A second species of aliens known as the Ashiec-tuen-Kai enter the solar system upon receiving a mysterious transmission. They send probes to investigate the source of the transmission. These are not the kind of probes as one might expect.
Here’s some background information I used to base the alien probes disguised as interstellar objects. This information was produced for me by AI before producing this chapter.
ChatGPT said:
Here’s a side-by-side comparison of the three known interstellar objects — 1I/ʻOumuamua, 2I/Borisov, and 3I/ATLAS — focusing on their nucleus / coma composition and activity.
| Feature | 1I/ʻOumuamua (2017) | 2I/Borisov (2019) | 3I/ATLAS (2025) |
|---|---|---|---|
| Type / activity | Asteroid-like; no visible coma or tail | Typical comet with strong coma & tail | Active comet with large, gas-rich coma |
| Nucleus size | 100–400 m (very elongated, extreme light curve) | ~0.4–1 km | Likely < 2.8 km radius (upper limit); possibly as small as a few hundred m |
| Dominant volatiles | None directly detected (no gas lines seen) | H₂O, CO, CN — ratios similar to Solar System comets | CO₂ dominant over H₂O (≈8:1 ratio) |
| Other detected species | None | C₂, CN, HCN, dust with “normal” composition | CO, OCS (sulfur), CN, Ni lines; water ice grains in coma |
| Dust / coma features | None | Dust coma/tail like ordinary comets | Dust coma unusually red, with strong polarization signal; sun-facing plume & “anti-tail” |
| Color / spectrum | Reddish (like outer Solar System bodies) | Slightly bluish (like Solar System comets) | Reddish coma; evolving color (red → greenish with CN/CO₂ emission) |
| Activity distance from Sun | None, even near perihelion (0.25 AU) | Strong water activity at ~2–3 AU | Water & CO₂ activity detected as far as 3.5 AU |
| Coma size | None | Typical (10⁴–10⁵ km scale) | Very large CO₂ coma, ~3 arcmin angular radius (~10⁶ km scale); anisotropic features |
| What’s unusual | Shape, acceleration (possible outgassing or radiation pressure effect) | Looked “ordinary” despite being interstellar | Chemistry exotic: CO₂-rich, high CN & OCS, unusual dust optical properties |
Takeaway
- ʻOumuamua: Unusual because it lacked a coma and had a weird shape/acceleration.
- Borisov: Surprising because it looked so ordinary — basically like a Solar System comet.
- ATLAS: Stands out for its chemistry (CO₂-rich, sulfur/nitrogen species), unusual dust optics, and large early activity far from the Sun.
Would you like me to also plot these three on a timeline chart (2017, 2019, 2025) showing their “most anomalous feature” visually, almost like a one-page infographic for quick reference?
You said:
You didn’t say anything about the metallic composition of the cores.
ChatGPT said:
You’re right — I didn’t address that directly. Here’s a core composition profile comparison of the three known interstellar objects — focusing on what we can reasonably say about their ices, organics, and metals.
🌌 Interstellar Object Core Composition Profiles
| Component | 1I/ʻOumuamua (2017) | 2I/Borisov (2019) | 3I/ATLAS (2025) |
|---|---|---|---|
| Water ice (H₂O) | No coma → not directly detected; models range from very little to hidden under crust | Clearly present, strong OH/H₂O activity | Present, but secondary to CO₂ |
| Carbon dioxide (CO₂) | Not detected (no coma) | Trace/typical levels | Dominant volatile (CO₂:H₂O ≈ 8:1) |
| Carbon monoxide (CO) | No detection | Present, like many comets | Present in addition to CO₂ |
| Sulfur species (e.g., OCS) | Unknown | Minor, typical | OCS detected, above many Solar System comets |
| Nitrogen species (CN, HCN, etc.) | Unknown | CN, HCN detected | Strong CN activity (coma glows greenish at times) |
| Organics (complex hydrocarbons / tholins) | Reddish reflectance suggests organic-rich surface | Dust coma shows organics, similar to Solar System comets | Dust coma redder than average; organic-rich dust inferred |
| Silicates (rocky minerals) | Likely present (reddish spectrum similar to D-type asteroids) | Detected in dust spectra | Detected in dust spectra |
| Metals (Fe, Ni) | No detection | Ni and Fe vapor lines detected in coma at ~2 AU — unusual but confirmed | Ni emission detected; implies Fe/Ni-bearing minerals in nucleus |
| Core size (solid nucleus) | 100–400 m (very elongated, aspect ratio ~6:1) | ~0.4–1 km | Likely < 2.8 km radius (upper bound); possibly smaller (~0.5–2 km) |
| Overall composition | Unknown, no coma; likely porous, organic-rich body | Very similar to Solar System comets (icy-rocky-organic mix with metals) | Chemically exotic: CO₂-rich ices, sulfur & nitrogen volatiles, silicates, Ni-bearing minerals |
Key Takeaways
- ʻOumuamua: We never saw a coma → its core composition is speculative. Probably icy/organic-rich, but no direct proof of metals or volatiles.
- Borisov: Looked like a typical Solar System comet, but proved that metals (Fe/Ni) can sublimate into the coma far from the Sun.
- ATLAS: Shares the Fe/Ni metallic trace signature, but diverges sharply in its volatile chemistry (CO₂-rich, sulfur- and nitrogen-bearing species, unusual dust optics).

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