Astronomy
The Chemical Composition of Pluto's Atmosphere and Its Seasonality
Quick fact
Pluto's atmosphere is mostly nitrogen (about 90%) with traces of methane and carbon monoxide, and its pressure fluctuates dramatically: it can double in a decade or nearly disappear when Pluto moves far from the Sun.
Why this is interesting
You know Pluto as a distant, frozen world—but did you know it actually has an atmosphere that can appear, thicken, and even almost vanish?