What is the atmospheric pressure on Pluto and how can it sustain gases?

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Discussion Overview

The discussion revolves around the atmospheric pressure on Pluto and the presence of gases in its atmosphere, exploring how these gases can exist given Pluto's distance from the Sun and cold temperatures. The conversation includes theoretical considerations and implications of sublimation processes.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants note that Pluto's surface contains various gases, including CH4 and H2SO4, and question how these can exist in such a cold environment.
  • One participant explains that while Pluto is far from the Sun, its highly eccentric orbit allows it to come closer at times, which may lead to sublimation of frozen gases into the atmosphere.
  • Another participant discusses the concept of boiling points, indicating that gases and liquids have boiling points dependent on temperature and pressure, and that solids can sublime into gas below the triple point.
  • A participant expresses a need to understand the atmospheric pressure on Pluto to conclude the role of sublimation in the presence of gases.
  • It is mentioned that the New Horizons spacecraft measured Pluto's surface pressure to be about 1 Pa (10 μbar), significantly lower than Earth's atmospheric pressure.

Areas of Agreement / Disagreement

Participants generally agree on the presence of gases and the role of sublimation, but there is no consensus on the implications of atmospheric pressure or the volatility of the gases discussed.

Contextual Notes

Some assumptions regarding the behavior of gases and the conditions on Pluto remain unresolved, particularly concerning the definitions of volatility and the implications of atmospheric pressure measurements.

John Dalton
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The New Horizon reached Pluto in April of previous year.
It shown that Pluto's surface contains mixtures of various gases , such as CH4 and gaseous H2SO4.
Now , the query of mine is that-
Pluto is situated very far from Sun and is very cold.
Please someone justify me how can this gases be present on the Planet.
I am ready to read any explanations theory.
 
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The atmosphere is primarily Nitrogen, but there is a small component of complex molecules.
As you say Pluto is far from the Sun, but it's orbit is highly eccentric, sometimes it's closer to the Sun then Neptune.
It may be that these molecules are frozen on the surface when Pluto is most distant,
but they sublimate to become part of the atmosphere when it's closer
 
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Gasses/liquids do not have a boiling "point". The have a boiling point at a specific temperature or a specific pressure. Below the triple point solids can still sublime into gas.
 
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Thanks to both of you.
I got a basic idea of this presence of gases.
It is due to sublimation.
Please don't mind , I have a query-
Are the gases volatile ?
 
John Dalton said:
Are the gases volatile ?
Can you clarify what you mean when you ask whether a gas is volatile? Normally, one would say that a liquid (or solid) is volatile or not based on how readily it will evaporate (or sublimate).
 
Sorry jbriggs444, I asked a wrong query I initially.
I meant to say that what is atmospheric pressure on the Pluto.
I think this is a strange question.
But I need to know this to conclude that the presence of gases on Pluto is due to sublimation.
(According to Stefan r stating that-
stefan r said:
Gasses/liquids do not have a boiling "point". The have a boiling point at a specific temperature or a specific pressure. Below the triple point solids can still sublime into gas.
 
John Dalton said:
what is atmospheric pressure on the Pluto.
Apparently the New Horizons spacecraft was equipped to obtain a fairly accurate measurement for that
https://en.wikipedia.org/wiki/Atmosphere_of_Pluto
Surface pressure of the atmosphere of Pluto, measured by New Horizons in 2015, is about 1 Pa (10 μbar), roughly 100,000 times less than Earth's atmospheric pressure.
 

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