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Jupiter was formerly twice its current size, had a much stronger magnetic field

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Re: Jupiter was formerly twice its current size, had a much stronger magnetic field

#31

Post by impendia »

fasteddie31003 wrote: post #20

I am deeply skeptical of any "research" that concludes something in the past. The scientific method relies on observation, experimentation, and replication, but these aren't possible with past events, so 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…

If we're to take your claims at face value, can we make any conclusions about the past at all?

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?

Re: Jupiter was formerly twice its current size, had a much stronger magnetic field

#33

Post by mystified5016 »

yubblegum wrote: post #19

I've always wondered about the core of these gas giants. I assume it is some liquid form of light elements. What is puzzling is the presence of the gas giants in the middle of solar system's planetary line up: why are they in the middle and the ones closer or further away from the central star are not like them? Is it the temperature gradient?

The core of Jupiter is thought to contain metallic hydrogen.

Re: Jupiter was formerly twice its current size, had a much stronger magnetic field

#34

Post by queuebert »

lazide wrote: post #4
rwmj wrote: post #2

Couldn't read the actual paper as it is paywalled, but does "twice its current radius" mean that it had a larger mass, and if so what happened to all that extra mass?

It was hotter, a lot hotter. 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…

> ... decreased by increased mass.

I don't think this is in general true for planets or stars. You're confounding multiple effects. For a fixed number of particles, increasing metallicity, which follows average particle mass, should reduce radius, but for a fixed metallicity and temperature, increasing particles will increase radius. Temp has the effects stated. You can roughly validate this by the fact that massive planets and stars are bigger than less massive ones. Obviously many other things start happening as stars reach end of life...

Re: Jupiter was formerly twice its current size, had a much stronger magnetic field

#35

Post by drob518 »

fasteddie31003 wrote: post #25
layer8 wrote: post #23

Earlier quoted context omitted.

Observations are inherently always about the past.

That’s true in a narrow sense—every observation records something that has already happened. But in science, observations can be tested, replicated, and used to predict future outcomes. The kind of "research" I'm skeptical of draws broad, causal conclusions about unique, unrepeatable past events where none of that is possible.

It’s always a theory, but what choice do you have? You can’t rerun the experiment again under controlled conditions. Your only choice is to theorize or not. Sure, there is more possible error in such theories compared to other theories where you can rerun the experiment multiple times to test it, but that doesn’t mean that a theory that can’t be tested is wrong.

Re: Jupiter was formerly twice its current size, had a much stronger magnetic field

#36

Post by pfdietz »

frutiger wrote: post #30
k__ wrote: post #29

Earlier quoted context omitted.

I'd assume these elements would be created in the sun and keep close to the sun, because of their higher mass.

All the heavier elements were created in a former star that went supernova. The solar system formed from the gas/dust after that. The heavier elements being formed in our sun now are going to stay there until something can tear it apart.

Some will be ejected back into space when the aged Sun becomes a planetary nebula (with a white dwarf at the center).

Re: Jupiter was formerly twice its current size, had a much stronger magnetic field

#37

Post by anton-c »

jessriedel wrote: post #17
greggsy wrote: post #15

Earlier quoted context omitted.

Could it cool and crystallise? Could those crystals then erode and reform again as sedimentary rocks to be come a solid planets like earyh? I understand that’s not how earth itself came to be, but it’s an interesting metamorphosis that I hadn’t previously considered.

Like the interior of the planet, the atmosphere is overwhelmingly hydrogen and helium. And helium is liquid even at 0 temperature unless under pressure, so presumably (?) would be liquid on the surface. These materials are mechanically very different than the silcates and metals dominating the Earth’s crust, and I don’t think we even have well measured bulk properties? Not sure what erosion processes would look like.

That's wild to think about. My mind is struggling to picture 'liquids on the surface' of Jupiter. No idea what that would look like.

Re: Jupiter was formerly twice its current size, had a much stronger magnetic field

#38

Post by twic »

yubblegum wrote: post #19

I've always wondered about the core of these gas giants. I assume it is some liquid form of light elements. What is puzzling is the presence of the gas giants in the middle of solar system's planetary line up: why are they in the middle and the ones closer or further away from the central star are not like them? Is it the temperature gradient?

It's made from something which can generate magnetic fields, since Jupiter has a very strong magnetic field with a lot of distinct inhomogeneous features, resulting in some interesting radio emissions:

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.

Re: Jupiter was formerly twice its current size, had a much stronger magnetic field

#39

Post by iwontberude »

fasteddie31003 wrote: post #20

I am deeply skeptical of any "research" that concludes something in the past. The scientific method relies on observation, experimentation, and replication, but these aren't possible with past events, so 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…

This is how young earth type misunderstandings begin. Thanks for bringing us inside the mind.

Re: Jupiter was formerly twice its current size, had a much stronger magnetic field

#40

Post by iwontberude »

layer8 wrote: post #23
fasteddie31003 wrote: post #20

I am deeply skeptical of any "research" that concludes something in the past. The scientific method relies on observation, experimentation, and replication, but these aren't possible with past events, so 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…

Observations are inherently always about the past.

PC is from the future
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