Tag: space

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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‘Massive’ comet hurtling toward us is larger than previously thought, could be alien tech, scientist says: ‘It could change everything for us’

Scientists have discovered that the 3I/ATLAS — a Manhattan-sized interstellar object that potentially has alien tech — is much larger than previously thought, according to a new report.

First discovered by NASA on July 1, the cosmic anomaly has been under watch by Harvard astrophysicist Avi Loeb and his team as it shoots across the solar system. The object, which is believed to be a comet, reportedly has interstellar origins, making it the third ever object from beyond the solar system ever detected after ‘Oumuamua, which was discovered in 2017, and 2I/Borisov in 2019.

Now the team has gleaned some “sizable” new intel on the interstellar visitor, namely that the “mass of 3I/ATLAS must be bigger than 33 billion tons,” per a blog post by Loeb.

They arrived at this number by calculating the object’s trajectory to find that ATLAS’s “gravitational acceleration” is “smaller than 49 feet per day, squared,” Futurism reported.

This was then compared to how much mass it was shedding via gases and dust particles to determine the size.

Loeb and co. also found that the diameter of its solid-density nucleus must be larger than 3.1 miles — the upper limit of current projections that are based on observations by the Hubble Space Telescope.

This makes it larger than “three to five orders of magnitude” more massive than its predecessors, ‘Oumuamua and 2I/Borisov.

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Unusual New 3I/ATLAS Discovery Suggests the Interstellar Comet is “Anomalously Massive”

The mysterious comet 3I/ATLAS appears to be extremely large, making it orders of magnitude more massive than two other confirmed interstellar objects observed in our solar system in years past, a new study suggests.

Based on a new analysis of the most precise tracking data collected on the object since its discovery in July, the interstellar comet appears to be “anomalously massive,” a finding that raises new questions regarding our expectations about interstellar objects that occasionally traverse our solar system.

The research was detailed in a new paper by Richard Cloete, Peter Vere, and Harvard astronomer Avi Loeb, which places new limits on the object’s apparent non-gravitational acceleration and overall mass.

The new findings are largely consistent with existing upper estimates for the unusual space object’s size, with some recent observations suggesting it could be up to three miles long.

An “Anomalously Massive” Interstellar Object

More than four months of optical measurements collected on 3I/ATLAS, compiled by the Minor Planet Center, were used by the team for their analysis, which compared 3I/ATLAS’s position to the trajectory that would be expected based on gravity alone.

Based on their results, the team found almost no measurable deviation from a gravitational path, which seems to point to the fact that the interstellar comet is experiencing some degree of non-gravitational acceleration, albeit a negligible amount.

This finding would also seem to suggest that the object’s nucleus must possess a minimum diameter of roughly five kilometers (slightly more than three miles), which makes it several orders of magnitude more massive than the first two known interstellar objects, ʻOumuamua and Borisov.

Between May and September, more than 4,000 astrometric measurements related to the motion of 3I/ATLAS were collected from 227 observatories around the world. Based on this data, an upper limit on non-gravitational acceleration for the interstellar comet could be calculated, which was less than 15 meters per day squared.

According to the team’s study, this finding, with consideration for the principle of momentum conservation, suggests that gas jets produced on the surface of the object as it continues to be warmed by heat from the Sun should result in a measurable push. Based on current observations, however, the lack of detectable deviation exhibited by the object appears to imply that 3I/ATLAS is quite massive.

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Resolute Space 2025: How the U.S. Space Force is Arming for Invisible Wars in the Stars

At Joint Base Pearl Harbor-Hickam in Hawaii, the U.S. Space Force launched its most ambitious training operation to date in July 2025.

Over 700 personnel, dubbed Guardians, teamed up with troops from allied nations to simulate battles in the vast emptiness above Earth.

This event, known as Resolute Space 2025, is aimed at preventing the rising danger of invisible assaults that could cripple global communications without firing a single shot.

The exercise began on July 8 and unfolded across multiple time zones, spanning roughly 50 million square miles. It integrated forces from about a dozen countries, including partners in Asia, Europe, and Australia, to practice seamless coordination.

The goal was to sharpen responses to disruptions in a chaotic setting, blending real-world assets with digital replicas for maximum authenticity.

In the scenarios, a designated aggressor group mimicked hostile nations by unleashing non-kinetic strikes on satellite networks. These included bursts of electronic static to drown out signals, sneaky hacks to spoof data feeds, and maneuvers to nudge orbits off course.

Defending teams raced to pinpoint the sources, restore functionality, and adapt tactics amid the fog of simulated chaos.

Orbital space previously served as a peaceful domain for navigation aids, intelligence gathering, and routine links between forces.

That illusion has shattered as countries have begun to explore space weaponry which could turn satellites into prime targets. Military planners now view the cosmos as a domain ripe for sabotage.

Adversaries like China and Russia have poured resources into tools that threaten U.S. assets without leaving debris trails. By mid-2025, China executed dozens of orbital missions, deploying over a hundred new objects to test grappling tech and signal blockers.

Russia, meanwhile, has experimented with nuclear options and co-orbital chasers that could shadow or disable enemy craft, fueling fears of rapid escalation.

Experts note these developments proceed at an alarming speed, outpacing Western defenses and risking a cascade of satellite failures.

The Space Force, established just six years prior, is exploring tactics to navigate these new challenges. Exercises like Resolute Space 2025 enhance the U.S.’s capabilities through flexible doctrines and cross-service teamwork necessarily to counter such evolving threats.

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‘City killer’ asteroid 2024 YR4 could shower Earth with ‘bullet-like’ meteors if it hits the moon in 2032

New simulations reveal that the infamous “city killer” asteroid 2024 YR4 could shower Earth with “bullet-like” debris if it hits the moon in seven years’ time, potentially triggering an eye-catching meteor shower — and endangering the satellites that orbit our planet.

2024 YR4 is a potentially hazardous asteroid measuring roughly 200 feet (60 meters) across, making it large enough to wipe out a large urban area if it were to hit Earth head-on. It was first discovered in December 2024 but made headlines earlier this year when scientists first predicted that there was a chance it could smash into Earth on Dec. 22, 2032. The odds of a collision peaked at 3.1% in February, which was enough to prompt NASA to study it extensively. However, subsequent analysis revealed there is zero chance of it impacting our planet.

But in April, researchers realized that, while Earth is no longer in the firing line, the space rock could still hit the moon. The odds of such a collision have grown slowly but steadily, and most recently jumped to 4.3% earlier this month. Experts will likely know the final likelihood by 2028, when the asteroid will make its next close approach to our planet.

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Astronomers uncover a hidden world on the solar system’s edge

A small team led by Sihao Cheng, Martin A. and Helen Chooljian Member in the Institute for Advanced Study’s School of Natural Sciences, has discovered an extraordinary trans-Neptunian object (TNO), named 2017 OF201, at the edge of our solar system.

The TNO is potentially large enough to qualify as a dwarf planet, the same category as the much more well-known Pluto. The new object is one of the most distant visible objects in our solar system and, significantly, suggests that the empty section of space thought to exist beyond Neptune in the Kuiper Belt is not, in fact, empty at all.

Cheng made the discovery alongside colleagues Jiaxuan Li and Eritas Yang from Princeton University, using advanced computational methods to identify the object’s distinctive trajectory pattern on the sky. The new object was officially announced by the International Astronomical Union’s Minor Planet Center and in an arXiv pre-print.

Trans-Neptunian objects are minor planets that orbit the Sun at a greater average distance than the orbit of Neptune. The new TNO is special for two reasons: its extreme orbit and its large size.

“The object’s aphelion — the farthest point on the orbit from the Sun — is more than 1600 times that of the Earth’s orbit,” explains Cheng. “Meanwhile, its perihelion — the closest point on its orbit to the Sun — is 44.5 times that of the Earth’s orbit, similar to Pluto’s orbit.”

This extreme orbit, which takes the object approximately 25,000 years to complete, suggests a complex history of gravitational interactions. “It must have experienced close encounters with a giant planet, causing it to be ejected to a wide orbit,” says Yang. “There may have been more than one step in its migration. It’s possible that this object was first ejected to the Oort cloud, the most distant region in our solar system, which is home to many comets, and then sent back,” Cheng adds.

“Many extreme TNOs have orbits that appear to cluster in specific orientations, but 2017 OF201 deviates from this,” says Li. This clustering has been interpreted as indirect evidence for the existence of another planet in the solar system, Planet X or Planet Nine, which could be gravitationally shepherding these objects into their observed patterns. The existence of 2017 OF201 as an outlier to such clustering could potentially challenge this hypothesis.

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Interstellar object 3I/ATLAS updates: Will we intercept it?

Will we send a spacecraft to intercept 3I/ATLAS?

Scientists first spotted 3I/ATLAS, the 3rd interstellar visitor ever identified in our solar system, in early July 2025. And since then, one question has been asked countless times: will we send out a spacecraft to take a closer look? On August 21, EarthSky’s Will Triggs spoke to University of Edinburgh astronomer Colin Snodgrass to find out the answer. Plus, Colin talked about ESA’s Comet Interceptor, an upcoming spacecraft that will be primed to intercept future interstellar objects. Watch in the player above, or on YouTube.

3I/ATLAS shrinks again

On August 7, 2025, NASA shared a new image of 3I/ATLAS (above) – the world’s 3rd known interstellar object – as well as provided an updated estimate of the size of the object’s nucleus, or core. Shortly after the object was first identified on July 1, 2025, 3I/ATLAS was estimated to have a diameter of about 20 km (12 miles). Then in late July – using data from the new Vera C. Rubin Observatory in Chile – the size estimate dropped to 10 km (6 miles). The latest analysis uses data from the NASA/ESA Hubble Space Telescope. It reduces the estimated diameter of 3I/ATLAS’s nucleus still further, to 5.6 km (3.5 miles).

And, the astronomers using Hubble data said, the object could be even smaller, as small as 320 meters (1,050 feet) across!

Plus, as you can see from the image, 3I/ ATLAS is looking more and more comet-like as it approaches our sun. It’s currently between the orbits of Mars and Jupiter.

The two previous known interstellar objects are 1I/ ‘Oumuamua and 2I/Borisov. ‘Oumuamua’s size is thought to be about 200 meters across at its widest (you’ll recall it has an elongated shape). And Borisov is thought to be less than a kilometer across.

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3I/ATLAS Was Just Spotted by the James Webb Telescope, Confirming an Odd New Discovery About the Strange Interstellar Comet

An unusual interstellar visitor speeding through our solar system was recently spotted by the powerful eye of NASA’s James Webb Space Telescope (JWST).

The American space agency revealed this week that its premier space observatory had captured new images of the comet, known as 3I/ATLAS, on August 6, 2025, using its Near-Infrared Spectrograph instrument.

Since that time, NASA researchers have been studying data collected about the object during Webb’s observations, with the latest insights appearing in a new preprint paper. The latest observations provide further confirmation that 3I/ATLAS is producing a large carbon dioxide-rich cloud of material around the object, commonly referred to as its coma.

Carbon Dioxide in Abundance

The unusual carbon dioxide abundance, previously detected in observations by NASA’s SPHEREx mission, is accompanied by traces of water, carbon monoxide, sulfur compounds, water ice, and an abundance of dust, according to the new findings made possible by Webb.

In the new paper by co-author Martin Cordiner and colleagues, 3I/ATLAS’s unusual ratio of carbon dioxide to water vapor is also noted as having been one of the highest ever measured in a comet. This is significant, as it suggests that 3I/ATLAS is quite distinct from the types of comets that originate within our Solar System.

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