In 2024, astronomers detected a faint blue glow moving across the night sky. The object, later designated 3I/ATLAS, was quickly confirmed to be traveling on a hyperbolic path—an orbit too fast and too open to belong to our Sun. With that, it entered the history books as only the third confirmed interstellar object ever observed.

For centuries, human beings have wondered whether the space between the stars is empty or alive with travelers. Each new interstellar detection—ʻOumuamua in 2017, Borisov in 2019, and now ATLAS—offers another chance to confront that question. And if early observations are any indication, 3I/ATLAS is already challenging what we think we know about the universe.

A visitor from beyond

3I/ATLAS was discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Hawaii, a survey designed to spot hazardous objects approaching Earth. But this particular detection was never a threat. Instead, the speed and trajectory of ATLAS revealed its origin: far beyond the solar system, traveling through interstellar space before swinging past the Sun.

While interstellar dust and molecules constantly stream through our solar system, large solid objects like this are exceedingly rare to spot. That rarity is what makes each new arrival scientifically priceless.

The puzzle of its appearance

From the beginning, ATLAS behaved strangely. Unlike Borisov, which resembled a conventional comet complete with a long tail, ATLAS does not appear to release large amounts of water vapor. Hubble Space Telescope images revealed something unusual: a diffuse glow on its sun-facing side, but no tail stretching behind it.

This breaks the pattern astronomers expect. A comet’s icy surface normally vaporizes in sunlight, producing a glowing tail pushed away by solar radiation. ATLAS seems to reflect or scatter light differently—perhaps due to dust, an unusual surface composition, or something less familiar.

Harvard astrophysicist Avi Loeb has written extensively on these anomalies. In one article, he asked whether ATLAS might even be generating its own light. In others, he drew comparisons to ʻOumuamua, which showed a puzzling acceleration without a visible tail. While most researchers continue to search for natural explanations, Loeb cautions against dismissing the possibility of something artificial.

How big is it?

Size estimates for ATLAS remain uncertain, but Loeb has suggested that the object may be smaller—or rarer—than it looks. If the glow comes from dust or gas surrounding a tiny core, the actual solid body could be much smaller than early measurements implied. That in itself would be unusual, because faint interstellar debris is harder to detect, yet ATLAS has proven relatively bright.

Another oddity is its shape. Imaging and modeling hint that ATLAS may be elongated, recalling ʻOumuamua’s cigar- or pancake-like geometry. If confirmed, that would mark the second time an interstellar visitor displayed an atypical form.

Could it be technology?

Few questions spark more curiosity than whether such an object might be artificial. In several essays, Loeb has raised the possibility that ATLAS could represent alien technology—perhaps a probe, fragment, or even a piece of discarded equipment from a distant civilization.

He frames the issue as a scientific test of humility: would humanity even recognize an extraterrestrial artifact if it passed through our neighborhood? Or would we insist on shoehorning every anomaly into familiar categories?

To be clear, no evidence currently proves ATLAS is technological. But as with ʻOumuamua, its combination of brightness, odd shape, and unusual light behavior has kept the debate alive. Loeb even likened it to a Turing test for astronomy, challenging us to distinguish between natural and potentially artificial origins.
Security and policy concerns

The mystery of ATLAS has spilled beyond academic journals. In early 2025, U.S. Congresswoman Anna Paulina Luna sent a formal letter to NASA requesting updates on the object. She raised concerns about the national security risks of unidentified interstellar visitors.

While many scientists stress there is no threat, the episode highlights how public officials are beginning to take such events seriously. After all, if even a tiny fraction of interstellar objects were artificial, the implications for security and diplomacy would be immense.

A chance for Juno?

Loeb and other researchers have pointed to a remarkable opportunity: as ATLAS passes near Jupiter, it may come within observational range of NASA’s Juno spacecraft. Though Juno was designed to study Jupiter’s atmosphere and magnetic field, it carries instruments that could, in principle, gather valuable data on ATLAS.
Intercepting the object directly would require technology we don’t yet have ready to launch. But future planning could allow humanity to mount rapid-response missions to the next interstellar visitor. Loeb argues that investment in such missions is essential, given the pace of discoveries and the fleeting nature of these encounters.

Should we try to communicate?

Another provocative question is whether humanity should attempt to send a message. If ATLAS were technological, should we announce our presence? Loeb raises the idea within the long-running debate about Messaging Extraterrestrial Intelligence (METI).

Some argue that any civilization advanced enough to send probes across light-years already knows Earth is inhabited. Others fear broadcasting our presence could be risky. For now, the question remains theoretical—but with objects like ATLAS passing through, it feels less abstract than ever before.

Beyond the anomalies

Of course, ATLAS may ultimately prove to be a natural object with unusual but explicable traits. Scientists are investigating possibilities ranging from exotic ices to “dark comets” that emit dust without gas. Even such outcomes would expand our understanding of what planetary systems beyond our own can produce.

As Loeb reminds us, science advances by investigating anomalies, not ignoring them. Each interstellar object forces us to expand the boundaries of what we expect.

Why it matters

So why should anyone care about an icy fragment hurtling through space? Because interstellar objects are direct messengers from other planetary systems. Unlike distant stars or exoplanets, these bodies come to us, carrying material and perhaps information about how other systems formed and evolved.

More importantly, they remind us of the possibility that we are not alone. Whether natural or artificial, ATLAS challenges us to look at the sky not as a static dome but as a cosmic crossroads, where the familiar meets the unknown.

A cosmic wake-up call

Avi Loeb has written that “extraordinary evidence requires extraordinary funding.” If humanity wants to be ready for the next interstellar arrival, we must invest in instruments, spacecraft, and missions that can capture these fleeting opportunities.

3I/ATLAS is a wake-up call. It may not be alien technology, but it demonstrates how little we know about the objects drifting between the stars. Ignoring it—or brushing off its anomalies— would mean missing a chance to expand human knowledge at the very frontier of science.

As host of All Things Unexplained, I often say that mysteries are invitations. ATLAS is precisely that: an invitation to curiosity, humility, and discovery. The question is whether we will accept it.