The National Weather Service says between -370 deg F and -400 deg F.Planet or not, it’s the coolest thing out there. Hard to believe it is smaller than our moon.
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For that matter, moons Ganymede and Titan are both bigger than Mercury. Deceptive.
Pluto
www.weather.gov
The atmosphere of Pluto as photographed by New Horizons.
Pluto and its largest moon, Charon.