3I/ATLAS Updte 10/31/25

The “Fibonacci signal” rumor vs the receipts on our interstellar visitor

Quick Take: Interstellar comet 3I/ATLAS just hit perihelion and is being watched by multiple spacecraft. A viral claim says it’s pulsing a “Fibonacci” pattern at 1420 MHz and might be artificial. There’s no credible detection of any engineered radio beacon. What we do have are solid measurements of water activity (via OH) and close-up imaging from Mars orbit ... all consistent with a natural comet. Live Science+3science.nasa.gov+3Space+3

What actually happened

• Where and when: NASA lists perihelion near Oct 30, 2025 at ~1.4 AU from the Sun; closest Earth distance ~1.8 AU — far, faint, and currently hidden behind the Sun from Earth. science.nasa.gov
• Spacecraft coverage: ESA’s ExoMars and Mars Express imaged 3I/ATLAS during its Mars-side pass in early October — the closest look so far by any spacecraft. Data show a diffuse coma; some frames show no obvious tail, which can happen depending on geometry and activity. European Space Agency+1
• Water detected: NASA’s Neil Gehrels Swift observatory detected OH (a by-product of water) when the object was ~2.9 AU from the Sun — unusually far for strong water activity, but still physically explainable. Live Science+2Space+2

About that “Fibonacci at 1420 MHz” claim

• The 1420 MHz frequency (the “hydrogen line”) is a classic SETI watch band, which helps rumors spread. But the viral Fibonacci-pulse story traces to sensational posts with no supporting telescope dataset; mainstream science desks tracking 3I/ATLAS report no such signal. newsweek.com
• Current observables (coma morphology, OH emission, photometry) match a natural comet. If a narrowband beacon existed, radio arrays would publish it fast... they haven’t. Space

Why this matters

• Rare opportunity: 3I/ATLAS is only the third confirmed interstellar object after ’Oumuamua and 2I/Borisov. Swift’s OH result is the first water activity ever measured for an interstellar visitor, a big clue about icy bodies from other stars. theguardian.com+1
• Hype vs. data: Fringe rumors can drown out real discoveries. This one is a textbook case where multi-mission receipts beat screenshots. European Space Agency

What we know vs what we don’t

We know

• Orbit is hyperbolic (unbound) and perihelion/closest-approach distances are safe. science.nasa.gov
• OH emissions imply active water loss ... “fire-hose” levels for that distance ... likely driven by buried ice and dust physics we’re still learning. Live Science

We don’t know

• The full composition and nucleus size/shape, or why it’s so water-active so far from the Sun. That’s why perihelion-side monitoring by Mars/Jupiter missions matters right now. Space

Pushback & context you’ll see online

• You’ll find headlines implying secret images or anomalies. Meanwhile, reputable coverage centers on Swift OH detections and Mars-orbiter imaging; neither supports an artificial-origin claim. Live Science+1
• Some outlets platform debate-y takes ... useful to read, but separate opinion from instrument data. Keep receipts handy. newsweek.com

What to watch next

• Post-perihelion releases from NASA/ESA pipelines and observatories now that geometry improves.
• Spectroscopy for other volatiles/metals; any non-gravitational accelerations will be modeled against outgassing first. Space

The receipts

• NASA: Object overview, perihelion/approach distances, status. science.nasa.gov
• ESA: ExoMars & Mars Express closest views from early October; context and geometry. European Space Agency
• Swift/Water detection: Peer-reviewed and newsroom coverage of OH detection at ~2.9 AU. Live Science+2Space+2
• Perihelion watchlists & mission coverage: What spacecraft are observing during the Sun-conjunction window. Space
• Rumor control / live updates: Roundups tracking claims vs. published data. newsweek.com