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Atmosphere of Pluto

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Pluto is a tiny dwarf planet far from our Sun. It is surrounded by a thin layer of gases called an atmosphere.

PIA20362-Pluto-Atmosphere-Released20160114
PIA20362-Pluto-Atmosphere-Released20160114

This atmosphere is very special because Pluto is the only object far beyond Neptune known to have one. Most of the air is made of nitrogen. There are also small amounts of methane and carbon monoxide. These gases come from ices on the surface that turn into vapor. The atmosphere is very thin compared to Earth. In fact, the pressure is only about 1/100,000 of the pressure we feel here.

MVIC sunset scan of Pluto
MVIC sunset scan of Pluto

There is a very interesting way this atmosphere works. High-energy cosmic radiation hits the gases in the air. This radiation causes the gases to react and form new, heavier compounds. These new things include ethane, ethylene, and acetylene. They also form nitriles and hydrogen cyanide. These heavier materials create a blue haze that covers the whole planet. The haze has many layers, sometimes as many as 20. These layers can reach altitudes of over 200 km.

Near-Surface Haze or Fog on Pluto
Near-Surface Haze or Fog on Pluto

Scientists have been studying Pluto's air since the 1980s. They used telescopes on Earth to watch stars pass behind the planet. This method is called an occultation. They also used a tool called spectroscopy to study the gases. In 2015, everything changed when a spacecraft named New Horizons flew very close. It gave us the first direct and reliable look at the lowest parts of the atmosphere. It measured the surface pressure to be about 1 Pascal. This was a huge step for science.

PIA19716 Alice Solar Occultation (cropped)
PIA19716 Alice Solar Occultation (cropped)

Pluto's atmosphere has many strange facts and numbers. The surface is very cold, but the temperature rises as you go up. This happens because of a greenhouse effect caused by methane. Near an altitude of 35 km, the temperature reaches its highest point. The methane content is about 0.25%, while carbon monoxide is about 0.0515%. The haze is also quite large. Some layers are more than 10 km thick. The vertical distance between haze layers is about 10 km.

PossibleCloudsonPluto
PossibleCloudsonPluto

Understanding Pluto helps us learn about other places in space. Its atmosphere is most like the atmosphere of Triton, another moon. In some ways, it even looks like the atmosphere of Mars. The way the ice moves on the surface changes Pluto's color and brightness. This happens because of seasonal changes as Pluto orbits the Sun. These changes can make the surface ice move by many meters. Watching these shifts helps scientists see how a tiny world works.

PossibleCloudsonPluto
PossibleCloudsonPluto
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🖼️ Images & Media (7)
File:PIA20362-Pluto-Atmosphere-Released20160114.jpg
PIA20362-Pluto-Atmosphere-Released20160114.jpg
File:MVIC sunset scan of Pluto.jpg
MVIC sunset scan of Pluto.jpg
File:Near-Surface Haze or Fog on Pluto.jpg
Near-Surface Haze or Fog on Pluto.jpg
File:PIA19716 Alice Solar Occultation (cropped).jpg
PIA19716 Alice Solar Occultation (cropped).jpg
File:PossibleCloudsonPluto.jpg
PossibleCloudsonPluto.jpg
File:PIA20373-Pluto-Atmosphere-Infrared-20150714.jpg
PIA20373-Pluto-Atmosphere-Infrared-20150714.jpg
File:PIA21061-Pluto-DwarfPlanet-XRays-20160914.jpg
PIA21061-Pluto-DwarfPlanet-XRays-20160914.jpg
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