Popular estimate of the Earth's atmosphere possibly wrong?

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Discussion Overview

The discussion revolves around the estimated mass of the Earth's atmosphere, specifically questioning the commonly cited figure of 5.15 x 1018 kilograms. Participants explore the calculations leading to this estimate and examine potential discrepancies in the numbers presented in various sources.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant notes that the commonly cited mass of the atmosphere is 5,100,000,000,000,000,000 kilograms and questions the validity of this figure based on pressure and surface area calculations.
  • Another participant confirms the mass as 5.15 x 1018 kg, reiterating the figure in response to the initial query.
  • A participant presents a calculation using the Earth's radius to derive a mass of approximately 5.1 x 1018 kg, suggesting that the initial multiplication may have been miscalculated.
  • There is a discussion about the surface area of the Earth and its relation to the mass estimate, with one participant asserting that they used an average radius to arrive at their figure.
  • One participant acknowledges a mistake in their earlier calculations after reviewing the discussion.

Areas of Agreement / Disagreement

Participants express differing views on the correct mass of the Earth's atmosphere, with some calculations leading to 5.1 x 1018 kg and others suggesting a discrepancy with the commonly cited figure. The discussion remains unresolved regarding the accuracy of the estimates and the calculations involved.

Contextual Notes

Participants reference different assumptions regarding the average radius of the Earth and the pressure exerted per square meter, which may affect the calculations. There is also a lack of consensus on the correct interpretation of the figures presented in various sources.

Dreksler
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TL;DR
My calculation says 5.1 quadrillion kg yet the frequently mentioned one says 5.1 quintillion kg.
So I just realized that on the internet the number that frequently pops up with regards to the total mass of the Earth's atmosphere is 5,100,000,000,000,000,000 kilograms. For example, the number is mentioned two times on the Wikipedia page for the Earth's atmosphere, there are more examples. Yet per square meter of surface, there is 100,000 pascals of pressure, which is 10,000 kilograms-force per meter square. The Earth's surface area is 510,000,000,000 meters. Multiplying 510,000,000,000 meters with 10,000 kilograms gets you the number of 5,100,000,000,000,000 kilograms and not the number of 5,100,000,000,000,000,000 kilograms, which is the number frequently mentioned. Am I missing something here?
 
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Google says ##5.15 \,\cdot\,10^{18}\text{ kg}.##
 
fresh_42 said:
Google says ##5.15 \,\cdot\,10^{18}\text{ kg}.##
I know, that is what I am questioning.
 
You seem to assume ##10,000 \text{ kg}## per square meter in accordance with the sources I saw. Then
\begin{align*}
4\pi \left(\dfrac{12,730,000\text{ m}}{2}\right)^2\cdot 10,000\text{ kg}\,\text{m}^{-2}=5,091,042,001,329,214,046.932\ldots \text{ kg}=5.1\cdot 10^{18}\text{ kg}
\end{align*}
 
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fresh_42 said:
You seem to assume ##10,000 \text{ kg}## per square meter in accordance with the sources I saw. Then
\begin{align*}
4\pi \left(\dfrac{12,730,000\text{ m}}{2}\right)^2\cdot 10,000\text{ kg}\,\text{m}^{-2}=5,091,042,001,329,214,046.932\ldots \text{ kg}=5.1\cdot 10^{18}\text{ kg}
\end{align*}
Multiplying 510,000,000,000 with 10,000 doesn't get you to the power of 15?
 
Dreksler said:
Multiplying 510,000,000,000 with 10,000 doesn't get you to the power of 15?
Sure, but I used an average radius for the Earth and got 510,000,000,000,000 square meters.
 
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fresh_42 said:
Sure, but I used an average radius for the Earth and got 510,000,000,000,000 square meters.
Okay, I get where I made the mistake now.
 
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