Would a high gravity rocky planet be guaranteed to have an atmosphere?Would oxygen pool in sink holes if the upper atmosphere was helium, hydrogen and methane?What are the requirements for an atmosphere retaining moon with a stable orbit arround an earth like planet with non-destructive tidal forces?What would happen to a high-pressure creature in a low-pressure atmosphere? (3atm)What would happen to a high-pressure creature in a low-pressure atmosphere (50atm)?How fast would a planet have to be spinning for the centrifugal/centripetal force to cancel out the force of gravity near the equator?Could a planet larger than earth with half the gravity have a denser atmosphere?What are the climatological effects to the surface of a planet where the atmosphere gives way to vaccum? (diagram included)5km artificial planet, with same gravity as on EarthCould a habitable planet with lower gravity have a thick atmosphere?How can this habitable planet have a moon with a naturally occurring atmosphere?

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Would a high gravity rocky planet be guaranteed to have an atmosphere?


Would oxygen pool in sink holes if the upper atmosphere was helium, hydrogen and methane?What are the requirements for an atmosphere retaining moon with a stable orbit arround an earth like planet with non-destructive tidal forces?What would happen to a high-pressure creature in a low-pressure atmosphere? (3atm)What would happen to a high-pressure creature in a low-pressure atmosphere (50atm)?How fast would a planet have to be spinning for the centrifugal/centripetal force to cancel out the force of gravity near the equator?Could a planet larger than earth with half the gravity have a denser atmosphere?What are the climatological effects to the surface of a planet where the atmosphere gives way to vaccum? (diagram included)5km artificial planet, with same gravity as on EarthCould a habitable planet with lower gravity have a thick atmosphere?How can this habitable planet have a moon with a naturally occurring atmosphere?













6












$begingroup$


I want to create a planet with a deep gravity well, say about 12G at the surface. At first I wanted the planet to have either no atmosphere or a very thin one. But I want this to be as close to realistic as possible. So, would a planet be guaranteed to have a thick atmosphere with a gravity well that deep?










share|improve this question









New contributor




Sean Kindle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$











  • $begingroup$
    Hi Sean, welcome to Worldbuilding.SE. You're asking two separate questions here. Could you please remove the second one (about escaping)? You are welcome to ask it in a new question, if it's not a duplicate. Thanks!
    $endgroup$
    – Cyn
    2 hours ago















6












$begingroup$


I want to create a planet with a deep gravity well, say about 12G at the surface. At first I wanted the planet to have either no atmosphere or a very thin one. But I want this to be as close to realistic as possible. So, would a planet be guaranteed to have a thick atmosphere with a gravity well that deep?










share|improve this question









New contributor




Sean Kindle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$











  • $begingroup$
    Hi Sean, welcome to Worldbuilding.SE. You're asking two separate questions here. Could you please remove the second one (about escaping)? You are welcome to ask it in a new question, if it's not a duplicate. Thanks!
    $endgroup$
    – Cyn
    2 hours ago













6












6








6





$begingroup$


I want to create a planet with a deep gravity well, say about 12G at the surface. At first I wanted the planet to have either no atmosphere or a very thin one. But I want this to be as close to realistic as possible. So, would a planet be guaranteed to have a thick atmosphere with a gravity well that deep?










share|improve this question









New contributor




Sean Kindle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$




I want to create a planet with a deep gravity well, say about 12G at the surface. At first I wanted the planet to have either no atmosphere or a very thin one. But I want this to be as close to realistic as possible. So, would a planet be guaranteed to have a thick atmosphere with a gravity well that deep?







reality-check planets gravity atmosphere






share|improve this question









New contributor




Sean Kindle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question









New contributor




Sean Kindle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|improve this question




share|improve this question








edited 1 hour ago







Sean Kindle













New contributor




Sean Kindle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









asked 2 hours ago









Sean KindleSean Kindle

335




335




New contributor




Sean Kindle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





Sean Kindle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






Sean Kindle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











  • $begingroup$
    Hi Sean, welcome to Worldbuilding.SE. You're asking two separate questions here. Could you please remove the second one (about escaping)? You are welcome to ask it in a new question, if it's not a duplicate. Thanks!
    $endgroup$
    – Cyn
    2 hours ago
















  • $begingroup$
    Hi Sean, welcome to Worldbuilding.SE. You're asking two separate questions here. Could you please remove the second one (about escaping)? You are welcome to ask it in a new question, if it's not a duplicate. Thanks!
    $endgroup$
    – Cyn
    2 hours ago















$begingroup$
Hi Sean, welcome to Worldbuilding.SE. You're asking two separate questions here. Could you please remove the second one (about escaping)? You are welcome to ask it in a new question, if it's not a duplicate. Thanks!
$endgroup$
– Cyn
2 hours ago




$begingroup$
Hi Sean, welcome to Worldbuilding.SE. You're asking two separate questions here. Could you please remove the second one (about escaping)? You are welcome to ask it in a new question, if it's not a duplicate. Thanks!
$endgroup$
– Cyn
2 hours ago










3 Answers
3






active

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5












$begingroup$

You ask a tricky question because the case you describe -- a rocky planet with 12G surface gravity -- is extremely unlikely. If the planet is defined as being rocky, then it's made of normal matter (not neutron star or white dwarf stuff) and to have 12G surface gravity, it would have to be quite large.



For a constant density sphere, the surface gravity increases proportional to the sphere's radius, so to have 12G surface gravity it would have to be around 12 times the diameter of the Earth. (The surface gravity is proportional to the planet's mass which is proportional to the cube of the radius. And surface gravity is also inversely proportional to the square of the radius (because the surface in further from the center and the inverse square law). The net effect is a proportionality to radius.)



Even rocks compress, so 12x is somewhat of an overestimate. Say it's "only" 10x the diameter of the Earth. It's still very difficult to see how a rocky planet 10x the diameter of Earth (meaning a mass of 1000 Earths -- greater than Jupiter!) could avoid picking up a huge atmosphere of gasses and being a typical Super Jupiter or even a small star.



About the only way I can think of is if the star it circles went through a very high luminosity phase and stripped away nearly all the atmosphere. (Since hot Jupiters are common, it seems unlikely that a planet that massive even one forming near a star could avoid a big atmosphere. It pretty much has to have had its atmosphere stripped later.) Not so clear that life would survive on it then.






share|improve this answer









$endgroup$




















    4












    $begingroup$

    Likely, but not guaranteed. Consider a large rocky planet very close to its star. There is certainly a possibility that the atmosphere would be boiled off / stripped away by the star.



    This would be the case if, for instance, Mercury were orders of magnitude more massive. If your large rocky planet is close enough to its star to make this case true, you will have to deal with strange conditions for your character. One example is the planet is likely to be tidally locked, with an extremely hot side always facing the star and an extremely cold side always facing away from the star.



    Whether humans have actually discovered a planet that meets these criteria is probably up for debate. Most inquiries into exoplanet atmospheres make the assumption that the existence or lack of atmosphere is unknown until the presence of an atmosphere is proven definitively.






    share|improve this answer









    $endgroup$




















      0












      $begingroup$

      Heavy metal world.



      1. 12G planet. You could ramp up the gravity by making the core more dense. Our planet has an iron / nickel core under the rocks, and those have atomic weights of 55 and 58. Uranium has an atomic weight of 238. So if you made the core out of uranium and other heavy friends your density is 5x that of earth. Those elements are rarer than iron but not crazy rare. Now your planet only needs to be 2.4x as big as earth to have your 12G. If you want your planet even smaller, you can invoke the stable superheavy elements from the undiscovered far reaches of the periodic table - the island of stability

      There could be other cool things about the uranium planet. Maybe natural fission goes on deep inside, which would make for rocking volcanoes. Could you take advantage of this to get off planet? Hmm... Also, the atmosphere would have a lot of radon, which would give everyone very low voices among other things.



      1. My understanding of atmosphere is that you need a magnetosphere to keep it in, gravity notwithstanding. Otherwise the solar wind will strip it away. Mars lost its magnetosphere and then lost its atmosphere because of that. No reason to think that the heavy planet would not have a magnetosphere.





      share|improve this answer









      $endgroup$












      • $begingroup$
        Important to bear in mind that a planet whose core was composed of uranium would detonate. Furthermore, neither the uranium planet nor one composed of transuranic elements from the 'island of stability', can form in nature.
        $endgroup$
        – Arkenstein XII
        56 mins ago










      Your Answer





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      3 Answers
      3






      active

      oldest

      votes








      3 Answers
      3






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      5












      $begingroup$

      You ask a tricky question because the case you describe -- a rocky planet with 12G surface gravity -- is extremely unlikely. If the planet is defined as being rocky, then it's made of normal matter (not neutron star or white dwarf stuff) and to have 12G surface gravity, it would have to be quite large.



      For a constant density sphere, the surface gravity increases proportional to the sphere's radius, so to have 12G surface gravity it would have to be around 12 times the diameter of the Earth. (The surface gravity is proportional to the planet's mass which is proportional to the cube of the radius. And surface gravity is also inversely proportional to the square of the radius (because the surface in further from the center and the inverse square law). The net effect is a proportionality to radius.)



      Even rocks compress, so 12x is somewhat of an overestimate. Say it's "only" 10x the diameter of the Earth. It's still very difficult to see how a rocky planet 10x the diameter of Earth (meaning a mass of 1000 Earths -- greater than Jupiter!) could avoid picking up a huge atmosphere of gasses and being a typical Super Jupiter or even a small star.



      About the only way I can think of is if the star it circles went through a very high luminosity phase and stripped away nearly all the atmosphere. (Since hot Jupiters are common, it seems unlikely that a planet that massive even one forming near a star could avoid a big atmosphere. It pretty much has to have had its atmosphere stripped later.) Not so clear that life would survive on it then.






      share|improve this answer









      $endgroup$

















        5












        $begingroup$

        You ask a tricky question because the case you describe -- a rocky planet with 12G surface gravity -- is extremely unlikely. If the planet is defined as being rocky, then it's made of normal matter (not neutron star or white dwarf stuff) and to have 12G surface gravity, it would have to be quite large.



        For a constant density sphere, the surface gravity increases proportional to the sphere's radius, so to have 12G surface gravity it would have to be around 12 times the diameter of the Earth. (The surface gravity is proportional to the planet's mass which is proportional to the cube of the radius. And surface gravity is also inversely proportional to the square of the radius (because the surface in further from the center and the inverse square law). The net effect is a proportionality to radius.)



        Even rocks compress, so 12x is somewhat of an overestimate. Say it's "only" 10x the diameter of the Earth. It's still very difficult to see how a rocky planet 10x the diameter of Earth (meaning a mass of 1000 Earths -- greater than Jupiter!) could avoid picking up a huge atmosphere of gasses and being a typical Super Jupiter or even a small star.



        About the only way I can think of is if the star it circles went through a very high luminosity phase and stripped away nearly all the atmosphere. (Since hot Jupiters are common, it seems unlikely that a planet that massive even one forming near a star could avoid a big atmosphere. It pretty much has to have had its atmosphere stripped later.) Not so clear that life would survive on it then.






        share|improve this answer









        $endgroup$















          5












          5








          5





          $begingroup$

          You ask a tricky question because the case you describe -- a rocky planet with 12G surface gravity -- is extremely unlikely. If the planet is defined as being rocky, then it's made of normal matter (not neutron star or white dwarf stuff) and to have 12G surface gravity, it would have to be quite large.



          For a constant density sphere, the surface gravity increases proportional to the sphere's radius, so to have 12G surface gravity it would have to be around 12 times the diameter of the Earth. (The surface gravity is proportional to the planet's mass which is proportional to the cube of the radius. And surface gravity is also inversely proportional to the square of the radius (because the surface in further from the center and the inverse square law). The net effect is a proportionality to radius.)



          Even rocks compress, so 12x is somewhat of an overestimate. Say it's "only" 10x the diameter of the Earth. It's still very difficult to see how a rocky planet 10x the diameter of Earth (meaning a mass of 1000 Earths -- greater than Jupiter!) could avoid picking up a huge atmosphere of gasses and being a typical Super Jupiter or even a small star.



          About the only way I can think of is if the star it circles went through a very high luminosity phase and stripped away nearly all the atmosphere. (Since hot Jupiters are common, it seems unlikely that a planet that massive even one forming near a star could avoid a big atmosphere. It pretty much has to have had its atmosphere stripped later.) Not so clear that life would survive on it then.






          share|improve this answer









          $endgroup$



          You ask a tricky question because the case you describe -- a rocky planet with 12G surface gravity -- is extremely unlikely. If the planet is defined as being rocky, then it's made of normal matter (not neutron star or white dwarf stuff) and to have 12G surface gravity, it would have to be quite large.



          For a constant density sphere, the surface gravity increases proportional to the sphere's radius, so to have 12G surface gravity it would have to be around 12 times the diameter of the Earth. (The surface gravity is proportional to the planet's mass which is proportional to the cube of the radius. And surface gravity is also inversely proportional to the square of the radius (because the surface in further from the center and the inverse square law). The net effect is a proportionality to radius.)



          Even rocks compress, so 12x is somewhat of an overestimate. Say it's "only" 10x the diameter of the Earth. It's still very difficult to see how a rocky planet 10x the diameter of Earth (meaning a mass of 1000 Earths -- greater than Jupiter!) could avoid picking up a huge atmosphere of gasses and being a typical Super Jupiter or even a small star.



          About the only way I can think of is if the star it circles went through a very high luminosity phase and stripped away nearly all the atmosphere. (Since hot Jupiters are common, it seems unlikely that a planet that massive even one forming near a star could avoid a big atmosphere. It pretty much has to have had its atmosphere stripped later.) Not so clear that life would survive on it then.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 2 hours ago









          Mark OlsonMark Olson

          11.7k12848




          11.7k12848





















              4












              $begingroup$

              Likely, but not guaranteed. Consider a large rocky planet very close to its star. There is certainly a possibility that the atmosphere would be boiled off / stripped away by the star.



              This would be the case if, for instance, Mercury were orders of magnitude more massive. If your large rocky planet is close enough to its star to make this case true, you will have to deal with strange conditions for your character. One example is the planet is likely to be tidally locked, with an extremely hot side always facing the star and an extremely cold side always facing away from the star.



              Whether humans have actually discovered a planet that meets these criteria is probably up for debate. Most inquiries into exoplanet atmospheres make the assumption that the existence or lack of atmosphere is unknown until the presence of an atmosphere is proven definitively.






              share|improve this answer









              $endgroup$

















                4












                $begingroup$

                Likely, but not guaranteed. Consider a large rocky planet very close to its star. There is certainly a possibility that the atmosphere would be boiled off / stripped away by the star.



                This would be the case if, for instance, Mercury were orders of magnitude more massive. If your large rocky planet is close enough to its star to make this case true, you will have to deal with strange conditions for your character. One example is the planet is likely to be tidally locked, with an extremely hot side always facing the star and an extremely cold side always facing away from the star.



                Whether humans have actually discovered a planet that meets these criteria is probably up for debate. Most inquiries into exoplanet atmospheres make the assumption that the existence or lack of atmosphere is unknown until the presence of an atmosphere is proven definitively.






                share|improve this answer









                $endgroup$















                  4












                  4








                  4





                  $begingroup$

                  Likely, but not guaranteed. Consider a large rocky planet very close to its star. There is certainly a possibility that the atmosphere would be boiled off / stripped away by the star.



                  This would be the case if, for instance, Mercury were orders of magnitude more massive. If your large rocky planet is close enough to its star to make this case true, you will have to deal with strange conditions for your character. One example is the planet is likely to be tidally locked, with an extremely hot side always facing the star and an extremely cold side always facing away from the star.



                  Whether humans have actually discovered a planet that meets these criteria is probably up for debate. Most inquiries into exoplanet atmospheres make the assumption that the existence or lack of atmosphere is unknown until the presence of an atmosphere is proven definitively.






                  share|improve this answer









                  $endgroup$



                  Likely, but not guaranteed. Consider a large rocky planet very close to its star. There is certainly a possibility that the atmosphere would be boiled off / stripped away by the star.



                  This would be the case if, for instance, Mercury were orders of magnitude more massive. If your large rocky planet is close enough to its star to make this case true, you will have to deal with strange conditions for your character. One example is the planet is likely to be tidally locked, with an extremely hot side always facing the star and an extremely cold side always facing away from the star.



                  Whether humans have actually discovered a planet that meets these criteria is probably up for debate. Most inquiries into exoplanet atmospheres make the assumption that the existence or lack of atmosphere is unknown until the presence of an atmosphere is proven definitively.







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered 2 hours ago









                  benben

                  7567




                  7567





















                      0












                      $begingroup$

                      Heavy metal world.



                      1. 12G planet. You could ramp up the gravity by making the core more dense. Our planet has an iron / nickel core under the rocks, and those have atomic weights of 55 and 58. Uranium has an atomic weight of 238. So if you made the core out of uranium and other heavy friends your density is 5x that of earth. Those elements are rarer than iron but not crazy rare. Now your planet only needs to be 2.4x as big as earth to have your 12G. If you want your planet even smaller, you can invoke the stable superheavy elements from the undiscovered far reaches of the periodic table - the island of stability

                      There could be other cool things about the uranium planet. Maybe natural fission goes on deep inside, which would make for rocking volcanoes. Could you take advantage of this to get off planet? Hmm... Also, the atmosphere would have a lot of radon, which would give everyone very low voices among other things.



                      1. My understanding of atmosphere is that you need a magnetosphere to keep it in, gravity notwithstanding. Otherwise the solar wind will strip it away. Mars lost its magnetosphere and then lost its atmosphere because of that. No reason to think that the heavy planet would not have a magnetosphere.





                      share|improve this answer









                      $endgroup$












                      • $begingroup$
                        Important to bear in mind that a planet whose core was composed of uranium would detonate. Furthermore, neither the uranium planet nor one composed of transuranic elements from the 'island of stability', can form in nature.
                        $endgroup$
                        – Arkenstein XII
                        56 mins ago















                      0












                      $begingroup$

                      Heavy metal world.



                      1. 12G planet. You could ramp up the gravity by making the core more dense. Our planet has an iron / nickel core under the rocks, and those have atomic weights of 55 and 58. Uranium has an atomic weight of 238. So if you made the core out of uranium and other heavy friends your density is 5x that of earth. Those elements are rarer than iron but not crazy rare. Now your planet only needs to be 2.4x as big as earth to have your 12G. If you want your planet even smaller, you can invoke the stable superheavy elements from the undiscovered far reaches of the periodic table - the island of stability

                      There could be other cool things about the uranium planet. Maybe natural fission goes on deep inside, which would make for rocking volcanoes. Could you take advantage of this to get off planet? Hmm... Also, the atmosphere would have a lot of radon, which would give everyone very low voices among other things.



                      1. My understanding of atmosphere is that you need a magnetosphere to keep it in, gravity notwithstanding. Otherwise the solar wind will strip it away. Mars lost its magnetosphere and then lost its atmosphere because of that. No reason to think that the heavy planet would not have a magnetosphere.





                      share|improve this answer









                      $endgroup$












                      • $begingroup$
                        Important to bear in mind that a planet whose core was composed of uranium would detonate. Furthermore, neither the uranium planet nor one composed of transuranic elements from the 'island of stability', can form in nature.
                        $endgroup$
                        – Arkenstein XII
                        56 mins ago













                      0












                      0








                      0





                      $begingroup$

                      Heavy metal world.



                      1. 12G planet. You could ramp up the gravity by making the core more dense. Our planet has an iron / nickel core under the rocks, and those have atomic weights of 55 and 58. Uranium has an atomic weight of 238. So if you made the core out of uranium and other heavy friends your density is 5x that of earth. Those elements are rarer than iron but not crazy rare. Now your planet only needs to be 2.4x as big as earth to have your 12G. If you want your planet even smaller, you can invoke the stable superheavy elements from the undiscovered far reaches of the periodic table - the island of stability

                      There could be other cool things about the uranium planet. Maybe natural fission goes on deep inside, which would make for rocking volcanoes. Could you take advantage of this to get off planet? Hmm... Also, the atmosphere would have a lot of radon, which would give everyone very low voices among other things.



                      1. My understanding of atmosphere is that you need a magnetosphere to keep it in, gravity notwithstanding. Otherwise the solar wind will strip it away. Mars lost its magnetosphere and then lost its atmosphere because of that. No reason to think that the heavy planet would not have a magnetosphere.





                      share|improve this answer









                      $endgroup$



                      Heavy metal world.



                      1. 12G planet. You could ramp up the gravity by making the core more dense. Our planet has an iron / nickel core under the rocks, and those have atomic weights of 55 and 58. Uranium has an atomic weight of 238. So if you made the core out of uranium and other heavy friends your density is 5x that of earth. Those elements are rarer than iron but not crazy rare. Now your planet only needs to be 2.4x as big as earth to have your 12G. If you want your planet even smaller, you can invoke the stable superheavy elements from the undiscovered far reaches of the periodic table - the island of stability

                      There could be other cool things about the uranium planet. Maybe natural fission goes on deep inside, which would make for rocking volcanoes. Could you take advantage of this to get off planet? Hmm... Also, the atmosphere would have a lot of radon, which would give everyone very low voices among other things.



                      1. My understanding of atmosphere is that you need a magnetosphere to keep it in, gravity notwithstanding. Otherwise the solar wind will strip it away. Mars lost its magnetosphere and then lost its atmosphere because of that. No reason to think that the heavy planet would not have a magnetosphere.






                      share|improve this answer












                      share|improve this answer



                      share|improve this answer










                      answered 1 hour ago









                      WillkWillk

                      115k27217480




                      115k27217480











                      • $begingroup$
                        Important to bear in mind that a planet whose core was composed of uranium would detonate. Furthermore, neither the uranium planet nor one composed of transuranic elements from the 'island of stability', can form in nature.
                        $endgroup$
                        – Arkenstein XII
                        56 mins ago
















                      • $begingroup$
                        Important to bear in mind that a planet whose core was composed of uranium would detonate. Furthermore, neither the uranium planet nor one composed of transuranic elements from the 'island of stability', can form in nature.
                        $endgroup$
                        – Arkenstein XII
                        56 mins ago















                      $begingroup$
                      Important to bear in mind that a planet whose core was composed of uranium would detonate. Furthermore, neither the uranium planet nor one composed of transuranic elements from the 'island of stability', can form in nature.
                      $endgroup$
                      – Arkenstein XII
                      56 mins ago




                      $begingroup$
                      Important to bear in mind that a planet whose core was composed of uranium would detonate. Furthermore, neither the uranium planet nor one composed of transuranic elements from the 'island of stability', can form in nature.
                      $endgroup$
                      – Arkenstein XII
                      56 mins ago










                      Sean Kindle is a new contributor. Be nice, and check out our Code of Conduct.









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