[1] https://arxiv.org/abs/2505.12652

Like stars, radius for a gas giant is increased by heat, and decreased by increased mass.

These two factors are rarely completely independent, of course, so it gets complicated. Especially in a star where masses are large enough to result in densities sufficient to cause fusion - and large releases of heat, which then cause decreased density, etc.

But all other factors being constant, the volume of a gas increases (and density decreases) as temperature increases.

See page 6 and the first couple paragraphs of page 7 in the paper for a breakdown.

Eventually Jupiter will cool enough it will be a small fraction of it’s current size, assuming that our understanding is correct and it doesn’t have enough mass to meaningfully result in fusion regardless of how dense it gets. [https://www.pas.rochester.edu/~blackman/ast104/jinterior.htm...]

In theory, it will even eventually cool to the point all those clouds and atmosphere are liquid (or even solid!) gas oceans. That is going to take awhile.

Wikipedia is a good place to start getting a feel for the possible history of the Solar System:

https://en.wikipedia.org/wiki/Jupiter#Formation_and_migratio...

https://en.wikipedia.org/wiki/Grand_tack_hypothesis

https://en.wikipedia.org/wiki/Nice_model

Why would you assume that? The heavier elements such as iron are likelier to move to the center of gravity.

https://www.ebsco.com/research-starters/science/jupiters-mag...

https://radiojove.gsfc.nasa.gov/library/sci_briefs/decametri...

The rotation of these features is the basis for the "system III" definition of longitude on Jupiter.

https://en.wikipedia.org/wiki/Jupiter#Internal_structure

> This has resulted in the theory that Jupiter does not have a solid core as previously thought, but a "fuzzy" core made of pieces of rock and metallic hydrogen.

https://en.wikipedia.org/wiki/Juno_(spacecraft)#Scientific_r...

This is all a very traditional view afaik and doesn’t explain where mantle light elements come from. For example there is a great deal of water that is in the mantle that drives geochemical changes in the mantle rocks. Was that there originally? Or was it put their after plate tectonics started and subduction sucked water into the mantle? I don’t know but I would assume there are plenty of geodynamics people who would have opinions more deeper than mine on the topic.

The four inner planets are all terrestrial. The four outer planets are gas (the last fwl sometimes distinguished instead as “ice”) giants.

There are dwarf planets (a separate category from, rather than sibcategory of, planets) closer and farther, but no known rocky planets beyond the gas/ice giants.

For example, suppose that I were to claim that the universe is exactly one hundred years old. George Washington, Genghis Khan, Julius Caesar, dinosaurs, etc. are all figments of our collective imagination.

If you deny the validity of research that makes conclusions about the past, on the grounds that such claims can't be tested or falsified -- then have you left yourself any means of making a counterargument?

Perhaps you mean, you don't understand or you wonder how it reconciles with the scientific method? It's an interesting question about theory.

To be 'deeply skeptical' is not meaningful, imho. All these people - including Newton, Darwin, Einstein, and so many more, including the entire scientific community - believe it. All these experiments replicate it. You are deeply skeptical about all of that and of all of them? What does it mean, even to you?

> we can't directly test or falsify historical claims. Instead, researchers infer conclusions based on indirect evidence like documents, artifacts, or statistical patterns—often without being able to isolate variables or rule out alternatives.

We can directly test the claims through many methods, for example that the stone tool was made 2.58 million years old, but we can't see 2.58 million years ago (except something that is 2.58 million light years away, of course). We can indirectly test claims, e.g., that tool use existed 2.58 million years ago, through many different methods.

You're right that it's not the same. What else can we do? Just quit and live in ignorance?

> If something is not falsifiable, it is not science in my book. Research that is falsifiable uncovers deep truths of nature that will benefit humanity's progress, which this kind of research will not.

You can call it what you want, but that doesn't change its value. Is this just a question of terminology?

By this proposed theory, we can't know anything that happened before now. We can't know what happened in ancient China - did the Han dynasty even exist? We can't know who won the Olympic marathon in 1928 without witnesses to tell us. We can't know what happened yesterday - human memory is certainly fallible, and otherwise you have only indirect evidence. That applies to every scientific paper, providing indirect evidence to us of what has happened, and mostly based on human memory. Did I write what you are reading? Where is your falsifiable direct observation?

We also can't know much of what is happening now. Most science data is based on indirect observation by devices and machines. Human sensory ability is limited and unreliable in many ways. What color is the light in the experiment? We measure that with a machine that gives us indirect information.

I think a key challenge to your theory is, how do we know anything at all?

> Importantly, these insights were achieved through independent constraints that bypass traditional uncertainties in planetary formation models—which often rely on assumptions about gas opacity, accretion rate, or the mass of the heavy element core

> The results add crucial details to existing planet formation theories, which suggest that Jupiter and other giant planets around other stars formed via core accretion, a process by which a rocky and icy core rapidly gathers gas. These foundational models were developed over decades by many researchers, including Caltech's Dave Stevenson, the Marvin L. Goldberger Professor of Planetary Science, Emeritus. This new study builds upon that foundation by providing more exact measurements of Jupiter's size, spin rate, and magnetic conditions at an early, pivotal time

https://www.caltech.edu/about/news/jupiter-was-formerly-twic...