3I/ATLASEvidence
Evidence · 3I/ATLAS
ALMA confirms deuterium-rich water independently
ALMA found water D/H above 6.6 × 10^-3, at least 40 times Earth's oceans and 30 times typical comets, with a different instrument and method from JWST.
What it means
Key questionWhat is 3I/ATLAS made of, and why is its chemistry so unlike a Solar System comet's?
No answer ahead yet
Openunchanged
Answer this evidence bears onAn icy body from a cold, metal-poor disc around an old star
Supports6 for, none against
Still possibleunchanged
What it implies
- The extreme water D/H is not an artefact of one instrument.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
11score
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
8score
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 1
Water D/H in 3I/ATLAS as a Probe of Formation Conditions in Another Planetary System
SRCSalazar Manzano et al. 2026
Cite it
Mysteries Department. (2026). ALMA confirms deuterium-rich water independently [Evidence EVD0DFQ3Q9YB4XN]. https://mysteriesdept.com/r/EVD0DFQ3Q9YB4XN
@misc{mysteriesdept_evd0dfq3q9yb4xn,
title = {ALMA confirms deuterium-rich water independently},
author = {{Mysteries Department}},
year = {2026},
note = {Evidence, catalog key EVD0DFQ3Q9YB4XN},
url = {https://mysteriesdept.com/r/EVD0DFQ3Q9YB4XN}
}