What is the pressure of outer space?

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The discussion focuses on calculating the pressure of outer space using the ideal gas equation, given the density of helium at approximately 1 atom per cm³ and a temperature of 3K. The ideal gas equation pV = nRT is suggested as a method, with the molar gas constant R provided for reference. To proceed, it's necessary to convert the mass and density of helium into a usable volume for the calculations. The conversation emphasizes the low pressure of outer space and the importance of accurate conversions in the calculations. Overall, the thread provides guidance on using fundamental gas laws to estimate pressure in a near-vacuum environment.
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I'm trying to calculate the pressure of outer space given the denisty of helium is of the order 1 atom per cm^3, temprature 3K.

1 atom per cm^3 => 10^6 per m^3.

It's a low pressure so I guess I can use the ideal gas equation. I also know the mass of a helium atom is 6.68x10^-27 kg.

What's the best route forward?

Best Regards, James.
 
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Why are you trying to calculate the pressure?

Either way you can use:
pV= nRT
where n is the number of moles and R = 8.31 J\cdot mol^{-1}\cdot K^{-1} and is the molar gas constant.

You will first need to convert the mass and density into a volume.
Hope this helps.
 
Last edited:
Hootenanny said:
Hope this helps.
That's great. Thanks.
 

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