This has always baffled me. I can’t really understand how they could just not have a surface no matter how far down you go. Obviously gravity has to pull the gasses together into some more dense form eventually… right?
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It’s still solid in the core. There just is no surface because there’s no point you can point to and say “yeah that’s where it gets solid”. It gradually gets denser and denser as you get closer to the core. Asteroid and whatnot burn and slow down till they stop as it gets too thick for them to move.
>Obviously gravity has to pull the gasses together into some more dense form eventually
Yes, but there isn’t necessarily a sharp phase transition. At high pressures and temperatures, there is a supercritical region, where the boundary between gas and liquid disappears. So there may be a boundary between liquid and solid, but it’s deep inside the planet.
At the core there will be heavier elements that sank through the lighter elements.
Think of it like a diver hitting the surface of a pool the gas atmosphere is like the water the asteroid sinks to the bottom and there is likely to be a relatively small rocky core at the bottom which eventually the asteroid will reach.
Imagine a swimming pool with a cloud of steam over it. Imagine that steam is pretty faint up top, just a haze, but gets more and more dense as you go down. Eventually the steam is so dense you can float in it, is that the surface of the water? Maybe, but there’s not really anyway to tell when you go from dense gas to liquid. Go even deeper and you reach water so dense you can’t move through it any more. Is that now solid ice? Again, maybe, but you can’t tell.
That could be called the “surface” since it’s basically solid, but the change from faint haze to solid ice is so gradual that there aren’t really any obvious boundaries between the layers. There’s no defined surface, the gas just gets denser as you go deeper.
🤷 we don’t know the answer to the last question for certain but we have pretty good guesses based off of different spectrums of EM waves and whatnot. Apart from that, asteroids burn up long before they hit the center
There is solid, a rocky core, to all of the gas giants, as far as we can tell. You are just sort of thinking about this in the wrong way: a gas giant is gassy (like earth atmosphere) on top of an ocean (the gas turns into liquid from cold and pressure), on top of rock.
A gas giant is really pretty much like earth in a away, if earth were totally covered by a thick ocean. They have an atmosphere, a thick “hydro”sphere (liquid cover), and a rocky center. Metal core perhaps as well. Generally speaking, because it is cold, the atmosphere tends to be cloudy, so all we see is mr comet or whatever smashing into the clouds. We can’t see it hit the ocean of methane (or whatever liquid it is), but we can see how the impact down below really mucks up the atmosphere above.
Maybe they have islands sticking up above the oceans but probably not. The oceans of methane or ammonia or whatever are generally too thick. Too much of the gas-forming stuff compared to rocky planets like earth that don’t have much gas-forming stuff. However, just because they have more gas, it does not mean that there is no rock. Just gas and liquid are a bigger proportion of the total.
As the pressure grows stronger the closer you get to the center the components of the gas giant turn to a solid state. It also happens with the ice giants, the water turns to a form of ice that only happens when there is so much water that the pressure of it’s weight doesn’t allow the water molecules to move
Gas giants are mostly made up of gas and have no solid surface. Instead of a solid surface, they have a thick atmosphere made up of hydrogen and helium, which gets denser as you go deeper into the planet.
Asteroids and comets that get pulled into the gravity of a gas giant will eventually fall into the atmosphere and be absorbed by the planet. The pressure and temperature inside the planet’s atmosphere increases as you go deeper, and at some point, the materials in the asteroids and comets will become so hot and dense that they will be compressed into a solid or liquid form.
The cores of gas giants are thought to be made up of rock and metal, similar to the cores of terrestrial planets like Earth. However, the cores of gas giants are much larger and more massive than the cores of terrestrial planets, and they are surrounded by layers of gas and other materials. The exact composition of the cores of gas giants is not well understood, and researchers are still studying these planets to learn more about their structure and evolution.
PBS Space time just did a video about supercritical fluid and touched on the gas giants a bit. It helped me to understand what is going on under the clouds of those planets.
[https://youtu.be/eyn7MusdQ9g?t=831](https://youtu.be/eyn7MusdQ9g?t=831)
I wondered this once, and found [this video](https://youtu.be/bjMqJ–aUJ8) which was pretty interesting.
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