**Was ‘Oumuamua a Space Probe? Is 3I/ATLAS Another?**
The humble residents of this pale blue dot have been on a quest to find alien civilization for more than a century. First, it was the “canals” of Mars. Then there were enigmatic radio “lighthouses.” And the famous “Wow” signal. All have ended up with mundane and mechanical explanations.
“It stands to reason that the Universe should be buzzing with activity, but we’ve been searching for signals for decades and haven’t heard zip,” bemoans the Planetary Society’s Kate Howells. One after another, theories about where and how technologically advanced interstellar civilizations can be found have fallen by the wayside.
But as technology advances, the scope for this search broadens. New telescopes, probes, and techniques are in the pipeline — along with new ideas of what to look for.
As one Breakthrough Listen project astronomer believes, the evidence may already be right there before us. We just haven’t recognized it yet.
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### Searching for Galactic-Scale Civilizations
Brian Lacki has released a set of three prepublication studies attempting to rationalize and measure the odds of a galactic-scale civilization. These, he argues, may already be in view. They are “radio-bright” galaxies — those broadcasting especially loud background noise.
“The trouble is that you can’t tell whether that emission is natural or artificial just from knowing how bright it is in the radio band,” Lacki told Universe Today. “We expect it is natural in almost all, if not all, cases.” The challenge, he adds, is separating a signal from the noise.
This is a problem other astronomers are tackling on a much narrower scale. They think they’ve found traces of water and carbon dioxide in the atmospheres of distant worlds. But telltale signs such as methane and oxygen are hard to discern.
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### Looking for the Right Signs of Life
The University of California thinks we’ve simply been looking for the wrong things. Methyl halides are much easier to detect and are produced by microbes critical in supporting more advanced life.
“If we start finding methyl halides on multiple planets, it would suggest that microbial life is common across the universe,” argues planetary scientist and study author Michaela Leung.
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### Signals Amid the Noise
A radio search of the heavens began in the 1960s with the Search for Extraterrestrial Intelligence (SETI). Despite the odd false alarm, ET is yet to phone home.
Lacki, however, believes the dial tone is out there — it may be so bright and so common that we mistake it as a natural part of the universe.
The Breakthrough Listen project, initiated in January 2016, conducted the most comprehensive radio survey of space yet, funded by global corporate and government donors. Their findings are now being released.
Lacki’s study, *Artificial Broadcasts as Galactic Populations*, posted to the preprint science journal arXiv, argues that radio-bright galaxies may be bursting at the seams with advanced civilizations.
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### Distinguishing Alien Signals from Black Hole Activity
The supermassive black holes at the center of most galaxies, including our own Milky Way’s Sagittarius A*, are radioactive, with activity varying depending on recent star consumption.
Lacki suggests the overlapping radio transmissions of millions of worlds across a galaxy might, at intergalactic distances, look like part of this background radiation. He estimates one in every 100 large galaxies could be sufficiently populated to contribute about one three-hundredth of a galaxy’s radio luminosity.
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### Atmospheres and Biosignatures
Extracting the spectral signature of life from light passing through the atmospheres of nearby worlds is also challenging. Current telescopes have difficulty detecting oxygen on Earth-like planets.
However, a study published in *The Astrophysical Journal Letters* suggests looking for methyl halides instead, which can be identified with as little as 13 hours of James Webb Space Telescope observation time, compared to days required for other biosignatures.
These gases indicate microbial life forms such as fungi, algae, and bacteria. The life they support doesn’t need to depend on oxygen.
“They’d be adapted to a very different type of environment, and we can’t really conceive of what that looks like, except to say that these gases are a plausible output from their metabolism,” argues astrobiologist Eddie Schwieterman.
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### Are We Normal or Abnormal?
Are we normal? Or abnormal? Should we base our expectations of life outside Earth on what we know here?
University of Columbia astronomer Professor David Kipping argues that humanity is a statistical outlier.
“Yes, the sun is one of billions of stars, but several properties clearly make it unusual among that sample,” he said.
Our Sun is a yellow G-dwarf star — making up only a few percent of the galaxy’s star population. Even among G-dwarfs, the Sun is somewhat odd for being a fairly quiescent, single star system with two Jupiter-sized planets.
Jupiter’s position in our solar system acts as a giant sponge, absorbing deadly asteroids and comets before they reach the inner rocky planets.
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### The Prevalence of Red Dwarf Stars
Most observed star systems tend to have giant planets hugging close to their stars, unlike our own.
The most common stars in the galaxy are M-dwarfs (Red Dwarfs), home to most of the approximately 6,000 extrasolar planets currently identified.
Yet, Earth does not orbit one, highlighting what Professor Kipping calls the “Red Sky Paradox.”
The volatile nature of Red Dwarfs may mean life doesn’t get a chance to advance to an advanced technological stage: because these stars are cooler, planets must orbit closer to remain in the “Goldilocks” zone, putting them at risk from intense solar flares and sunspots.
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### The Time Factor in Detecting Alien Life
“Our own planet’s signals have probably only reached about 100 light-years into space,” writes the Planetary Society’s Howells. “We’ve only been broadcasting electromagnetic communications for about that long, and nothing can travel faster than the speed of light — hence the limited distance.”
Professor Kipping puts this into perspective:
> “The stelliferous (active star) period of the universe extends until 10,000 Gyr (giga-years) from now, yet here we are living in the first 0.1 percent of that window, when the universe is just 13.8 Gyr old.”
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### Hope and the Search Continues
“There’s the hopeful idea that we’re just the first ones to get to this point of development,” explains Howells.
“There’s the fun, far-out idea that advanced aliens prefer to expand in virtual reality rather than colonize other planets. And there are lots more ideas in between.”
Perhaps we’re not listening or looking for the right things. Perhaps we’re too impressed with our own technology, assuming other civilizations haven’t long since moved on to much more advanced means.
“Maybe alien tech uses communication methods we don’t understand or can’t harness yet, like quantum entanglement,” Howells adds.
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### Challenges in the Longevity of Civilizations
Dr. Manuel Scherf and Professor Helmut Lammer of the Austrian Space Research Institute highlight that the influence of plate tectonics on atmospheric carbon dioxide imposes a time limit for a planetary civilization to go interstellar.
“At some point, enough carbon dioxide will be drawn from the atmosphere so that photosynthesis will stop working,” says Scherf. “For Earth, that’s expected to happen in about 200 million to roughly 1 billion years.”
Worlds also require atmospheres with at least 18 percent oxygen to support larger, complex animals and allow the crucial invention of fire.
Anything less won’t sustain larger animals; anything over 21 percent makes fire uncontrollable.
“Without fire, the smelting of metal would be unfeasible and a technological civilization would be impossible,” they explain.
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### What Does This Mean for Extraterrestrial Intelligence?
Taking these factors into account, Scherf and Lammer argue that a planet with 10 percent carbon dioxide could sustain photosynthesis for 4.2 billion years.
Any civilization developing there must survive a minimum of 280,000 years to have a chance of overlapping with another civilization in the same galaxy.
“For 10 civilizations to exist at the same time as ours, the average lifetime must be above 10 million years,” Scherf says.
The numbers of extraterrestrial intelligences (ETIs) are likely low and strongly depend on the lifetime of a civilization.
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### The Final Word
As of now, there is an absence of evidence for any such civilization’s existence.
But remember, absence of evidence is not evidence of absence.
“The only definitive answer we can ever get to the question of whether other life exists out there is ‘yes,’” Howells concludes. “Until we get that confirmation of alien life, the possibility will always remain that we just haven’t found it yet.”
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*So, was ‘Oumuamua a space probe? Is 3I/ATLAS another? As of now, there’s no conclusive evidence to support those ideas. Perhaps advanced civilizations are out there, but their signals and signs remain elusive — hidden in the cosmic noise or beyond our current detection capabilities.*
https://nypost.com/2025/10/18/tech/alien-hunt-breakthrough-why-scientists-are-changing-their-search-focus/
