Harvard astrophysicist Avi Loeb has published a new hypothesis about the interstellar object 3I/ATLAS, and it doesn’t toe the NASA line in fact it leans ever more toward it being alien technology.
Where official channels continue to classify 3I/ATLAS as a comet, Loeb highlights a growing stack of inconsistencies: collimated jets, a stable 16.16-hour pulsing brightness pattern, and electromagnetic activity detected in SETI-relevant frequencies. Taken individually, they could be dismissed as rare. Taken together, they form something harder to wave away.
3I/ATLAS is only the third known object to enter our solar system from interstellar space. It was first classified as a comet due to its faint coma and gas emissions, but Loeb’s review of recent observational data points to physical behaviours inconsistent with natural comet dynamics.
The Pulse
The object exhibits a 16.16-hour periodic variation in brightness, a highly regular signature recorded photometrically across multiple observations. At first glance, this might be explained by rotation. But Loeb’s analysis shows a dimensional mismatch: the rotation required to create such a variation would imply a much larger nucleus than what Hubble data confirms (2.8 km radius).
That leaves a different source: pulsing jets from the coma itself. But that’s not standard behaviour either. Natural comet jets, driven by sublimating ice, erupt chaotically and directionally toward solar heating. Here, the brightness pulses come on schedule. Regular, repeatable, and detached from the Sun.
This is what Loeb calls the “heartbeat” anomaly. And it suggests something inside is regulating the emission.
Jet Collimation That Defies Rotation
On 9 November 2025, new images showed something else: collimated jets extending over a million kilometres. Clean, linear plumes, not smeared out as they should be if the nucleus were rotating at 16.16 hours and ejecting material at typical comet speeds (~400 m/s).
The physics don’t work. With standard thermal outflow speeds, the object would complete hundreds of rotations before the ejected material reached that distance, resulting in a smeared, spiralling trail. That’s not what’s been observed. The jets appear stable, persistent, and oddly directionally consistent, some even pointing away from the Sun, which further breaks from comet norms.
The only natural workaround would require a volatile pocket repeatedly exposed by rotation and perfectly shadowed again. Possible? Theoretically. Likely? Not very.
Radio Signals in SETI Channels
There’s more. Narrowband absorption signals at 1665 and 1667 MHz, frequencies in the so-called “Water Hole” region, long considered optimal for interstellar communication, were detected in correlation with peak aerodynamic stress on the object.
Now to be clear: OH (hydroxyl) absorption is expected in cometary comas. But what’s not expected is the clean, selective nature of the signal, nor the fact that it coincides with mechanical activity. Loeb notes that the timing suggests a systemic link between physical and electromagnetic behaviours, something hard to explain as coincidence.
There’s no evidence of a continuous transmission, SETI arrays like MeerKAT looked and found nothing beyond that narrowband absorption. But the nature of the signal doesn’t need to be continuous to raise questions.
What Does This Mean?
Loeb’s conclusion is not that we’ve discovered alien tech. It’s that a technological hypothesis explains more with fewer assumptions than the increasingly complex natural ones. Instead of six or seven exceptions to explain each anomaly away, one coherent explanation, intentional regulation, resolves most of them.
He doesn’t claim certainty. He does argue that refusing to investigate the possibility is unscientific.
Where NASA Stands
NASA continues to label 3I/ATLAS a comet. That’s expected, they’re institutionally cautious. But the growing mismatch between standard models and observation puts pressure on that position. If future high-resolution imaging shows no rotational smearing, if the pulse stays stable, and if radio events keep lining up with physical events, something will have to give.
Loeb’s full anomaly breakdown offers a working hypothesis: this could be an artificial object using controlled thrust and energy modulation to move through space efficiently and quietly. If that turns out to be true, this isn’t a comet at all. It’s an engineered probe.