Charon from Pluto

Digital work

In 1988 the atmosphere of Pluto was detected for the first time during a stellar occultation. New Horizons spacecraft arrived at Pluto in July 2015. It found a surprisingly robust hazy atmosphere on the dwarf planet. The haze extends at least 160 kilometers (100 miles) above the surface. Clouds, haze, winds, micro snowflakes,... could all be part of Pluto's dynamic weather system. Clouds and haze must be made of the very constituents of its atmosphere: molecular nitrogen and some carbon monoxide and methane. The presence of clouds, however, is dependent on the existence of a temperature gradient, like that on Earth. And with clouds must come some form of rain or, at Pluto's distance from the Sun, snow. It is thought that clouds in Pluto's atmosphere may be composed of tiny frozen spherules of nitrogen or carbon monoxide, rather than liquid or snowflakes.
Charon, the faithful companion, is seen in Pluto's sky with a size of 3º, six times our Moon from Earth.