Depends whether we’re talking about human time or geological (saturniological?) time. Over astronomical eons, the hydrogen would definitely boil off. Presumably solar heating would also melt the hydrogen metal and also boil much of it off.
And since we’re talking elliptical orbits, would Saturn have the same elliptical orbit, same semimajor axis and perihelion?
So many interesting possibilities, few of which I really understand… but this one I’m especially wondering about:
Um. I thought the theory went that life began in water? Which means there was water there first. So, maybe we don’t have to cook some of Saturn’s hydrogen into water like I first thought? If Earth already had ample water on hand, shouldn’t Saturn also have it? They condensed from the same cloud of stuff, didn’t they?
Perhaps the water/ice is already there, buried between or mingled with the other ices in its layers? The wikipedia article did cite silicon and oxygen in the layer above the rocky core, maybe it’s already in the form of water?
Or did Earth get the water later on somehow? Who was it, Velikovsky maybe, who had one of the outer planets ping ponging around the solar system and somehow dumping water on Earth. Or comet bombardments or something? I mean, the water is clearly here.
You don’t cook hydrogen into water. It reacts with oxygen to make water. No oxygen, no extra water.
The question becomes - where might the oxygen come from to combine with hydrogen to make water? What tiny proportion of oxygen that exists within Saturn is most probably already bound with hydrogen as water. The tremendous, huge, extra hydrogen is not going to find any unbound oxygen to bind with. The only places that have free oxygen in any useful quantity got it there by pushing back against the natural tendency of oxygen to react with just about anything it meets (like hydrogen). That push back needs sophisticated chemical mechanisms that are externally powered. For instance photosynthesis. Which is where life comes in. No life, not much chance of seeing any free oxygen.
Which leaves us where we came in. The gas giants contain humongous amounts of hydrogen. There just isn’t any freely available oxygen around to get more water. Saturn almost certainly has water in it. From much the same sources as the Earth. But it won’t be getting any more, no matter how much hydrogen it has.
Yes, Saturn has quite a bit of water. It’s just a very small proportion, compared to the elemental hydrogen.
So the obvious question is - how much water? that’s where all of the oxygen is. Would a giant water world with a iron core emerge over eons as the hydrogen blows away with the solar wind? Are there enough silicates to also be significant? Would methane over time merge into other longer-chain hydrocarbons?
Traveling inward toward the center of the planet, the increased pressure causes the liquefied gas to become metallic hydrogen. Saturn does not have as much metallic hydrogen as the largest planet, Jupiter, but it does contain more ices.
Like Jupiter, Saturn is suspected to have a rocky core surrounded by hydrogen and helium. However, the question of how solid the core might be is still up for debate. Though composed of rocky material, the core itself may be liquid.
… things are hotter within the rocky core. There, temperatures can reach as high as 21,000 degrees Fahrenheit (11,700 degrees Celsius).
During the formation of Saturn the core would have been created first. Research suggests that Saturn’s rocky core is between 9 to 22 times the mass of Earth.
Even after eventually boiling off the lighter elements, it would still be a decent sized planet outclassing Earth.
Something not discussed is what happens to the stability of the system as Saturn slowly goes from 95 earth masses to about 20 or less. I presume if the process is slow enough, it would not disrupt Earth being in the Trojan point.
Thanks to this thread I decided to dust off and reinstall my old copy of universal sandbox on steam, to run the simulation. I didn’t take the effort to set Saturn to match earth’s exact eccentricity but just set it to be circular with a 1 year period.
FIrst I think the extra gravity of Saturn pulling the earth more towards the sun caused it to be pulled into a lower orbit, after about 20 years the year was only 351 days long, and earth started catching up with Saturn. I sport an evil grin as calamity seems to be in the offing. But then as it got close, it got accelerated into a higher orbit with a period of a bit over 1 year and so started lagging further and further behind, until Eventually Saturn caught up behind it and started pulling it backward. This slowed it down and brought it into a lower orbit with a shorter period once again causing it to move ahead to start catching up to Saturn, at which point it started falling behind, and the cycle continued, with a period of about 85 years.
While I’m somewhat disappointed by the lack of global catastrophe, the dynamics of the situation is really cool so I can’t wait to get onto the dope and show the world my amazing discovery.
Of course the first thing I see when i get back to the thread is Chronos lounging, or so I imagine, in his corduroy jacket with the elbow patches, smoking a pipe and waxing professorially. “Of course, it will follow a horseshoe orbit. Astronomy 101 my good chap, we’ve know this for centuries. Now off with you I have to get back to refining our understanding of dark matter to account for the existence of cottage cheese.” Hard learned rule of the dope, whatever amazing scientific fact you’ve discovered, Chronos already knows it.
Did you have Jupiter in the sim?
Yes, why do you ask?
I admit that I didn’t pay much attention to it, but I think it just hangs out in its original orbit not really noticing the missing Saturn.
I don’t know if Saturn ever would lose that much mass, and even less so before the sun goes red giant and dies.
But your example (and I’m not sure if you knew this and so meant it), is pretty close to the limits of the L4 and L5 points. The smaller mass needs to be less than about 4% the mass of the larger mass (I thought heard 1/27th somewhere, but I’m not finding that reference, but that’s the same general ballpark.)
If that limit is exceeded, and the Earth is now 5% the mass of Saturn then the orbits become unstable. The Earth is now pulling on Saturn enough that it becomes a three body problem, and those are (almost) always inherently unstable.
I was just curious as to whether there was any evidence of Jupiter’s influence. Eventually it is pretty much a sure bet that Jupiter will cause enough of a compounding effect that the system will lose stability. But eventually is a rather long time.
There has been some suggestion that the gas giants formed closer in, and their chaotic interaction moved them out to their current positions over the eons. I would guess, given enough time, the same thing might occur again.
Hey, don’t be too hard on yourself. I anticipated the horseshoe orbit, but I had no idea what the relative period would be. Plus, it’s always nice to get experimental, or at least pseudo-experimental, confirmation of theory.
And I really need to get myself a jacket with elbow patches. Always wanted one of those.
Oh, you meant put Jupiter into earths Orbit instead of Saturn. Running that simulation so far it seems to give the same result but the cycle is much less, somewhere around 35 years.
Actually, no, but that is an interesting result as well.
I was just wondering about very long term evolution of the system with Jupiter in its existing orbit. In principle it should matter.
Could put both of them in Earth’s orbit. That should be fun. Or maybe one in Venus’ orbit, the other in Earth’s.
Just a quick bump and update. I went off to the kitchen to get something to eat, and something must have happened in the mean time (T=400 years). When I came back Jupiter and the earth seem to be orbiting in opposite directions with the earth eccentric orbit taking it in to an orbit to intersect Venus and out beyond mars. So presumably at some point the Earth got a bit too close. So I think for the sake of the environment Chronos will have to be satisfied with “pseudo-experimental” data and I’ll put my plans to actually move Jupiter and get the real experimental data that he wanted on hold.
That’s probably for the best. I don’t think that you could get mover’s insurance for such a trip anyway.
If you would take a close look at Saturn’s own retinue, you have almost exactly that configuration with Janus & Epimethus. It is not a “horseshoe orbit”, it is a co-orbital path.
Technically, a horseshoe orbit and co-orbital orbits are the same thing. In a co-orbit, the two bodies change their orbits when they get close to each other, with the more massive body changing by a lesser amount. When the difference in masses of the two bodies are great, the orbit of the larger body only changes by a very small amount. So that’s ignored and we just focus on the smaller body and call that orbit a horseshoe. But really, the same thing is happening in both situations.
And a “horseshoe orbit” is only “horseshoe-shaped” in the peculiar frame of reference where the larger planet is at rest. Which of course also leads to all sorts of crazy shapes for the orbits of everything else, too, but they’re crazy in a way that’s less interesting and more just crazy.
The important question is, given that Saturn and Earth each have a satellite retinue, and the co-orbital arrangement is inevitable, what is the fate of those bodies? I mean, if you bring the hundred-odd things orbiting Saturn down here, most of them would rapidly sublimate in the heat; if you just grab Saturn, all those things wander the cold solar system until they end up somewhere (timing Saturn’s move would probably make a difference whither).
But then, there is also old Luna. You have these two co-orbital planets bouncing off each other, what effect does that have on the Moon’s orbit? Would it move into a period resonance with the planets’ transit cycles? Or might it settle into the actual transit resonance such that it would be handed off from one planet to the other on each pass?
My guess is that most likely, Luna would fall victim to chaos. It might stay with Earth for a while, or maybe go through one or two peaceful hand-offs, but sooner or later (probably sooner), it’d end up flung into some crazy high-eccentricity solar orbit, and thence eventually yeeted entirely out of the system.