3I/ATLAS – Visitor or Voyager? Author: Dean Bordokas, Citizen Contributor, Asgardia On 29 October the interstellar comet 3I/ATLAS skimmed 126 million kilometres from the Sun and began the long climb out of our Solar System—never to return. Telescopes on the ground and in space are still downloading the data, but ...
3I/ATLAS – Visitor or Voyager?
Author: Dean Bordokas, Citizen Contributor, Asgardia
On 29 October the interstellar comet 3I/ATLAS skimmed 126 million kilometres from the Sun and began the long climb out of our Solar System—never to return. Telescopes on the ground and in space are still downloading the data, but a small group of researchers is asking a deliberately provocative question: could the object’s behaviour be easier to explain if it were engineered rather than evolved?
THE ANOMALY CHECKLIST
1. Orbit aligned with the ecliptic plane to within one degree—probability ≈ 1 in 180.
2. Rotation axis parallel to the Sun-line to within eight degrees—probability ≈ 1 in 20.
3. Carbon-dioxide-driven jet still active three months after perihelion—unprecedented for a first-time comet.
4. No turn-off of the sun-facing “anti-tail” as the nucleus rotates—implies a permanent dayside.
5. Closest approach to Earth only 1.8 AU—closer than any previously recorded interstellar object.
Individually, each oddity can be blamed on coincidence or poorly understood ice physics. Collectively they sketch an object that acts as though it were designed to ride the star’s gravity, keep one face to the Sun, and maintain a continuous, narrow exhaust plume pointed straight at the star.
A SELF-CONSISTENT TECHNOLOGICAL MODEL
Assume a 10-metre central bus wrapped by a 100-metre sun-shield that doubles as a radiator and solar array. Frozen CO₂ stored behind the shield sublimates at 195 K, is ionised by on-board electric grids, and expelled sunward at 30 km s⁻¹. The thrust—only a few newtons—adds 4 km s⁻¹ of delta-v over the fly-by, enough to trim the trajectory without betraying itself as an obviously powered manoeuvre. The same exhaust plume doubles as a micrometeoroid shield and an infrared cloak, hiding the hot engine from distant spectrographs.
FALSIFIABLE PREDICTIONS
- High-resolution 4.3 µm spectra (JWST, VLT) should show CO₂⁺ lines Doppler-shifted opposite to the nucleus motion and a conspicuous absence of the H₂O/CO ratio normal in comets.
- Radar ranging (Goldstone, FAST) will yield a radar albedo 10–100× smaller than a 10 km icy body and a mass-to-area ratio consistent with a thin-film shield plus a few-tonne spacecraft bus.
- Post-5 AU photometry should dim faster than the canonical 1/r² law once the CO₂ tank is exhausted.
ASGARDIA’S ROLE – WHAT YOU CAN DO
Asgardia has no national telescopes—yet—but we have 1.1 million pairs of eyes and laptops. Here’s how to help constrain (or kill) the technological hypothesis:
1. Grab any public images of 3I/ATLAS
- Las Cumbres Observatory, Minor Planet Center, ATLAS, PAN-STARRS and ZTF archives all offer free FITS files.
- Pick the “V” or “r” filters for consistency.
2. Reduce and measure
- Use your favourite software (AstroImageJ, Siril, Python/Photutils, IRIS, etc.) to calibrate (bias/dark/flat) and perform aperture photometry.
- Record mid-exposure UTC, magnitude (or flux), filter, and 1-σ uncertainty.
- Convert magnitudes to flux if you like (zero-points are in the FITS headers).
3. Watch for the break
- Plot magnitude vs. heliocentric distance (r) beyond 5 AU.
- A natural comet fades as 5 log r. If the slope suddenly steepens, the outflow has quit—exactly what an exhausted CO₂ tank would produce.
4. Upload and document
- Post your light-curve (CSV or PDF) in the pinned thread “3I/ATLAS Citizen Photometry” on the Asgardia member portal.
- Include your name, observatory/code, reduction steps, and nightly seeing so professional analysts can weight your points.
5. Keep going
- 3I/ATLAS will drop below magnitude 23 by late 2026; every extra month you can squeeze out tightens the limit on any residual activity.
Extraordinary claims require extraordinary evidence—but extraordinary evidence begins with ordinary data, meticulously reduced. Either we will kill the technological hypothesis with hard numbers, or we will become the first generation to measure the exhaust plume of someone else’s spacecraft. Both outcomes beat wondering forever.
Clear skies,
Dean
Member, Asgardia
