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If phosphine is present, what produces it?

Asked 26 Oct 2026 by ·3 answers·0·0 following
Three answers, none aheadNone is ahead yet. See what would settle it.

Where it stands

Three answers have been proposed. None is ahead on the evidence yet. Three are still possible.

Why it matters

Phosphine should not survive in Venus's oxidising atmosphere, and surveys of known abiotic routes find none that makes enough⁠[1]⁠[2]. A confirmed detection would mean either a gap in Venus chemistry or something stranger.

Answers 3

None of these.
Not tested enough to call either way
Evidence: none yet
Still possible
Production by microbes living in the clouds.
Not tested enough to call either way
Evidence: 1 for
Still possible
Unknown photochemistry or geochemistry.
Not tested enough to call either way
Evidence: 1 for, 1 against
Still possible

History

  1. Greaves et al. puts forward: unknown photochemistry or geochemistry.
  2. Greaves et al. puts forward: production by microbes living in the clouds.
  3. Mogul et al.: pioneer Venus spectra suggest several reduced species and redox disequilibrium in the middle clouds.For: Unknown photochemistry or geochemistry.
  4. Bains et al.: no known gas-phase, surface, subsurface or photochemical route produces enough phosphine.Against: Unknown photochemistry or geochemistry.
  5. Bains et al.: the authors present a strictly aerial biosphere as an extreme possibility, not a conclusion.For: Production by microbes living in the clouds.
  6. Asked on this site
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