AceyAceyAcey t1_j1kz006 wrote on December 25, 2022 at 5:24 AM

Neptune is the smallest Jovian planet in our Solar System, and Earth is the largest rocky planet. There’s a category of exoplanets called sub-Neptunes / super-Earths that are between them in size. If one of them orbited something like Jupiter or a brown dwarf, then maybe that could happen. But it might be more of a double-planet at that point, if the larger one doesn’t quite dominate it’s orbit.

As for whether they could form like that, I’m guessing no, Jupiter had to suck in a lot of its neighborhood to get so massive, and there wouldn’t be enough left for a sub-Neptune. But perhaps it caught one when migrating out. 🤷

7sv3n7 t1_j1l04vg wrote on December 25, 2022 at 5:38 AM

To piggy back on his question ive been curious about Jupiter being all gas. Doesn't it attract a lot of asteroids? And if it absorbed its neighbors it must have a rocky center right? (Obviously im missing something here just wanted to figure out what)

erunaheru t1_j1l4l9a wrote on December 25, 2022 at 6:34 AM

Even if there's a core of silicon, carbon, nickel, and iron, it's so squished that I don't think you could call it rocks, it's some crazy form of matter that's hard for human brains to comprehend (at least my brain).

LumberjackWeezy t1_j1l7lz5 wrote on December 25, 2022 at 7:15 AM

I heard metallic hydrogen was a possibility.

AceyAceyAcey t1_j1m5cv5 wrote on December 25, 2022 at 3:01 PM

The inner core of Jupiter is likely rock around the diameter of Earth. The outer core is liquid metallic hydrogen: not quite dense enough to be a complete plasma (electrons stripped from the atoms), but dense enough to act as a metal in the chemistry sense of the word (electrons can flow freely). This is why Jupiter has such a strong magnetic field, as magnetic fields require liquid metal that moves (Jupiter rotates in around 10 hours).

In fact, if you use an old TV with bunny ears to pick up the broadcasts, and you tune it to a station without anything so you see the snow, that snow is composed of / caused by three things: the Sun’s magnetic field, Jupiter’s magnetic field, and the Cosmic Microwave Background (CMB).

OtisTetraxReigns t1_j1q8ovb wrote on December 26, 2022 at 3:11 PM

That inner core would be liquid rock, no? Must be insanely hot in there.

AceyAceyAcey t1_j1qgsng wrote on December 26, 2022 at 4:15 PM

I mean, the Earth’s inner core is solid due to the high pressure. My understanding is that gas giants’ cores are also solid due to the even higher pressure.

-_Skadi_- t1_j1l5wjf wrote on December 25, 2022 at 6:51 AM

“According to most theories, Jupiter has a dense core of heavy elements that formed during the early solar system. The solid core of ice, rock, and metal grew from a nearby collection of debris, icy material, and other small objects such as the many comets and asteroids that were zipping around four billion years ago.”

Here:

AceyAceyAcey t1_j1m4ywz wrote on December 25, 2022 at 2:58 PM

The core of Jupiter is likely rocky. I’ve seen out there claims it could be a giant diamond, but that’s unlikely.