{"id":122449,"date":"2025-09-08T08:08:10","date_gmt":"2025-09-08T08:08:10","guid":{"rendered":"https:\/\/www.newsbeep.com\/uk\/122449\/"},"modified":"2025-09-08T08:08:10","modified_gmt":"2025-09-08T08:08:10","slug":"the-more-astronomers-watch-interstellar-comet-3i-atlas-the-weirder-it-gets","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/uk\/122449\/","title":{"rendered":"The More Astronomers Watch Interstellar Comet 3I\/ATLAS, the Weirder It Gets"},"content":{"rendered":"

When NASA\u2019s ATLAS survey first spotted<\/a> the interstellar comet 3I\/ATLAS in July 2025, astronomers recognized it as a rare and intriguing visitor from beyond our solar system.\u00a0<\/p>\n

Yet, with each new observation, 3I\/ATLAS has only grown stranger, upending expectations of what an interstellar traveler should look like or how it should behave.<\/p>\n

In the past two months, the world\u2019s most powerful telescopes, including Hubble, JWST, SPHEREx, and TESS, have locked onto 3I\/ATLAS, revealing that this interstellar comet refuses to play by the rules.<\/p>\n

From its extraordinary composition, an unusually high carbon dioxide\u2011to\u2011water ratio, to its ambiguous size and trajectory, each new data point deepens the mystery, turning what might have been a straightforward comet study into a frontier of interstellar science.<\/p>\n

\"3I\/ATLAS\"A composite image showing the movement of 3I\/ATLAS, as seen by the ESO\u2019s Very Large Telescope (Credit: ESO\/O. Hainaut)<\/p>\n

Since its discovery on July 1, 2025, by the ATLAS survey telescope in Chile, 3I\/ATLAS has been recognized as the third confirmed interstellar object to pass through our solar system, following \u2018Oumuamua<\/a> in 2017 and 2I\/Borisov<\/a> in 2019.\u00a0<\/p>\n

From early on, the world\u2019s major observatories converged on the interstellar comet, each uncovering incredibly rare and unusual traits that set it apart from familiar comets.\u00a0<\/p>\n

NASA\u2019s James Webb Space Telescope (JWST) deployed<\/a> its near\u2011infrared spectrograph on August 6, revealing a coma dominated by carbon dioxide, far more so than water\u2014a composition virtually unheard of in known comets. The JWST maps displayed distinct emissions at 4.3 \u03bcm (CO\u2082), faint water at 2.7 \u03bcm, and carbon monoxide at 4.7 \u03bcm.<\/p>\n

Complementing JWST\u2019s data, the SPHEREx observatory gathered observations from August 7 to 15, capturing nuclear and dust properties of 3I\/ATLAS. Initial findings revealed a strong point-source signature, without significant extended structure, adding a layer of ambiguity about the comet\u2019s nucleus.\u00a0<\/p>\n

Meanwhile, Hubble delivered some of the sharpest imagery yet, revealing that 3I\/ATLAS has a dusty coma and nascent signs of a tail. These findings offer strong evidence so far that the alien visitor is indeed a comet, albeit a highly unusual one.\u00a0<\/p>\n

The actual size and physical characteristics of 3I\/ATLAS continue to remain elusive.\u00a0<\/p>\n

Early measurements<\/a> from the Hubble Space Telescope placed the comet\u2019s nucleus somewhere between 0.2 and 3.5 miles (0.32 to 5.6 km) across. Later observations<\/a>, however, suggested it could be far larger\u2014between 6.2 and 12.4 miles (10 to 20 km) in diameter, potentially making it the largest interstellar object ever observed.<\/p>\n

Supporting this, pre-observation data from the Vera C. Rubin Observatory showed that 3I\/ATLAS\u2019s apparent diameter expanded by roughly 3,700 miles in less than two weeks between late June and early July. Scientists note this rapid growth aligns with the behavior of comets that become more active as they draw closer to the Sun.<\/p>\n

\"3I\/ATLAS.\"(Credit: NASA\/JPL)<\/p>\n

Beyond its composition and size, 3I\/ATLAS\u2019s trajectory adds another layer of intrigue.\u00a0<\/p>\n

The comet\u2019s hyperbolic trajectory, meaning its path isn\u2019t bound by the Sun\u2019s gravity, immediately identifies it as originating outside our solar system. In fact, 3I\/ATLAS\u2019s trajectory has an extremely high orbital eccentricity, making its path appear nearly straight rather than curved.\u00a0<\/p>\n

Additionally, 3I\/ATLAS is traveling at remarkably high hyperbolic excess velocity, moving at a speed of roughly 130,000 mph relative to the Sun. That makes it more than twice as fast as \u02bbOumuamua, which crossed the solar system at approximately 58,000 mph, and nearly double the speed of 2I\/Borisov, which reached around 72,000 mph. The sheer pace of 3I\/ATLAS sets it apart as the fastest interstellar object ever recorded.\u00a0<\/p>\n

Adding to the mystery, 3I\/ATLAS is traveling on a retrograde orbit that runs almost perfectly along the plane of the solar system\u2019s ecliptic. In other words, it\u2019s moving in the opposite direction of the planets while still hugging the same flat disk in which they all orbit the Sun. This combination is highly unusual, as interstellar objects are expected to arrive from random orientations and not from a path so neatly aligned with our planetary plane.\u00a0<\/p>\n

3I\/ATLAS\u2019s origin point is just as surprising as its unusual orbit. The interstellar visitor was first spotted entering the solar system from the southern celestial hemisphere, arriving from a direction almost opposite the \u201csolar apex,\u201d or the point in the sky toward which the Sun and nearby stars are moving.\u00a0<\/p>\n

Astronomers had long assumed that most interstellar objects would be discovered coming from that apex, essentially catching up to us from behind. Instead, 3I\/ATLAS came in from the other side, suggesting that either our expectations about the flow of interstellar debris need rethinking, or that detection bias has kept us from spotting similar objects in the past.<\/p>\n

Of all its strange features, scientists have been especially struck by 3I\/ATLAS\u2019s unusually high abundance of carbon dioxide.<\/p>\n

\u201cOur observations are compatible with an intrinsically CO\u2082\u2011rich nucleus, which may indicate that 3I\/ATLAS contains ices exposed to higher levels of radiation than Solar System comets, or that it formed close to the CO\u2082 ice line in its parent protoplanetary disk,\u201d researchers noted in a follow-up study<\/a> using data from JWST just published in late August.\u00a0<\/p>\n

A comet with such a high carbon dioxide\u2013to\u2013water ratio likely formed in an environment very different from our own, perhaps closer to a CO\u2082 ice line or under intense radiation fields that locked in ices in ways unlike any comet native to our solar system.<\/p>\n

Moreover, unlike most comets, 3I\/ATLAS\u2019s enormous estimated size and unusually sluggish tail formation hint at a physical makeup or evolutionary history unlike anything astronomers have observed before.\u00a0<\/p>\n

Not all of the explanations for 3I\/ATLAS\u2019s unusual characteristics have been grounded in conventional cometary science.\u00a0<\/p>\n

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In a controversial, non-peer-reviewed paper<\/a> released in mid-July, Dr. Avi Loeb and two colleagues suggested that 3I\/ATLAS could be alien technology, deliberately navigating our solar system, possibly even with \u201chostile\u201d intent. To their credit, Dr. Loeb and his co-authors framed the work as \u201clargely a pedagogical exercise,\u201d and more of a thought experiment than a firm claim.<\/p>\n

Still, the mere suggestion that 3I\/ATLAS might be some form of extraterrestrial technology has drawn swift and widespread rebuttals from the broader scientific community.\u00a0<\/p>\n

\u201cAny suggestion that it\u2019s artificial is nonsense on stilts, and is an insult to the exciting work going on to understand this object,\u201d University of Oxford astronomer and member of the team that simulated 3I\/ATLAS\u2019s galactic origins<\/a>, Dr. Chris Lintott, told Live Science<\/a>.\u00a0<\/p>\n

In a preprint<\/a> released at the end of August, an international team of astronomers affirmed that all available evidence indicates that 3I\/ATLAS\u2014like its predecessors, Oumuamua and 2I\/Borisov<\/a>\u2014is of natural origin. Still, the researchers contend that searching for potential technosignatures in interstellar visitors remains a worthwhile pursuit.<\/p>\n

As researchers point out, many of humanity\u2019s deep space probes are already on interstellar trajectories, destined to drift past the outskirts of other star systems over the next tens of thousands of years. With that in mind, the notion that an advanced alien civilization might have launched similar probes that one day wander into our cosmic neighborhood is not so far-fetched.<\/p>\n

Notwithstanding its unprecedented and puzzling traits, the overwhelming consensus for now is that 3I\/ATLAS is a naturally formed interstellar comet.<\/p>\n

3I\/ATLAS will reach perihelion on October 29\u201330, 2025, at approximately 1.4 astronomical units from the Sun\u2014inside Mars\u2019s orbit. It will then come within around 168 million miles of Earth in mid\u2011December, offering one more shot at observation before it heads back into the void of outer space.\u00a0<\/p>\n

For astronomers, that fleeting passage represents both an extraordinary opportunity and a sobering reminder. Unlike planets or asteroids bound to the Sun, interstellar visitors like 3I\/ATLAS offer only a narrow window for study before they vanish forever.<\/p>\n

Scientists will now have just a few months to gather as much data as possible, continuing to measure its composition, structure, and probing the secrets locked within its alien ices. Once it slingshots past the Sun and recedes into interstellar space, it will be gone for good, carrying its mysteries with it.\u00a0<\/p>\n

Whether 3I\/ATLAS ultimately reshapes our understanding of the universe is still uncertain. However, so far, this interstellar traveler has already shown that the cosmos may be far stranger than we ever imagined.<\/p>\n

Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter:\u00a0@LtTimMcMillan. \u00a0<\/a>Tim can be reached by email:\u00a0tim@thedebrief.org<\/a>\u00a0or through encrypted email:\u00a0LtTimMcMillan@protonmail.com<\/a>\u00a0<\/p>\n

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