Tag: space

First Evidence for a Non-Gravitational Acceleration of 3I/ATLAS at Perihelion

By the date of its perihelion, 3I/ATLAS displayed the first evidence of a non-gravitational acceleration. The report (accessible here) was filed by Davide Farnoccia, a navigation engineer at NASA’s Jet Propulsion Laboratory in Pasadena who received his PhD in Mathematics from the Galileo Galilei School of Graduate studies at the University of Pisa, Italy.

The non-gravitational acceleration was measured at the perihelion distance of 1.36 times the Earth-Sun separation (defined as an astronomical unit or `au’), equivalent to 203 million kilometers. It had two components in the orbital plane of 3I/ATLAS:

· A radial acceleration away from the Sun of 135 kilometers (=9×10^{-7}au) per day squared.

· A transverse acceleration relative to the Sun’s direction of 60 kilometers (=4×10^{-7}au) per day squared.

If 3I/ATLAS is propelled by the rocket effect of ejected gas, then momentum conservation implies that the object would lose half its mass over a characteristic timescale equal to the ejection speed divided by the measured non-gravitational acceleration. For a thermal ejection speed of a few hundred meters per second, the evaporation half-life of 3I/ATLAS is 6 months. This implies that over the month it takes 3I/ATLAS to cross a spatial scale of order its perihelion separation from the Sun, 3I/ATLAS would lose about a tenth of its mass. Such a massive mass loss should be detectable in the form of a large plume of gas surrounding 3I/ATLAS during the upcoming months of November and December 2025.

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Did 3I/ATLAS Just Show Signs of Technology? Interstellar Object Displays ‘Non-Gravitational Motion’ as it Swings Past the Sun

A new report on the enigmatic interstellar visitor 3I/ATLAS has revealed deeper insights into the object’s behavior, which include signs of non-gravitational motion during its recent closest approach to the Sun.

Presently, most astronomers maintain that the space object, discovered in July 2025, is a natural comet, based on a growing body of data that confirms this interpretation. The object is the third known interstellar visitor that has entered our planetary neighborhood from another star system.

3I/ATLAS is also helping confirm data that suggests such objects probably make appearances far more frequently in our Solar System than previously known. With its glowing gassy envelope—what astronomers call a coma—and other key traits that have manifested as the object has moved closer to the Sun, little doubt has been left about the interstellar visitor’s identity as a natural object.

However, there are still some experts who interpret its recent activity as being noteworthy indicators—if additional related phenomena were to be confirmed in future observations—which some might expect to associate with objects of technological origin. So what does the latest data reveal, and why does it still have some astronomers divided over whether 3I/ATLAS might show signs associated with intelligent life?

What the New Report Reveals

A recent report by researcher Davide Farnoccia with NASA’s Jet Propulsion Laboratory offers some of the latest data on the gravitational characteristics displayed by 3I/ATLAS during its journey through our Solar System.

Farnoccia specializes in the study of small objects and their orbits, which includes “nongravitational perturbations” some space objects display, as well as whether some near-Earth objects (NEOs) may pose an impact hazard to Earth.

According to Farnoccia’s report, 3I/ATLAS follows a hyperbolic orbit, displaying an eccentricity of e = 6.1373 (rounded). This figure is important, as it significantly exceeds the accepted value of 1 that astronomers recognize as being required to escape the Sun’s gravity. This means that the object’s trajectory confirms that 3I/ATLAS is not gravitationally bound to our Solar System, confirming astronomers’ suspicions that once it completes its recent planetary drive-by visit, the object will continue back into interstellar space.

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Mysterious Interstellar Object 3I/ATLAS “Comes Alive” Near the Sun — NASA on Alert

The much-anticipated interstellar visitor 3I/ATLAS has finally reached its closest approach to the Sun — and it’s doing things no natural object should. As telescopes around the world capture its fly-by, early data reveals unexpected behavior, deepening one of the most intriguing space mysteries in years.

This massive, Manhattan-sized object is only the third known interstellar body to enter our solar system, after ‘Oumuamua (2017) and 2I/Borisov (2019). But 3I/ATLAS is turning out to be the most enigmatic of all — and even NASA scientists are struggling to explain what they’re seeing.

A visitor unlike any other

Discovered in July by the ATLAS telescope in Chile, 3I/ATLAS immediately drew attention due to its hyperbolic trajectory, confirming that it originated beyond our solar system. But what truly astonished astronomers was its size and chemical makeup.

New data from the James Webb Space Telescope (JWST) shows that the object’s coma — the glowing halo of gas and dust — is dominated by carbon dioxide (CO₂), with a CO₂-to-water ratio of nearly 8:1, far higher than any known comet. Scientists also noted a strange anti-tail — a stream of dust pointing toward the Sun rather than away from it — a phenomenon rarely seen and poorly understood.

Even more puzzling, the object emits a brilliant green hue, a sign that something “has switched on” as it neared the Sun, according to recent optical observations. Some astronomers suspect this is due to chemical excitation from solar radiation, while others say the spectral pattern doesn’t match any known natural process.

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Harvard Scientist Accuses NASA of Coverup About Mysterious Comet

Harvard astrophysicist Avi Loeb has once again leveled accusations against NASA during an interview on the Joe Rogan Experience, this time claiming the agency is deliberately withholding a key image of the mysterious interstellar comet 3I/ATLAS.

The alleged photograph, taken by the High Resolution Imaging Science Experiment (HiRISE) camera aboard the Mars Reconnaissance Orbiter (MRO), shows the comet when it passed within 30 million kilometers of Mars, which is a rare close encounter for an object originating from outside our solar system, according to Loeb, who chaired the Harvard’s Department of Astronomy from 2011 to 2020.

Loeb also said that he directly contacted the HiRISE principal investigator to request access to the data, but his request fell on deaf ears.

“I wrote to the principal investigator of HiRISE, asking, ‘Can I get the data? I’m a scientist,’” said Loeb, who said he received “no response” from NASA.

The comet, designated 3I/ATLAS, has exhibited several unusual characteristics that have fueled speculation. Unlike typical comets, it displays jet-like emissions directed toward the Sun rather than away from it, a phenomenon that defies standard models of cometary outgassing, the New York Post reports. Additionally, 3I/ATLAS lacks a visible cometary tail and has been observed spouting nickel without accompanying iron that compositions not commonly seen in natural solar system bodies.

Loeb has previously speculated that the Manhattan-sized object could be of alien origin, though he tempers this with caution. In his view, the more probable explanation is “terrestrial stupidity” rather than evidence of extraterrestrial intelligence. Nonetheless, the comet’s non-gravitational acceleration and its trajectory raise questions. Loeb has suggested these features could indicate reconnaissance activity if the object were artificial, though he emphasizes this as a low-probability scenario.

“If 3I/ATLAS is a massive mothership, it will likely continue along its original gravitational path and ultimately exit the Solar system,” Loeb wrote in a blog post in September. “In that case, the Oberth maneuver might apply to the mini-probes it releases at perihelion towards Solar system planets.”

“Science is guided by evidence and not by expectations,” the Harvard astrophysicist continued. “We can find the answer to the above question by monitoring the sky during November and December 2025, and searching for any unusual activity of 3I/ATLAS or any new objects that came out of it.”

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Astronomers Say They Just Detected Radio Signals Coming from This Comet

Evidently, it’s a big week for news involving comets, as a team of astronomers now reports the detection of an intriguing series of radio signals emanating from one of the speeding objects (no, not that comet) currently making its way through our solar system.

The surprising news comes to us courtesy of a research team led by the Shanghai Astronomical Observatory of the Chinese Academy of Sciences, and was reportedly made possible with the Tianma Radio Telescope.

During multi-band radio observations of comet 12P/Pons-Brooks, the team detected an interesting series of radio signals coming from the returning comet, which is also one of the brightest comets astronomers have ever seen.

At a glance, this all sounds pretty tantalizing… but what does the detection of radio signals from a comet in our solar system actually mean?

A Returning Comet Stops In

First discovered in 1812, 12P/Pons-Brooks possesses an orbital period of around 71 years, meaning that this is actually the fourth time astronomers have had an opportunity to watch it during its journeys through the solar system.

During their recent observations of the Halley-type comet, the Chinese team says they measured the rate at which water was being produced by 12P/Pons-Brooks, which revealed the most distant known detection of ammonia molecules known to astronomers from such observations.

Since comets are known to contain a variety of icy components—many of which are as old as the solar system itself—they are ideal for observations by astronomers, particularly when these materials begin to bake off as the speeding objects make their way toward the Sun.

In the case of comets like 12P/Pons-Brooks, the presence of volatile ices shows that they haven’t been subjected to large amounts of thermal evolution since they were born in our solar system eons ago. Because of this, the study of the ices they carry and their composition offers a way for astronomers to look back in time at the chemical and thermal conditions that were present in our planetary neighborhood around 4.6 billion years ago.

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Manhattan-sized space object 3I/ATLAS has grown a tail — a possible sign of alien ‘maneuver’: Harvard scientist

New images reveal the Manhattan-sized interstellar object 3I/ATLAS has started to sport a tail, indicating that it could possibly be a “maneuvering” alien craft, one Harvard scientist suggested.

After exhibiting signs of an incredibly strange “anti-tail” since first cropping up in the solar system in July, 3I/ATLAS is now showing evidence of a true cometary tail, images taken by Spain’s Nordic Optical Telescope in the Canary Island in September revealed.

These new images shows materials being peeled off behind the 33-billion ton object as it travels toward the sun and is hit with up to 33 gigawatts of solar radiation, Harvard astrophysicist Avi Loeb wrote in a recent paper.

However, the succession of an anti-tail and then the presence of a tail could be indicative of “controlled maneuvering” and a high-impact Black Swan event.

3I/ATLAS’s anti-tail was a plume composed of mostly carbon dioxide and water with trace amounts of cyanide and a never-seen-in-nature nickel alloy that has only been used in human manufacturing.

“[I]f the object is an alien spacecraft slowing down,” Loeb wrote, then the anti-tail would be evidence of a “braking thrust” maneuver which would naturally change to a tail as the slowing procedure completed.

The International Asteroid Warning Network added 3I/ATLAS to its list of targets earlier this week, and began monitoring the object for scientific purposes.

The group wrote on its website: “While it poses no threat, comet 3I/ATLAS present a great opportunity for the IAWN community to perform an observing exercise due to its prolonged observability from Earth and its high interest to the scientific community.”

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3I/ATLAS is Leaving a Mysterious “Hidden” Trail of Particles in Its Wake—Now Scientists Have a Plan to Intercept It

While comet 3I/ATLAS and its dusty tail remain far out of the reach of Earthly spacecraft, astronomers say the unusual interstellar object has produced a secondary “hidden” trail of charged particles marking its path through our solar system.

Now, a pair of scientists with the European Space Agency (ESA) has proposed a bold idea: it may be possible to sail a pair of NASA and ESA spacecraft through the mysterious visitor’s “ion tail.”

The idea was advanced by a pair of researchers in a new paper, which argues that the trajectory of NASA’s Europa Clipper spacecraft and the European Space Agency’s (ESA) Hera spacecraft could allow them to pass directly through the trail of ions left in 3I/ATLAS’s wake.

Doing so might offer astronomers a rare opportunity to collect samples of material from other worlds, which the odd interstellar comet has ejected during its unprecedented visit.

Mission Into an Interstellar Object’s Odd “Ion Tail”

Between October 30 and November 6, 2025, the trajectories of the Europa Clipper and Hera space missions may briefly align with the ion trail left by 3I/ATLAS, allowing their instruments to collect information through detections of charged particles carried outward from the object by the solar wind.

“During the period 30 October – 6 November 2025, it is predicted that Europa Clipper will potentially be immersed within the ion tail of 3I/ATLAS, providing the opportunity to detect the signatures of an interstellar comet’s ion tail, write authors Samuel Grant and Geraint Jones in their paper, which appeared on the preprint arXiv.org server on October 15, 2025.

“Characteristic changes to the solar wind are also expected to be observed,” the authors say, which will likely include what they characterize as “a magnetic draping structure” potentially emanating from the comet.

Even prior to Europa Clipper’s potential passage through the mysterious ion tail of 3I/ATLAS, Grant and Jones believe that the ESA’s Hera spacecraft “will possibly be immersed within the ion tail of 3I/ATLAS during the period 25 October – 1 November 2025.”

Neither spacecraft will be endangered during their potential transit of the interstellar comet’s tail of charged particles, although the implications of doing so could end up being profound, in that they may offer the first opportunity to make indirect observations of material samples from another star system.

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Interstellar Object Is Spraying Something Weird, Scientists Find

A new analysis of our solar system’s interstellar interloper, 3I/ATLAS, reveals that it’s spewing huge amounts of water — and astronomers can’t immediately explain why.

The object, which is widely believed to be comet, showed strong ultraviolet emissions that are unmistakable telltales of hydroxyl gas (OH), a byproduct of water, when astronomers imaged it with NASA’s Neil Gehrels Swift space telescope before it disappeared behind the Sun. The emissions could only be spotted from space because the ultraviolet light would get absorbed in the atmosphere.

Their findings, detailed in a new study published in The Astrophysical Journal Letters, argue that the presence of all this OH indicates the comet is ejecting water vapor at a torrential rate of about 88 pounds per second — around the same rate as a fire hose running at full blast, according to a press release about the findings.

The most extraordinary thing is that this was spotted happening pretty far from the Sun, at a heliocentric distance of about three astronomical units (AU) away, or three times the distance between the Earth and our star. Typically, comets stray much closer to the Sun before the water ice in their core, called a nucleus, begins to sublimate, or instantly transform from a solid to a gas. Something else must be driving all the water dumping from 3I/ATLAS — which also implies, tantalizingly, that the comet must harbor considerable stores of water for this process to keep going.

“When we detect water — or even its faint ultraviolet echo, OH, — from an interstellar comet, we’re reading a note from another planetary system,” coauthor Dennis Bodewits, a professor of physics at Auburn University, said in the release. “It tells us that the ingredients for life’s chemistry are not unique to our own.”

It’s another example of the fascinating strangeness of interstellar objects like 3I/ATLAS. Think of it as a sample of somewhere very far away, perhaps tens of millions of light years, careening straight past our doorstep. That it’s in many ways bizarre compared to local comets hints at just how unique these unimaginable alien realms must be, and how we have so much more to understand of how star systems form and how their structures may evolve.

Typically, a comet’s coma, a huge halo of gas and dust that give comets their glowing appearance, begin to form as the object nears the Sun — or another star, presumably — and heats up. The heat either sublimates or vaporizes the material in its nucleus, which is many times smaller than the tail that catches our eyes from the ground, stretching behind the comet.

3I/ATLAS’s coma has already surprised us in many ways. Its chemistry is strange compared to our own comets, and it appears to have an astonishingly high ratio of carbon dioxide to water.

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Newest 3I/ATLAS Images Reveal Mysterious Interstellar Visitor in “Challenging Observation” by ESA Spacecraft

Highly anticipated new images of the interstellar comet 3I/ATLAS as it made its nearest pass to the planet Mars last week have been released by the European Space Agency (ESA), showcasing both the opportunities—and the challenges—that viewing the unusual object presents.

The new images, obtained by the ESA’s ExoMars Trace Gas Orbiter, reveal a view of the alien comet similar to those obtained in July by NASA’s Hubble Space Telescope, although at much closer range.

Additional data may have also been obtained by ESA spacecraft as 3I/ATLAS passed Mars, although the agency said it presently remains unclear whether the ExoMars or its sister spacecraft, the Mars Express orbiter, may have collected spectrographic information that could enable chemical analysis.

Initially discovered in early July, 3I/ATLAS has captured the fascination of the astronomical community due to its unusual characteristics, which include its size, speed, and a range of behaviors that are not consistent with comets native to our solar system.

During the interstellar comet’s recent flyby past Mars, the ESA trained the cameras aboard its ExoMars and Mars Express orbiter toward the object, although the shorter exposure times of the latter spacecraft prevented it from being able to obtain any imagery of the object.

Fortunately, ExoMars is equipped with the Colour and Stereo Surface Imaging System (CaSSIS) camera, which has a resolution of 11.36 micro-radians (≈2.34 arcseconds) per pixel, translating to 340 km per pixel at 30 million km distance.

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Was the “Wow! Signal” Emitted from 3I/ATLAS?

The “Wow! Signal” was detected on August 15, 1977 as a strong narrowband radio signal by Ohio State University’s Big Ear radio telescope. Its origin was inferred to be extraterrestrial. The latest natural explanation (accessible here) hypothesized that the “Wow! Signal” was caused by a sudden brightening of the hydrogen line emitted from an interstellar cloud, triggered by a strong transient radio source, such as a flare from a highly magnetized neutron star (magnetar).

The “Wow! Signal” originated from the sky coordinates of Right Ascension (RA)=19h25m=291 degrees and Declination (Dec)=-27 degrees.

On August 12, 1977, the interstellar object 3I/ATLAS was at a distance of about 600 times the Earth-Sun separation (AU) — corresponding to a light-travel time of about 3 days. It had the sky coordinates of RA=19h40m=295 degrees and Dec=-19 degrees. These parameters can be inferred accurately given the lack of non-gravitational acceleration for 3I/ATLAS, as inferred in my latest paper (accessible here).

Hence, the “Wow! Signal” was separated by approximately 4 degrees in RA and 8 degrees in Dec from the direction of 3I/ATLAS. The chance of two random directions in the sky being aligned to that level is about 0.6 percent. If the “Wow! Signal” originated from 3I/ATLAS, how powerful was the transmitter?

The detected intensity of the “Wow! Signal” was in the range of 54–212 Jansky with a bandwidth of about 10 kilohertz. At the distance of 600 AU, this corresponds to a source power of 0.5–2 gigawatts, the output of a typical nuclear reactor on Earth.

The “Wow! Signal” was observed at a frequency of 1420.4556±0.005 megahertz, blue-shifted by about 10 kilometers per second towards Earth relative to the central frequency of the hydrogen line. This blueshift is of the same order of magnitude but smaller than expected from the approach velocity of 3I/ATLAS towards the Sun, 60 kilometers per second.

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