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Thread: Planet of extreme temperatures and itís effects

  1. #1
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    Planet of extreme temperatures and itís effects

    So I am curious about this.
    So letís imagine a planet.
    This planet has 0.60 Earth radii and 0.198 Earth masses, itís density is 5.052 g cm/3 as a result.
    The planet is 4 billion years old.
    It has a magnetic field and there are volcanoes and plate tectonics but less activity than Earth.
    It also has a 26 hour rotation rate.
    Now say the atmosphere is 0.1 atmospheres at this pressure water boils at 115 degrees F.
    The area where we will focus on has a fresh water lake twice the size of the Caspian Sea.
    During the day in the summer in this certain area it reaches 130 degrees F during the day and at night 50 degrees F.
    During the winter it reaches 20 degrees F during the day and -70 F at night.
    During spring/fall temperatures reach 90 F during the day and 10 at night.
    Now I set the parameters for my question.
    Would water stay liquid in this area on average or would you have a frozen lake in winter, liquid in fall/spring and evaporated in the summer.
    Iím trying to establish if a planet this extreme will have liquid water or just seasonal liquid water on the surface. I gave details of the size and such to describe the world. I gave specifics because if it was general I wouldnít have given a clear picture.

  2. #2
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    I am of the opinion that the water in the lake would stay liquid, but that the top of the lake would freeze, possibly several feet of ice at the top. The bottom of the lake would probably stay close to 38F, or somewhat warmer if there were volcanic vents at the bottom. Look for example at Lake Baikal at what happens to it in the Winter.
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  3. #3
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    The planet you are describing is a Mars-like planet, a fifth of the mass of Earth. Whether or not you could get seasonal water levels in the lake you are describing really depends on the total water vapour level on this planet. If this lake is the only lake on the planet, then it would evaporate in summer, but the water from the lake would spread out to cover the rest of the planet's surface and would never reform into a lake.
    On the other hand, if this lake is part of an extensive water cover on the planet, and the humidity of the atmosphere is relatively high, then there is a good chance that enough water will fall inside the lake's water catchment area and will flow downhill to reform the lake in autumn winter and or spring.

    Take a look at various endorheic lakes around the Earth - some are in very dry parts of the world, and they rarely get enough water to be considered lakes. Other lakes receive plenty of water from the surrounding landscape. Many of these lakes are salty.
    Last edited by eburacum45; 2020-Aug-21 at 12:48 PM.

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    So if the lake was more like 5 times the size of the Mediterranean Sea would it still be a seasonal lake or stay mostly liquid with partial evaporation and freezing periods? Iím also curious if larger bodies of water could exist on the surface? Iím doing for at least 60% of the planet having water.

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    Quote Originally Posted by KTevolved365 View Post
    So if the lake was more like 5 times the size of the Mediterranean Sea would it still be a seasonal lake or stay mostly liquid with partial evaporation and freezing periods? I’m also curious if larger bodies of water could exist on the surface? I’m doing for at least 60% of the planet having water.
    I think eburacum45's great point was essentially that the small planet size would mean a thin atmosphere, which really couldn't keep the body of water from evaporating in the Summer. I'd like to add that it MIGHT be possible that during the first 500 million years of that planet being around, that it might have had enough of a magnetic field to keep the solar wind from removing it's Hydrogen (and water), so that it might have been able to keep a thicker atmosphere, and so you might contrive to have a situation like you are hoping for for your story, but there wouldn't be advanced life forms, the atmosphere would be mostly methane, ammonia, CO2, and water vapor, and there would still be a lot of rocks falling from the sky, and volcanism.
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  6. #6
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    I'd cover the planet in numerous large lakes or small seas, if you want the planet to have a recurrent liquid water season. Otherwise the rest of the planet be so dry it would would absorb the available water like a sponge.

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    Quote Originally Posted by eburacum45 View Post
    The planet you are describing is a Mars-like planet, a fifth of the mass of Earth. Whether or not you could get seasonal water levels in the lake you are describing really depends on the total water vapour level on this planet. If this lake is the only lake on the planet, then it would evaporate in summer, but the water from the lake would spread out to cover the rest of the planet's surface and would never reform into a lake.
    Actually, no.
    Surprising, but thatīs the case.
    How much water do you think is on average in Earthīs atmosphere?
    12 900 cubic km.
    Lake Superior alone is 12 100 cubic km.
    Caspian Sea is 78 000 cubic km. And the OP specified twice the size of Caspian Sea.
    Quote Originally Posted by eburacum45 View Post
    Take a look at various endorheic lakes around the Earth - some are in very dry parts of the world, and they rarely get enough water to be considered lakes.
    Quite often.
    The key here is that only shallow lakes can dry up seasonally. There are many broad and very flat depressions in dry areas, where the runoff spreads out as a layer shallow enough to dry up in a season, like Lake Eyre But when a steeper and therefore deeper depression exists, like Mono Lake or Dead Sea, it fills too deep to evporate in a season.
    Quote Originally Posted by eburacum45 View Post
    Other lakes receive plenty of water from the surrounding landscape. Many of these lakes are salty.
    Yes, if they are terminal. There are also freshwater lakes in dry areas, like lake Kinneret or Utah. The key here is having overflow.

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    Quote Originally Posted by KTevolved365 View Post
    So if the lake was more like 5 times the size of the Mediterranean Sea would it still be a seasonal lake or stay mostly liquid with partial evaporation and freezing periods? I’m also curious if larger bodies of water could exist on the surface? I’m doing for at least 60% of the planet having water.
    5 times the size of Mediterranean Sea is about the size of Arctic Ocean. Which does freeze - and stays liquid under the pack ice.

    How big was Vastitas Borealis when it was full? Area, depth, volume?

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    Quote Originally Posted by antoniseb View Post
    I think eburacum45's great point was essentially that the small planet size would mean a thin atmosphere, which really couldn't keep the body of water from evaporating in the Summer.
    And mistaken. As pointed out, you cannot accommodate that much water vapour in atmosphere - thick or thin. Itīs going to precipitate back from the atmosphere, somewhere on the planet. In summer, it means rains, maybe thunderstorms. And the water rapidly returning to lake via swollen rivers like Volga or Cooperīs Creek.
    Quote Originally Posted by antoniseb View Post
    I'd like to add that it MIGHT be possible that during the first 500 million years of that planet being around, that it might have had enough of a magnetic field to keep the solar wind from removing it's Hydrogen (and water), so that it might have been able to keep a thicker atmosphere, and so you might contrive to have a situation like you are hoping for for your story, but there wouldn't be advanced life forms, the atmosphere would be mostly methane, ammonia, CO2, and water vapor, and there would still be a lot of rocks falling from the sky, and volcanism.
    Wrong dates.
    The outflow channels on Mars operated much after 500 million years. Why, I think even the valley systems operated much after 500 million years.
    What precisely was the date, and pressure of Martian atmosphere, when last outflow channel formed?
    Does the areology of Martian rocks show free ammonia?
    The sedimentary valleys are identified precisely by scarcity of rocks having fallen on them.

    And now we are talking of a planet expressly slightly bigger than Mars - escape speed 0,57 Earth vs. 0,45 of Mars, and expressly a magnetic field. I think such planet could keep atmosphere and hydrosphere like young Mars in long term.

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    Quote Originally Posted by chornedsnorkack View Post
    ... I think such planet could keep atmosphere and hydrosphere like young Mars in long term.
    OK! Thanks for taking a bit more time to think it through than I did. Your argument seems reasonable.
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  11. #11
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    So basically you are saying the planet could keep large bodies of liquid water long term. That it water would evaporate during the day and rain/snow during night or when it is colder? I suspected as much.

  12. 2020-Sep-18, 12:07 PM

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