Possibly. The atmosphere gets thicker and thicker as you get closer to the center, then eventually becomes liquid once the pressure is high enough. If the pressure at the center is great enough, it can have a solid core, but that doesn’t necessarily mean it’s ‘rocky’. Like if a gas giant was made entirely of helium, the core might just be solid helium if the pressure is high enough
Rocky core usually means heavy metals. Jupiter can have high enough pressure for its light elements like hydrogen and methane to form solids but that’s not really what is meant by Rocky core.
Earth has iron nickel etc. in its core.
They could have started out as big rocky planets early in the formation of the solar/star system, and with such gravity they’d attract the available hydrogen that is not yet drawn all the way to the main star, thus gain more mass and pull even more of the remaining materials (gas and solid alike) until all are either concentrated into (relatively) stable bodies in some equilibrium or flung out of the core system into the Kuiper belt and Oort cloud.
Other than that, as others said, the pressure in gas giants’ core could be enough to turn hydrogen into solid state, so technically they would have a solid core anyway (unless they are massive enough that the compressed hydrogen start doing fusion, in which case said core would be more plasma than solid, I guess).
Jupiter and Saturn, at least, don’t have distinct, compact, solid rock/metal cores, as was once thought. They instead have very fuzzy/dilute cores extending to over half their radii. These dilute cores consist of a soup of heavier elements (than hydrogen and helium) mixed with, even dissolved in, the liquid metallic hydrogen that makes up much of the interiors of the gas giants. The concentration of heavier elements gradually decreases from the center outward, without a well-defined boundary.
It will have the most dense stuff at the center. Asteroids and whatnot will have hit the planet and ‘rocky’ stuff will make it’s way down until they hit stuff that’s more dense than they are.
However, as a percentage of the planet, it may not be all that significant so it may not be correct to think of it as having a rocky core. They undoubtedly have ‘rocks’ inside them though if that helps.
Not your question, but Earth doesn’t have a rocky core in the way you’re probably thinking. The inner and outer core are both nickel-iron, a very dense set of metals. The rocks in the mantle are significantly lighter and float on top of them. But while the outer core is liquid nickel-iron under high temperature and pressure, the even higher pressure in the inner core leads to a solid metal inner core despite also being higher temperature. It’s really quite remarkable.
We know this from seismic data. Any time there’s an earthquake we can get readings from all over the world showing us waves and reflected waves and giving us some indication of the density (underground nuclear explosions, whose origin is very precise, are even more useful). But there’s no way we can get anywhere this level of data fro any other world! It’s all really very uncertain and quite a bit of it comes from modelling and theory (built on the data we see on earth) rather than actual data.
The interior of Jupiter and Saturn are in excess of 10,000 degrees Celsius, Tungsten boils at 5,500 C, so there shouldn’t be any solid or liquid down there. However, the pressure at the center of Jupiter is 4,000 Giga Pascal. Familiar definitions of solid, liquid, and gas just don’t apply to what’s going on down there.
Smaller, colder gas giants like Neptune and Uranus do have rocky cores. The temperature at their core is intense too, but like our own core the pressure evens out with the heat, allowing solid iron, nickle, and silicates.
Totally, most gas giants actually do have a rocky or metallic core. So even though they look like giant clouds of gas from the outside, deep down, like way deep, there’s usually a solid-ish center. Jupiter and Saturn, for example, are believed to have these dense cores. Scientists think the cores might be a mix of rock, metal, and ice, stuff that stuck together when the planets were forming.
Mostly depends on how technical an answer you want.
Do gas giants have a core consisting of solids? Not really. But neither does earth precisely. With the temperature and pressure it ends up with crystalline structure but not solid per se. Give a quick read up about earth’s molten core. But it’s crazy hot. And there’s crazy high pressure. High enough to make hydrogen metallic. Plausibly helium too.
Do they have a collection of heavier elements at their cores ? Undoubtedly yes. Earth has ~45 tonnes of meteoric material that falls through its atmosphere every day. One can imagine a gas giant being more massive would collect more, though distance from a sun and a lot of other factors. To oversimplify the heavier the element the more strongly it’s drawn to the core. And since nothing is really solid it differentiates.
So yeah. The cores of the giants would probably mostly (depending on the layer) be solid at typical earth surface temperature and pressure
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Possibly. The atmosphere gets thicker and thicker as you get closer to the center, then eventually becomes liquid once the pressure is high enough. If the pressure at the center is great enough, it can have a solid core, but that doesn’t necessarily mean it’s ‘rocky’. Like if a gas giant was made entirely of helium, the core might just be solid helium if the pressure is high enough
Rocky core usually means heavy metals. Jupiter can have high enough pressure for its light elements like hydrogen and methane to form solids but that’s not really what is meant by Rocky core.
Earth has iron nickel etc. in its core.
They could have started out as big rocky planets early in the formation of the solar/star system, and with such gravity they’d attract the available hydrogen that is not yet drawn all the way to the main star, thus gain more mass and pull even more of the remaining materials (gas and solid alike) until all are either concentrated into (relatively) stable bodies in some equilibrium or flung out of the core system into the Kuiper belt and Oort cloud.
Other than that, as others said, the pressure in gas giants’ core could be enough to turn hydrogen into solid state, so technically they would have a solid core anyway (unless they are massive enough that the compressed hydrogen start doing fusion, in which case said core would be more plasma than solid, I guess).
Jupiter and Saturn, at least, don’t have distinct, compact, solid rock/metal cores, as was once thought. They instead have very fuzzy/dilute cores extending to over half their radii. These dilute cores consist of a soup of heavier elements (than hydrogen and helium) mixed with, even dissolved in, the liquid metallic hydrogen that makes up much of the interiors of the gas giants. The concentration of heavier elements gradually decreases from the center outward, without a well-defined boundary.
It will have the most dense stuff at the center. Asteroids and whatnot will have hit the planet and ‘rocky’ stuff will make it’s way down until they hit stuff that’s more dense than they are.
However, as a percentage of the planet, it may not be all that significant so it may not be correct to think of it as having a rocky core. They undoubtedly have ‘rocks’ inside them though if that helps.
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Not your question, but Earth doesn’t have a rocky core in the way you’re probably thinking. The inner and outer core are both nickel-iron, a very dense set of metals. The rocks in the mantle are significantly lighter and float on top of them. But while the outer core is liquid nickel-iron under high temperature and pressure, the even higher pressure in the inner core leads to a solid metal inner core despite also being higher temperature. It’s really quite remarkable.
We know this from seismic data. Any time there’s an earthquake we can get readings from all over the world showing us waves and reflected waves and giving us some indication of the density (underground nuclear explosions, whose origin is very precise, are even more useful). But there’s no way we can get anywhere this level of data fro any other world! It’s all really very uncertain and quite a bit of it comes from modelling and theory (built on the data we see on earth) rather than actual data.
The interior of Jupiter and Saturn are in excess of 10,000 degrees Celsius, Tungsten boils at 5,500 C, so there shouldn’t be any solid or liquid down there. However, the pressure at the center of Jupiter is 4,000 Giga Pascal. Familiar definitions of solid, liquid, and gas just don’t apply to what’s going on down there.
Smaller, colder gas giants like Neptune and Uranus do have rocky cores. The temperature at their core is intense too, but like our own core the pressure evens out with the heat, allowing solid iron, nickle, and silicates.
Totally, most gas giants actually do have a rocky or metallic core. So even though they look like giant clouds of gas from the outside, deep down, like way deep, there’s usually a solid-ish center. Jupiter and Saturn, for example, are believed to have these dense cores. Scientists think the cores might be a mix of rock, metal, and ice, stuff that stuck together when the planets were forming.
Mostly depends on how technical an answer you want.
Do gas giants have a core consisting of solids? Not really. But neither does earth precisely. With the temperature and pressure it ends up with crystalline structure but not solid per se. Give a quick read up about earth’s molten core. But it’s crazy hot. And there’s crazy high pressure. High enough to make hydrogen metallic. Plausibly helium too.
Do they have a collection of heavier elements at their cores ? Undoubtedly yes. Earth has ~45 tonnes of meteoric material that falls through its atmosphere every day. One can imagine a gas giant being more massive would collect more, though distance from a sun and a lot of other factors. To oversimplify the heavier the element the more strongly it’s drawn to the core. And since nothing is really solid it differentiates.
So yeah. The cores of the giants would probably mostly (depending on the layer) be solid at typical earth surface temperature and pressure