An unusual observation was made on Pluto’s moon Charon by astronomers when the New Horizons space probe flew by the planet in 2015.
The probe found a large red spot on Charon's north pole.
Astronomers believe that Charon is picking up atmospheric gases escaping Pluto's gravitational pull.
The gas, tholin, will stay for Charon's winter until the sun grows closer, evaporating the temporary red cloud.
(With inputs from NBC News)