Updated: November 10, 2025 — No threat to Earth; closest approach remains mid‑December.
Key points at a glance
- First radio detection: South Africa’s MeerKAT radio telescope has detected OH (hydroxyl) absorption lines at 1665/1667 MHz from 3I/ATLAS, a classic signature of natural comet activity. The observation was made Oct. 24 and reported to The Astronomer’s Telegram; it’s being widely covered today. 1
- New post‑perihelion imagery: Images captured Oct. 31–Nov. 9 reveal a complex, multi‑jet structure; today (Nov. 10) the ion tail is clearly visible in fresh telescopic shots. 2
- Trajectory & safety: 3I/ATLAS passed perihelion around Oct. 30 (~1.4 AU from the Sun) and will remain ~270 million km (1.8 AU) from Earth at closest approach on Dec. 19, 2025—comfortably distant. 3
- Not the other comet in the news: A newly found object, C/2025 V1 (Borisov), is trending but is unrelated to 3I/ATLAS despite superficial similarities. 4
- Rumor control: Claims that 3I/ATLAS “changed color” are not supported by data, according to researchers analyzing recent observations. 5
What’s new today (Nov. 10)
Radio proof of “cometness.” After weeks of speculation, astronomers have the clearest radio evidence yet that 3I/ATLAS behaves like a normal comet: MeerKAT detected hydroxyl (OH) absorption at 1665 and 1667 MHz during a deep observation on Oct. 24 while the object was near the Sun in the sky. OH is produced when water from a comet’s coma is broken apart by sunlight, and these specific radio lines are a textbook marker of that process. The team also notes earlier non‑detections on Sept. 20 and 28, underscoring that activity ramped up near perihelion. 1
Fresh images, fresh structures. Post‑perihelion images compiled this week show at least seven jets, including “anti‑tails” that point sunward due to viewing geometry and dust dynamics. A British Astronomical Association composite from Nov. 9 shows a long “smoking” tail with twin anti‑tail features, making 3I/ATLAS an unusually rich target for ongoing Hubble and Webb follow‑ups. 2
Tail recovered today. In pre‑dawn Europe today (Nov. 10), the Virtual Telescope Project reports a distinct ion tail as the object moves into a more favorable morning‑sky geometry—explaining why some earlier images looked “tailless.” 6
Where 3I/ATLAS is now—and the road ahead
- Perihelion: ~Oct. 30, 2025 at ~1.4 AU (just inside Mars’ orbit). 3
- Visibility window: Professional observers have already recovered the comet in the morning sky as of today; broader Northern‑Hemisphere observing windows improve later in November as elongation increases. (ESA notes a late‑November reappearance for general observing after the Sun gap.) 6
- Closest to Earth:Dec. 19, 2025 at roughly 270 million km (1.8 AU)—still far. Expect continued professional imaging and spectroscopy; this is not a naked‑eye spectacle. 7
How to (realistically) observe it
- Expect a telescope target, not a sky show. At this distance and activity level, naked‑eye viewing is not expected; amateur imaging will favor moderate to larger apertures under dark, steady pre‑dawn skies and a low eastern horizon. (Professionals and advanced amateurs are already resolving the ion tail.) 6
- Timing: Aim for pre‑dawn, as elongation increases through November; consult updated ephemerides or sky‑simulation tools for your latitude to ensure safe, Sun‑aware pointing. (General safety/trajectory context via NASA.) 3
What scientists are focused on
- Activity drivers & jet physics. Multi‑jet morphology and anti‑tails offer a laboratory for dust‑gas coupling, rotation states, and surface heterogeneity on a truly interstellar body. New images from Oct. 31–Nov. 9 are fueling these analyses. 2
- Chemistry in radio & IR. The MeerKAT OH detection cements water‑related activity; complementary spectra from space telescopes (Hubble/Webb) are probing CO₂, H₂O, CO and ices to trace how deep‑frozen volatiles behave after eons in interstellar space. 1
- No threat, but a trove of data. Agencies emphasize zero impact risk and a substantial multi‑mission campaign (Hubble, Webb, Mars orbiters/rovers, ESA’s Juice later this month, and more) to capture a rare, third‑ever interstellar visitor. 3
Rumor control: color changes, “no tail,” and alien talk
- Color claims: Headlines suggesting 3I/ATLAS “changed color” multiple times aren’t supported by the data. Researchers say recent brightening simply indicates the gas coma contribution to overall brightness, not a verified chromatic flip. 5
- “No tail” images: Near perihelion, viewing geometry can hide or foreshorten tails; today’s pre‑dawn imaging shows an ion tail as geometry improves. 6
- Artificial‑object speculation: While individual commentators continue to hypothesize exotic origins, the OH radio detection and the multi‑jet/tail morphology are entirely consistent with a natural comet. 1
Frequently asked questions
What is 3I/ATLAS?
The third confirmed interstellar object observed in our solar system, discovered July 1, 2025 by the NASA‑funded ATLAS survey. It follows a hyperbolic (unbound) path and is leaving the solar system after this pass. 3
How close will it get to Earth? Is it dangerous?
It will pass at about 270 million km (1.8 AU) on Dec. 19, 2025—no threat. 7
Why is the radio detection important?
OH lines at 1665/1667 MHz are a hallmark of cometary water chemistry; detecting them from 3I/ATLAS is strong, independent evidence of natural comet activity. 1
Can I see it without a telescope?
No—optical brightness will remain faint. Skilled amateurs may record it with telescopes and sensitive cameras under dark, steady, pre‑dawn skies. 6
What’s next for spacecraft observations?
Hubble and Webb continue spectral monitoring; ESA’s Juice is attempting observations in November, with data likely downlinked in early 2026 due to geometry and antenna constraints. 7
Bottom line for Nov. 10, 2025
The story today is confirmation and clarity: a radio detection that dovetails with fresh jet/tail imagery, steady agency guidance on safety and dates, and a reminder not to confuse 3I/ATLAS with today’s unrelated newcomer, C/2025 V1. Science—not speculation—is winning the day. 1
