The detail that breaks it: the easier-to-evaporate compound is buried deeper than the harder one.

The detail that breaks it: the easier-to-evaporate compound is buried deeper than the harder one. Sunlight cooks a surface from the top down. The easy stuff should leave first, from the top. 3I/ATLAS shows the reverse. The only way that happens is if the top was already burned off before it got here. https://t.co/TaX0kQMksL