According to story, they seem to be looking at methane absorption spectrum. By the abrupt transitions described, I would ***-u-me that we are hearing descriptions of phase transitions for short-chain organics-- butane, ethylene, ethane, ethanol, acetylene,... As you said, Antoniseb, knowing the depth of the window would give us a clue as to the temp/pressures that apply.

Just as we get transparent air, clouds, rain, sleet, hail, snow, and 'wintery mix' from phase changes of a relatively minor atmosphere component, coupled to minor changes in temp/press.

I love a good mystery! S

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Ignoramus et ignorabamus.-- Reymond

Wir mussen wissen. Wir werden wissen.--Hilbert

Pick one.