THE HYDROGEN/HELIUM DISTRIBUTION IN THE OUTER PLANETS

AND

THE DISTRIBUTION OF THE NOBLE GASES THROUGHOUT THE SOLAR SYSTEM.

THE MECHANISM THAT BROUGHT THEM ABOUT.

By T. Frank Lee, MAppSc., BSc., etc., January, 2009. 102 Mill Street, Ballarat, 3350, Victoria, Australia.

The Single Body Breakup Hypothesis of the origin of the Solar System allows one to suggest a simple, ore-dressing mechanism that permits the prediction of the qualitative variation of the chemical make-up between the planets, satellites, meteorites, and the comets. In this paper the mechanism will first be described (and elaborated further on in the paper) as given in my 1994 book followed, as examples, by those parts of the study that were carried out during testing of the idea on the helium/hydrogen and noble gases distributions between the relative bodies.

p.138. 2. CHEMICAL DISTRIBUTION WITHIN THE POSTULATED BROWN BODY.

In Section 1 the postulated brown body immediately before breakup was argued as having a shelled structure of decreasing specific gravity outwards, and was deduced as being so by linking in consecutive order the present (uncompressed) planet densities (except Venus before Earth. F.L., 2009):- Mercury, Venus, Earth, Mars, the “silicate” satellites, the medium density “icy” satellites, the light “icy” satellites, Neptune, Uranus, Jupiter, and Saturn. ------ Though the brown body was probably almost always a prolate ellipsoid it was mostly investigated in relation to density as if it were a spheroid and it will be discussed as such now. The mathematics presented in Section 1, in the opinion of the writer – and particularly for Tests 1 to 10 (pp. 11 to 28) -, confirmed this assumption of decreasing density outwards from the brown body.

It has also been postulated in Section 1 that the brown body underwent most of its development as the gradually building core of a protostar. Inside-out collapse of a molecular cloud has been accepted from previous workers as a beginning of the Solar System but it has been suggested in this paper that in-fall was differential, the heavier materials (elements and compounds) moving more rapidly inwards than the lighter materials. It was this differential movement which resulted in the density stratification within the protostar core, a development which was reinforced by rotation of the whole mass. In effect there were two separating mechanisms: differential in-fall and a cyclone (rotation) effect similar to that used in mineral separation in mining plants. This latter would have become increasingly important as the brown body developed and would have been strongest at the instant that the protostar core was ejected and became a satellite of the resulting Sun formed from the collapse of the remainder of the protostar.

The brown body structure developed by the gradual concentration of heavy elements and, as the elements reached temperatures allowing combination, of compounds (together with the existing dust) in the rotating body. That is not to say that all heavy elements and compounds concentrated at the centre of the body and all the lighter near the outer face. Because the protostar developed by “inside-out” collapse of a dense core consisting of a “cosmic” mixture of gas and dust, the shelled structure that gradually formed would always have been a mixture. Also, concentration of elements and compounds would depend in part on volatility. None-the-less, there was differentiation, even if incomplete, and it should have been most complete in the very outer shell(s) of the body.

Immediately prior to breakup the silicate core showed, at least to some extent, a shelled structure. The centre would be expected to have contained a higher proportion of iron, iron sulphide, and nickel/iron besides the dominant pyroxene and olivine; and away from the centre higher calcium felspar. Near the outer surface of the silicate core sodium, potassium, and aluminium silicates should have tended to form; in the case of sodium and potassium because of high reactivity and because they form felspars of lower specific gravity than the calcium feldspars. At the surface of the silicate core hydrous minerals would be expected. It is certain that the core of the brown body was hot. However, if, as is to be argued, some meteorites formed at about the surface of this zone then the surface must have been a skin of plastic to solid rock. That is, the temperature must have been somewhere about 1500K. This is stated because the refractory inclusions of meteorites are generally solid, igneous rock fragments which have come from fragmentation of a rock mass; yet some of these fragments have been found to be intruded by veinlets of igneous rock, iron sulphide, and/or iron.

About the silicate core would have collected a dominantly “water” (at least in composition – it may have been steam) shell, possibly underlain by, or its lower levels mixed with, organic compounds and its outer levels higher in carbon dioxide. This thin shell would have been surrounded by a gaseous shell of CO₂, N₂, Ar, etc. – again showing some differentiation. Helium and hydrogen would probably have appeared in this zone but be only a small proportion. Then, moving outwards, hydrogen, helium, and neon would rapidly have dominated, and differentiation would gradually have resulted in dominant hydrogen at the outer surface of the composite body.

The above chemical description is what is required of the postulated brown body. The following sections will compare this with the actual compositions of the planets to see if they broadly obey this description.

It is important to note here that the composition of the brown body after its separation from its parent protostar would not have had a composition of solar abundance. The difference, however, would have been small. A rough calculation has suggested that for the rock-forming elements the maximum difference would have been about 6%. Because of the body’s gradational differentiation into shells, somewhere in one of the shells would be an approximation of solar abundance for the lighter gases and this would probably be somewhere about the top of the Uranus shell. (I note Cole (1988) on p.570 wrote, “—although helium is deficient in the outer regions of Saturn –“ and “The compositions of Jupiter and Saturn are not far removed from the solar abundances, although models (see, for example, Cole 1984a) of these planets suggest a rather lower proportion of the light elements than would be expected if the solar abundance were followed closely. Uranus and Neptune have a still greater proportion of heavier materials, --“, and on p.571 “It would seem more likely that the compositions of the terrestrial planets were always fundamentally different from those of the major planets. The same is true of the satellites.”)

As the differentiation of the brown body took place over a long period of time, from commencement of protostar formation to brown body breakup, and as the body was for a large part of this time rotating fairly strongly, there should also have been some separation of the different isotopes of the elements. In the case of the heavy elements such as Fe, Si, and S the separation of isotopes would probably have been insufficient to be analytically determinable. It should be possible, however, to detect the difference for the light elements such as H, He, Ar, and C; and to use these differences to test the hypothesis by comparing prediction with fact. Oxygen is a more complex element ------

Literature studies were carried out on a number of elements and the data collected was viewed to see if the qualitative order of abundance ratios agreed or disagreed with those predicted by the Hypothesis. The elements studied and discussed appear in SECTION 3. COMPARISON OF THE POSTULATED BROWN BODY CHEMICAL DISTRIBUTION WITH THE PRESENT PLANETS, which begins on p.142 and ends on p.202. They were: (a) The Hydrogen/Helium Distribution in the Outer Planets; (b) Deuterium Distribution Throughout the Planets; (c) Noble Gas Distribution Throughout the Planets and a comment on the Terrestrial Atmospheres; (d) Oxygen Isotope distribution Throughout the Planets and Other Bodies; (e) The Elements Carbon and Nitrogen and the Suggested Origin of the Atmospheres of the Terrestrial Planets; (f) Composition of the Satellites; (g) The Appearance of Previously Determined Ratios in the Basic Materials of the Planets; (h) Appearance of the Ratios in Gaseous Body Calculations. The Brown Body Shape. Only sub-sections 3(a) The Hydrogen/Helium Distribution --- and parts of sub-section 3(c) Noble Gas Distribution --- will be given here; as examples of the attack method.

p.142 As has been said, the brown body formed three clearly different shelled zones, even though they would have interacted at their touching surfaces. These were the gaseous shelled zone, (the main bulk of the body), the “water” or hydrous mixed zone of intermediate density ranging around about an AW/MW of 20 (a very thin shell), and the shelled silicate core zone containing the bulk of the denser elements and compounds. Because the bulk of the brown body consisted of hydrogen and helium the gaseous zone of the body would be dominantly these gases. They will be looked at first.

(a) The Hydrogen/Helium Distribution in the Outer Planets.

It is clear from the above discussion that the most hydrogen-rich planet of the four major, gaseous planets (or alternatively the least helium-rich) must be Saturn. This should be followed by Jupiter, and Uranus; and Neptune should be the least hydrogen rich (or alternatively the most helium rich) of the four. This has recently found to be so, much to the surprise of research workers as the planetesimal (read nebula) theory did not predict it. Conrath et al (1991) list the following helium mass fractions for the four planets, pointing out that the remainder of each planet is almost solely hydrogen. Neptune 0.32 ± 0.05, Uranus 0.26 ± 0.05, Jupiter 0.18 ± 0.04, Saturn 0.06 ± 0.05.

The order of decreasing helium abundance for the planets is as for that by the hypothesis and therefore supports the hypothesis.

It was also with some fascination that I realised the following ratios existed between the published figures: 0.32/0.26 = 1.231; 0.26/0.18 = 1.444 or 2.1% from 2^1/2 (2.0% from 1.19²); 0.18/0.06 = 3 (1.23²x1.19⁴ = 3.03, i.e. [1.23x1.19²]²)

Also note 0.32/0.06 = 5.333 = 1.23275⁸; 0.32/0.18 = 1.778 or 2.6% from 3^1/2 and 0.26/0.06 = 4.333 = 1.44280⁴.

Alternatively, for hydrogen: 0.68/0.74 = 0.91892 = 0.979⁴; 0.74/0.82 = 0.90244 = 0.975⁴; 0.82/0.94 = 0.87234 = 0.983⁸. (also note that 0.68/0.94 = 0.72340 (= 1.38236^-1) or 0.10% from 0.98¹⁶.)

That is, the three ratios which continually appeared in Section 1, viz. 1.23, 1.19, and 0.98 appear in the helium/hydrogen ratios. It suggests to me that the distribution of the helium and hydrogen either derived from the physical parameters of the brown body at breakup or, probably more likely, were responsible for the physical parameters at breakup. It suggests that a centrifuge-like process did take place in the body.

(c) Noble Gas Distribution Throughout the Planets and a Comment on the Terrestrial Atmospheres.

Sub-section (c) begins on p. 147 and to the end of p.150 outlines the thinking and deficiencies of the “accepted” origin envisaged by the astronomical community. Then:

p.151. If the hypothesis presented in this paper is correct then it is necessary that it offer an explanation for the distribution of the noble gases. Such an explanation will now be attempted. Because of the limitations of this paper the explanation will only be outlined. It will not be a mathematically rigid attack.

First I note the abundances of the noble gases (taken from Anders and Ebihara, (1982) normalised to Si, which is taken as 1x10⁶ atoms. Helium is included. He 2.18x10⁹, Ne 3.76x10⁶, Ar 1.04x10⁵, Kr 45.3, Xe 4.35.

Imagine the development of a solar system exactly as it occurred in conditions and time as ours did, but in which only noble gases, including helium, occurs. It is required that the abundance ratios of the gases be the same as in our Solar System, i.e. ratios with xenon as 1 of: He 5.01x10⁸, Ne 8.64x10⁵, Ar 2.39x10⁴, and Kr 10.41.

Then as inside-out collapse takes place and the “protostar” forms, its rotation will gradually increase. The body will behave something like material in a cyclone in an ore treatment plant. It will gradually develop stratification, the heaviest gas xenon tending to concentrate towards the centre, the lightest gas helium tending to concentrate towards the outer surface, and the intermediate gases at varying distances from the centre depending on their atomic weights. While collapse continues it is not possible for the gases to ever completely separate, even when the rotation of the body approaches breakup. None-the-less, a distinct shelled structure will develop. Xenon will tend to concentrate at the centre, though it will still exist at ever diminishing abundance outwards towards the outer layers of the body. Similarly krypton will tend to concentrate in a zone somewhat outside the xenon concentration zone but will exist in diminishing abundance inwards into the xenon zone and outwards towards the outer layers of the body. And so on for the lighter argon, lighter still neon, and lightest helium.

Because helium is so dominant in the body, being some 10³x more abundant than neon, 10⁴x more abundant than argon, and so on, it will permeate virtually the whole body and might even be recordable at the centre, even though concentrated towards the outer surface of the body. A similar argument applies for neon, though it would be expected that its abundance in the outer parts of the helium zone would be very low because of its 5x higher atomic weight. Similarly, argon and krypton would probably permeate the inner parts of the body to the core. Compared to xenon they are only 1/4 and 2/3 its atomic weight. But compared to helium and neon they are 9x and 2x, and 21x and 4x heavier, respectively, and so their abundances in the outer shells of the gas body would be extremely small; probably not recordable.

As previously written (p.140) the separation mechanism is to take place over such a large time-span that not only will the gases tend to separate from one another but also their isotopes will tend to separate, the heavier tending to concentrate in zones nearer the body centre and the lighter farther away. Thus the body will become a rotating mass of gas showing a tendency to separate gas concentrations overlain by a tendency to separate isotope concentration.

Now visualise this mass of gas superimposed on and permeating through a similar rotating and stratified body of matter to form in total our hypothesised pre-Solar System brown body. Immediately we can say that because H₂ has 1/4 the atomic weight of He the noble gas sphere would not (measurably) extend to the outer surface of the brown body. The outer shells would be H₂-richer compared to progressively inner shells.

In effect, adding the remaining matter gives a silicate core which, while it is permeated by a noble gas mixture, will act as a barrier to gases moving inwards.

Ejection of the brown body from the protostar means infall of matter from outside the body ceases and cyclonic separation due to rotation is the only mechanism acting. Continued rotation of the body will result in a new, similarly developed abundance gradient within the gaseous part of the body but with the base level being, approximately, the silicate core face. It is important to remember two points concerning this face. Firstly, it occurs only 1/10th of the brown body radius from the centre and secondly it occurs at about AW/MW 40. Thus the effect of this new base will have little effect on the lightest, and little effect on the heaviest, gases. The newly developed abundance gradient will gradually mask the older outside the silicate core. In fact a period could be reached in its evolution when parts of one or both of the noble gases krypton and argon concentration zones could have an abundance (mass and/or isotopes) approximating the original abundance of the protostar.

It is now intended to show that the noble gas distributions outlined above explain the noble gas distributions found in the Solar System. We have already done so concerning the helium distribution, which is reflected in the major planets.

According to the hypothesis the Earth was once a shell within the silicate core – below a thin hydrous shell, a thin silicate satellite shell, and a Mars shell. Consider the neon of this Earth shell. While I cannot make quantitative predictions the above description does allow me to make qualitative predictions about the Earth shell. Clearly the neon in the silicate would be a remnant of that of the original gas separation, before development of the abundance distribution with the silicate face as base. This is because by the time of formation of the liquid silicate core most of the neon would have moved outwards away from the inner parts of the body and little neon would have penetrated inwards after silicate core formation. That is, the neon in the Earth’s mantle should have a heavier isotope concentration than the original (solar abundance) neon.

However, when Earth stripped from the Mercury/Venus core, and immediately before ejection, its centre would have been approximately 23000 km (p.25) from the centre of protoJupiter. It moved from approximate shell distance 7500 km to sphere distance 23000 km. It would displace lighter gas, and the denser gas would fall towards the Mercury/Venus core. Then, as Earth moved outwards on ejection it would have captured gas because of its size (chiefly at its commencing location?) to form an atmosphere. It would be expected that Earth at the beginning of ejection would have lain mostly outside the second xenon concentration zone, possibly largely outside the second krypton zone, but within the argon and lower reaches of the neon zones. (However, much of the argon and neon may have been incorporated in Neptune when the core of protoJupiter split into a silicate body and a dense gas body. But see below.) That is to say, the neon of the atmosphere should be isotopically heavier than the rock-occluded neon.

Turning again to Sasaki and Nakazawa (1988), under “Origin of terrestrial Ne”, the following ²⁰Ne/²²Ne ratios are given: solar-type (solar wind) 13.6; terrestrial (atmosphere) 9.8; planetary-type meteoritic 8.2; deep-sea basaltic and volcanic glass – slightly higher than 9.8 (Craig and Lupton obtained 10.3 for Kilauea volcano gas.)

That is to say, the quantitative assessment of the Neon isotope ratios is as actually occurs: atmospheric heavier, occluded somewhat lighter, and solar abundance lightest. Further, as the hypothesis requires the meteorites to largely have originated at about satellite and Mars position it would be expected that their neon would be isotopically near but heavier than that of Earth if the gas was mostly picked up at particle ejection. Sasaki and Nakazawa give a figure of 8.2 compared with Earth’s 9.8, which is in qualitative agreement. (Earth type meteorites – splatter during Earth ejection – should have Earth-type readings. F.L.,2009.)

One other point can be raised with regard to neon. The hypothesis requires that the neon largely concentrated in the gaseous envelope of the brown body at a distance from the centre which would have meant it lay in the shell that ultimately became Neptune. That means that neon abundance in the gas sampled by the terrestrial planets (effectively the base of the Jupiter shell/top of the Uranus shell) would be very low, considerably lower than the solar abundance. And of course this is the case. There is therefore a possible test of the hypothesis; does Neptune have measurable neon? Virtually all should be at or near the centre of the planet but a little may still be near its surface. I have no information on the neon in Neptune.

Turning to xenon; a qualitative consideration of the xenon on the Earth, given by the hypothesis, is that most would be from the silicate, and little would have been captured with the atmosphere. Also, there should be a predominance of the heavy xenon isotopes and a lack of light isotopes compared with the solar value. This has been found to be so (see Sasaki and Nakazawa.).

With neon and xenon isotopes registering as they do then qualitatively argon and krypton in atmosphere and mantle should be about equal in composition as they lie near the about 40MW silicate face – and this is found to be so. Actually, the light isotopes of krypton are fractionally more dominant. Thus it is possible to predict approximately the noble gas isotope distribution on Earth.

A little more support is given by Fig. 1 of Sasaki and Nakazawa’s paper. In it are the plots of xenon isotopes for two meteorites. The light isotopes plot with the SUCOR values while the heavy isotopes lie between the Earth and SUCOR plots. This is where they should occur if the meteorites originated where the hypothesis suggests, viz. in the Mars and/or silicate satellite shells of the brown body.

It was written above that Earth “would have lain mostly outside the second xenon concentration zone, possibly largely outside the second krypton concentration zone, but within the argon and lower reaches of the neon zones.” As Earth moved outwards the hypothesis requires that Venus formed; and it would have lain deeper in the gas body. Argon being so abundant (1/36 of neon but 9990x krypton), and also with an atomic weight near that of the material at the silicate face, Venus would have been expected to lie in a “denser” argon atmosphere than the farther out Earth. That is, it is to be expected that the atmosphere captured by Venus would have a higher argon concentration than that of Earth. Even neon could have been more concentrated at the Venus level as the Earth would have lain within the largely neon-depleted Jupiter shell, most of the neon probably being incorporated in Neptune and Uranus.

Hoffman et al (1979) state concerning the atmosphere of Venus, “Preliminary examination of the data indicates the presence of surprisingly large concentrations of ³⁶Ar, ³⁸Ar, and ²⁰Ne ---- the absolute abundance of ³⁶Ar in the Venus atmosphere must be approximately 200 to 300 times larger than that on Earth. The abundance of ²⁰Ne is apparently also high in the atmosphere of Venus, comparable to that for ³⁶Ar. The abundance ratio [³⁶Ar]/[³⁸Ar] in the Venus atmosphere is, however, similar to values observed for Earth, meteorites, and the Moon.”

“---- The abundance of ⁴⁰Ar on Venus appears similar to that for Earth.” [Due to a similarity of ⁴⁰K in the planets? Expected if they touched and show similar silicate minerals.]

So the hypothesis can also account for the greater argon density on Venus compared to Earth.

The qualitative argument on argon concentration can be extended. As has been said, the formation of the silicate core resulted in a new base for noble gas abundance distribution. Argon has an AW of 40, which is close to the mass change at the silicate face. Argon is also relatively abundant. Therefore it is to be expected that the gas zone directly above the “hydrous” shell, argued in Section 1 as lying between the silicate and gaseous parts of protoJupiter, would be argon rich. There should also be free nitrogen present in this zone. The nitrogen should dominate the argon as it is 24x more abundant.

The hypothesis requires the satellites to be ejected first from protoJupiter; with the “icy” either ejected with or just before the “silicate” satellites. (The point being made here supports ejection of the “icy” before the “silicate”. [none-the-less it has been emphatically proved since 1994 that the two sets were ejected at the same time--2009.]) The large mediumdensity “icy” satellites are believed to consist mostly of water ice. Two of the largest have atmospheres. The hypothesis requires at least part, probably all, of the atmospheres to have been collected near the point of ejection. In the case of the satellites, then, the atmospheres should be dominantly nitrogen, and argon should be present. (So, too, should hydrocarbon, probably as gas.)

Thompson and Squyres (1990) state on p.337, “Titan. ---- The atmosphere is composed of N₂, with a few percent of CH₄ and possibly a heavier component such as Ar.” Cole (1988), on p.579, states, “The composition of the atmosphere of Titan (the only atmosphere for an icy satellite) is 85% nitrogen, 15% argon and 1% methane.” In an article by various authors on Neptune in Science 246 (1989), on p.1437, Triton is described as having an atmosphere mainly nitrogen with a trace of methane near the surface. In Section 1 Titan is suggested as being ejected before Triton. (This has since been shown to be the case, but not as envisaged at the time.—2009) It would therefore be expected to have more of the relatively rare argon in its atmosphere than Triton.

The hypothesis appears to account for the quantitative variation of the noble gases on the different terrestrial planets and the satellites. In doing so it follows a definite, required pattern and shows that the variations are not random or accidental. This is quite opposite to the proposals put forward based on the Planetesimal Theory (read Nebula Theory). Yet it is possible to see a similarity between the definite development based on the hypothesis and the random developments based on Planetesimal Theory. For example, a secondary atmosphere derived from planetesimals or comets replacing a primordial atmosphere would look very similar to a stratifying original “atmosphere” being modified by the appearance of a liquid, near-immiscible core within a brown body.

But is there quantitative evidence to support the hypothesis development? Probably yes; and it will now be attempted to show that it is so.

The origin of the atmospheres of the terrestrial planets was still undecided and in debate by 1992. Shukolyukov (1992) attacked the problem of the non-radiogenic gases distribution in a slightly different way; -------. Several pages follow on his analysis and my comments on it but the pages are not being given here. Graphs were required to compare his results and mine. Despite him making some errors in formulae (e.g. changing from log to ln accidentally(?)) and mathematics his argument was good. If he had not accepted the Nebula Theory, and if he had plotted distance squared instead of distance of the planets from the Sun, he would have obtained good graph plots. F.L., 2009.