacki knows. KP.RU investigates.
We do not see them; they do not see us.
There should be many intelligent beings out there. Or so it seems. According to fairly convincing calculations by astronomers, our galaxy alone—the Milky Way—is filled with planets similar to Earth. That is, those suitable for life as we understand it: rocky, with an appropriate radius, orbiting stars like the Sun, and located in the so-called habitable zone, where it is warm enough for liquid water to exist on the surface.
However, the chances of discovering neighbors not too far away are extremely slim. Civilizations are not long-lasting. Just as they emerge, like us, for unknown reasons, they can vanish due to some catastrophe—a pandemic, a natural disaster, or nuclear war. Resource depletion could also trigger a collapse.
Even civilizations that survive catastrophes decline and stop emitting characteristic technosignatures—visible signs of industrial activity from afar. Local inhabitants no longer prioritize science; their focus shifts to survival and avoiding a return to savagery. As a result, no one makes any effort to detect anything “intelligent” in the surrounding or distant cosmos, let alone travel to other worlds. Any starships, if they existed, have broken down. Telescopes and other research equipment have rusted away.
The harsh truth of the universe: over billions of years, life could have arisen and perished many times, at different moments and in different places, separated by thousands of light-years.
The probability that highly advanced civilizations exist simultaneously—not too far apart—is vanishingly small.
A Dyson sphere: roughly how structures built by highly advanced civilizations around their stars might look.
An example from our reality: when we observe no technosignatures on planets discovered so far—with climates favorable by human standards—we conclude that no one is there. But in reality, the local civilization may not have reached an industrial stage—its members, clad in animal hides, might still be burning fires in caves—or they might have reverted to a wild state.
Finding “intelligent beings” that reveal nothing to outside observers is incredibly difficult. For Earthlings, with current and even future telescopes, this remains beyond reach.
You are searching in the wrong way.
Yet there is a way to clarify the situation. The research proposed by astrophysicist Lacki will not allow us to detect neighbors currently existing in observable space—simultaneously with us. But it will enable us to understand that intelligent life once thrived in the Milky Way.
The scientist is referring not merely to inconspicuous intelligent creatures like us, but specifically to highly advanced civilizations whose technological level was once incomparably higher than humanity’s.
The existence of such advanced beings could not have gone unnoticed. The question is: where are these traces?
Many astrophysicists involved in the search for extraterrestrial intelligence, including Lacki, are somehow convinced that most far-advanced aliens build so-called Dyson spheres—massive constructions that allow them to harness the energy of their stars. The innovator believes these could be detected. But not the current, operational “spheres”—rather, those from a “past life.” Lacki proposes searching for their remains, into which alien structures transformed billions of years ago, long before we ever existed.
Rovers photograph strange objects on Mars—for example, something resembling a pistol.
The scientist’s logic is as follows: even super-advanced civilizations decline due to some tragic set of circumstances. “Spheres” left unattended break down, collapse under gravitational forces, and crumble until they first become small fragments and eventually turn into micron-sized dust.
Over billions of years, clouds of such interstellar “technogenic dust” could have encountered the Solar System multiple times as it, together with the Milky Way’s spiral arm, orbits the galactic center.
The dusty remains of highly advanced civilizations could have fallen anywhere—including on Earth. But it is easier to search for them on the Moon—within the local dust that has remained largely unchanged for billions of years. There is no need for a special mission to retrieve it; one could sift through the dust brought back by American astronauts and Soviet automated stations.
The presence of technosignatures in lunar dust would be revealed by characteristic inclusions—some high-tech metals and alloys.
Highly advanced civilizations might have also inhabited the Solar System. Before us. For instance, Jason Wright, a professor of astronomy and astrophysics at Pennsylvania State University, believes in the existence of predecessors. He substantiated his unconventional views in the International Journal of Astrobiology. The professor proposed not only sifting through dust for microscopic traces. In his opinion, it would be worth looking into the depths, where something larger might be hidden.
The professor emphasized that one to two billion years ago, Earth, Mars, and Venus were all habitable. Our planet had already become sufficiently comfortable, Mars had not yet dried up and frozen, and the greenhouse effect had not yet destroyed Venus, turning it into a scorching hell.
Wright is certain: searching for traces of predecessors on Venus is futile—everything has been corroded by acid. And on Earth’s surface, nothing remains of previous civilizations—whether local or foreign. Our planet’s environment does not favor the long-term preservation of anyone’s traces. However, deep underground, perhaps something could be found. For example, machine parts. Or even entire devices. Or fossils that were once bones.
From an archaeological perspective, Mars is also promising—especially its subsurface. And, of course, the Moon, which lacks air currents that could destroy or bury artifacts.
“We would immediately understand that we have discovered something ‘completely alien,'” the professor assured, inspiring so-called virtual archaeologists who, almost every week, find traces of past—intelligent—life on Mars or the Moon by examining photographs sent by satellites or research rovers.
About the Author
