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I am going to argue for the notion that when planetary subsystems form, they may form multiple small proto planets, and then their would be an argument about who is going to be a planet and who was going to be a moon. Possibly with some merging.
This makes sense to me at least for Jupiter.
I am not a professional of any kind, and am in fact retired, so I have no career to damage. And I have time to spare before my next event tonight.
I will start with the usual suspects, interplanetary gasses and dust. I will speculate to add the possibility of pre-existing solid fragments, that would have come from objects ejected from other stars, and "aerobraked" into a solar disk. This will add random factors, and can help to explain in part why most solar systems do not resemble ours per sizes and locations of planets per size.
I will dwell on the solar disk for a bit, and ask, if it had a gravitational field, magnetic field, electric properties, and perhaps a tenuous atmosphere.
I will say yes it would have had a collective gravity field, that might have helped to defend a tenuous atmosphere from the fierce solar wind from the sun. I presume it would have had a magnetic field(s), but don't know the implications of that. I definitely don't know how electrical effects would have behaved, but I expect that there would have been such.
One thing I am curious about is the notion of a snow line that the asteroid belt was supposedly behind, but is now outside of.
I also wonder about the shading effects of the disk for planets forming within it. I should think that it would have shaded the Earth, (and possibly a moon), from the dim suns heat. So, I am not at all sure about the "Snow Line" story.
And I may have it wrong, but I visualize the proto-Earth and possibly a proto-Moon forming inside of a sub-disk spinning within and interacting at its edges with the disk around the sun.
That sub-disk might have had a tenuous atmosphere held in place slightly by the sub-disk gravity and the gravity of the forming objects within. The edge of the disk even if stripped of gasses at some point, the dust would help to slow the solar wind and protect the gasses that might remain for a time.
Here is are links you might look at if you care:
Earth formed faster than thought:
https://www.foxnews.com/science/earth-f … xperts-say
Water forms within the Earth:
https://www.newscientist.com/article/21 … he-mantle/
Water from interstellar materials:
https://newatlas.com/space/interstellar … rth-water/
Another factor is that to some degree the disk(s), were like a mix master. Materials baked by the sun with little in the way of volitile materials remaining, and materials which might be icy coming inwards. But important objects moving around would have been "Presolar Grains in Primitive Ungrouped Carbonaceous Chondrite".
Which you might read about here.
http://www.spaceref.com/news/viewsr.html?pid=52848
I also mentioned that there would likely be pre-formed chunks in the peanut butter, from objects ejected from other stellar systems. This should randomize the number of nucleation points in a sub-disk, if sub-disks did exist. Eddies in the solar disk. The would likely promote earlier accretion of objects in such a presumed eddy sub-disk. And as I said this could be a randomizing factor, so that in general no system of objects would form in the same way.
And I am going very far out there now. It is possible that for the Earth / Moon??? sub-disk there would have been two or more of these objects present. However, I think the process would continue without them, but take a bit longer.
Taking a look at Jupiter, I can speculate that five significant nucleation points developed at some point, perhaps not at similar times though.
Jupiter itself, Callisto, Ganymede, Europa, and Io. With or without a interstellar object as the start.
I do think that this is true, that the biggest accumulation of accretion would have shined the brightest both from condensation and radioactive decay. It may have cut off short or at least choked off further accumulation into other forming bodies.
Aluminum 26:
http://www.psrd.hawaii.edu/April04/aste … ing%20star.
Quote:
Almost all meteorites are chips of asteroids. Their mineralogical and chemical properties show that they have been heated to varying amounts, from a little (only 25 oC or so) to melting at more than 1100 oC. Isotopic dating shows that meteorites formed near the beginning of the solar system 4.55 billion years ago. What was the source of energy to heat them? The leading candidate is the decay of short-lived radioactive isotopes such as aluminum-26 (26Al). This isotope has a short half-life, only 700 thousand years. It decays rapidly, releasing heat as it does so. Studies of chondritic meteorites prove that 26Al was present when the solar system formed, so it is the logical source of heat to warm up and even melt asteroids.
Of the two asteroids visited by the Dawn spacecraft, one was dry, and one icy (It is thought).
Vesta dry, Ceres icy. One theory is that Vesta formed before Ceres, and so it had greater heating from Aluminum 26 decay. Vesta though I believe has hydrated minerals remaining, clays I think.
So, what about Jupiter and Earth and Aluminum 26?
I am going back to the idea that both of them shined like stars for a while.
So, if there was a sub-disk for the Earth / Moon??? then it might have had a snow line at one point. A place where sticky ices could glue things together. Same for Jupiter.
For Jupiter, it is tempting, so I will to speculate that Ceres formed first at a snow line, and then as Jupiter cooled, Ganymede, then Europa, then Io. Although tidal heating is named for why IO is almost dry, (And that makes sense), but I think I see a pattern where Callisto and Ganymede have the most ice (Not sure who wins), Europa has less, and Io has little or none. This might align with a pattern of formation where the first formed and the furthest away formed earlier, before the gasses were swept away, and also the dust. The sun and Jupiter also driving gasses and water vapor away from themselves over time. Jupiter becoming less bright over time, and the sun getting brighter.
In a nursery for proto-planets in a sub-disk presumed for the Earth / Moon???, similar would happen, with the biggest object likely shining the brightest. Also, if you did have a binary planet forming, the big one would try to occupy the barycenter pushing the the runt out to where the snow line might be. I anticipate a "Squeeze" snow line. I guess the Earth and the Sun would be pushing the gasses, and vapors (Same thing), into a mid point of the sub-disk. Here it might be possible to accrete a Moon by sticky icy processes, and at the same time the Earth using a hot compressive process to accumulate more matter from the sub-disk.
You might say, that the snow line was closer to the asteroid belt, but in a very changeable structure a sub-disk would shade its interior, while having two flat faces facing what we might call the North and South universe. Cold. My reference to North and South is for how we see the Earth now.
The assumption is that the sub-disk was collapsing and becoming denser, and so perhaps offering some shade, edge on to the sun. And I did mention that the solar disk was likely a mix-master, which could have fed more icy objects into this sub-disk for a while.
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Well, I feel more comfortable with the Jupiter model, but I also think it is possible that we had a condensed/glued proto-moon nearly from the start.
I reconcile this to the more popular model, by speculating that the Moon then later did accumulate more mass from direct impacts, and from ejecta from impacts of the Earth, the Moon being a natural collector of some of that. Indeed those could have heated the impactors and the surface materials of the Moon up, and dried out much of any volatile materials in these materials which would become much of the surface of the Moon.
And of course I will hide behind this for a while:
https://phys.org/news/2020-05-carbon-em … birth.html
Quote:
The findings by the researchers suggest that the moon has a large amount of ancient carbon beneath its surface, and it has likely been there since the moon was formed. How it could have persisted on a very hot early moon remains a mystery. The researchers also note that their approach could be applied to the study of other celestial bodies in the solar system and that they intend to use it to learn more about carbon emissions from Mercury and Phobos.
The Lunar Mare apparently is volcanic material from further down, and they say it has more Carbon.
Quote:
They also found that some parts of the moon have been emitting more carbon than others—the basaltic plains, for example, emit more carbon than the highlands.
So, pessimistically I wasted your time, and this is all wrong, but optimistically, it may be that we might find that if you drill baby drill, you can get some materials that we though were not available to us on the Moon.
Hydrogen? Well, the solar wind would likely cover up occasional emissions.
Oil??? Well that is a long shot. Umm..... Well the Moons surface is cold, so might prohibit seeps, and also impactors might cover up anything that did seep out. But I agree it is a very, very long shot for that.
But if the core of the Moon was accreted, it might be rather wet. I could argue that perhaps being colder inside, it has less ability to cook up stuff to push to the surface.
But yes, I will submit to the Theia theory as the more likely formation of the Moon, until any more evidence of a wet core is uncovered.
https://en.wikipedia.org/wiki/Giant-impact_hypothesis
I have noticed that most people subscribe to a polar method. Binary. People have to get red in the face spit shouting to settle an argument. Team games, chess, I think probably the Chinese game of "Go" (I only understand the name).
But I prefer to entertain multiple theories, and hope to get greater evidence over time to distribute greater probability rankings to them.
We need to go to the Moon.
We don't need to establish an Orthodox Religion over a scientific theory to establish social dominance.
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Last edited by Void (2020-07-25 18:47:41)
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Ceres is too icy to have formed in its presence location. It is probably a Kuiper belt object, that entered its present location around the time of the late heavy bombardment.
Theia, the body that struck the Earth in the early days of the solar system, is believed to have been an Earth coorbital. It formed at the Earth-Sun L5 or L4 point. Its orbit may have become unstable because it grew too large. Or maybe it was struck by a heavy object and forced out of the metastable position. We may never know. I think it is entirely plausible that Earth already possessed a naturally accepted moon, before the giant impact. The present moon could be a mixture of the original accreted moon and material blasted off of the Earth. That would explain how the moon managed to retain hydrogen and carbon in its mantle.
I think the solar system could have evolved differently. Maybe we could have ended up with another Mars sized planet at one of the Jupiter-Sun Legrange points. As it is, we have only the relatively small Trojan asteroids. Mars could have grown larger than it did, if Jupiter had been a little less massive.
Last edited by Calliban (2020-07-25 19:05:09)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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Oops! Yes, but Ceres would have had Aluminum 26, which might have boiled it, if it formed the same time as Vesta. So the rule still applies, unless indeed it was formed with extra ice, which is totally possible.
We need more evidence. I think the evidence for Carbon of the Moon is accumulating. I think that emissions of Hydrogen would be masked by the solar wind. Also Hydrogen being tiny probably would have passed out of the Mare lavas a long time ago. I do know that there are gas eruption from the Moon sometimes. That might give clues.
This is fun:
https://sservi.nasa.gov/articles/erupti … r-flashes/
Quote:
A volatile story
“If you tie all this together in one package, you can convince yourself there’s a story here,” says Paul Spudis of the Lunar and Planetary Institute in Houston, Texas. “At one time the Moon had volatiles; it might still have some remnant of those in the deep interior,” he says. It could be that gravitational forces from Earth and the Sun act to squeeze the gas out through cracks in the Moon’s crust. But nobody knows whether this process might be gradual or sudden. Exactly what makes up the gas — or if it even causes TLPs — is also unknown.
In a paper accepted for publication in the 20 May issue of the Astrophysical Journal, Crotts writes that the debate over whether TLPs are real “unfortunately has taken place in the unrefereed scientific literature”. He compares reports by different observers at different time periods to infer whether TLP reports were imaginary, or if they were copycat reports of a few real sightings.
Crotts rules out such biases, suggesting a natural origin for the flickers. In an accompanying paper published last year, he identified a correlation between TLPs and lunar out-gassing events. Still, Crotts acknowledges in his latest paper that the onus is on “those who would convince us that TLPs are real”.
So, if those cracks go far enough down, perhaps there could be an atmosphere with significant pressure at the bottom of them. Total speculation on my part though.
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Last edited by Void (2020-07-25 19:30:30)
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Aluminum 26, new notions about it in the early solar system.
https://phys.org/news/2020-07-radioacti … crets.html
Quote:
Studying radioactive aluminum in stellar systems unlocks formation secrets
An international team of astronomers including Stella Offner of the University of Texas at Austin has proposed a new method for the formation of aluminum-26 in star systems that are forming planets. Because its radioactive decay is thought to provide a heat source for the building blocks of planets, called planetesimals, it's important for astronomers to know where aluminum-26 comes from. Their research is published in the current issue of The Astrophysical Journal.
"Atoms like aluminum and its radioactive isotope aluminum-26 allow us to perform solar system 'archeology,'" Offner said. "It is exciting that the abundances of different atoms today can provide clues about the formation of our solar system billions of years ago."
Since its discovery in the Allende meteorite in 1976, astronomers have debated the origin of the considerable amount of aluminum-26 in our early solar system. Some have suggested that it was blown here by supernova explosions and winds from massive stars. However, these scenarios require a good deal of chance: Our sun and planets would have to form at exactly the right distance from massive stars, which are quite rare.
Offner's team has proposed an explanation that does not require an outside source. They propose that aluminum-26 formed close to the young sun in the inner part of its surrounding planet-forming disk. As material fell from the disk's inner edge onto the sun, it created shockwaves that produced high-energy protons known as cosmic rays.
Leaving the sun at nearly the speed of light, the cosmic rays slammed into the surrounding disk, colliding with the isotopes aluminum-27 and silicon-28, changing them into aluminum-26.
Due to its very short half-life of about 770,000 years, aluminum-26 must have been formed or mixed into the young sun's surrounding planet-forming disk shortly before the condensation of the first solid matter in our solar system. It plays an important part in the formation of planets like Earth, since it can provide enough heat through radioactive decay to produce planetary bodies with layered interiors (like Earth's solid core topped by a rocky mantle and above that, a thin crust). The radioactive decay of aluminum-26 also helps to dry out early planetesimals to produce water-poor, rocky planets.
This schematic of the proposed mechanism shows a cutaway view of a young star and the disk of gas surrounding it, in which planets may form. The gas parcel Offner's team modeled is depicted as a cluster of red dots. The 'inner disk' is the region from the star out to Earth's distance from the Sun (1 Astronomical Unit, or about 93 million miles). Some fraction of the enriched outflow gas may fall onto the disk where the cosmic ray irradiation is weak. Regions I and II denote different regions of cosmic ray transport. Credit: Brandt Gaches et al./Univ. of Cologne
Aluminum-26 appears to have a fairly constant ratio to the isotope of aluminum-27 in the oldest bodies of our solar system, the comets and asteroids. Since the discovery of aluminum-26 in meteorites (which are chips off of asteroids), a significant amount of effort has been directed towards finding a plausible explanation for both its introduction into our early solar system and the fixed ratio between aluminum-26 and aluminum-27.Offner's team focused their studies on a transition period during the sun's formation: when the gas surrounding the young star becomes depleted and the amount of gas falling onto the sun decreases significantly. Nearly all young stars undergo this transition during the last few tens to hundreds of thousands of years of formation.
As our sun was forming, infalling gas followed magnetic field lines to its surface. This produced a violent shockwave, the "accretion shock," that accelerated cosmic rays. These cosmic rays streamed outwards until they hit gas in the planet-forming disk and caused chemical reactions. The scientists calculated different models for this process.
"We found that low accretion rates are able to produce the amounts of aluminum-26, and the ratio of aluminum-26 to aluminum-27 that is present in the solar system," said the paper's lead author, Brandt Gaches of Germany's University of Cologne.
The proposed mechanism is generally valid for a wide range of low-mass stars, including sun-like stars. It is in these systems that astronomers have discovered the majority of exoplanets now known.
"Cosmic rays that were accelerated by accretion onto forming young stars may provide a general pathway for aluminum-26 enrichment in many planetary systems," Gaches concluded, "and it is one of the great questions if the proposed mechanism of acceleration through shockwaves will be observed in forming stars."
I don't have all that much to say about this, except that if this is true, we may be able to better understand why the objects that are in our solar system are as they are.
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Last edited by Void (2020-07-29 09:21:31)
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I guess I do have ideas.
It is apparent that science is beginning to slowly address the notion that radiations can be helpful to life.
It is already supposed that it may convey Oxidizers into to oceans of Europa.
Aluminum 26 might melt ice in small worlds, and also create chemicals useful to life during it's decay.
I did read an article that says that scientists are investigating Cosmic Rays for Mars. Can they promote life supporting chemicals.
A fungi that they are investigating for radiation protection, seems to actually use radiation to grow it's biology. They are interested in it for radiation shielding.
https://nerdist.com/article/chernobyl-f … ion-study/
https://www.firstpost.com/tech/science/ … 44381.html
Quote:
The mould that was found in the area has not only been staying alive, but is feeding off of the radiation to grow.
So, the above brings me to a few thoughts. Are we sure that there can be no photosynthesis with U.V. radiation? Or is it possible that plants that use visible light are just too dominant for another realm of method to emerge?
I am also thinking about Brown Dwarf stars. Often called "Failed Stars".
Do they have a significant solar wind after they cool off, or can they accrete gas and dust at a slow rate after cooling off?
It there a chance that they then can generate sufficient Aluminum 26 that will keep world in orbit around them alive? A curious matter. If somehow some of them can, then this is a new method to power a biosystem for long periods of time.
I don't know what kinds of solar winds Brown Dwarfs have. I presume that after they cool off they have none.
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Last edited by Void (2020-07-29 09:49:48)
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More about radiation and life.
Red Dwarf stars:
Proxima Centauri "b".
https://en.wikipedia.org/wiki/Proxima_C … bitability
Scientific reporting seems to be manic depressive. Too pessimistic, and then to optimistic.
So, far the pessimists say that for the most part the strong solar winds of most red dwarfs would strip the atmospheres off of their planets.
OK, I will run with that. One word, "Europa".
If tidally locked and stripped of atmosphere, shouldn't it be possible for the cold side of the planet to hold a ice covered sea? An what if it is a slow rotation planet, I believe they can call it a 3:2 resonance rotation. Our Moon and Mercury show how perhaps ice can be retained in shadowed areas even on such worlds.
The great fun part of this though is in my opinion you can then have ice covered oceans at the orbit of Mercury, and apparently out to the orbit of Jupiter and beyond, by various means.
In my little world, I will consider the continuing life evolution for such worlds over a long span of time. The luminosity might be a thing to watch. Ummm....I am going to pinch down my sample to the orbit of Venus to the outer limits of the Asteroid belt.
This could mean that if you eventually re-evolved an atmosphere for these planets, they could have atmospheric pressures of from .33 bar to 10 bar, to have a wet Earth like surface.
It is said that some of these planets would have magma oceans on the star facing side due to the magnetic flares inductive nature. For Trappist world (7) we might expect gravitational resonance to heat them.
So, presuming that a baby flare star does strip the atmosphere from its worlds, and you even so have a ice covered ocean similar to Europa. Then the radiation we so fear, may be a energizing thing for life in the ice covered oceans.
And over very long time periods we expect the Red Dwarfs to spin down, and be less active, less flares. Eventually do these planets evolve a new atmosphere? And a water supporting surface?
I am inclined to think it may be.
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Last edited by Void (2020-07-29 10:17:20)
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