A new theory of the origin of the terrestrial planets appears to solve longstanding scientific riddles.
Researchers have encountered repeated frustration in their efforts to agree on how Earth came to have a significant amount of water. Meanwhile, the giant impact theory of the origin of the Earth-Moon system requires an elaborate scenario that seems impossible to verify and is undermined by new evidence. And none of the scores of hypotheses of the cause of the mass extinctions of prehistory has gained acceptance. Yet the new theory of the origin of the terrestrial planets can solve all three problems, and minor ones as well.
The presence of water on Earth has long stood out as an anomaly in the formation of the solar system. The solar wind and radiation pressure pushed water molecules out beyond the “snow line” around 4.5 AU (Astronomical Unit—the distance of Earth to the Sun) where it can be found in abundance in the ice giants Uranus and Neptune as well as in moons and comets.
A common explanation for the oceans—that Earth was bombarded by water-bearing comets—has never been substantiated and has always seemed hard to believe. The ratio of deuterium to hydrogen in comets is roughly double the ratio in the water on Earth, except for those that formed close to the orbit of Jupiter. Also, the flux of comets required would be several orders of magnitude larger than appears realistic, given estimates of numbers of comets in the solar system, including its outer fringes. Similar considerations hold for asteroids, many of which are not known to carry large amounts of water. However, some asteroids from the asteroid belt and from the area between the early-stage Jupiter and Saturn may have delivered a small amount of water to Earth, and embryos from the outer asteroid belt might have delivered more. Still, as one researcher states, “the bulk of Earth’s water must have been supplied during its formation, rather than steadily throughout geologic time.”(1)
A second model—that icy planetesimals from the outer solar system drifted into the early inner nebula—has been proposed to account for the presence and movements of water in the inner solar system in its nascent years.(2) But no claim is made that this model actually accounts for the large oceans on Earth or for the discrepancy between them and the much smaller amount of water on Mars and its virtual absence from Venus.
New theory and findings regarding the origin of Venus, however, can explain why Earth has so much water.
We now have a commonsensical explanation of ancient myths that Venus emerged from Jupiter—that Venus was pulled from the outer solar system by the gravitational field of Jupiter and passed near the gas giant, thereby heating up from the tidal force caused by Jupiter’s immense gravitational field, losing its presumed ice, gaining a rock-filled cometary tail stripped from its own surface, and being steered into the inner solar system. All this seems to have happened around 2500 B.C. when Venus first began to be mentioned by the ancients. In addition, an Egyptian iconographic source clearly depicts Venus as a comet and appears in a context that can be considered to make it probative.
In the early years of the solar system, Jupiter’s gravitational field is generally thought to have directed a high number of planetesimals into orbits on the fringes of the solar system but also some into the inner solar system. So, too, we can suppose that at an early stage in Earth’s history, it was orbiting outside of Jupiter and then was pulled by Jupiter into the inner solar system around 4.5 billion years ago.(3)
The anomalously high level of neon in the Earth’s atmosphere (4) may also be a legacy from the time of Earth’s origin in the area beyond Jupiter. However, the Earth, Mars, and Mercury may have been pulled into the inner solar system by Jupiter’s gravity before they had had time to accumulate gas, or they might have lost any gas they originally had (as Venus might also have done) in the peripheral passage of Jupiter.
While Jupiter’s gravitational pull ensures that no large object can remain for more than perhaps 30 million years in the Jupiter-Saturn slot (5), rapid accretion in the early solar system would have permitted Earth quickly to attain a high mass by impacts with planetesimals. Meanwhile, we know that the regions around the outer planets are exceptionally clear of debris, suggesting that it was all swept up long ago by Saturn, Uranus, and Neptune. But there is one exception.
The slot between Saturn and Uranus appears to contain zones where debris could have orbited from the beginning of the solar system until the present without being vacuumed up into these large planets. However, this area is also very clear of debris. How to explain this? One explanation would be that this was the slot of Venus, which cleaned up this debris until, shortly before 2500 B.C., Saturn’s gravitational pull, a collision, or some other cause steered it in the direction of Jupiter, which directed it into the inner solar system. (This might have been the pathway of Earth, Mars, Mercury, and the Moon billions of years earlier; at least this would be consistent with the close match of oxygen isotope ratios between Earth and Moon, suggesting that they originated in the same region.) Until then, such a distant planet would not have been visible to skywatchers on Earth.
Various physical features of Venus—e.g., that it appears old yet has a new surface, that it contains 150 times as much deuterium relative to hydrogen compared to Earth (a sign of a large amount of water in the past), and that it seems to have a residual tail (the famous Black Drop, plus a long gaseous tail)—match the explanation that it passed near Jupiter into the inner solar system. In light of this, the perception that Earth appears to have undergone a parallel process billions of years before should challenge scientists to hunt for similar kinds of evidence regarding the Blue Planet.
All four terrestrial planets, and the Earth’s Moon as well, presumably had highly eccentric orbits when they first entered the inner solar system. Curiously, Mercury (21% eccentricity) and Mars (9%; varies from 0 to 14%) still possess the most eccentric orbits of the eight planets, but Earth (<2%) and Venus (<1%) have exceedingly circular ones. The apparent speedy circularization of the orbit of Venus has been one of the main (but inaccurate) criticisms of the ancient accounts and evidence that suggest that it emerged from Jupiter and careened around the inner solar system.
What properties do Earth and Venus share that would have led their orbits to become circular? Several hypotheses seem worth investigating.
First, the Earth has oceans, and both planets have thick atmospheres, that could have created plasticity that reduced the eccentricity of their orbits. Second, both were very hot in their early years in the inner solar system, and this heat could have increased their plasticity and hence made them more pliant to the gravitational pull of the Sun, which would have tended to render their orbits more circular. Third, the giant cometary tail of Venus and the Earth’s Moon could have in parallel fashion tended to lessen the eccentricity. Fourth, they both interacted with other planets in ways that could have made their orbits more circular. Fifth, Venus seems to have had an ovoid shape until its surface had cooled sufficiently to take on a somewhat more spherical shape.(6) Comet Venus appears to have moved in the direction of its major axis, and this would have added to its length and malleability under gravitational forces and hence its tendency to circularize its orbit. An originally ovoid Comet Venus would be consistent with the extremely slow, retrograde rotation of the current Venus, as would befit a planet that had only recently gained a largely spherical shape.
In fact, scientists generally recognize that rapid circularization must occur in the presumably originally highly elliptical orbits of short-term comets that end up with circular orbits, otherwise they would lose their material when interacting closely with the Sun on hundreds of thousands of highly elliptical passes. Comet Venus was evidently one of such comets, even if we do not know the actual reasons that these comets rapidly circularize their orbits.(7) Velikovsky’s theory suggests that electromagnetic forces also played a significant role in rapidly circularizing Venus’ orbit, though it does not specify how they would do so.
In keeping with OSSO, one can see a solution to the puzzle of the origin of the Earth-Moon system that makes sense of the capture theory, long dismissed as implausible because of tight parameters of velocity and location that the Moon would need to fulfill. Initially, a mid-sized protoplanet (“Merculuna”), which had come from an orbit close to the original orbit of Earth outside of Jupiter, would have heated up tremendously on its passage around the gas giant. The gravitational force exerted by Jupiter would have separated Merculuna into two pieces. One, containing the main iron core, would have continued on into the inner solar system, where it became Mercury. The other, composed of a small amount of iron but mostly of silicate rock, with most of the volatiles including water burned away by the heat, and with a long cometary tail of rock and dust shed from its surface, would also have escaped Jupiter and proceeded into the inner solar system.
This molten Comet Moon would have been malleable and, with its long tail, prone to becoming entangled with the gravitational field of Earth. Its separation from Mercury would have left it skewed both in shape and in elemental distribution, with the separation stripping crust off the near side. The original basin now filled with the giant, irregular Oceanus Procellarum on the near side, for instance, was clearly not created by an impact and may be a scar left by a separation event. The resultant skew may have made the Moon even more susceptible to capture by Earth’s gravity. Likewise, it is perhaps not a coincidence that almost all of the few depressions filled with maria on the far side are along the periphery.
The tight parameters of the old capture theory would give way to generous parameters within which Comet Moon—exceedingly responsive to tidal forces—could have easily fit; and it would end up orbiting the Earth (itself perhaps still in a somewhat molten state that would enhance its responsiveness to tidal forces from the Moon) in an initially highly eccentric but gradually circularizing orbit, slowly cooling and losing its cometary tail yet retaining the memory of its molten state in the magma ocean of its surface and in what has now been shown to be a rather small molten outer core and an extremely hot, dense, solid inner core.(8) (Mercury possesses a molten core.(9)) This scenario of a Moon with a highly eccentric orbit upon capture provides a nice match with data regarding the Moon’s three principal moments of inertia, which are not consistent with the giant impact theory, though they can be stretched to appear to fit it.(10)
The recent finding that lunar melt inclusions protected by crystals contain fairly high levels of water as well as other volatiles (11) seems consistent with this scenario of high, steady heat that caused the outgassing of all volatiles except those in the crystals whereas it seems very inconsistent with the impact theory of the origin of the Moon, which entails an ultra-high energy event that would presumably have melted the crystals. As the authors of the lunar melt inclusion article note, their evidence rules out the arrival of water after the heating that the crystals withstood; the water was pre-existing—a good match with an origin in an icy Merculuna in the outer solar system.
In effect, Comet Moon was hot enough to lose surface matter that then formed a tail, to outgas almost all volatiles, to have a magma ocean, and to be sufficiently malleable that the Earth’s gravitational field could capture it; but not so hot as to destroy the crystals that encapsulated volatiles or to smooth out the indented surface where the near side had been torn apart from Mercury.
This theory of the origin of the Moon possesses several other advantages over the current widely accepted Giant Impact theory, including being less dependent on a complicated sequence of events subsequent to the impact. The theory also provides explanations of Mercury’s molten core; relatively high orbital eccentricity; very high iron content; and skewed distribution of magnetic field so that the northern hemisphere has a higher magnetic field,(12) consistent with a separation event in which Jupiter’s gravitational field pulled material from the southern hemisphere. (Earth’s geomagnetic field is similarly skewed.) Instead of two giant impacts with complicated post-impact scenarios, a single separation event during the peripheral passage of Jupiter would account for the distinctive features of the Moon and Mercury.
Because Mercury has 4.5 times the mass of the Moon, it would have been more resistant to heating up during the peripheral passage of Jupiter than the Moon was, consistent with the irregular distribution of its iron, which would otherwise have pooled in spherical configuration in the core. Mercury would also have been less subject to Jupiter’s gravitational pull after separation and so might have followed a slightly more distant trajectory from Jupiter. The consequently relatively lower (but still high) temperature could explain why Mercury has much higher levels of potassium and sulfur, which presumably would have been outgassed from the very hot Comet Moon. New data from the MESSENGER orbiter are very consistent with a Mercury-Moon separation event whereas they undermine competing hypotheses such as a giant impact that caused Mercury to lose a putative original thick coating of silicate rock.(13)
The measured maximum intensity of Mercury’s magnetic field is 400 nanoteslas, while the maximum intensity of the Moon’s is 313 nanoteslas. Given the very wide ranges possible, these make a rather close match.
When did all this happen? One hypothesis is that the separation of the Moon from Mercury as they passed Jupiter occurred between 4 billion and 3.8 billion years ago. Then they both passed repeatedly through the asteroid belt on their initially highly eccentric orbits and were heavily bombarded there before moving to their present orbits, just as happened with Venus for a much briefer period. This scenario would obviate the need for the hypothesized anomalous Late Heavy Bombardment yet be consistent with the geological evidence of at least one or two major impacts on the Moon around 3.7 billion years ago.
Comets Earth and Mars
According to OSSO, Jupiter’s gravitational field would also have pulled the Earth into the inner solar system. As mentioned above, the close match between the oxygen 16 and 18 ratios of the Earth and Moon suggests that the Earth was originally formed in the same region of the solar system beyond Jupiter as the Moon. Tidal heating caused by passing Jupiter would account for evidence that the Earth’s surface once had a magma ocean, and shedding of surface materials could have created a comet tail. But several factors must have kept the Earth from losing virtually all its water, as Venus seems to have. First, Earth may have had a more massive ice covering than Venus. Second, it may have had a higher proportion of water ice compared to the methane ice and ammonia ice of early Venus. Third, a thick atmosphere might have prevented the outgassing of Earth’s water, though presumably a great deal was lost in this way. Fourth, Earth contained and still contains a great amount of water stored in deep rock formations; conceivably, so does Venus.
As with the Moon and Mercury, it appears that Mars and the Earth originally formed a single protoplanet (“Terramars”), and the immense gravitational and magnetic fields of Jupiter pulled Mars out of the Earth as the protoplanet passed by. Here are some reasons to think that this is in fact correct: 1) Earth and Mars are the only terrestrial planets with significant amounts of water (Mars had much more in the past); 2) the higher density of the Earth would be consistent with a larger body from which the smaller, less dense Mars was extracted in a separation event, on the analogy with Mercury and the Moon; 3) the 9.5:1 ratio of mass between Earth and Mars is likewise consistent with such an extraction; and 4) the sharp difference between the northern and southern hemispheres of Mars could have arisen from a separation event that left the northern hemisphere crust thin and vulnerable to subsequent remodeling by flood basalts provoked by other causes, though a later giant impact (14) also played a major role in shaping the northern hemisphere. The extreme extent of the Borealis planitia, its irregular, non-elliptical shape, and the 2-3 km scarp that surrounds it are signs of such a pre-impact birth scar, fittingly all on the opposite side of the planet from the tidal bulge of the southern highlands, which is not accounted for by the giant impact alone.
The remanent magnetism in banded stripes of alternating polarity in Mars’ southern hemisphere is reminiscent of the magnetism of the spreading zones beneath the Earth’s oceans (but much stronger than Earth’s equivalent) and indicative of a powerful, dynamo-driven alternating dipole magnetic field. It represents an anomaly in a Mars that lacks a dynamo and has only a tiny, non-dipole magnetic field. In the context of OSSO, however, it can be interpreted as having been formed by the original magnetic field of Terramars. The catastrophic passage past Jupiter and interaction with the giant planet’s immense gravitational and magnetic fields greatly diminished the dynamo in Earth while ending it entirely in Mars. In turn, this suggests that Earth’s plate tectonics and geomagnetic field go back to Terramars. Since weathering and plate tectonics have destroyed any evidence of the original surface of the Earth, Mars’ southern hemisphere, though heavily bombarded, contains the only remaining original surface of Terramars.
In an early version of the old, generally discredited fission theory of the origin of the Earth-Moon system, the Pacific Basin was a scar left over from the separation of the Moon from a rapidly rotating Earth. But according to OSSO, the geomagnetic field, modeled as if a bar magnet dipole were buried inside the Earth, is displaced hundreds of kilometers off center in the direction of the Pacific Basin because Mars was separated from Earth there as Terramars passed Jupiter. In theory, not only the skew of the geomagnetic field but also the Pacific Basin itself and the Hawaiian and South Pacific hotspots are physical leftovers from the separation of Mars from the Earth. So is the South Atlantic Magnetic Anomaly on the opposite side of the world whereby the Van Allen radiation belt comes close to Earth as a consequence of the skew in the geomagnetic field.
Given the long, tangled history of plate tectonics, continental drift, and other intervening phenomena, the present-day Pacific Basin has of course changed considerably since its origin in the primeval Panthalassic Ocean, itself a descendant of the original Mirovia Ocean. Still, seismic anisotropy reveals a unique pancake-like pattern at 160 km depth, approximately centered on the island of Hawaii (15), though Mars’ emergence was not necessarily centered on the Hawaiian hotspot, and it may have left an oval wound extending into the South Pacific with its hotspots and anomalies.
A separation of Earth and Mars would reduce the number of Peripheral Passages of Jupiter by one, thus in a sense simplifying the entire OSSO theory. In two cases (Merculuna and Terramars), a separation event would have occurred. In the third one (Venus), the pull of Jupiter’s gravity might have caused an elongation of the planet into an ovoid shape, as depicted in ancient iconography, suggesting that Venus, too, had been very close to experiencing its own separation event while passing Jupiter—i.e., that stretching to the point of separation was a normal process during a Peripheral Passage of Jupiter. Just three instances in 4.5 billion years help overcome the objection that it was very unlikely that Jupiter would throw the planets into exactly the right direction to enter the inner solar system (without hitting the Sun) instead of dispatching them to the far reaches of the solar system. These were appropriately rare events.
Thus we can explain the anomalous lopsidedness of the terrestrial planets as a consequence of Jupiter’s gravitational pull during Peripheral Passages. The southern hemisphere of Mars and the far side of the Moon are both tidal bulges that were pulled out by Jupiter’s gravitational field. On Mars the northern hemisphere crust is 35 km thick while the southern highlands crust is 80 km. On the Moon, the near side crust is 60 km thick while the far side crust is 100 km thick. The center of mass of Mars is displaced to the north by 3.5 km from the center of figure, while the center of mass of the Moon is displaced about 2 km toward the near side from the center of figure. Meanwhile, Mercury has a considerably higher amount of iron in its northern hemisphere than in the south, while both the Earth’s inner core and its center of mass are asymmetrical. In both cases of separation, the lighter molten rock would have more readily been pulled by Jupiter’s gravity into the tidal bulges. Of course, there would have been no corresponding tidal bulges on the opposite side of Mars and the Moon to Jupiter because the protoplanets would have separated into two parts there.
We can expect that the larger partner planet emerging from the separation would have a higher density, being more resistant to the tidal force from Jupiter than the smaller one; and this is indeed the case: the uncompressed density of Mercury is 5.40 g/cc while that of the Moon is 3.35, and the density of the Earth is 4.20 while that of Mars is 3.30. Venus has a density of 4.20, which is roughly in line with that of the Earth if one considers that the separation of Mars from Earth caused only a relatively minor loss of mass; and the density of Venus is situated between the densities of Mercury and the Moon. In other words, crustal thickness, displacement of center of mass, and uncompressed density of the terrestrial planets all yield results consistent with being the consequences of a Peripheral Passage of Jupiter.
One can predict that similar bulges (Ishtar Terra and Aphrodite Terra are the leading candidates, perhaps both arising as a less-than-total lock-on of Venus to Jupiter during Peripheral Passage dragged the tidal bulge across the surface of Venus) and distribution of elements, from light to heavy across the planet, will be found on Venus. (Tidal locking could also have caused the anomalous very slow, retrograde rotation of Venus.) The first description of the shape of Venus, by Francesco Fontana in 1646, noted that “the orb of Venus is not a perfectly rounded sphere, for if the circle were completed of Venus as seen in these observations, it would not be perfectly round, but an oval shape.”(16) Indeed, from certain angles Venus still appears to have an ovoid shape, as in this 1974 NASA image.
OSSO must lead us to revise current views on
1. the importance of impacts. They clearly played a significant role but not so dominant a one as has been supposed. Close encounters have shaped the inner solar system in fundamental ways;
2. the presence of iron and other refractory elements in the early inner solar system. There is no sign that substantial amounts of them accreted to the terrestrial planets after they migrated to the inner solar system. So it appears that, while the larger dust particles spiraled into the Sun from Poynting-Robertson drag, radiation pressure and solar wind pushed the smaller particles of refractory elements out to the asteroid belt and volatiles to the “snow line” (4.5 AU) (hence the thick dust in the first image above is misleading). In a kind of astrophoresis, radiation pressure and solar wind would have pushed each element and molecule out to a characteristic distance or farther. In turn, inferences from the supposition that Mercury, with its high iron content, formed in its current location must be revisited. For instance, we cannot infer that the cores of Uranus and Neptune contain little or no iron; it would have been readily available if they formed in the vicinity of Jupiter and Saturn. Evidence for the recent finding that asteroids of the CL chondrite class were the source of Earth’s volatiles can be reinterpreted to mean that CL chondrites and Earth originated in the same region of the solar system (17);
3. the Late Heavy Bombardment, which appears never to have happened;
4. the Giant Impact theory of the formation of the Earth-Moon system, which is incorrect; and
5. Venus. OSSO offers telling evidence and explanations that make much more believable the mythical accounts of the Ancients and, following them, the interpretation of Immanuel Velikovsky that Venus emerged from (in fact, passed close to) Jupiter and entered the inner solar system shortly before 2500 B.C. It provides simple, parsimonious solutions to otherwise poorly explained anomalies of this remarkable planet.
OSSO also leads to a theory of the causation of great mass extinctions of prehistory (they were the result of encounters of Earth and Mars with its eccentric orbit) for which there is telling evidence: The Martian Theory of Mass Extinctions.
A Correct Theory?
In addition to providing a good match for the entire range of evidence, which this theory appears to do, a correct theory ought to resolve in an especially powerful manner at least a few anomalies that competing theories fail to explain in any persuasive way. OSSO offers three such solutions: for the reversed magnetic striping on the southern hemisphere of Mars (the southern hemisphere is the original surface of the Pacific Basin region of Terramars), for the lopsidedness of all the terrestrial planets (it is the result of tidal forces generated by Jupiter’s gravity), and for the Pacific Basin’s peculiar features—its round shape, its unique geology, and the skew in the geomagnetic field over the North Pacific (they were formed by the emergence of Mars upon passage of Jupiter). In each case, rather than relying on a convenient ad hoc solution (e.g., an impact), the cause is intrinsic to the workings of OSSO.
Therefore, it seems hard to deny that OSSO is correct.
1. J. Kelly Beatty, Carolyn Collins Petersen, and Andrew Charkin. The New Solar System. 4th ed. Cambridge MA: Cambridge University Press, 1999, p. 183; A. Morbidelli et al. (2000) “Source regions and timescales for the delivery of water to the Earth”. Meteoritics & Planetary Science 35, 1309-1320. Largish ice formations in shadowed polar craters on Mercury are also ascribed to cometary or asteroidal impacts 18-53 million years ago but could at least as well be explained by upwelling and freezing of aboriginal deep, pure water in response to the shock of otherwise dry impacts. David J. Lawrence et al. “Evidence for Water Ice Near Mercury’s North Pole from MESSENGER Neutron Spectrometer Measurements.” Sciencexpress/ http://www.sciencemag.org/content/early/recent/29 November 2o12.
2. Cyr, Kimberly E. et al. (1998) “Distribution and Evolution of Water Ice in the Solar Nebula: Implications for Solar System Body Formation”, Icarus 135, 537-48
3. The idea that the origin of the Earth as well as of Venus was connected with Jupiter can be found in James P. Hogan. Kicking the Sacred Cow: Heresy and Impermissable Thoughts in Science. Riverdale, New York: Baen, 2004. Hogan hypothesizes the emergence of the two planets from the gas giant. The idea that Earth originated in the outer solar system, thereby accounting for its water, has been suggested by various researchers. Long ago Thomas Jefferson Jackson See argued that the Moon had come from the outer solar system, perhaps pulled by Jupiter’s gravity. Findings that billions of planets are wandering through space quite unattached to any galaxy suggest that Jupiter-like planets regularly fling them out of their solar systems, but we can see that it is only on rare occasions that one of such planets would be flung in such a way as to end up orbiting the very small target of the local sun. “Cast Adrift in the Milky Way, Billions of Planets, All Alone.” The New York Times, May 18, 2011.
4. Morbidelli et al., Ibid.
5. Stuart Ross Taylor. Solar System Evolution: A New Perspective. New York: Cambridge University Press, 1992, 27; see also the second edition (2001). The details regarding the outer solar system are taken from Taylor and from Michael A. Seeds. The Solar System. 5th ed. Belmont, California: Thomson, 2007.
7. Charles Ginenthal. Carl Sagan & Immanuel Velikovsky. Tempe AZ: Falcon, 1995, p. 404
8. http://news.sciencemag.org/sciencenow/2011/01/at-long-last-moons-core-seen.html?ref=hp. The concept of a hot, deformable Moon (but without a cometary origin or tail) can be found in R.R. Winters and R.J. Malcuit, “The Lunar Capture Hypothesis Revisited,” The Moon 17 (1977), 353-8. The authors calculate that reasonable parameters would permit about one-fourth of the energy of deformation to be dissipated, thus permitting capture of the elastic Moon by the Earth to occur. The addition of a cometary tail would reinforce this conclusion. In other words, the capture of Comet Moon has been (approximately) mathematically modeled. Generalizing the results, we can see that they would also apply to the rapid circularization of the orbit of Venus, though the narrow time constraint there requires further modeling.
9. J.L. Margot et al. “Large Longitude Libration of Mercury Reveals a Molten Core.” Science 4 May 2007, 10-4
10. Ian Garrick-Bethell, Jack Wisdom, Maria T. Zuber, “Evidence for a Past High-Eccentricity Lunar Orbit,” Science 313 4 August 2006, 652-5
11. E.H. Hauri et al. “High Pre-Eruptive Water Contents Preserved in Lunar Melt Inclusions.” www.sciencexpress.org / 26 May 2011 / 10.1125/science.1204626
12. The New York Times, 17 June 2011
13. Richard A. Kerr, “Mercury Looking Less Exotic, More a Member of the Family”. Science, Vol. 333, 30 September 2011, 1812 and the detailed articles in the same issue
14. Jeffrey C. Andrews-Hanna, Maria T. Zuber, W. Bruce Banerdt, “The Borealis basin and the origin of the martian crustal dichotomy,” Nature 453, 26 June 2008, 1212-15
15. C. Gaboret, A.M. Forte, J.-P. Montager. The unique dynamics of the Pacific Hemisphere mantle and its signature on seismic anisotropy. Earth and Planetary Science Letters 208 (2003), 219-33. See especially Figure 4, p. 227. In general, the geology of the Pacific Basic contains many features consistent with an emergence of Mars. In a list of hotspot/melting anomaly locations, for instance, Pacific plate hotspots score consistently much higher in terms of flow rate than Atlantic and Indian Ocean counterparts, and they are only matched by several at the near edges of the adjacent Nazca and Australian plates (G.R. Foulger and D.M. Jurdy, eds. Plates, Plumes, and Planetary Processes. Boulder CO: Geological Society of America, 2007, pp. 65-78, replicated in G.R. Foulger. Plates vs Plumes: A Geological Controversy. Oxford: Wiley-Blackwell, 2010, pp. 15-6). The 1-km high Hawaiian swell and the 500-m high South Pacific Superswell also mark the Pacific Basin as idiosyncratic. In effect, the controversy over mantle plumes might well derive in large part from the anomalies left by the emergence of Mars.
16. Helge Krogh, The Moon that Wasn’t. The Saga of Venus’ Spurious Satellite. Basel: Birkhauser, 2011, 10
17. C.M.O’D. Alexander et al. The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets. Science. Vol. 337, 10 August 2012: 721-723.