• AnIndefiniteArticle@sh.itjust.works
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    3 months ago

    It has such a massive hydrogen atmosphere that the temperatures and pressures turn it into a metallic plasma below a certain depth (in literature referred to as the “Plasma Phase Transition”), and that plasma dissolved/ate the planet.

    This metallic hydrogen plasma is basically indistinguishable from that found in stars. In fact, Jupiter is a Y-class brown dwarf star because of this morphology.

        • rhombus@sh.itjust.works
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          3 months ago

          This is a list of astronomical objects with the spectral type Y. They are a mix of brown dwarfs and planetary-mass objects.

          Spectral type Y objects are not all brown dwarfs, they just have a similar elemental composition. Jupiter doesn’t have the mass to be considered a brown dwarf, they are 13-80 times the mass of Jupiter by definition.

          • AnIndefiniteArticle@sh.itjust.works
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            3 months ago

            That mass-based definition is outdated and does not consider recent observations of the interiors of Jupiter and Saturn made by the Juno and Cassini spacecraft. It is a reflection of cold-war era fusion chauvinism and is due to get an update. Jupiter is a star, Saturn straddles the boundary between star and planet.

            • Zagorath@aussie.zone
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              3 months ago

              Jupiter is a star, Saturn straddles the boundary between star and planet

              I would suggest that a brown dwarf straddles the line between star and planet (the Wikipedia page begins with (“Brown dwarfs are substellar objects”) and that therefore Jupiter is, at best, straddling the line between star and planet, and therefore Saturn is solidly a planet.

              • CheeseNoodle@lemmy.world
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                3 months ago

                I believe there is an object called a brown sub-dwarf which jupiter would clasify IF it wasn’t part of a planetary system that basically represents the smallest type of failed star, however since jupiter formed from a protoplanetary disc it is indeed a planet. It really is a bit of an issue with our classifications that they’re context dependant though. E.g the moon on its own could be a dward planet, earth orbiting at the same distance as pluto would also be a dwarf planet even with no other changes.

              • AnIndefiniteArticle@sh.itjust.works
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                3 months ago

                I like what you’re trying to do, but I disagree with merging brown dwarfs with planetary class objects because their interior structures and evolution are so different. Brown dwarfs are closer to stars than planets. The only difference between brown dwarfs and fusing stars is whether fusion occurs at the core. Planets are very very different in structure, morphology, and evolution.

                This is how I suggest we classify things:

                Let’s start by splitting things into two classes: planetary class and stellar class with Saturn at the boundary. This is a separation based on internal morphology and dynamics.

                Stellar class objects then get split into two further subclasses: fusing stars (suns) and non-fusing stars (brown dwarfs).

                Saturn exists at the boundary between the planetary class and the stellar class. Jupiter is solidly within the “brown dwarf” non-fusing stellar class of objects. The sun is a “fusing star”, which is also within the stellar class.

                • Zagorath@aussie.zone
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                  3 months ago

                  I mean, you can choose to define things however you want for your personal headcanon.

                  But for communication to work, people need to agree upon meanings. I’m guessing you don’t have a PhD in astrophysics, so your opinions are very unlikely to sway the consensus opinion on how these things are defined. And it’s their definitions that most lay people are going to take our cues from.

                  But even from the perspective of trying to come up with your own definitions…it’s rather poor practice to define things by presupposing your desired outcome. They didn’t define a planet vs dwarf planet by reference to Pluto, even though their desired goal was to exclude Pluto. They found actual criteria and used those. The definitions you’re giving, by stating “stellar class with Saturn at the boundary” does not work as a very good definition. Though again, you’re free to use that for yourself if you want…so long as you understand you will have severe difficulty communicating with others.

  • JohnDClay@sh.itjust.works
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    3 months ago

    I’ve heard a theory that there’s solid metallic hydrogen at the core from the absolutely immense pressure, but it hasn’t been confirmed.

    • Buddahriffic@lemmy.world
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      3 months ago

      Jupiter would have certainly had countless rocky, icy, and any other category of asteroid fall into it over the last several billions of years, so it’s not all hydrogen.

      And I’m not sure if solid is the right word. It’s denser than solids we’re used to, but it’s not necessarily making any bonds between nearby atoms, so they might flow to some degree.

      Though even if is solid at some point, it won’t necessarily be a sudden change from gas to solid or even gas to liquid to solid. The pressure is so high it might be more of a gradient than a surface like we’re used to here.

      • JohnDClay@sh.itjust.works
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        3 months ago

        Here’s what I was taking about. The idea is under the right temps and pressures you’d get a lattice of single hydrogen atoms instead of hydrogen atom pairs. It could potentially be meta stable after being produced, but that’s still to be determined.

        https://youtu.be/nMfPNUZzG_Q

    • Buddahriffic@lemmy.world
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      3 months ago

      First death is friction heat as you enter the atmosphere. Avoid it with a heat resistant vehicle or suit.

      Next death is from extreme vibrations from the turbulence caused by supersonic winds. Avoid it with an aerodynamic and strong vehicle body that can withstand and stabilize in incredibly high winds.

      Next death is lack of oxygen. But you probably have some oxygen system on that vehicle anyway just to get there.

      Next is the freezing temperatures, around -145 C. Ok add some heating to your craft.

      Next is the crushing pressure, passing 1000x earth’s atmospheric pressure and it just gets higher from there. Hope you didn’t use carbon fibre for your vehicle’s main structural integrity!

      Then, if you’re not crushed anyways despite whatever you used to mitigate the previous one failing, there’s extreme heat to deal with again, just more of it this time. No known substance can withstand the heat, especially considering the pressure is still just increasing.

      Further down is the metallic hydrogen layer. Assuming you haven’t already been converted to plasma, you probably will at this point.

      And further down is the core that includes “rock” but I use the term pretty loosely.

      Some of your atoms might eventually make it there but will likely spend a long time just blowing around in the atmosphere after they were vaporized.