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Is there methane in the air at Gale crater?

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. Of the two narrower questions under it, none is answered yet.

Why it matters

Curiosity's detections are the only direct, in-situ measurements of Martian methane, and the orbiter's non-detections can be reconciled with them only by an unknown fast process⁠[1]⁠[2]. The 2025 re-analysis puts the rover data themselves in question⁠[3].

Answers 3

Evidence: 4 for, 2 against
Disputed
None of these.
Not tested enough to call either way
Evidence: none yet
Still possible
Evidence: 2 for, 1 against
Still possible

History

  1. Webster et al. puts forward: methane is present near the surface at Gale at a background of a few tenths of a ppbv, with occasional…
  2. Webster et al.: background 0.41 ± 0.16 ppbv over five years with spikes of about 7 ppbv.For: Methane is present near the surface at Gale at a background of a few tenths of a ppbv, with occasional…
  3. Giuranna et al.: mars Express PFS recorded methane over the Gale region a day after a rover spike in 2013.For: Methane is present near the surface at Gale at a background of a few tenths of a ppbv, with occasional…
  4. Webster et al.: ozone cannot be confused with methane at TLS resolution.For: Methane is present near the surface at Gale at a background of a few tenths of a ppbv, with occasional…
  5. Webster et al.: night-time values of 0.52 ± 0.10 ppbv against daytime 0.05 ± 0.22 ppbv in the same season.For: Methane is present near the surface at Gale at a background of a few tenths of a ppbv, with occasional…
  6. Webster et al.: a strong day-night difference is not an obvious product of a leak.Against: The rover's methane readings are an instrumental artefact, chiefly methane leaking from the foreoptics…
  7. Montmessin et al.: the orbiter's limits near Gale are up to four times below the rover's background for the same season.For: The rover's methane readings are an instrumental artefact, chiefly methane leaking from the foreoptics…
  8. Viscardy et al. puts forward: the rover's methane readings are an instrumental artefact, chiefly methane leaking from the foreoptics…
  9. Viscardy et al.: the foreoptics chamber held methane three to four orders of magnitude above the sample cell; leaks under 0.1…Against: Methane is present near the surface at Gale at a background of a few tenths of a ppbv, with occasional…
  10. Viscardy et al.: unreported diffusion experiments give a gas-transport coefficient that makes small leaks plausible.For: The rover's methane readings are an instrumental artefact, chiefly methane leaking from the foreoptics…
  11. Asked on this site
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