3I/Atlas is back in dark skies, and the chatter is loud. 3I/Atlas has emerged from solar conjunction with a brighter coma, a longer ion tail, and even a sun-facing anti-tail in some frames. Chatter about it “gaining speed” combines the normal speed-up near the Sun with a smaller, model-dependent nudge from outgassing that astronomers are still refining. NASA’s latest facts page puts the numbers on record and reiterates the object’s hyperbolic, one-time flyby.
As per the NASA Science facts and FAQs report dated November 13, 2025, the comet accelerated from about 137,000 mph to around 153,000 mph at perihelion on October 30, then will slow as it recedes, which is expected for a Sun flyby on an unbound trajectory. Avi Loeb is pressing a more provocative read. As per a Medium post dated November 14, 2025, Avi Loeb stated,
“Technological thrusters which point their exhaust towards the Sun would accelerate away from the Sun,”
tying that idea to the post-perihelion jet geometry seen in recent images. The mainstream view remains that 3I/Atlas is behaving like an active comet under solar heating and the solar wind, with measurements ongoing.
What do the new images actually show, and why do they look “weird”
Across August to mid-November, 3I/Atlas evolved from a compact, reddish dust-dominated coma to a brighter coma with a clear, lengthening ion tail. The Virtual Telescope Project’s November images resolve a cleaner tail structure after perihelion, which is expected once solar heating and the solar wind reshape the flow of gas and dust.
In several processed frames, observers also report a sunward anti-tail. That feature can look counterintuitive, but it is a perspective effect when Earth crosses the comet’s orbital plane and larger dust lingers along that plane. Space.com’s post-perihelion coverage documents the tail growth and tracks the timeline around the October 30 perihelion.
Hubble’s July pre-perihelion imaging already showed 3I/Atlas shedding dust from the sunward side while riding a hyperbolic path. That dataset set a nucleus size limit and flagged active behaviour well before the late-October brightening.
In parallel, a preprint by David Jewitt and Jane Luu measured how the comet’s brightness rose with decreasing heliocentric distance and argued the activity is compatible with volatile outgassing, likely dominated by carbon dioxide. Together, these data make the current post-perihelion tail morphology look less like a surprise and more like a continuation under different lighting and geometry.
Color buzz has also swirled around 3I/Atlas. Ion tails are blue-green because ionized gases scatter sunlight differently than dust, and their direction is set by the solar wind, not by the comet’s motion. As per Space.com report dated November 7, 2025, Qicheng Zhang stated,
“We don’t have any evidence for the gas coma changing colors,...Our result just showed that the gas coma is likely still around and contributing substantially to the overall brightness,”
clarifying that renewed gas emission can make a coma look bluer without implying a fundamental change in the object. In short, the “weird” images of 3I/Atlas match standard comet physics.
Is 3I/Atlas “gaining speed”? Gravity versus non-gravitational acceleration
Anybody diving toward the Sun speeds up to perihelion and then slows on the way out. That is plain gravity on a hyperbolic track. For comets like 3I/Atlas, anisotropic outgassing can add a small push that orbit-fitters capture as non-gravitational terms. NASA’s current FAQ shows the measured speed rising into perihelion then declining, consistent with the expected arc, and notes that the non-gravitational effects are being tracked as more astrometry arrives.
The International Asteroid Warning Network has turned 3I/Atlas into a community exercise to improve comet astrometry and reduce biases from fuzzy comae, with an observing window from November 27 to January 27 and check-ins scheduled through early February. Both agencies stress safety. 3I/Atlas remains on an unbound fly-through and poses no impact risk.
What Avi Loeb is arguing and how that compares to the consensus
Loeb has emphasized two points about 3I/Atlas. First, he highlights structured jets and an apparent sunward anti-tail in post-perihelion frames. Second, he argues that if a non-gravitational acceleration is confirmed and is hard to reconcile with standard outgassing budgets, a technological explanation should remain on the table. As per a Medium post dated November 14, 2025, Avi Loeb remarked,
“The series of collimated jets in post-perihelion images of 3I/ATLAS extend out to a million kilometers towards the Sun and 3 million kilometers away from the Sun,”
Adding that such features could arise from either “sunlight heating pockets of ice” or “thrusters on the surface of a spacecraft.” The consensus view is more conservative.
NASA’s facts and Hubble analyses describe a small nucleus with active outgassing, while preprints and ground-based reports show photometric trends and morphology consistent with a volatile-driven coma and tail. Pending spectroscopy and continued astrometry will sharpen the models, but nothing in hand requires a non-natural origin for 3I/Atlas.
Stay tuned for more updates.
NEW YORK, NEW YORK - APRIL 12: Avi Loeb, Frank B. Baird, Jr. Professor of Science at Harvard University speaks on stage as Yuri Milner and Stephen Hawking host press conference to announce Breakthrough Starshot, a new space exploration initiative, at One World Observatory on April 12, 2016 in New York City. (Photo by Bryan Bedder/Getty Images for Breakthrough Prize Foundation)