Gary S. Hurd, Ph. D.
An Answers in Genesis article by Michael J. Oard, Problems for 'giant impact' origin of moon (2000), is sadly typical of their standard fare: there is never absolute certainty in science, and not every question is resolved in complete detail therefore science is bunk and God created everything just a few thousands of years ago. If that were not enough, AiG contributors rarely bother, or perhaps lack the ability to even get the scientific questions properly framed and presented.
Oard, a retired meteorologist, seems to have largely based his article on two scientific sources, one published in Nature, Lissauer (1997), and one from Science, Halliday & Drake (1999). As we shall see in a moment, he really took his paper from fellow creationist Jonathan Sarfati (1998). Oard gets it wrong in his first sentence, "Evolutionary astronomers have great trouble accounting for the origin of the moon." Evolution, or "evilution" in creationese, and astronomy are obviously quite separate sciences, although there are obvious interdisciplinary studies. Secondly, Oard has greatly exaggerated the magnitude of the conceptual and theoretical problems associated with the "accounting" he demands. Two errors of fact and reasoning per opening sentence are about par for AiG. For example see "Dino Blood Redux" or "Boiled Creationist with a Side of Hexaglycine: Sarfati on Imai et al. (1999)".
Oard didn't do much better in his second sentence either, "There have generally been three competing hypotheses, but they all have serious physical problems: ..."
The critical error there is his use of the word "generally". Writing in 2000 CE no one informed on the then current astronomical understanding could have suggested that the hypotheses listed; the fission hypothesis (eg. proposed in 1879), the coaccretion hypothesis (called the Condensation, or co-creation theory by Oard), and the capture hypothesis, were anything other than historically rejected ideas. They had indeed been rejected in the early 1970s because, like all rejected scientific hypotheses, they had not succeeded in matching with independently observed phenomena, in particular the chemical compositions of the Earth and Moon (O.Neil, 1991), and the improved computational results for the physical dynamics of the Earth/Moon system. It was based on these observations that the Giant Impact Hypothesis was first proposed in the mid 1970s. This is of course Oard's next error of fact, because he claimed in his paper that the impactor hypothesis was only developed in the 1990s. These factual errors are not trivial, because they are all the result of Oard misrepresenting referenced scientific sources he supposedly used. This degree of error could not be by accident.
To explore how Oard abused science generally and Lissauer specifically, consider the following quotes:
Oard, "He even cited an only half-joking statement in a university astronomy class about 20 years ago by Irwin Shapiro: since there were no good (naturalistic) explanations, the best explanation is that the moon is an illusion! This counts as strong evidence for the moon's special creation".
Lissauer, "All in all, developing a theory of lunar origins that could make sense of data obtained from the Apollo lunar landing programme proved very difficult. So much so, in fact, that when I took a class on our planetary system from Irwin Shapiro two decades ago, he joked that the best explanation was observational error — the Moon does not exist".
The differences in intent and meaning (and humor) between Lissauer's own words and Oard's gross misrepresentation should be clear to the most naive observer. Plus, without explanation or any justification, Oard claims a remembered joke from the 1970s as, "... strong evidence for the moon's special creation". Could anyone other than a creationist make such a bizarre claim? (Well, yes there are crystal gazers, palm readers and astrologists, but other than people of that ilk)?
Oard also commits a form of academic slight-of-hand by mentioning that Lissauer is commenting on Shigeru Ida et al., which gives him another scientific reference, but one he never actually addressed. What did Ida et al. have to say about the origin of the Moon? From their abstract, "Theoretical simulations show that a single large moon can be produced from such a disk [circumterrestrial disk of debris generated by a giant impact on the Earth] in less than a year, and establish a direct relationship between the size of the accreted moon and the initial configuration of the debris disk".
Next Oard cites a paper by the universally acclaimed expert about everything, Herr Doktor Professor Anonymous. Written for Discover magazine in 1997, the anonymous article referred to some computational models which resulted in impact scenarios that failed, or as Oard wrote, "...the results have strained the hypothesis to the breaking point". The fundamental error Oard makes here is common to creationists - the testing of scientific hypotheses is always to the breaking point. In scientific work the goal is never to selectively pick bits and pieces of reality that can shore-up failed superstition, but to rigorously test every notion with every bit of available information. The history of science is littered with "beautiful theory destroyed by ugly fact".
Oard moves on to a paper by Halliday & Drake (1998) that appeared in Science magazine. This was a review of some papers presented to the "Origin of the Earth and Moon Conference", Monterey, December 1998. Halliday & Drake early in their paper said of the Giant Impact Hypothesis, "A recent conference in Monterey, California, showed that, although a general picture may be emerging, many issues remain hotly debated". Most of those issues raised have, in the intervening seven years, been resolved. See the review by Herbert Palme (2004), and atmospheric models by Genda & Abe (2003). In their review Halliday & Drake noted that, "In spite of a growing consensus, some workers still dislike the entire Giant Impact Theory, on both dynamical and geochemical grounds". None the less, they correctly concluded, "We have recently come a long way in obtaining hard constraints on the origin of Earth and the moon. The issues have changed from discussion of whether or not there was a giant moon-forming impact to debates about the accretion rates of the Earth and the chemical, isotopic, and physical effects of such catastrophic accretionary scenarios".
As an example of that conclusion, one paper presented at that important conference was, "Is There An Alternative For The Huge Impact-Generated Atmosphere?" Gerasimov et al. (1998). Their short answer = No, except ...! They also pointed out that significant contributions were apparently made to the Earth's composition from later, smaller impacts (for example see Chyba et al. 1990, Bada et al. 1994, Blank et al. 2001). Equally obvious are the later contributions of weathering and most importantly life itself, (Canfield et al. 2000, Catling et al. 2001, and for a strong background paper see Holland 1999).
Oard next mentioned briefly a paper by Ruzicka et al. (1998) and quoted from their conclusion that, "... there is no strong geochemical support for either the Giant Impact or Impact-triggered Fission hypotheses". Oard has presented this in a misleading manner leaving an average reader the impression that Ruzicka et al. reject both hypotheses. We need to read this with some care. First, Ruzicka et al. (1998) are arguing that the data available over seven years ago could not select between the "Giant Impact" and the "Impact-triggered Fission" hypotheses. The Impact-triggered Fission Hypothesis was a hybrid of the impact and 1879 fission hypotheses. As described by O'Neill in 1991, it proposed that a giant impact resulted in a Moon largely comprised of crustal Earth - a hypothesis that was later highly modified (see Wänke, 1999). Ruzicka et al. (1998) further argued that the amount of lunar material that derived from the protoEarth was extremely low (O'Neill had proposed up to 80%). A later paper by Ruzicka et al. (2001) goes even further and argues that a giant impact could have produced the Moon with negligible material derived from the protoEarth, overturning both O'Neill and Wänke as well as others. The geochemical questions regarding the origin of the Earth/Moon system are indeed complex. But this is how science works best - by more sensitive and accurate studies acquiring new data. The critical insights of the last decade are reviewed by Palme (2004) which will be discussed below.
Sarfati gets Plagiarized
The capping irony is that Michael Oard's "paper" is merely a trivial reworking of AiG creationist Jonathan Sarfati's 1998 bloviation, "The moon: the light that rules the night". I was a college professor for many years and I regretfully flunked more than one student for plagiarism less blatant than that of Oard. For example, both of these AiG hacks take issue with the "... the unsolved problem of losing the excess angular momentum". (Yes, Oard used that identical phrase and many more directly from Sarfati, he even took the distorted reference to Irwin Shapiro's humorous remark from Sarfati). Sarfati presented this "excess angular momentum" as a "proof" that the radiometric dating of the Moon's formation could not be correct, and that this for some reason disproved the theory of evolution. Oard seems happy just that it is a "problem" for them "evilusionists". But like all creation science, their "proofs" and "problems" are more apparent then real. As pointed out by Palme (2004):
An off-center collision of a Mars-sized projectile with Earth would produce the present high angular momentum of the Earth-Moon system and would eject enough material into Earth orbit so that the dust could accumulate to form the Moon.
Sarfati has his own problems with reality beyond those parroted by Oard. For example, Sarfati claims that there are special purposes behind the Divine creation of the Moon. The first of these is "... for the moon is to show the seasons which will allow the invention of calendars by man... so people could plant their crops at the best time of the year". The event of seasons is of course the combined result of the elliptic orbit of the Earth around the Sun, and the Earth's canted spin axis. The physical reality is that the Moon does not show the seasons, and as a simple point of archaeological and historical fact, agriculturalists employ solar calendrics. The contrasting use of Lunar and Solar calendars between nomads who can't employ solar observation, and sedentary agriculturists who do is even thought to be reflected in the biblical story of Samson and Delilah.
Current State of the Art
In his review "The Giant Impact Formation of the Moon", Science, Herbert Palme (2004) examined computational simulations of the proto-Earth/giant impactor collisions demonstrating that both bodies were differentiated into core/crust systems and that the bulk of the lunar mass is from the crust of the impactor.
It is important to read the opening paragraph of his paper which previews the main results of decades of scientific progress in lunar studies which he later discusses:
During the past 30 years, a scenario in which a giant object collided with Earth has emerged as the leading theory for Moon formation. An off-center collision of a Mars-sized projectile with Earth would produce the present high angular momentum of the Earth-Moon system and would eject enough material into Earth orbit so that the dust could accumulate to form the Moon. The first numerical simulations of this hypothesis nearly 20 years ago used about 3000 particles whose trajectories were followed through the entire collision. In a new set of simulations published in Icarus, Canup used up to 120,000 particles and a new equation of state that describes the behavior of material at extreme pressures and temperatures. Although the results are not very different from the earlier calculations of similar impacts, they include the most detailed predictions to date of the provenance of the material that makes up the Moon. This is crucial for geochemical arguments relating Earth mantle and Moon. [Original references deleted]
Several of Sarfati and Oard's key arguments are found to be rejected; 1) the Giant Impact Hypothesis is not a sudden phenomena of the 1990s, 2) the "angular momentum problem" is not a problem, 3) the "equations of state" that Oard claimed rendered the simulations unrealistic were vindicated (..."the results are not very different from the earlier calculations of similar impacts, ..."), 4) the impactor need not be larger than Mars (as opposed to 2X- Sarfati, or 3X- Oard), and as we see in the following material, 5) geochemical questions, largely about trace element isotope ratios, are resolved:
"The material that ends up in orbit around Earth and from which the Moon is made comes predominantly from the leading, outer regions of the projectile. These regions do not collide directly with Earth, and after the initial impact they expand to distances of several Earth radii where they are placed into stable Earth orbits by gravitational torque. The impactor core loses energy by its more direct collision with Earth, is thus more strongly decelerated, and (after distortion by gravitational forces) largely collides again with Earth." Palme (2004).
Origin of Moon material. Mapping of results of a giant impact simulation onto the original configuration of Earth and impactor; x and y axes are in units of 1000 km. (A) The red particles escape the system, the yellow-green particles end up in the orbiting disk from which the Moon is made, and the blue particles accrete to Earth. (B) The highest temperatures are reached for material at the location of the first collision. <Reprinted from (2), figure 3, with permission from Elsevier.> CREDIT: R. CANUP/SOUTHWEST RESEARCH INSTITUTE. GIF image called from Science 2004.
What is the short form of the current hypothesis regarding the lunar origin? Simply, around 4.5 billion years ago, the proto-Earth was struck an off-center blow by a planetesimal about the size of Mars. Both objects had differentiated structures separated into cores and weathered complex mantels (for example, see Zolensky et al. (1999), and Whitby et al. (2000) for weathering products observed in meteorite). The majority of the lunar mass is formed from the mantel of the impactor, the core and the majority of the impactor's atmosphere became entrained as part of the Earth. Actually, the scientific argument is over - all that is left is the mopping up of the details.
Oard copied his "ideas" and much of his text from fellow AiG creationist Jonathan Sarfati. There is so much overlap that any debunking of Oard is also applicable to Sarfati. Sarfati acknowledged that much of his paper derived from a book by John C. Whitcomb and Donald B. DeYoung, The Moon: Its Creation, Form and Significance published in 1978. Today we find some of their arguments still recycled in the new creationism, Intelligent Design, as in the book The Privileged Planet (2004). This is notable because the ID creationists claim to be totally distinguished from the discredited "scientific creationism".
Oard's biggest, and most revolting lie was that the Giant Impact Hypothesis was proposed after the historical hypotheses of the Moon's origin were rejected because "They (we evilutionists) must have a naturalistic hypothesis for all origins, including the moon's, so will believe almost any hypothesis to fill the void". If scientists were at all inclined to "believe almost any hypothesis" there would never have been any disputes or the scientific rejection of the ideas that failed to fit with observed phenomena. This is the same striving for truth, and questioning of even minor details by scientists that feeds Oard with papers to distort. The willing rejection of reality exhibited by Oard is the hallmark of young Earth creationists and other fantasists.
Anonymous, Recipe for a moon, Discover 18(11):25–26, 1997.
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Catling, David C., Kevin J. Zahnle, Christopher P. McKay 2001 "Biogenic Methane, Hydrogen Escape, and the Irreversible Oxidation of Early Earth", Science 293 (5531): 839
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Genda, Hidenori & Abe, Yutaka 2003 "Survival of a proto-atmosphere through the stage of giant impacts: the mechanical aspects", Icarus 164, 149-162 (2003).
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Oard, Michael 2000 "Problems for 'giant impact' origin of moon", Technical Journal 14(1):6–7 April
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Palme, Herbert 2004 "The Giant Impact Formation of the Moon", Science Vol. 304 977-978
Institut für Geologie und Mineralogie, Universität zu Köln, 50674 Köln, Germany. E-mail: email@example.com
Pepin, R. O. 1997 "Evolution of Earth's Noble Gases: Consequences of Assuming Hydrodynamic Loss Driven by Giant Impact", Icarus 126, 148-156 (1997).
Ruzicka, A., Snyder, G.A. and Taylor, L.A., 1998 "Giant Impact and Fission Hypotheses for the origin of the moon: a critical review of some geochemical evidence", International Geology Review 40:851–864
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