A new study finds that Pluto is “spray-painting” the red poles of its big moon Charon.
The paint is actually Pluto's continually escaping atmosphere. Methane and other gases from Pluto end up coating Charon's frozen poles, which are so cold and where winters are so long that this buildup remains for decades. A chemical transformation, via solar radiation, turns the polar caps dark red.
Planetary scientist Will Grundy of Lowell Observatory in Arizona bases his findings on observations by NASA's New Horizons spacecraft. He says it's a new phenomenon for scientists and akin to “spray-painting.”
His study was reported by the journal Nature on Wednesday, 16 months to the day after New Horizons' historic flyby of Pluto.