Would the water remain in lquid form?

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Discussion Overview

The discussion centers on whether water in the oceans would remain in liquid form if Earth's atmospheric pressure were reduced to 0.10 bar, which is 10% of current atmospheric pressure. Participants explore the implications of this reduced pressure on boiling points, temperature variations, and the effects of evaporation.

Discussion Character

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

Main Points Raised

  • Some participants propose that with an atmospheric pressure of 0.10 bar, the boiling point of water would be 113 degrees F, raising the question of whether the ocean would reach this boiling point given the temperature variations.
  • Others argue that significant temperature differences above the ocean would be limited due to the need to heat a substantial layer of water and the effects of evaporation, which would restrict temperature increases.
  • A participant questions whether a thinner atmosphere would actually result in greater temperature extremes, suggesting that the heat capacity of the ocean would still play a critical role in temperature changes.
  • Concerns are raised about the rate of evaporation, with a participant noting that even under optimal conditions, evaporation rates are limited, which could affect the overall temperature of the ocean.
  • Another participant inquires about the potential impact of reduced atmospheric pressure on the latent heat of vaporization of water.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether the ocean would remain liquid or reach boiling point under the proposed conditions. Multiple competing views are presented regarding the effects of atmospheric pressure and temperature variations.

Contextual Notes

Limitations include assumptions about temperature distribution, the effects of evaporation, and the heat capacity of the ocean, which are not fully resolved in the discussion.

willstaruss22
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Lets say Earths atmospheric pressure was reduced to 0.10 bar which is 10% Earths atmospheric pressure. The boiling point at this pressure is 113 degrees F. Due to the atmosphere being thinner there is a greater temperature difference with higher highs and lower lows in a 24 hour period.
Lets say in a large area over the pacific ocean the air temperature in the day time reaches 130 degrees F and the temperature in the night time reaches 60 degrees F. This temperature difference is over a 24 hour period over a body of water. Would the oceans reach boiling point given the atmosphere is reaching above the boiling point for the given atmospheric pressure or will it remain a constant liquid because of the lower temperature?
 
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willstaruss22 said:
Lets say Earths atmospheric pressure was reduced to 0.10 bar which is 10% Earths atmospheric pressure. The boiling point at this pressure is 113 degrees F. Due to the atmosphere being thinner there is a greater temperature difference with higher highs and lower lows in a 24 hour period.
Lets say in a large area over the pacific ocean the air temperature in the day time reaches 130 degrees F and the temperature in the night time reaches 60 degrees F. This temperature difference is over a 24 hour period over a body of water. Would the oceans reach boiling point given the atmosphere is reaching above the boiling point for the given atmospheric pressure or will it remain a constant liquid because of the lower temperature?

You can't get such a large temperature difference above the ocean. At daytime the sun will shine into the water, and it will have to heat a layer some tens of meters thick. Evaporation will limit the temperature rise also. Even with the sun directly overhead and all energy going into evaporation., you can only evaporate 1.6 mm/hour. ( 1kw/m^2 sunshine and 2.26 MJ/kg to evaporate water)

rapid cooling at night over a warm ocean will surely produce clouds or fog.
 
Even with an atmosphere 10% as thick as Earths the temperature difference won't be as big? I always thought that there would be bigger highs and lows with a thinner atmosphere.
 
willstaruss22 said:
Even with an atmosphere 10% as thick as Earths the temperature difference won't be as big? I always thought that there would be bigger highs and lows with a thinner atmosphere.

But to get the air above the ocean to heat up, you've got to heat up the ocean first, and the heat capacity of the ocean hasn't changed.
 
willem2 said:
Even with the sun directly overhead and all energy going into evaporation., you can only evaporate 1.6 mm/hour. ( 1kw/m^2 sunshine and 2.26 MJ/kg to evaporate water)
.

Would a change in atmospheric pressure change the latent heat of vaporization of the water?
 
So basically the ocean would remain liquid even with an atmosphere this thin? Interesting and i also forgot that there is a lot of water to heat up.
 

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