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You may remember my question here, part of which assumed that all humans would die in one way very quickly, with minimal destruction to the planet.

This question will ask about the way humans would die:

We all know about water's phase changes.

Let's say that the core of the Earth overheated, sending heat waves upward to the surface. The heat vaporizes most of the water, sending gas (steam) into the atmosphere. The gas pushes out most of the air into space and only steam remains. This effectively wipes out the human race in hours.

After hundreds of years, the steam contracts back onto the surface of the planet after Earth's core cools down due to human inactivity¹.

Is this a plausible theory? Could it actually work if Earth overheated?

Some quick diagrams made by me:

Before overheating of Earth: enter image description here Overheating: enter image description here

¹As pointed out in comments, humans probably couldn't affect the Earth's core, but just assume it did for the moment.

I am relying on little knowledge in the scientific field so just tell me if I am being an idiot and my theory is bonkers.

user11111111111
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    I think you are underestimating, by several orders of magnitude, the power that would be needed to "evaporate all of the water in a few hours". That kind of power would easily kill all of the humans in minutes, by itself. – SJuan76 Feb 01 '21 at 20:57
  • @SJuan76 True, but I need it to work this way so, in the end, the atmosphere is a void of nothing (no gasses or elements). – user11111111111 Feb 01 '21 at 20:58
  • Argon, radon, helium ...etc. are constantly being leaked from the core always, are you also trying to prevent this? Are you just looking for an Earth sized planed with some scattered H-2O around and no party-atmosphere, like the Moon but bigger? – Escaped dental patient. Feb 01 '21 at 21:02
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    @Tantalus'touch. I am trying to prevent as many gasses as possible from being in the atmosphere. I understand that some are impossible to eliminate in this scenario, which is fine. Assume that the planet is Earth. – user11111111111 Feb 01 '21 at 21:05
  • @Nai45 Does it need to be sudden or can it be gradual? A collapse of the earth’s magnetic field should leave the atmosphere vulnerable to solar rays stripping away the atmosphere. Given enough time earth should be mostly atmosphereless. – cHARLES cHESS Feb 01 '21 at 21:22
  • (1) "The gas pushes out most of the air into space": That is not how gases work. Gases mix, they don't push each other. (And steam is actually lighter than air anyway.) (2) "After hundreds of years, the steam contracts back onto the surface": And what exactly kept it as a gas for "hundreds of years"? (3) Human activity has exactly nothing to do with the temperature of Earth's core. – AlexP Feb 01 '21 at 21:28
  • @AlexP Possibly, but I would like you to try an experiment I found online that lead me to this theory. Follow the steps and draw your own conclusions.
    1. Place a small amount of water in an Erlenmeyer Flask.
    2. Place an alcohol burner under a mesh stand and have the Erlenmeyer Flask on top.
    3. Light your burner.
    4. Heat your Erlenmeyer flask until you have a steady stream of steam.
    5. Put a balloon on top of your flask.
    6. Allow cooling for 3 minutes.
     – user11111111111 Feb 01 '21 at 21:33
  • You will see that the heat causes the water to vaporize, making the steam rise and push the air upward out of the flask (atmosphere). When you put the ballon on, the steam contracts downward. This creates an empty void that the ballon will be drawn into. – user11111111111 Feb 01 '21 at 21:35
  • @AlexP I do understand your 3rd point though... maybe humans could cause too much radioactivity or something like that to heat up the core? What would you recommend? – user11111111111 Feb 01 '21 at 21:39
  • Just wondering, why the downvotes? – user11111111111 Feb 01 '21 at 21:56
  • The diagram is nice, but doesn't tell us anything you hadn't already said in the text. Please provide us something quantitative to work with to clarify your conceptualization. – Escaped dental patient. Feb 01 '21 at 22:03
  • "The heat causes the water to vaporize": yes, true. "Making the steam rise": no, not really; what happens is that the heat makes the water boil, that is, it raises the vapor pressure of water above the pressure of the surrounding gas. In your thought experiment, the oceans will boil, with the water vapor displacing the air near the surface of the ocean. As the water vapor expands, its pressure will drop to equal the pressure of the surrounding gas at which point they will mix. – AlexP Feb 01 '21 at 22:07
  • @AlexP Ah, yes. This helps, thank you! – user11111111111 Feb 01 '21 at 22:09
  • "Why the downvotes?" Because you are speaking of lberating a fantastic amount of energy, of which one thousandth would blow off the atmosphere all by itself with no need to go all the way to boil the oceans. There is about 200 times more water in the ocean than air in the atmosphere, and the heat of vaporization of water is huge. And because you are overkilling the humans about ten thousand times -- one ten thousandth of the amount of energy needed to boil off the oceans would surely kill all humans dead. – AlexP Feb 01 '21 at 22:14
  • @AlexP I think my question is being misunderstood. I don't really care how the humans die, I just want to know if the atmosphere could be destroyed in this particular way for my own reasons. – user11111111111 Feb 01 '21 at 22:16
  • Yes, the atmosphere would most certainly be destroyed. Of course, Earth will also most certainly be dramatically changed. See, rock is a pretty good thermal insulator. The core of the Earth is already pretty hot, about 5000° C or 9000° F; but the heat flux through the surface is minuscule. To increase the heat flux to a value where water at the bottom of the ocean will start to boil you need to increase the temperature of Earth's core at values more similar to the core of a star. Interesting stuff happens with such a hot core, with no chance of Earth remaining even remotely the same. – AlexP Feb 01 '21 at 22:21
  • @AlexP You have given me some very helpful comments. If you chose to compile them into answer form I would willingly accept it. – user11111111111 Feb 01 '21 at 22:22

1 Answers1

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No, gases generally do not displace each other. A concentrated heavier gas may pool at the bottom and displace lighter gases - but water vapor is lighter than most atmospheric gases. A gas coming out from a high pressure container can push other gases aside - but in this scenario we have no high pressure container.

Higher temperature would accelerate the loss of atmosphere to space - but water would be lost first.

Alexander
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  • But couldn't the atmosphere serve as a high-pressure container? It may not be small but it definitely has high pressure. – user11111111111 Feb 01 '21 at 21:37
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    @Nai45 - evaporating water would be subject to the same pressure as the atmosphere itself, so the vapor won't be able to push gases away. Even if there was such a push, it could be sustained only for a short period of time, because heavier atmospheric gases would diffuse back to the surface. – Alexander Feb 01 '21 at 21:47
  • True, thank you! – user11111111111 Feb 01 '21 at 21:57