Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: jeffreyH on 20/12/2017 23:14:49
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Was the sun formed exclusively from hydrogen and helium, just hydrogen or some heavier elements?
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The gaseous cloud from which the Sun and planets formed contained a small proportion of heavier elements from supernova events
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Some of the elements in the sun are detectable from its spectrum ...
https://en.wikipedia.org/wiki/Fraunhofer_lines#Naming
They include elements which are too heavy to have been made in our Sun.
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That leads to a different question. The very first stars in the universe could not have contained heavier elements and must have burnt fast and exploded in supernova. Was there enough time for enough of these to seed the whole universe with heavier elements?
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It is thought that the Big Bang would have produced a mix of elements something like:
(https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis#Characteristics[/url) mass abundances of about 75% of hydrogen-1, about 25% helium-4, about 0.01% of deuterium and helium-3, trace amounts (on the order of 10−10) of lithium, and negligible heavier elements.
Hydrogen and Helium do not radiate energy well, which would have resisted gravitational collapse into stars.
It is thought that the first stars (a hypothesized group dubbed "Population III") would have been very massive, as only a very intense gravitational self-attraction could overcome the internal pressure of hot hydrogen & helium. Such stars would have burnt all their fuel very rapidly and exploded as a supernova, seeding the cosmos with heavier elements.
Later stars (Population II) and today's Population I stars tend to be much smaller, with much higher proportions of heavier elements.
See: https://en.wikipedia.org/wiki/Stellar_population#Population_III_stars
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Some of the elements in the sun are detectable from it's spectrum ...
https://en.wikipedia.org/wiki/Fraunhofer_lines#Naming
They include elements which are too heavy to have been made in our Sun.
The thing I don't understand is how can humans make heavier elements than the sun, using only mild earth conditions, yet also assume the sun, with far more extreme conditions can't do squat? Is it because humans can use fission and fusion, while we only allow the sun to use fusion, so we can cheat and play god?
In modern times, the most important star making material is water; H2O. Water is composed of Hydrogen, which is the most abundant atom of the universe and oxygen which is number three. Water contains hydrogen in a form that is easier for gravity to influence; hydrogen bonding. Water is also the second most abundant molecule in the universe and exists primarily as ice crystals.
Water is also useful to star formation because water expands when it freezes and contracts when it melts. In terms of star formation, a cloud of ice being compressed by gravity will eventually heat until the melting point is reached. The 10% loss of volume, as the ice melts and becomes liquid, can cause an affect I like to call fusion hammer. It creates a secondary collapse which helps induce fusion via D2O. No other material, abundant enough to form stars, does the fusion hammer dance.
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It is thought that the Big Bang would have produced a mix of elements something like:
(https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis#Characteristics[/url) mass abundances of about 75% of hydrogen-1, about 25% helium-4, about 0.01% of deuterium and helium-3, trace amounts (on the order of 10−10) of lithium, and negligible heavier elements.
Hydrogen and Helium do not radiate energy well, which would have resisted gravitational collapse into stars.
It is thought that the first stars (a hypothesized group dubbed "Population III") would have been very massive, as only a very intense gravitational self-attraction could overcome the internal pressure of hot hydrogen & helium. Such stars would have burnt all their fuel very rapidly and exploded as a supernova, seeding the cosmos with heavier elements.
Later stars (Population II) and today's Population I stars tend to be much smaller, with much higher proportions of heavier elements.
See: https://en.wikipedia.org/wiki/Stellar_population#Population_III_stars
So hydrogen and helium alone are very bad for star formation. I am going to be thinking more about this.
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The thing I don't understand is how can humans make heavier elements than the sun, using only mild earth conditions, yet also assume the sun, with far more extreme conditions can't do squat? Is it because humans can use fission and fusion, while we only allow the sun to use fusion, so we can cheat and play god?
I think the main difference is that we have a much richer palette to begin with--the sun is >70% hydrogen, and only has impurities of other elements, while the earth has rich deposits of carbon, nitrogen, oxygen, sulfur, silicon, phosphorus and many metals like magnesium, aluminum, iron, titanium, as well as traces of elements that were formed by stars much more massive and violent than the sun (like platinum, rhodium, uranium etc.) which we have been able to use to do pretty much anything "impressive".
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It is thought that the Big Bang would have produced a mix of elements something like:
(https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis#Characteristics[/url) mass abundances of about 75% of hydrogen-1, about 25% helium-4, about 0.01% of deuterium and helium-3, trace amounts (on the order of 10−10) of lithium, and negligible heavier elements.
Hydrogen and Helium do not radiate energy well, which would have resisted gravitational collapse into stars.
It is thought that the first stars (a hypothesized group dubbed "Population III") would have been very massive, as only a very intense gravitational self-attraction could overcome the internal pressure of hot hydrogen & helium. Such stars would have burnt all their fuel very rapidly and exploded as a supernova, seeding the cosmos with heavier elements.
Later stars (Population II) and today's Population I stars tend to be much smaller, with much higher proportions of heavier elements.
See: https://en.wikipedia.org/wiki/Stellar_population#Population_III_stars
So hydrogen and helium alone are very bad for star formation. I am going to be thinking more about this.
Yes, the simple elements have very few electronic transitions so conversion of kinetic energy (temperature) to EM radiation is slow and ineffective below a certain temperature (you need enough thermal energy to make the atoms glow when they hit--and due to the spacing of the energy levels in hydrogen, cooling below about 1000 K (ca . 700 °C) is difficult.
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The thing I don't understand is how can humans make heavier elements than the sun, using only mild earth conditions, yet also assume the sun, with far more extreme conditions can't do squat? Is it because humans can use fission and fusion, while we only allow the sun to use fusion, so we can cheat and play god?
I think the main difference is that we have a much richer palate to begin with--the sun is >70% hydrogen, and only has impurities of other elements, while the earth has rich deposits of carbon, nitrogen, oxygen, sulfur, silicon, phosphorus and many metals like magnesium, aluminum, iron, titanium, as well as traces of elements that were formed by stars much more massive and violent than the sun (like platinum, rhodium, uranium etc.) which we have been able to use to do pretty much anything "impressive".
The inner planets of our solar system are rocky and contain all these larger elements. The outer planets are more gaseous. If you extrapolate, the sun should have substantial heavier elements being closer to the rocky planets than the gaseous ones. it should have the most heavy elements being number one in the alignment.
The denser and heavier elements, from super nova remnants, would be the most likely to form the nucleation core of the collapsing dust and debris cloud, from which the solar system would form. This heavy atom core becomes the sun. Now the sun has the same precursors as the earth.
Another conceptual concern is say we assume the solar system formed from super nova remnants. If our solar system, via the sun is mostly hydrogen, why did the original star go supernova, if there was still so much hydrogen left over? One possible explanation is the extra hydrogen was on the surface, and not readily available to the core, so the core was fooled into thinking it is out of fuel.
If the excess hydrogen was on the outside, the blast profile should project these light materials furtherest out, while the heavies that from form the blast, would stay closer. If the nucleation center of the solar system is based on heavies and most of the hydrogen has been blasted farthest away, how does the sun get the hydrogen? It was already concluded that hydrogen and helium has too much entropy to form the nucleation center.
I tend to think that the discovery and idea of a supernova was so intoxicating, that many have become love blinded. It sort of like falling in love, and seeing what we want to see in your beloved, which may not always have the same logical consistency, without the rose colored glasses.
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The thing I don't understand is how can humans make heavier elements than the sun, using only mild earth conditions, yet also assume the sun, with far more extreme conditions can't do squat? Is it because humans can use fission and fusion, while we only allow the sun to use fusion, so we can cheat and play god?
I think the main difference is that we have a much richer palate to begin with--the sun is >70% hydrogen, and only has impurities of other elements, while the earth has rich deposits of carbon, nitrogen, oxygen, sulfur, silicon, phosphorus and many metals like magnesium, aluminum, iron, titanium, as well as traces of elements that were formed by stars much more massive and violent than the sun (like platinum, rhodium, uranium etc.) which we have been able to use to do pretty much anything "impressive".
The inner planets of our solar system are rocky and contain all these larger elements. The outer planets are more gaseous. If you extrapolate, the sun should have substantial heavier elements being closer to the rocky planets than the gaseous ones. it should have the most heavy elements being number one in the alignment.
The denser and heavier elements, from super nova remnants, would be the most likely to form the nucleation core of the collapsing dust and debris cloud, from which the solar system would form. This heavy atom core becomes the sun. Now the sun has the same precursors as the earth.
The sun certainly has heavy elements in it--much more than the earth has. But the key here is the concentration. The earth is almost 35% iron by mass, while the sun is less than 0.15% iron by mass.
Another conceptual concern is say we assume the solar system formed from super nova remnants. If our solar system, via the sun is mostly hydrogen, why did the original star go supernova, if there was still so much hydrogen left over? One possible explanation is the extra hydrogen was on the surface, and not readily available to the core, so the core was fooled into thinking it is out of fuel.
I am not an expert in star formation or cosmology, but my understanding is that the mass of any single supernova is a tiny fraction of the mass in the region of space that it showers its guts across, and that because most of the atoms in the universe are hydrogen (and some helium), the next generation of stars will still be mostly hydrogen (and some helium), and only be enriched a little bit with the emissions from the supernova.
If the excess hydrogen was on the outside, the blast profile should project these light materials furtherest out, while the heavies that from form the blast, would stay closer. If the nucleation center of the solar system is based on heavies and most of the hydrogen has been blasted farthest away, how does the sun get the hydrogen? It was already concluded that hydrogen and helium has too much entropy to form the nucleation center.
A) the sun was not the center of any blast, our metals are from distant supernovae.
B) The amount of hydrogen a body has is largely determined by its mass and temperature. The sun is very hot, but it is also very massive, enough so that the hydrogen only escapes very slowly. The gas giants in our system are not nearly as large as the sun, but are still quite massive, and very cold. The inner planets and asteroid belt are too small and warm to have held on to their H2, which was either captured by the sun, or blasted away by the solar wind.
I tend to think that the discovery and idea of a supernova was so intoxicating, that many have become love blinded. It sort of like falling in love, and seeing what we want to see in your beloved, which may not always have the same logical consistency, without the rose colored glasses.
I suppose you would know something of intoxicating phenomena/theories--you seem quite taken with water and entropy yourself! :P :)
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The thing I don't understand is how can humans make heavier elements than the sun, using only mild earth conditions, yet also assume the sun, with far more extreme conditions can't do squat?
Yes, humans have been able to produce elements heavier than Uranium, by using particle accelerators to smash together heavy elements like lead. This is a form of nuclear fusion, 1 atom at a time, ie it takes a phenomenal amount of energy to create one atom of Livermorium (element 116).
- But we didn't make the lead and uranium - these were already present when the Earth formed.
The temperature of a substance is a measure of the average kinetic energy of its particles. The interior of the Sun has a temperature of around 17 million degrees, which represents a very high velocity for a hydrogen nucleus, but still a non-relativistic velocity
- Even early particle accelerators could accelerate ions to velocities where relativistic effects become significant, which is equivalent to temperatures far higher than the interior of the Sun
The Sun is fusing hydrogen (1 proton) into Helium, using temperatures of around 17 million degrees. Humans have only produced uncontrolled fusion in a Deuterium/Tritium mixture, which has a far lower ignition temperature than normal Hydrogen.
In modern times, the most important star making material is water; H2O.
If we consider the Sun a "modern" (Population I) star, that would imply that the Sun's mass is over 80% oxygen. In fact it is slightly under 1% by mass. So water was not an important star-making material for the Sun.
See: https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements#Universe
The chemical abundance of elements in stars is about 73% hydrogen today - and this ignores vast clouds of neutral hydrogen which are raining down on to galaxies and driving star formation. These are hard to detect spectroscopically, but can be detected by the Lyman Alpha Forest, see:
https://en.wikipedia.org/wiki/Lyman-alpha_forest#Use_as_a_tool_in_astrophysics
If the excess hydrogen was on the outside
This depends on how well the star is mixed by convection. Stars with extensive convection will burn all their hydrogen to Helium.
metals like magnesium, aluminum, iron, titanium, as well as traces of elements that were formed by stars much more massive and violent than the sun (like platinum, rhodium, uranium etc.)
Nuclear fusion in massive stars can produce elements up to iron and nickel.
Elements slightly heavier than nickel can be formed during the fury of a supernova - but nothing as heavy as uranium.
It is thought that most elements heavier than gold were sprayed into space as neutron stars collided - just such an event was detected this year by the LIGO+VIRGO gravitational wave detectors. Astronomers announced that they had seen a light curve consistent with the decay of radioactive gold.
See: https://en.wikipedia.org/wiki/Stellar_nucleosynthesis#Key_reactions
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That leads to a different question. The very first stars in the universe could not have contained heavier elements and must have burnt fast and exploded in supernova. Was there enough time for enough of these to seed the whole universe with heavier elements?
Clearly, yes, thee was.
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I was thinking it may not have been the primary mechanism.
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I was thinking it may not have been the primary mechanism.
Can you elaborate?
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Sorry, I missed your reply. Well in a supernova explosion the debris will be ejected spherically. As the sphere of debris expands its density drops. The distances involved in the distribution of this material means that only a tiny proportion of heavier elements will reach any remote system and take maybe thousands or hundreds of thousands of years to do so. The formation of stars would likely happen much sooner than when this material arrives. So the stars themselves may well be depleted in heavier elements. The planets that are still forming are more likely to benefit from this as surface coatings. This still does not explain the iron cores of planets.
The only reasonable explanation would be that supernovas were the norm in the very early universe. However, this would mean far more heavy elements present in stars such as the sun. So there may be a conundrum here.
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You could always say that the solar wind from a star would drive away heavier elements back into planet forming disks.
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Sorry, I missed your reply. Well in a supernova explosion the debris will be ejected spherically. As the sphere of debris expands its density drops. The distances involved in the distribution of this material means that only a tiny proportion of heavier elements will reach any remote system and take maybe thousands or hundreds of thousands of years to do so. The formation of stars would likely happen much sooner than when this material arrives. So the stars themselves may well be depleted in heavier elements. The planets that are still forming are more likely to benefit from this as surface coatings. This still does not explain the iron cores of planets.
The only reasonable explanation would be that supernovas were the norm in the very early universe. However, this would mean far more heavy elements present in stars such as the sun. So there may be a conundrum here.
It may well be that the radius of enrichment is only a few light years (if we know how much carbon is flung out of a supernova, and we know the carbon content of the sun (assuming it is second generation--I don't know how many supernovae worth of carbon the sun may have...), we can estimate the distance from the supernova, assuming it is the only source of carbon.
I believe that there are localized parts of the galaxy (and presumably others) where many stars are formed. These so-called nurseries may well be fed by local supernovae. (I took a cosmology course a really long time ago, so some of this might be out of date or misremembered, but also seems to be in line with what wikipedia says: https://en.wikipedia.org/wiki/Star_formation ).
My understanding is that the young stars fling each other out of the nest (along with some clouds of what will eventually be their planets, moons, asteroids, comets etc.). These solar systems then find their own orbit within the galaxy. Some people believe that our sun was formed in the open cluster M67
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Thanks. That does make sense.
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So the stars themselves may well be depleted in heavier elements.
Massive stars can produce elements up to iron by nuclear fusion. Less-massive stars (like the Sun) are unlikely to produce any element beyond carbon.
The large stars that undergo a supernova are likely to end up as neutron stars or black holes.
So they are severely depleted in all normal elements - both light and heavy.
The planets that are still forming are more likely to benefit from this as surface coatings.
There is a suspected instance of this - there are deposits of Iron-60 in a thin layer on the Pacific seafloor.
Iron-60 is expected to be produced in a supernova, and has a half-life of 2.6 million years.
See: https://en.wikipedia.org/wiki/Near-Earth_supernova#Past_events
This still does not explain the iron cores of planets.
Planets and dwarf planets are defined by their ability to pull themselves into a spherical shape.
Any object having this level of mass will be severely heated and melted by the collisions of the planetesimals from which it formed, plus radioactive decay from Uranium and Thorium (these heavy elements are formed in neutron star collisions, rather than supernovae).
In a molten body, the denser material is likely to sink to the center, forming a nickel-iron core.
See: https://en.wikipedia.org/wiki/Planetary_differentiation
In 2023, a space probe is planned to be sent to the asteroid Psyche, which appears to be the metallic core of an asteroid.
See: https://en.wikipedia.org/wiki/Psyche_(spacecraft)
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The article highlights a disagreement about the timing and location of the supernova as the source for the Iron-60. I do believe the source was a supernova. I think overall neutron star mergers, rather than simply supernovae, are a more likely source for the majority of the heavier elements in planets.
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I think overall neutron star mergers, rather than simply supernovae, are a more likely source for the majority of the heavier elements in planets.
It comes down to mass and frequency.
It is thought that about 3 supernovae should occur per century in our galaxy (although the clouds of dust probably hide many of them). This happens to any massive star, including some that are truly enormous. They dump lots of matter into interstellar space.
I saw an estimate that there is about 1 neutron star merger every 800 centuries in our galaxy. This requires 2 massive stars in close proximity to go supernova (but not too heavy, or one or both will turn into a black hole). Then you must wait billions of years while they slowly radiate away their angular momentum as gravitational waves, before they finally merge.
That’s why the elements from helium to iron (produced by fusion and released in supernovae) or nickel and cobalt or so (mainly produced from iron by neutron capture during a supernova) are far more abundant than the really heavy elements like gold and above (mainly produced by neutron star mergers).
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Another concern I have with conventional thinking of star formation, is many of the limits we assume of our sun is based on its internal temperature, but not on its internal temperature and pressure. In the real world, temperature and pressure can result in new phases of matter, that temperature alone cannot define.
As an example, at 5000C water is an ionized gas of dissociated radials. If we add sufficient pressure, like that of the core of the earth, water at that same temperature will change into a solid metal. This metallic phase allows a whole new range of properties, that one would not expect, if we assume temperature properties only.
As another example, the core of Jupiter is thought to be metallic hydrogen. One is not dealing with high pressure hydrogen gas with random motion following a bell curve Rather we are dealing with an orderly solid, that conducts electricity very well. There is room for huge voltages and huge magnetic affects.
One might even assume our early forming sun, went through a metallic hydrogen core phase, similar to that of Jupiter, capable of generating huge voltages within a rigid matrix. As the sun added more and more material, which added work and pressure, the sun's core may not necessarily have evolved as hydrogen plasma gas phase core. It may have ended up with an evolving plasma metallic hydrogen phase. This core would approach fusion in a different way.
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@evan_au Then it looks like the supernova explanation wins out over neutron star mergers.
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There is still one thing that puzzles me. Why isn't the earth just a uniform mix of all the elements. We have pockets of iron, silver and such like. We cannot mine for particular metals just anywhere.
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There is still one thing that puzzles me. Why isn't the earth just a uniform mix of all the elements. We have pockets of iron, silver and such like. We cannot mine for particular metals just anywhere.
This has to do with the history of the planet as well as the densities, solubilities, and chemical reactivities of the different elements. When the earth was formed, it was in a molten state for a long enough time for most of the really heavy stuff to sink to the core (mostly iron, with some nickel and cobalt and traces of other dense metals that are soluble in molten iron, like platinum, iridium, osmium, gold... Actually, I believe that one of the reasons bismuth is fairly common in the crust despite its high atomic number (83, compared to gold at 79), is that it is not soluble in iron at all.
Mineral deposits can be formed by tectonic motions bringing elements from deep down up towards the surface (think of sulfur from volcanos and gemstones from mountains), or from bodies of water that have dried up over the centuries (thus concentrating compounds that are soluble in water, like borax.)
Some mineral deposits are due to life itself. Almost all of the limestone (and marble) around the world is composed of the exoskeletons of marine organisms, which were able to extract ezymatically extract CO2 from the atmosphere and combine it with calcium to make calcium carbonate.
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many of the limits we assume of our sun is based on its internal temperature, but not on its internal temperature and pressure.
You underestimate scientists.
Helioseismology studies temperature, pressure and convection speeds within the sun.
The Lawson criterion for nuclear fusion includes temperature, pressure and time.
See:https://en.m.wikipedia.org/wiki/Lawson_criterion
plasma metallic hydrogen phase.
This is partly a self-contradiction.
A plasma is so hot that the electrons are ripped off the nuclei, and the electrons and nuclei form a gas.
A conductive metal may be a solid or liquid. The atoms are in contact, so the outer electrons form a conduction band, where they act a bit like a gas. The inner electrons are still locked to a particular nucleus.
As an example, at 5000C water is an ionized gas of dissociated radials. If we add sufficient pressure, like that of the core of the earth, water at that same temperature will change into a solid metal.
Much of the Earth’s core is iron, so there won’t be much water there.
It is true that hydrogen will form a metallic solid at Jupiter pressures, but Jupiter is mostly hydrogen, without enough oxygen to make much water.
the core of Jupiter is thought to be metallic hydrogen... we are dealing with an orderly solid, that conducts electricity very well. There is room for huge voltages and huge magnetic affects.
I agree. Scientists on Earth study these phase changes in diamond anvils. The Juno spacecraft is currently studying the internal density and magnetic field of Jupiter.
Scientists expect Jupiter’s magnetic field to originate in convection in Jupiter’s liquid hydrogen metallic outer core, rather than the solid hydrogen metallic inner core.
See: https://en.m.wikipedia.org/wiki/Magnetosphere_of_Jupiter
One might even assume our early forming sun, went through a metallic hydrogen core phase, similar to that of Jupiter,
That is possible.
However, Jupiter has had around 4 billion years to cool down from the heat of its formation, and form orderly layers.
In contrast, the early Sun was in the center of a maelstrom, continually bombarded by planetesimals. It is thought that stars ignite fusion in 10s of millions of years, so there was probably little time for the center of the Sun to spend in a solid hydrogen state.
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Neutron star collisions and gold production featured in a recent episode of Brian Cox’s Infinite Monkey Cage podcast.
See: http://www.bbc.co.uk/programmes/b09kxt28
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Much of the Earth’s core is iron, so there won’t be much water there.
It is true that hydrogen will form a metallic solid at Jupiter pressures, but Jupiter is mostly hydrogen, without enough oxygen to make much water.
The existence of metallic water, in the earth's core, is a result of chemical potential and not density or entrainment. The layering of the earth from surface, to the mantle, to the outer core and then to the core, correspond with a phase diagram of water, based on the estimated conditions of the inner earth. Much of this understanding and data for water is relatively new, while the current models are based on old data and old assumptions such as density differences.
For example, water in the earth's crust, not even very far down, exists in a hydrothermal state, which is water above its critical point. This phase of water can dissolve most minerals, as well decompose most organics. The solubility of minerals in super critical water increases with temperature and pressure. There is a chemical potential for super critical water to eat downward in the direction of the core, since this is the place of highest temperature and pressure; water is driven by free energy.
Water is well known for its astonishing range of unusual properties, and now Thomas Mattsson and Michael Desjarlais of Sandia National Laboratories in New Mexico have suggested yet another one. They found that water should have a metallic phase at temperatures of 4000 K and pressures of 100 Gpa, which are a good deal more accessible than earlier calculations had indicated.
Metallic water
The two researchers used density functional theory to calculate from first principles the ionic and electronic conductivity of water across a temperature range of 2000–70,000 K and a density range of 1–3.7 g/cm3. Their calculations showed that as the pressure increases, molecular water turns into an ionic liquid, which at higher temperatures is electronically conducting, in particular above 4000 K and 100 GPa. This is in contrast to previous studies that indicated a transition to a metallic fluid above 7000 K and 250 GPa. Interestingly, this metallic phase is predicted to lie just next to insulating "superionic" ice, in which the oxygen atoms are locked into place but all the hydrogen atoms are free to move around.
The temperature of the earth core is about 5,700 K (5,400 °C; 9,800 °F). The pressure in the Earth's inner core is slightly higher than it is at the boundary between the outer and inner cores: it ranges from about 330 to 360 gigapascal (3,300,000 to 3,600,000 atm). This is in the range of the metallic water phase. The superionic ice phase, just outsider the core, with its hydrogen proton currents is very corrosive to metallic iron; super acid. The water is rusting the iron core and releasing energy. This is driven by the continuity of water from surface to core and solar evaporation. Solar evaporation adds the positive charge to the atmosphere, which is felt all the way to the core, over time. The net flux of electrons upward is reflected in the slight negative charge of the oceans.
Relative to Jupiter, if it has a metallic hydrogen core and is made mostly of hydrogen, then it follows that the answer to the original topic, did or could the sun form from a cloud of hydrogen, is possible. This is because the less massive Jupiter, can consolidate hydrogen, just short of the hydrogen phases needed for fusion.
In terms of a metallic hydrogen plasma, hydrogen is unique in the sense the each atom of hydrogen only has one electron. The mobility of the electrons in a metallic phase, essentially means no hydrogen atom has its own personal election in a hydrogen metal. The ionized electrons are being shared by the solid metallic matrix, due to the application of temperature and pressure.
If we add more and more pressure and temperature, the dwell time for any electron, on any given hydrogen proton gets shorter and shorter. To make this less repulsive, due to the extreme pressure restrictions, the elections and protons will attempt magnetic addition, sort of similar to orbitals. A simple spin addition of the hydrogen protons can allow them to get closer due to magnetic addition. The result will add grains to the hydrogen metal.