As the third confirmed interstellar object pierces our solar system, Comet 3I/ATLAS has ignited a fierce scientific showdown. Discovered in July 2025 by NASA’s ATLAS survey, this visitor from beyond our stellar neighborhood reached perihelion on October 29, 2025, prompting Harvard astrophysicist Avi Loeb to revive his provocative hypothesis: Could it be alien technology? NASA, however, has firmly classified it as a natural comet, bolstered by recent radio observations and imaging data.

The object’s hyperbolic trajectory—excess velocity of 52 km/s—confirms its extrasolar origin, akin to predecessors ‘Oumuamua (1I) and Borisov (2I). But 3I/ATLAS stands out with peculiarities: an unusually straight path deviating minimally from interstellar space norms, high nickel content in its composition, and brightness fluctuations defying standard cometary models. Loeb, in a July 2025 preprint on arXiv, argues these traits suggest artificial engineering, potentially a probe releasing devices at Jupiter. Harvard CfA preprint.

Anomalous Trajectory Under Scrutiny

Loeb’s statistical analysis highlights a 1-in-1,000 odds for such a precise Jupiter encounter, implying intent. ‘The implication of alien technology would be huge and therefore we must take it seriously,’ Loeb told Newsweek ahead of perihelion. Yet, NASA’s Goldstone radar and Hubble data show outgassing consistent with icy bodies, not propulsion.

Post-perihelion, South Africa’s MeerKAT telescope captured the first radio signals from 3I/ATLAS on November 11, 2025—narrowband emissions at 1.4 GHz matching hydroxyl radicals from water ice vaporizing under solar heat. ‘This is further proof of its completely natural origins,’ reported Live Science, effectively countering technosignature claims.

Radio Waves Seal Natural Verdict?

NASA’s November 19 briefing released images from eight observatories, including JWST’s NIRSpec data revealing pristine ices older than our solar system. ‘3I/ATLAS is a comet,’ emphasized NASA officials, dismissing rumors. SPHEREx spectra confirmed CO and methane, hallmarks of comets, with no infrared anomalies suggestive of machinery. NASA Science.

Yet Loeb persists. In a Medium post, he questioned if natural comets could harbor happiness in their primitiveness, while recent X posts from his account speculate on ‘technological devices’ at Jupiter. Posts on X from NASA reiterate: ‘Everything we have seen is on par with observed behaviors of comets.’ NASA on X.

Loeb’s Latest Pushback

Diving deeper into composition, Webb detected elevated nickel-iron ratios, potentially from a metal-rich parent star. Loeb’s team posits this could indicate engineered debris, but peers attribute it to formation in a high-metallicity environment. A WIRED analysis notes the radio signal’s OH maser aligns perfectly with solar proximity heating, not modulated transmissions.

Trajectory modeling by JPL refines its path: inbound from Lyra constellation, outbound past Jupiter in 2026. No collision risks, but its passage offers unprecedented data on extrasolar chemistry. Dynamicists calculate a 0.1% chance of natural alignment this precise, fueling debate—but simulations incorporating chaos from birth cloud scattering normalize it.

Decoding the Chemical Time Capsule

Perihelion images from SOHO showed a 10-km nucleus with a diffuse coma, expanding post-swingby. Unlike ‘Oumuamua’s non-outgassing weirdness, 3I/ATLAS displayed classic jets. Reuters reported NASA rejecting ‘alien spacecraft rumors’ outright on November 19. Reuters.

Industry insiders note funding implications: Loeb’s Galileo Project scans for signals, while SETI repurposes Allen Telescope Array beams. Skeptics like Alan Fitzsimmons argue anomalies stem from observational biases in ATLAS’s wide-field detection.

Observational Campaigns Intensify

Post-perihelion fading limits ground optics, shifting focus to space assets. New Horizons, en route to Kuiper Belt, may image it in 2026 at 10 AU. Vera Rubin Observatory’s 2025 commissioning promises better early detection of future visitors. Debate underscores paradigm tension: extraordinary claims demand extraordinary evidence, absent here.

Recent X buzz amplifies divide—Avi Loeb posts on statistical improbabilities, NASA counters with data dumps. A SlashGear piece claims radio signals ‘end the debate,’ but Loeb retorts composition outliers persist. SlashGear.

Future Probes and Paradigms

As 3I/ATLAS recedes, its legacy challenges assumptions. Natural or not, it proves interstellar objects are common—perhaps trillions roam the galaxy. For insiders, the real win is methodological: rigorous spectroscopy trumps speculation, pushing boundaries without leaping to ET.