In paper A a simple, physical origin was given for the five planets Mercury, Venus, Earth, Uranus, and Neptune, with a few tests of its correctness. There are a number of others. The five planets were stated to come from the internal breakup of a super-planet, called protoJupiter in paper A. This protoJupiter originally consisted of a series of shells in decreasing density outwards, which shells now form Mercury (core), Venus, Earth, Mars, "silicate" satellites, "icy" satellites, Neptune, Uranus, and Jupiter. Jupiter is the remainder of this super-planet after ejection of the other bodies. It is necessary to determine from where protoJupiter - and Saturn (not yet considered) - came.

Passing backwards in time from the formation of the lesser planets, it can be validly proposed that the satellites came into being immediately before them (paper C) in the same way as the lesser planets. Before the satellites, then, there were two planets in existence, viz. Saturn and a protoJupiter containing all the masses and volumes of the other planets and satellites. The obvious step backwards in time from this state, which can be shown was an unstable, transitory state, is to assume that an even larger body than protoJupiter existed and that it contained the masses and volumes of all the planets and satellites. Saturn, being the planet with the least density, should have its mass and volume placed as a shell surrounding protoJupiter. For want of a better term I shall call this largest body a "brown" body.

ProtoJupiter would have had a mass of 2101.11x10²⁴ kg and a radius of 74007 km; the brown body a mass of 2669.71x10²⁴ kg and a radius of 85332 km. That is, if the brown body had been spherical. But was it? What if it was prolate ellipsoidal in shape? Rotating prolate ellipsoidal bodies of a uniform gas have been thoroughly studied in the field of hydraulics over the years; since about the time of MacLaurin. Poincare’s studies of Jacobi’s ellipsoids of rotating gas showed that when the (triaxial) ellipsoid attained the axial ratios of:

a/R = 1.8858, b/R = 0.8150, and c/R = 0.6507

the ellipsoidal body of gas broke into two unequal parts. The product of the three above ratios is: 1.23 x 1.23^-1.

The study of the Solar System which led to these papers suggested the hypothesised prolate ellipsoidal brown body had axes of a = 128001 km and b = c = 69683 km if the shorter axes were equal. The ratios to sphere radius for the ellipsoid axes ratios is thus:

a/R = 1.50004 and b = c/R = 0.81661.

The product of the three axis ratios is 1.23 x 1.23^-1. The two bodies, the one determined by a gas formula and the other by planetary volumes, are thus equivalent. It is possible that a rotating, elongating brown body of Solar System volume broke into two parts on reaching an a-axis length of 1.5R (eccentricity 0.83883 = 1.19214^-1. 1.19 is a Universe ratio.)

Increasing elongation of the rotating brown body would have tended to concentrate the lighter, outer (Saturn) shell at one end of the a-axis, finally resulting in Saturn separating but initially resting beside protoJupiter. Both bodies would have become more spherical. It can be shown that protoJupiter at this stage would have had a moment of inertia factor "f" of 0.4, and at the instant before separation Saturn in all probability had the same or nearly the same factor.

Saturn presently has an "f" of 0.22, Jupiter of 0.25; Saturn a rotation of 2.1702141x10^-4 rad.sec^-1, Jupiter of 1.7733482x10^-4 rad.sec^-1. Determining the rotations of the two bodies for "f" = 0.4 gives:

Jupiter, 1.1083426x10^-4; Saturn, 1.1936177x10^-4 rad.sec^-1;

i.e. the rotations are closely similar; as one would expect if they originated as proposed.

If the planets formed by splitting of a single body then there should be a simple relationship between their obliquities of the rotation axis (tilts). Put another way, knowing the tilt of one of them it should be possible to calculate the tilt of the other. The relationship shown between the tilts of the lesser planets (paper A) and the satellites (paper C) does not apply for these two planets as they formed by fission, not be ejection. The required relationship is given in the following paragraph.

ProtoJupiter had an "f" of 0.4. Assume that when Saturn became independent it internally collapsed, while still touching protoJupiter, to give its present "f" of 0.22. Further, as is not impossible, assume a force occurred at the contact of the two bodies at right angles to their plane of rotation. Then it can easily be shown that:

Tilt of Saturn = (tilt_pJxR_pJxM_pJx0.4)/(R_SxM_Sx0.22)

Because of Jupiter’s great mass compared to the sum of the lesser planets it is unlikely that the tilt of protoJupiter would have been very much different to that of present Jupiter, despite the subsequent ejection of protoJupiter’s core. Therefore insert Jupiter’s tilt value in the formula for tilt_pJ.

The tilt of Saturn calculates as 25.55° to the Jupiter orbit plane. When the difference between the two orbit planes is added the sum is 26.73^o, the same as the angle measured from the normal of Saturn’s orbit plane. The measured angle may vary with varying assumptions but the conclusion does not change: the tilt calculation supports the idea that a brown body split into a protoJupiter and Saturn.

But why, then, did protoJupiter break up? Easy! The brown body did not break into perfect proportions. It is possible to argue that Saturn should have had a mass of about 525.81x10²⁴ kg and protoJupiter a mass of 2143.98x10²⁴ kg. (Note: 2143.98/525.81 = 4.07733, within 1.39% of 1.19⁸; 2669.71/525.81 = 1.22519⁸, within 3.09% of 1.23.) Separation not being perfect there was an imbalance of forces in what was required to be a closed force system. Adjustment of forces could only be achieved by adjustment of mass within protoJupiter. Adjustment of mass inside protoJupiter resulted in collapse of the outer part of the body and ejection of the moved inner mass. This resulted in force imbalance and the process was repeated until the combined force/impulse mechanisms gave force equality for the closed system.

The making of a Jupiter and a Saturn was inevitable. The making of, and number of, the lesser planets (there had to be terrestrial and gaseous on opposite sides of Jupiter if lesser planets were present) depended on how imperfect was the splitting of the brown body.