# Cosmic-ray processing explains the CO2 and the red colour

> Models of galactic cosmic-ray processing reproduce 3I's CO2 enrichment and red slope in the outer 15 to 20 m, and explain the late methane as layering…

Source: https://mysteriesdept.com/mysteries/3i-atlas/evidence/EVD0DFQ3VE858GD/cosmic-ray-processing-explains-the-co2-and-the-red-colour  
Publisher: Mysteries Department  
Licence: CC BY 4.0 (credit Mysteries Department and link the page)  

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[3I/ATLAS](https://mysteriesdept.com/mysteries/3i-atlas)Evidence

Evidence · 3I/ATLAS

# Cosmic-ray processing explains the CO2 and the red colour

Models of galactic cosmic-ray processing reproduce 3I's CO2 enrichment and red slope in the outer 15 to 20 m, and explain the late methane as layering made in transit with an exposure age of 0.9 to 3.1 billion years.

Suggestive0

## What it means

Key question[What is 3I/ATLAS made of, and why is its chemistry so unlike a Solar System comet's?](https://mysteriesdept.com/mysteries/3i-atlas/questions/QST0DFQ0HS0K7SD/what-is-3i-atlas-made-of-and-why-is-its-chemistry-so-unlike)

No answer ahead yet

**Open** unchanged

Answer this evidence bears on[A crust made by cosmic rays on the journey](https://mysteriesdept.com/mysteries/3i-atlas/answers/ANS0DFQ17SXMJ3A/a-crust-made-by-cosmic-rays-on-the-journey)

Supports2 for, none against

**Still possible** unchanged

What it implies
1.

Some of the inbound oddities may describe 3I's journey rather than its birthplace.For the key question: What is 3I/ATLAS made of, and why is its chemistry so unlike a Solar System comet's?

## Next steps 2

1

Compare gas lost with crust depth

Could shiftFair odds~20 h

[On: What is 3I/ATLAS made of, and why is its chemistry so unlike a Solar System comet's?](https://mysteriesdept.com/mysteries/3i-atlas/questions/QST0DFQ0HS0K7SD/what-is-3i-atlas-made-of-and-why-is-its-chemistry-so-unlike)

**11** score

Details

Use the compiled production rates (Frincke and Seligman's table) to date when more than 20 m of surface had gone, and check whether the composition changed then. A change at that point favours the crust; a change well before or after weakens it.

2

Test whether a cosmic-ray crust can raise D/H to 1 per cent

Could shiftFair odds~30 h

[On: What is 3I/ATLAS made of, and why is its chemistry so unlike a Solar System comet's?](https://mysteriesdept.com/mysteries/3i-atlas/questions/QST0DFQ0HS0K7SD/what-is-3i-atlas-made-of-and-why-is-its-chemistry-so-unlike)

**8** score

Details

Run the cosmic-ray processing model forward to predict how much a 20-m processed crust changes water D/H and 12C/13C. If processing cannot reach the measured ratios, the birthplace reading is strengthened; if it can, the isotopes no longer date the body.

Ranked by how likely each is to move the key question, for the time it takes

## Sources 2

[Delayed Methane Detection in 3I/ATLAS: GCR-Driven Subsurface Stratification and Interstellar Exposure Age Constraints](https://mysteriesdept.com/sources/SRC0DFPWGSFWDG1/delayed-methane-detection-in-3i-atlas-gcr-driven-subsurface)

Rawat 2026

SRC

[Interstellar Comet 3I/ATLAS: Evidence for Galactic Cosmic Ray Processing](https://mysteriesdept.com/sources/SRC0DFPWGSFK2GK/interstellar-comet-3i-atlas-evidence-for-galactic-cosmic-ray)

Maggiolo et al. 2025

SRC

## Cite it

```
Mysteries Department. (2026). Cosmic-ray processing explains the CO2 and the red colour [Evidence EVD0DFQ3VE858GD]. https://mysteriesdept.com/r/EVD0DFQ3VE858GD
```

Key

**EVD** 0DFQ3VE858GD

Kind

Evidence

Tier

Suggestive

Found in

[Session 1](https://mysteriesdept.com/mysteries/3i-atlas/sessions/SES0DFQC03S98K5/session-1-3i-atlas-opened-the-literature-to-november-2026) · 2 Nov 2026

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