The author hypothesizes the earth-moon combination was essential for human life on earth

From the Mother Molecular Birth Cloud to Planetary Composition, Mass and Spin at various solar radial distances the formation of the solar system during the T Tauri Birth Phase is reasonably well understood, and yet right here in the terran-lunar system is still the greatest mystery: How actually did this double planetary system come to be where it is? Or, more to the point, how did the thin film bio-sphere on terra's surface get here? The inner solar system is generally composed of HOT, dry, rocky planets as a natural consequence of the gravitational, thermal and magnetic gradients in the T Tauri Phase. That means only refractories will precipitate out of solution whereas volatiles like H₂O won't. Thus Mercury, Venus, Earth and Luna are natural products of radial distance in the proto-solar nebula. So then, how is it that earth's surface is sopping wet, or 70% covered with water, when nearby Luna is BONE DRY?

Sounds like a good mystery doesn't it? A conundrum worthy of Sherlock Holmes' full attention. If it was an easy problem it would have been solved long ago. The first attempt was by George Darwin (Charles' son): The proto-earth was spinning so fast that the moon was thrown off as a blob and the Pacific Ocean is the "hole" left behind. This was good enough for your average Victorian-age man-on-the-street to swallow, but this theory falls apart almost immediately. There isn't enough spin angular momentum (as orbital momentum) in the system to account for it. Where is the Pacific Ocean water in lunar regolith, ala Apollo mission results? The moon would orbit directly in the terran equatorial plane, not some 17° (6.7° from the solar ecliptic) away. And, a spherical moon-blob would be roche-shredded/taffy- pulled into a long stream of mini-moons; a partial RING system would emerge beyond the Roche Lobe, not a spherical moon. And so G. Darwin's theory slips in to scientific history but it reappears later in an ironic twist.

The next theory is accretion from the original ring system of Terra. Saturn with its rings or the sun with its rings (planets) show how 99%+ goes into the massive spherical core of the accretion vortex but 99%+ of the original spin angular momentum of the molecular birth cloud or dust lane stays behind in orbit as orbital momentum. The terran accretion vortex was just beyond the intense magnetic field (that falls off as the inverse cube) of the proto-sun in the brief T Tauri Phase. Thus is has a pro-grade spin and like a miniature solar system differentiates into refractory core and volatile rich rings. Thus it is reasonably certain that terra had an original ring system similar to Saturn, and its tilt/obliquity can be understood as the coalescence of 2 1/2 vortices that produced the 23.45° tilt similar to Uranus' extreme tilt.

Lunar accretion from a disc/ring system (alone) has many problems such as where are the volatiles in lunar regolith, and why isn't luna orbiting in terra's equatorial plane (like Saturn's natural moons)? And so accretion-from the-original-ring-system doesn't make it as an explanation of how the earth-moon system formed, but it does contain one true fact: Terra did begin with a volatile rich ring system of gas/dust/ planetisimals which is central to the RC /RC scenario. Without it, we wouldn't be here.

The next failed theory is Impact-Splash wherein a "Mars" impacts the proto earth and Splashes out the proto-moon debris into stable earth orbit beyond the Roche Lobe at 16,000 km. Future science historians will refer to this theory as "ptolemaic" or "Lestade-like". It fails on at least 2 basic points: statistics and chemistry.

Since the "Mars" sized impactor has to be in an earth crossing orbit prior to the collision, its orbital area in the solar ecliptic is in the range of 10E16 kmE2 whereas the target area in earth's cross sectional area to impact and relaunch 1% of earth mass beyond 16, 000 km is about 1% of 127,528,700 kmE2, or 1,275,287 kmE2. Also, we know that the entire lunar surface was completely melted (all rock-clocks reset) at 4. 4 B and that the solar system formed 4.6 B years ago, so that the "Mars" impactor had at most 400 million " shots " at terra in those (max) 200 million years. Thus, putting those numbers together gives about a 1 in 125 chance for the Mars impactor to hit the 1% target area on the earth' s terminator in a max 200 million year period. Then when you factor in different orbital inclinations, say from 100 to 10,000, the probability for Impact-Splash happening as stated rapidly approaches ZERO. Since there were only a handful of large bodies in the inner solar system to start with (Wetheril1's analysis) then I-S is seen as highly improbable at best.

The other great failure of I-S is chemistry. When you impact 6.4x10E23 Kg into 6x10E24 Kg at 11 kps, you get some 3.87x10E31 Joules of kinetic energy release, or a GAMMA RAY BURSTER similar to the Shoemaker-Levy comet fragments hitting Jupiter. Even 1% of that energy, 3.87x10E29 J, spread all over the earth's surface is some 7.6x10E10 J/cmE2; MORE than enough to plasma-fry any volatiles present. In other words, I-S produces a true twin to Venus: HOT, dry, sterile. All the 0 of H₂0 would be snarfed up by Si/AI/Mg to make a bit more mantle rock (Si0₂/Al₂0₃/Mg0) and the freed H₂ would float off into space to be carried off b y the solar wind. From a chemical viewpoint then, if I-S had happened as stated, you wouldn't be sitting there reading this; there would have been NO OCEANS on this planet, and thus no biosphere/life film.

0h, reply I-Sers, it must have been a COMET BARRAGE that later added the H₂0 to the planet. This is like equants/epicycles in Ptolemaic Astronomy. There are about 1.35x10E9 kmE3 of ocean water today. The Skylab mission discovered the large hydrogen plume from upper atmosphere solar dissociation of H₂0 so that we know the ocean was even more massive in the past. We know the ocean was basically in place 3.9 B years ago, or .5 B after 4.4 B. If your average comet delivers about .5 kmE3 to the earth's surface as liquid water then you would need about 5.6 comets hitting the earth, and ONLY the earth, each and every year for 500,000,000 years. So, where is that comet-wet H₂O in lunar regolith, or on Venus? The Magellan Mission found that Venusian rock is super ceramic hard because it contains ZERO water as a lubricant. And the excess Du in the Venusian atmosphere is from solar/cosmic radiation (Venus has no real magnetosphere) not some long lost, comet barrage ocean.

Oh well, then the ocean water MUST have come from the mantle, say I-Sers. Wrong again. Geochemists have shown in the "water gap" analysis that at mantle temperatures/pressures the 0 of H₂0 is once again snarfed up by Si/A1/Mg; you just get more rocks, not H₂0 seeping up out of the deep mantle.

So, Impact-Splash is seen as just one more failed moon theory that falls apart on close inspection. Of course many will go to their grave believing in it as a religious faith/professional hubris but science is the search for truth not hubris. So, where did I-S go wrong? Answer: Velocity retardation at perigee. For a large incoming body to be captured into stable earth orbit it has to be slowed down. Otherwise, it is gravitationally slung-shot back into another solar orbit on a parabolic escape orbit. This is exactly how spacecraft are redirected from Jupiter to Saturn to Uranus to Neptune. . . . So, rather than the extreme scenario of direct earth impact there has to be another alternative way to get a lunar mass into the correct orbit around terra. There is in fact another way: RC/RC or Roche Capture/Remnant Core. It explains EVERYTHING.

A plausible scenario then: There were THREE accretion vortices at the Martian radial distance of 2.27x10E8 km in the T Tauri Phase. Two of them coalesced to form Mars with its 25° tilt but the third orbited far away; becoming the junior partner/major moon of Mars: Luna, in a wide ranging, resonant orbit dance.