Interstellar Comet 3I/ATLAS Today (Nov. 27, 2025): UN Planetary‑Defense Drill Begins, New Trajectory Data and Fresh “Alien Probe” Claims

As of November 27, 2025, Earth’s newest interstellar visitor is back in the pre‑dawn sky, at the center of a United Nations planetary‑defense exercise and a wave of viral speculation. Here’s what’s actually happening with comet 3I/ATLAS today.

Quick overview – what’s new on November 26–27, 2025

Over the last 24 hours, several key developments around 3I/ATLAS have hit the news:

UN planetary‑defense drill starts today (Nov. 27)
The International Asteroid Warning Network (IAWN), working under a UN framework, is kicking off a “comet astrometry campaign” that uses 3I/ATLAS as a training target. The observing window runs from November 27, 2025 to January 27, 2026, with a mid‑campaign check‑in on December 9 and a closing teleconference on February 3. ^[1]
NASA & ESA: still a comet, still no threat
NASA’s official 3I/ATLAS page reiterates that the object is on a hyperbolic, one‑way path, will pass Earth no closer than about 1.8 AU (~270 million km / 170 million miles) on December 19, and poses no danger. ^[2] ESA, meanwhile, reports that Mars‑orbiting spacecraft have improved the orbit prediction by a factor of ten, further confirming the safe trajectory. ^[3]
New articles highlight a “course change” near perihelion
International Business Times and others report that high‑precision tracking now shows a small but statistically significant non‑gravitational acceleration around the comet’s Oct. 29 perihelion, sparking renewed debate about how strong its jets must be. ^[4]
UN drill & new images drive fresh public interest
Explainers from Starwalk, TS2 and IBTimes tie the UN astrometry campaign, new multi‑spacecraft images and the December 19 closest‑approach date into a single narrative, which has pushed 3I/ATLAS even deeper into the mainstream news cycle. ^[5]
Speculative “alien probe” takes on Jupiter go mainstream
A Vice feature published on November 26 dives into Harvard astronomer Avi Loeb’s claim that 3I/ATLAS may release probes near Jupiter next March, while stressing that NASA scientists overwhelmingly see a natural comet. ^[6]
Viral videos & “spinning comet” clips are debunked
New coverage in outlets like The Economic Times and The Times of India recaps social‑media footage that appears to show odd motion or rotation, and then points out that the clips are unverified and not backed by any space agency data. ^[7]

With that context, let’s zoom out, then back in, on what 3I/ATLAS actually is and why today matters.

What is comet 3I/ATLAS?

3I/ATLAS (also cataloged as C/2025 N1 (ATLAS)) is the third confirmed interstellar object ever seen passing through our solar system, after 1I/ʻOumuamua (2017) and 2I/Borisov (2019). ^[8]

Key facts:

Discovered: July 1, 2025 by the ATLAS survey telescope in Río Hurtado, Chile. Astronomers later found “pre‑discovery” images going back to mid‑June. ^[9]
Why ‘3I’? The “I” stands for interstellar, and the “3” marks it as the third such object discovered. ^[10]
Orbit: Strongly hyperbolic, meaning it’s not bound to the Sun and will never return. Tracing the orbit backward shows it came from outside our solar system. ^[11]
Perihelion: Closest approach to the Sun on Oct. 29, 2025, at about 1.36–1.4 AU, between Earth and Mars. ^[12]
Closest approach to Earth: About 1.8 AU (~270 million km) on Dec. 19, 2025 — nearly twice Earth’s distance from the Sun. ^[13]
Size: Hubble and other data suggest a nucleus somewhere between ~0.3 and 5.6 km across, with the most likely size under 1 km. ^[14]

Spectroscopy from JWST, the Very Large Telescope and other facilities shows that 3I/ATLAS is unusually rich in carbon dioxide and relatively poor in water compared with many solar‑system comets, while still emitting familiar gases like cyanide and nickel vapor. That mix suggests it may have formed in a very cold, distant region of another star system, and could be older than our own Sun. ^[15]

Where is 3I/ATLAS today – and can you see it?

In late November 2025, 3I/ATLAS has swung around the Sun and moved back into the pre‑dawn sky for Earth‑based observers.

Ephemerides compiled by sites like TheSkyLive and JPL show the comet currently glowing around magnitude 9–10, far too faint for the naked eye, but reachable with a medium amateur telescope under dark skies. ^[16]
It’s currently placed low in the eastern sky before sunrise, in and around the constellation Virgo, gradually moving northward as the weeks go on. ^[17]

How to observe 3I/ATLAS (summary):

Use at least an 8‑inch (200 mm) telescope with a wide‑field eyepiece. ^[18]
Head to a dark location with a clear view of the eastern horizon.
Start scanning about 90–120 minutes before local sunrise; detailed coordinates can be pulled from online sky charts or astronomy apps that now list 3I/ATLAS. ^[19]

Even with good gear, expect a fuzzy patch or small coma, not a dramatic naked‑eye spectacle. The scientific excitement around 3I/ATLAS comes from what it can tell us about other star systems, not from a cinematic show in our sky.

A UN planetary‑defense drill starts today – why 3I/ATLAS is the perfect practice target

The headline development for November 27, 2025 is the start of an official IAWN comet astrometry campaign focused on 3I/ATLAS. ^[20]

What the campaign actually is

According to the International Asteroid Warning Network (IAWN) and the Minor Planet Center:

The campaign runs from Nov. 27, 2025 to Jan. 27, 2026.
It is the 8th IAWN observing campaign, designed to teach and test techniques for measuring comet positions (astrometry) as accurately as possible. ^[21]
Observers worldwide — from professional observatories to advanced amateurs — are encouraged to submit precise measurements that will be combined into improved orbit solutions.

Crucially, official documents stress that this is a training and capability‑building exercise, not a response to a threat. 3I/ATLAS is ideal because:

It’s faint but trackable for weeks.
It’s moving fast and on a hyperbolic path, similar to what a real hazardous interstellar object might do. ^[22]

Astronomy outreach sites and UN‑linked statements have had to explicitly reassure people: seeing “IAWN + 3I/ATLAS + planetary defense” in the same sentence does not mean a hidden impact risk — it means practice while a rare interstellar target is available. ^[23]

ESA and NASA nail down the trajectory

Another big thread in this week’s coverage is how well we now know where 3I/ATLAS is going.

Mars gave ESA a new angle

In mid‑November, ESA announced that its ExoMars Trace Gas Orbiter (TGO) swung its camera away from Mars for several days in early October to capture 3I/ATLAS as it flew past the Red Planet at about 29 million km distance. Triangulating TGO’s view with Earth‑based telescopes shrunk the uncertainty in the comet’s path by a factor of 10. ^[24]

That improved orbit:

Confirms that 3I/ATLAS is on a safe outbound trajectory, with no impact scenarios for Earth.
Lets astronomers point spacecraft and big telescopes far more precisely to catch it in the coming weeks.

ESA also notes that its JUICE mission, en route to the Jupiter system, is currently observing the comet near its most active phase, though the data won’t arrive on Earth until early 2026 due to bandwidth and planning constraints. ^[25]

Multi‑mission imaging campaign

NASA’s updated overview shows a “fleet” of observatories that have already imaged 3I/ATLAS:

Mars Reconnaissance Orbiter (HiRISE) and MAVEN produced some of the closest views and ultraviolet maps during the comet’s early‑October Mars flyby. ^[26]
PUNCH, STEREO and SOHO — heliophysics spacecraft designed to watch the solar wind and corona — managed to pick the comet out of their fields by stacking multiple images, tracing a faint tail as it dove behind the Sun. ^[27]
Hubble and JWST have measured its size and composition, showing that it is a small nucleus embedded in a bright, CO₂‑rich coma. ^[28]

A widely shared NASA‑based press briefing last week, summarized by Live Science and Space.com, hammered one core message: “3I/ATLAS is a comet. It looks and behaves like a comet, and all the evidence points to it being a comet.” ^[29]

Strange jets, “missing” tail – what’s actually anomalous?

If you’ve seen dramatic headlines about “never‑before‑seen structure” or “physics‑defying jets,” they’re drawing from a mix of peer‑reviewed work, NASA images and more speculative commentary.

What the data show

Hubble and ground‑based telescopes see multiple narrow jets and at least one prominent sunward jet or “anti‑tail”, sometimes giving the impression that the comet’s dust is streaming toward the Sun rather than away from it. ^[30]
Some images show a faint or hard‑to‑see classic dust tail, even though the comet clearly has strong activity. ^[31]
Polarimetric observations (studying how light is polarized when it scatters off dust) find an unusually deep “negative polarization” branch that doesn’t match most known comets or asteroids, hinting at very strange dust grain properties. ^[32]

These quirks suggest that 3I/ATLAS is not just a copy‑paste of a typical solar‑system comet. Its dust and gas behavior may reflect:

An exotic mixture of ices (CO₂‑dominated, low water).
A different surface texture or grain size distribution.
Geometry effects — depending on where Earth is relative to the comet’s orbital plane, tails and anti‑tails can appear or disappear. ^[33]

Where the sensationalism creeps in

Outlets like USA Herald and some IBTimes pieces lean into the most extreme interpretations, highlighting calculations that — under specific assumptions — suggest the comet’s mass loss and jet collimation are hard to reconcile with simple models of outgassing ice. ^[34]

Most comet researchers, however, argue that we’re still early in the modeling:

Changing the dust size, gas speeds, or nucleus shape can dramatically alter the inferred energy budget.
CO₂‑driven jets can be more focused and energetic than familiar water‑driven ones.
Multiple teams are still analyzing the same images with different assumptions.

In other words, 3I/ATLAS is weird, but probably in a “new‑type‑of‑comet” way, not in a “violates physics” way.

Jupiter, non‑gravitational forces and the “alien probe” narrative

Some of the most viral coverage this week centers on Avi Loeb’s claim that 3I/ATLAS might be a technological object targeting Jupiter.

What the mainstream science says

Dynamical studies and orbit fits show that:

Around perihelion on Oct. 29, the comet experienced a measurable non‑gravitational acceleration — essentially a small “extra push” beyond what gravity alone would provide. ^[35]
For comets, this is expected: jets of gas and dust act like tiny thrusters, and JPL’s orbit‑fitting software includes such terms routinely.
Updated calculations project that 3I/ATLAS will pass near Jupiter on March 16, 2026, but still tens of millions of kilometers away — nowhere near a collision. ^[36]

A recent paper highlighted by IFLScience suggests that Jupiter’s gravity may slightly deflect the comet’s outgoing path, giving scientists a valuable test case for 3‑body dynamics involving interstellar visitors. ^[37]

NASA’s public stance, echoed in multiple interviews, remains that nothing in the data requires advanced technology or dark matter to explain the motion; a natural, very active comet is enough. ^[38]

What Loeb and others are proposing

Loeb’s Medium essays and multiple news summaries (including Vice, IBTimes and the New York Post) argue that:

The non‑gravitational acceleration is too large to be explained by conventional outgassing unless the comet is shedding an implausibly large fraction of its mass. ^[39]
Orbit solutions place the March 16, 2026 flyby at roughly the same distance as Jupiter’s Hill radius (~53 million km) — the region where the planet can retain moons — which he interprets as suspiciously “fine‑tuned.” ^[40]
In more speculative pieces, he suggests 3I/ATLAS could be a “mothership” deploying probes into Jupiter orbit, and has even taken public bets that alien technology will be found by 2030. ^[41]

These ideas are very much minority views. Vice’s November 26 article captures the tension well: NASA scientists “prefer to keep the discussion tethered to reality,” describing 3I/ATLAS as a “regular, if weird, comet made of ice and dust”, while Loeb continues to push for technosignature searches near Jupiter. ^[42]

Bottom line: the Jupiter encounter is scientifically exciting, but no agency has found evidence that 3I/ATLAS is an artificial craft. Claims to the contrary are speculative and not supported by current observations.

Viral footage, “spinning” clips and what TOI & ET say about them

Social media is flooded with short videos claiming to show 3I/ATLAS spinning, zig‑zagging or pulsing.

Recent explainers from The Economic Times and The Times of India provide some much‑needed reality checks: ^[43]

Many clips are time‑lapse stacks of long‑exposure frames, where the comet’s apparent motion, camera wobble or image processing artifacts can look like spiraling or “dancing” behavior.
3I/ATLAS is currently over 1.8 AU from Earth and far too small for ordinary cameras to resolve any detailed motion. It appears as a pointlike or slightly fuzzy source, even in most professional images.
Neither NASA nor ESA has confirmed any unusual rotation beyond what you’d expect from a comet with a roughly 16‑hour spin period derived from photometric studies. ^[44]

Both outlets explicitly caution readers that:

The visuals circulating online are unverified, and no space agency has confirmed any exotic motion. Current claims should be treated as speculation until validated observations are released. ^[45]

Why 3I/ATLAS is a scientific goldmine

Beyond the hype, 3I/ATLAS is already reshaping how astronomers think about comets between the stars.

A different kind of comet

Recent papers and NASA summaries highlight that 3I/ATLAS:

Has been active far from the Sun, with detectable dust production beyond 6 AU, more like a “dynamically old” comet than a pristine frozen block. ^[46]
Shows rapid brightening and color changes as it approached, consistent with a transition from reddened surface dust to fresh icy grains in the coma. ^[47]
Exhibits extreme negative polarization in scattered light, suggesting surface and dust properties unlike any well‑studied solar‑system comet. ^[48]
Likely originated in the Milky Way’s thick disk, meaning it could be billions of years older than the Sun, carrying material from an ancient planetary system. ^[49]

A rehearsal for future threats

Even though 3I/ATLAS is harmless, it’s functioning as a dress rehearsal for two big challenges:

Rapid response to fast interstellar objects
Its >200,000 km/h speed through the inner solar system leaves a short observational window — exactly the kind of situation planetary‑defense teams worry about. ^[50]
Making the most of random flybys
ESA’s ExoMars and JUICE observations, and NASA’s multi‑mission campaign, demonstrate how existing spacecraft can be re‑tasked in creative ways — a skill that could be crucial if a truly hazardous object were discovered on short notice. ^[51]

Key dates ahead for 3I/ATLAS

For readers tracking the story going forward, here are the main milestones:

Nov. 27, 2025:
IAWN comet astrometry campaign opens (today), running through Jan. 27, 2026. ^[52]
Early December 2025:
3I/ATLAS becomes better placed again in the morning sky after solar conjunction, with ongoing observations from ground‑based telescopes and JUICE. ^[53]
Dec. 19, 2025:
Closest approach to Earth at about 1.8 AU — still very far, but the best time for coordinated photometry and spectroscopy campaigns. ^[54]
Jan. 27, 2026:
IAWN campaign ends; data will be used to benchmark how well the global community can track a fast, faint interstellar object. ^[55]
March 16, 2026:
Jupiter flyby at ~50–60 million km distance, after which the comet heads off into interstellar space, never to return. Astronomers hope NASA’s Juno and ESA’s JUICE can search for any subtle effects in Jupiter’s environment — purely as a scientific test, not because they expect alien technology. ^[56]

Fast FAQ: 3I/ATLAS today

Is 3I/ATLAS dangerous?
No. NASA, ESA, the UN and IAWN all concur that 3I/ATLAS poses no impact threat to Earth. Its minimum distance from us is about 1.8 AU, far outside any realistic danger zone. ^[57]

Is 3I/ATLAS an alien spacecraft?
There is no evidence that 3I/ATLAS is artificial. A few researchers, most prominently Avi Loeb, have proposed highly speculative scenarios, but the data are fully consistent with an unusually active, CO₂‑rich comet from another star system. ^[58]

Why is everyone talking about Jupiter?
Current orbit models show that 3I/ATLAS will pass near Jupiter’s gravitational sphere of influence in March 2026. That’s an excellent opportunity to study how an interstellar object interacts with a giant planet’s gravity — and, for speculative thinkers, a tempting place to imagine “probe drops.” Mainstream planetary scientists see it as a physics experiment, not a covert mission. ^[59]

Can I see 3I/ATLAS myself tonight?
Possibly, if you have decent amateur gear: a telescope of 8 inches or more, dark skies, and accurate coordinates from a sky app or ephemeris service. It will appear as a faint smudge just before dawn in the eastern sky, not a dramatic naked‑eye sight. ^[60]

Why is the UN running a drill if there’s “no threat”?
Because practice matters. The IAWN campaign is about sharpening tools and teamwork for future objects that might be dangerous. 3I/ATLAS is a convenient, real‑world test subject that happens to be completely harmless. ^[61]

Is It A Comet or Alien Technology?