James Webb Detects 5.11-Micrometre Signal on Pluto and Titan, Defying Lab Identification
Updated
Updated · spacedaily.com · Jul 5
James Webb Detects 5.11-Micrometre Signal on Pluto and Titan, Defying Lab Identification
2 articles · Updated · spacedaily.com · Jul 5
Summary
A 2026 Webb spectroscopy study found the same unexplained absorption dip at about 5.11 micrometres on the surfaces of Pluto and Titan, marking a repeatable feature on two distant frozen worlds.
No confirmed molecule has matched the signal in laboratory spectra, leaving the feature formally unidentified even though it appears to come from surface material rather than either world's atmosphere.
Pluto's version is roughly three times broader than Titan's, suggesting related but not identical material produced by chemistry both worlds share: methane and nitrogen processed by sunlight into complex organics.
Next steps center on more Webb mapping of Titan and new lab tests of methane-nitrogen ice mixtures at frigid temperatures to see whether a common compound or compound family explains both signals.