THE "BULK CHEMISTRIES" OF VENUS AND JUPITER*
Copyright © 1976 by Ralph E. Juergens.
[* This article is a modified version of one of 22 essays contained in an Anthology presented to Dr.
Immanuel Velikovsky on December 5, 1975, in honor of Dr. Velikovsky and the 25th anniversary of
Worlds in Collision; it is our hope to publish the Anthology in its entirety. - The Ed.]
At a recent symposium on "Velikovsky and the Recent History of the Solar System"
(McMaster University, June 1974) David Morrison of the Institute for Astronomy at the University
of Hawaii at Manoa raised an old argument against Worlds in Collision:
". . . consider the bulk composition of Venus. From its mean density alone, which is nearly
the same as that of the Earth, it is clear that Venus must be composed of refractory or rocky materials
with the addition of a metallic component. But such a composition is entirely at odds with the known
chemistry and structure of the Jovian planets. Jupiter, with a mean density only one quarter that of
Venus, has a composition of basically the solar sort, with the bulk of its material made of hydrogen
and helium, which together account for at least 90% of the mass of Jupiter. The amount of rocky and
metallic material in Jupiter today is no more than a few times the amount in Venus. Quite simply, the
chemistry of Venus and Jupiter could hardly be more different."
In all charity, this argument can hardly be viewed except as one more example of
At the very least, Morrison is guilty of confusing observation with inference and misleadingly
characterizing both as "known." In any objective sense, nothing is known of the chemistry and
structure of either Jupiter or Venus.
This same argument surfaced within a few weeks of the publication of Worlds in Collision.
Frank S. Hogg, then director of David Dunlop Observatory, put the question to readers of the
Toronto Globe & Mail (April 22, 1950): "If Venus was thrown out of Jupiter, why should Venus be
made up of material three to four times as dense as Jupiter?"
Hogg's phraseology was inexcusable in a scientist of his distinction; his choice of the wording
"as dense as Jupiter" instead of a less suggestive but more accurate reference to the mean densities
of the two bodies must be construed as a deliberate move to mislead the reader. Even more
objectionable, however, was Hogg's failure to mention that the structural model of Jupiter then in
vogue was in no way incompatible with Velikovsky's hypothesis.
This model had been developed in the 1930's by Rupert Wildt: "The outer 18 per cent of the
radius [of Jupiter] is composed chiefly of hydrogen compressed to the density 0.35 times water. The
next 39 per cent of the radius is a layer of ice compressed under the very great pressure down there
to the density 1.5 times water. The remaining 43 per cent of the radius of the model is a rocky core
having a mean density 6. 0 times water." This quotation is from R. H. Baker's Astronomy, 4th edition
(1946), page 200, with emphasis added.
Now a rocky core of such proportions, some 38,000 miles in diameter, would contain enough
material of more-than-sufficient mean density to yield 100 planets the size of Venus, even if a great
quantity of matter had to be "wasted" in the process of issuing each of them. (In the 1920's, Harold
Jeffreys calculated that Jupiter might have a rocky core of some 400 Venus-masses.) Velikovsky's
thesis requires only that about one percent of such a mass, or an equivalent amount of matter from
somewhere in the interior of Jupiter, was at one time expelled or tom from the parent body.
It may be significant that Wildt himself, taking his turn at blasting Worlds in Collision in a
joint effort by Yale University professors (New Haven Register, June 25, 1950), raised no objection
to the proposed origin of Venus. Apparently he saw no problem in the disparity in the mean densities
of Jupiter and Venus.
Wildt's model of Jupiter was in no sense capricious or a product of pure guesswork. It
satisfied, first of all, the overall low-mean-density restriction deduced from such observational data
as the apparent size of the planet and the dynamical behavior of its satellites. It also took into account
the implications of the Jovian equatorial bulge. All such straightforward evidence pointed then, as
now, to a high-density core of considerable size. Nevertheless, Wildt was among the first to
challenge his own model, and this on the rather flimsy grounds that a massive core of heavy elements
violated prevailing professional opinion about the origin of the Sun and the Solar System.
The problem, as he imagined it (Monthly Notices, Royal Astronomical Society 107, 84,
1947), was that his model attributed too little hydrogen - less than ten percent by mass - to
the giant planet.
As G. E. Satterthwaite recently recalled (Astronomy & Space, Vol. 1, No. 2, 1972), this
feature "raised a considerable difficulty, for it was considered that the giant planets were condensed
from a cloud of material similar to that of which the Sun is constituted. Unlike the terrestrial planets,
however, they would have retained most of their original mixture [of hydrogen and helium, as well
as other elements] due to their strong gravitational fields."
Thus the relatively hard evidence that went into Wildt's model was tempered with a large
measure of cosmogonical speculation. From about 1950 onward, all models accepted for publication
in establishment journals began to reflect the growing consensus that Jupiter must be mostly
One of the first of this genre was that developed by Harrison Brown (Astrophysical Journal
I I 1, 641, 19 50), another early critic of Worlds in Collision. Brown trimmed Jupiter's rocky core
to about nine Earth-masses - a good start in the premised direction, but still leaving enough heavy
matter to make more than ten Venus-sized planets.
Later investigators completed the job. P. J. E. Peebles (Ap. J. 140, 328, 1964), W. B.
Hubbard (Ap. J. 155, 333, 1969, and Ap. J. 162, 687, 1970), and R. Smoluchowski (Ap. J. 166,
435, 1971), to mention only a few, managed to do away with all, or practically all Jovian refractory
This, of course, required some ingenuity. Dynamical considerations still dictated a massive,
high-density core for Jupiter. So the only solution worthy of sanction by the consentient
cosmogonists was to build this core of high-density hydrogen.
The possibility that under immense pressure hydrogen might condense to a liquid or solid
metallic state was raised on theoretical grounds long ago by Wigner and Huntington (J. Chem. Phys.
3, 764, 1935). At the time, this proposal was regarded simply as a quaintly interesting idea. But in
the 1960's it came into its own as the salvation of the Jupiter-modelers and their entrenched notions
of Jovian origins. Jupiter's core must be made of high-density hydrogen!
As the 1970's dawned, few authorities doubted this conclusion, and none appeared willing to
raise his voice against it. Many minds seemed to have lost sight of what was really known and what
was simply postulated in framing the problem of the structure of Jupiter.
Witness an item on "the continuing search for metallic hydrogen" in Industrial Research for
April 1973: "To date, the only evidence that hydrogen can exist in the form of a solid metal comes
indirectly, from astronomical studies of the planets. 'It has been determined that although the mass
of Jupiter is some 300 times that of the earth, the density of its material is very low,' explains Neil W.
Ashcroft, associate professor of physics at Cornell University.
" 'Observational data has [sic] shown that the composition is almost completely hydrogen -
14 out of 15 atoms on Jupiter are hydrogen atoms. The tremendous mass of the planet composed
of the lightest element could be explained only if the hydrogen existed in another, denser state.' "
Once again, assuming that Ashcroft was correctly quoted, we may object to the careless and
misleading use of "density" in place of 6 c mean density." Much more objectionable, however - and
quite wrong–is his reference to a Jovian composition "almost completely hydrogen" as something
derived from "observational data."
Recently what might be taken at first glance as a bright sign has appeared in the form of a
retreat by at least two theorists from the idea of an all-hydrogen core. M. Podolak and A. G. W.
Cameron, keeping the faith by assuming an initial mix of elements agreeable with received opinion,
traced the hypothetical formative process for Jupiter in great detail. Their computer readouts
indicated that the giant planet should have a rocky core of some 40 Earth-masses (Icarus 22, 123,
1974 - emphasis added).
Thus, even in the context of accepted beliefs concerning the origin of the Solar System, it has
been found possible to come halfway back to the Wildtian rocky core in one leap. But this finding
is only as valid as its first assumptions; it need not be too highly applauded.
The premise that 14 of every 15 atoms on Jupiter are now, or ever were, hydrogen is purely
conjectural, just as is Morrison's statement that at least 90 percent of the planet's mass derives from
hydrogen plus helium. The only rationale for such positions is a highly speculative and quite
conceivably erroneous chain of deduction: (1) The Solar System must have originated as an entity
by condensation from a single, primordial, solar nebula of dust and gasses; (2) this nebula must have
consisted of a blend of chemical elements practically identical to that now present in the atmosphere
of the Sun; and (3) all the planets must initially have reflected this composition, modified only by their
positions in the evolving nebula and the time sequences of their individual condensations.
To me, as the author of a hypothesis that the Sun is not fueled internally by thermonuclear
reactions and is therefore not necessarily kept mixed by convective processes, it strains credulity to
attempt to infer the elemental mix of a primitive nebula from a look at the Solar atmosphere. But this,
of course, is another story.
In any case, however, it is patently illogical to mount an attack on Velikovsky's thesis, in
which the planet Venus has a catastrophic origin far from its present position in the Solar System,
with arguments based on totally different first assumptions.
The bulk chemistries of both Jupiter and Venus are now unknown. The bulk chemistry of the
Earth is largely unknown, except by way of more or less educated guesses. The probability is that
all these matters, however interesting they may be as subjects for speculation, will forever remain
[*!* Image] Venus
[*!* Image] Jupiter