Self-Replicating Alien Probes Might Already Be Operating in Our Solar System, Says New Research
Could there be alien machines quietly working somewhere in our Solar System right now?
A new scientific study suggests that it’s not only possible but even likely that self-replicating probes—machines capable of making copies of themselves—might already be here. The research comes from Professor Alex Ellery, an engineer at Carleton University in Canada, who has long explored the concept of Von Neumann probes, a theoretical kind of self-replicating spacecraft named after mathematician John von Neumann.
Ellery’s new paper, titled “Technosignatures of Self-Replicating Probes in the Solar System,” was recently published on arXiv. It proposes that these autonomous machines could have been sent by advanced extraterrestrial civilizations and might even have left behind detectable traces—or technosignatures—within our own cosmic backyard.
What Are Self-Replicating Probes?
The idea of self-replicating spacecraft isn’t new. Back in 1949, John von Neumann introduced the concept of a “universal constructor”—a machine that could reproduce itself using raw materials from its surroundings. Scientists later applied this idea to space exploration, suggesting that an advanced civilization could send out a single probe capable of self-replication. Each copy would build another, leading to exponential exploration of the galaxy.
According to various models, such probes could, in theory, spread through an entire galaxy within a few million years. That’s remarkably quick on cosmic timescales. Ellery’s latest research revisits this idea and raises an intriguing possibility: if civilizations elsewhere have developed such technology, their probes might already be in our Solar System.
Why Would Extraterrestrials Send Such Probes?
Ellery’s study identifies survival as the most obvious motivation. Civilizations, like living organisms, might want to ensure their continuity beyond the lifespan of their home star. Self-replicating probes could help them secure resources, avoid extinction, or assess potential threats from other civilizations.
He also notes that not all exploration is driven by curiosity alone. Civilizations could have practical or even defensive reasons for spreading their technology—such as reconnaissance, establishing early-warning systems, or gathering intelligence. These motivations echo patterns seen in human exploration, which historically has often been driven by greed, fear, or the search for resources, rather than pure science.
Unlike biological beings, machines aren’t limited by the same constraints. Self-replicating probes wouldn’t need life support systems, food, or oxygen, and they could withstand much higher acceleration forces during interstellar travel. All the materials they’d need—metals, silicates, and other elements—could be harvested along the way from asteroids, moons, and even interstellar debris.
How These Probes Might Operate
Ellery suggests that the activities of such interstellar probes would follow a logical sequence, broken down into six key stages:
- Targeting resources: The probes would start by identifying moons, asteroids, and other bodies rich in minerals or metals.
- Building surveyors: Using those materials, they’d construct smaller surveyor probes to map out the Solar System and locate other resource-rich areas.
- Establishing bases: They would set up manufacturing sites or “factories” on suitable bodies like moons or large asteroids.
- Replicating themselves: At these bases, the probes would begin constructing more copies—both of themselves and specialized units for various tasks.
- Long-term exploration: Once replication stabilizes, they would systematically explore the Solar System in detail, possibly cataloging life-bearing worlds.
- Carrying out missions: In advanced stages, they might build space habitats such as O’Neill Cylinders, or even engage in directed panspermia—seeding other worlds with life.
Each of these steps could leave behind technosignatures, physical or chemical traces that scientists on Earth might one day detect.
What Would These Technosignatures Look Like?
Ellery highlights several possible clues that could hint at the past or present operation of self-replicating probes:
- Unusual isotope ratios: Advanced probes might use nuclear reactors for power. Certain isotope ratios, like thorium-232, neodymium-144, or barium-137, could indicate the remnants of such activity, especially on the Moon.
- Magnetic or geological anomalies: Artificial excavation or buried metallic structures could create unusual magnetic fields or surface patterns.
- “Gifts” or artifacts: Ellery even speculates that a probe might have left behind devices or materials deliberately hidden within asteroidal metals—a kind of “technological gift” that would only be discovered once a civilization reached a sufficient level of sophistication.
- Asteroid mining patterns: Mining activity carried out by machines would likely differ from natural erosion processes, though distinguishing the two would be challenging.
Ellery concludes that the Moon is the best place to start searching. Its surface is stable, resource-rich, and close to Earth, making it a logical hub for extraterrestrial operations. He also points out that future lunar missions could naturally double as technosignature hunts, analyzing soil samples for isotopic or magnetic anomalies.
Rethinking the Search for Extraterrestrial Intelligence
For decades, the Search for Extraterrestrial Intelligence (SETI) has largely focused on listening for radio signals from distant stars. But Ellery argues that it’s time to expand that search inward—into our own Solar System.
He suggests that SETI researchers should look for artifacts rather than just transmissions. If self-replicating probes really exist, the odds of finding evidence might be higher on the Moon, Mars, asteroids, or in the Kuiper Belt, rather than light-years away.
This approach also ties into the famous Fermi Paradox—the apparent contradiction between the high probability of alien life and the lack of evidence for it. If self-replicating probes can spread through a galaxy so efficiently, why haven’t we found any? Ellery’s answer: maybe we simply haven’t looked in the right places yet.
What This Means for Future Exploration
The next few decades will see humanity returning to the Moon and pushing farther into the Solar System. NASA and private companies are planning permanent lunar bases, asteroid mining operations, and missions to Mars. According to Ellery, these ventures could do double duty—searching for both natural resources and possible signs of alien technology.
Future robotic missions could scan for subsurface magnetic anomalies, strange isotopic ratios, or unusual metallic concentrations. Some of these searches might even repurpose data from existing lunar orbiters or asteroid missions. The results could be groundbreaking—either ruling out the idea of alien probes or revealing that we’ve had visitors all along.
How Realistic Is This Idea?
While fascinating, it’s important to note that this study is highly speculative. No physical evidence currently supports the presence of alien probes in the Solar System. However, Ellery’s argument is grounded in logic: if interstellar travel is possible for advanced civilizations, then self-replication is the most efficient method for exploration.
Distinguishing artificial signatures from natural geological activity would be difficult. Space weathering, impacts, and erosion could easily erase ancient traces. Yet, as Ellery points out, the potential reward—discovering evidence that humanity is not alone—is worth the effort.
The Bigger Picture
Von Neumann probes are a cornerstone of many scientific and science-fiction discussions about the future of space exploration. They represent both the promise and peril of self-replicating technology. On one hand, they could help humanity colonize the stars; on the other, if uncontrolled, they could multiply endlessly—a scenario sometimes called the “Berserker Hypothesis.”
Ellery has previously explored how humans could build their own self-replicating probes using technologies like 3D printing, automation, and robotics. He even proposed safeguards—such as limiting the number of replications each probe can perform—to prevent runaway scenarios.
This intersection of real-world engineering and speculative astroengineering makes the topic especially compelling. It blends engineering feasibility, cosmic curiosity, and existential questions about our place in the universe.
The Next Step
Ellery’s proposal doesn’t claim proof of alien machines—it simply offers a new perspective on where and how we might find them. As humanity begins its next era of exploration, it may be time to include technosignature searches alongside mining surveys and resource mapping.
Who knows—perhaps the next lunar drilling project or asteroid mission could uncover something far more extraordinary than expected: evidence that we’ve already been visited.
Research Reference: Technosignatures of Self-Replicating Probes in the Solar System – Alex Ellery (arXiv, 2025)
