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Volume 2, Number 2 March/April 1997
A bimonthly newsletter of the Creation Research Society.

This Web version of Creation Matters lacks the "Creation Calendar" as well as photos and special graphics found only in the print version. The latter is automatically sent to members of the CRS along with the peer-reviewed CRS Quarterly.

Contents:
Life_on_Mars? A Mars Rock Update
Planets_or_Preconceptions?


Life on Mars? A Mars Rock Update


by Kurt Howard, M.S.

Kurt Howard's Master of Science degree is in geology.

In August 1996, television and print media announced with great excitement the possibility of ancient life on Mars. This provocative news was based on certain findings in a meteorite believed to have originated on Mars. Four components in this meteorite suggested to researchers the existence of ancient life on Mars. First, there were tiny structures inferred to be bacterial fossils. Then, in close association with these alleged fossils, there were three components often associated with terrestrial life: magnetite, iron sulfide, and certain organic compounds called polycyclic aromatic hydrocarbons (PAHs). The initial announcement was reviewed in an earlier issue of Creation Matters (Wood, 1996). The objective of this update is to provide more details about the ongoing research and latest findings. It is clear that many scientific, philosophical, and economic issues are impacted by this purported discovery.

Origin of meteorites

Based on comparison of reflectance spectra between meteorite minerals and potential parent body spectra (McSween, 1994), it is believed that the great majority of meteorites have come from asteroids that have undergone collision in orbit. Several groups of meteorites have now been identified: stony chondrites (84%); stony achondrites (8%); stony irons (1%); and irons (7%). Within the stony achondrite class, there is a group designated SNC, named after three specific meteorites: the Shergotty, Nakhla, and Chassigny. While differing in many respects from each other, the SNC meteorites have two characteristics which set them apart from other meteorites: viz., their relatively young age and their oxygen isotope ratio (17O/18O).

It is because of their relatively young, evolution-based radioisotope age - 180 million years to 1300 million years - that it was proposed that the SNC meteorites could not have come from the asteroids (McSween, 1994). The asteroid bodies are said to have formed, along with the rest of the solar system, 4.5 billion radioisotope years ago. But, because they are relatively small bodies, they must have cooled down long before 1300 million years ago. Neither would they have had any remaining magmatic activity and resultant mineral crystallization as late as 1300 million years ago. Thus, it was proposed that the SNC meteorites came instead from a planet. The most likely candidate from a petrological and dynamic perspective is Mars.

ALH84001 is the designation for the Antarctic meteorite claimed to contain fossilized ancient life. It has many features that make it quite distinct from the other achondrites, but its oxygen isotope ratio (17O/18O) places it unequivocally in the SNC group of Martian meteorites (McSween, 1994). However, ALH84001 is unique among the SNC meteorites, which number about 12, in the following respects: it is comprised mostly of orthopyroxene (95%); it has 1% carbonate while the other SNC meteorites only have trace amounts; based on fracture patterns, it evidently experienced two or more shock events; and it is much older - 3000 to 4500 million radioisotope years.

Petrological "history"

Table 1 shows the evolutionary petrological history of ALH84001 using reported radioisotopic dates. These dates are all suspect, however, because their significance depends on the validity of certain assumptions. For example, in the Rb-Sr, Sm-Nd, and K-Ar dating methods involving the use of isochrons, this writer saw no attempt to verify the assumption of initial isotopic homogeneity. Furthermore, an initial isotopic correlation may yield an apparent isochron, but one that is petrologically meaningless (Zheng, 1989). This problem is also consistently disregarded.

The first events recorded in ALH84001, planetary accretion and differentiation, have been dated using Sm-Nd model ages. These ages are dependent on a correct initial 143Nd/144Nd ratio. To determine that initial ratio requires the assumption of initial isotopic homogeneity. Again, the validity of this assumption is generally not addressed by researchers.

The next event recorded is the first shock, which is evidenced by the presence of shock breccia, pervasive cracking, and the polygonization of orthopyroxene (Treiman, 1995). After the first shock episode, the next event, aqueous alteration, is evidenced by the presence of zoned carbonate globules, a structure that has not been found on the other Martian meteorites. Based on the assumption that the they formed under equilibrium conditions, high temperatures of about 700 C are required for this unique combination of zoned carbonates - magnesite, siderite, and ankerite. On the other hand, if one assumes the carbonate was formed metastably (i.e., not under equilibrium conditions), this would allow lower temperatures of formation (i.e., 0 C to 80 C). Support for low temperatures of formation comes from oxygen isotopic ratios, and from reasoning that at high temperatures there would be a high rate of diffusion and elimination of the delicate Fe-Mg carbonate zoning. The NASA research team chose to assume the low temperature scenario, which allows for the formation of carbonate by means of bacterial activity (McKay et al., 1996).

High-powered scanning electron microscopy revealed the presence of tiny spherules (0.1 micron) and tubules which the researchers infer to be bacterial fossils (McKay et al. 1996). These spherules are an order of magnitude smaller than terrestrial bacteria and have been termed nannobacteria by Folk (1993) who first identified similar structures in terrestrial limestone. However, much controversy surrounds these formations, even in terrestrial materials, and since no bacterial cell walls or other organelles have ever been identified, their true nature remains problematic. Thus, since no specific bacterium has been positively identified, it is possible that these spheroidal structures have resulted from inorganic precipitation.

Stable isotope biochemistry

Stable isotope chemistry of ALH84001 does not support the presence of biologic activity on Mars. Organic processes, such as bacterial carbon metabolic pathways, invariably select 12C rather than 13C, thus causing biologic carbonates to be depleted in 13C (Tucker and Wright, 1990). The ALH84001 carbonate, on the other hand, is enriched in 13C, precluding its being formed by biologic activity. Furthermore, within the ALH84001 carbonates, there are Fe-sulfides (pyrite and pyrrhotite) and Fe-oxides (magnetite). Certain terrestrial sulfur-metabolizing bacteria produce Fe-sulfides. However, just as with carbon selectivity, sulfur-bacteria have a preference for 32S rather than 34S (Shearer and Papike, 1996). Since the ALH84001 Fe-sulfides are enriched in 34S, this again precludes the activity of sulfur-metabolizing bacteria. Magnetite, also found in the ALH84001 carbonate globule, can be produced by terrestrial magnetotactic bacteria as suggested by McKay et al. (1995), but is also very commonly precipitated inorganically.

The second shock experienced by ALH84001, 8 to 15 Ma, is evidenced by: the formation of maskelynite from plagioclase; microfault offsets cutting silicates, oxides, and carbonates; and radial cracks around maskelynite and chromite grains. It is suggested that this second shock resulted from a meteorite impact on Mars with sufficient force to produce ejecta, including ALH84001, which reached escape velocity (5 km/sec) and entered into solar orbit.

The length of time ALH84001 stayed in space is determined by the abundance of certain cosmogenic nuclides such as 10Be and 22Ne. These isotopes are produced by the activity of cosmic rays while material is in space. The validity of dates obtained from these isotopes is dependent in turn upon certain assumptions. One assumption relates to the amount of shielding from cosmic rays experienced by the meteorite's internal minerals. This in turn depends on assumptions regarding the thickness of the ablation layer which was lost on entry into Earth's atmosphere. Other important assumptions include the occurrence and timing of one or more collisions in space which would break up the meteorite, allowing for greater cosmic ray exposure. Another has to do with how much exposure to cosmic rays was experienced while the rocks were still on the surface of Mars. Finally, whether radioactive saturation was reached in the minerals is crucial to the determination of exposure age. In any case, for the radionuclide 10Be, based on specific choices from among the above assumptions, a cosmic exposure age of 8 Ma was determined; and, for the radionuclide 22Ne, 15 Ma (Nishiizumi et al., 1986; Pal, 1986).

Gas analysis

McKay et al. (1996) indicated that analyses of the noble gases trapped within glassy inclusions of one of the SNC meteorites (EET79001) revealed that these gases were very similar to the gases analyzed by the Viking spacecraft that landed on the surface of Mars. This was taken as very strong proof of Martian origin for all the SNC meteorites. However, analyses of gases in the same type of glassy inclusions from ALH84001 revealed noble gas composition very different from that found on Mars by the Viking spacecraft (Ash et al., 1996). This raises questions about the parent body of ALH84001; viz., is it really from Mars?

Because the issue of earth contamination was sure to be raised, McKay et al. (1996) went to great lengths to exclude this possibility. In their laboratory very strict controls were employed. For example, a lunar rock chip was carried through the same analysis procedure as was ALH84001 without finding the critical spheroidal texture present in ALH84001. This indicated that the structure is not an artifact of laboratory processing. Attempts to grow cultures from the meteorite samples were negative. Organic compounds (PAHs) found in ALH84001 have not been found in other Antarctic meteorites. On the other hand, it was recently announced that PAHs have been found in Antarctic ice, and they are definitely not of biogenic origin (Becker et al., 1997). The PAH concentration in ALH84001 increases with depth into the meteorite. This condition could result from Antarctic-derived PAHs being dissipated from the surface by ultraviolet radiation exposure. Sulfides found in ALH84001 are not the result of contamination since sulfides are not found in Antarctica. Antarctic weathering deposits contain sulfur in the form of sulfates because of the oxidizing environment. Finally, no other Antarctic meteorite contains the amount of carbonate found in ALH84001, suggesting that these carbonates are not the result of contamination.

On the other hand, in order to account for discrepant radioisotopic dates, at least three research groups have suggested contamination of some of the meteorite fractions. Jagoutz et al. (1994) suggested Pb earth contamination to support their view that the Pb radioisotopic dates represent mixing lines. The mixing line explanation was offered because the Pb isotopic dates were very discordant with the 4.5 Ga Nd isotopic date (Jagoutz et al., 1994). Ash et al. (1996) suggested contamination with K-salts to support discordant Ar isotopic dates. Entrapped earth atmospheric argon has been suggested to explain measured argon isotopic ratios (Miura et al., 1994). However, these suggestions of contamination are not based on empirical evidence. They were offered by these researchers as unverified explanations for discrepant radioisotopic dates.

Getting here from there

Skepticism has been expressed about whether a meteorite impact would be able to eject rocks from the surface of Mars. Much effort has been expended in developing models for this mechanism. To provide extra expulsion power, it has been suggested that frozen carbon dioxide and/or water vapor under the surface of Mars was vaporized by the impact of a huge meteorite, providing a jet-assist for the ejected debris. The distribution and size of Martian craters are being investigated to find craters large enough to allow for the proposed ejection mechanism. This search has been constrained by issues of young versus old Martian terrain, based on the view that the age of Martian terrain is related to crater density. Since ALH84001 is thought to be old, it is believed likely to have originated from a portion of the Martian surface that is also old. Therefore, the search has been for a very large crater in a part of Mars that is highly cratered.

Edward Anders reviewed the alleged evidence for life processes in ALH84001 in a recent Science magazine letter (Anders, 1996). He stated that an inorganic explanation is at least equally plausible, and is, by Occam's Razor, preferable. The PAH composition of ALH84001 is similar to the organic molecular composition of carbonaceous chondrite meteorites whose abiotic origin is commonly accepted. The association of the PAHs with the carbonates may be attributed to a greater surface area or adsorption capacity of the carbonate. The chemical zoning within the carbonate globules involves the successive precipitation of MnCO3, then CaCO3 followed by MgCO3. This sequence corresponds to the increasing solubility products of Mn, Ca, and Mg carbonate. Carbonaceous chondrite meteorites commonly contain magnetite and pyrrhotite formed under abiotic conditions. Finally, Anders stated that the NASA researchers did not even compare the greigite (Fe3S4) they found in ALH84001 with abiotic greigite from nature and the laboratory before proposing a biogenic origin.

Crystal structures

The most recent research into ALH84001 involved study of the microstructure of the magnetite crystals by Bradley et al. (1996). They have raised major doubts as to their biogenic origin. Using very high resolution Transmission Electron Microscopy (TEM), they observed that many of the magnetite crystals were shaped like whiskers and plates, and contained screw dislocations. These morphologies have frequently been observed in the laboratory, in fumaroles and hydrothermal solutions where temperatures were over 500 C. Maximum possible temperatures for life processes is considered to be 120 C. Magnetite crystals produced by terrestrial, magnetotactic bacteria invariably are single-domain grains with a high degree of crystal perfection. If the alleged ALH84001 nanofossils are in fact high temperature asymmetrical magnetite crystals, these findings cast a dark shadow on the likelihood of a biological origin of several of the components of the meteorite.

Table 2 summarizes the many unanswered questions and differences of interpretation which remain in the scientific community regarding meteorite ALH84001. Close scrutiny of the references cited in this paper reveals that too often scientists may uncritically accept concepts and interpretations that further their own research program and funding. In evaluating such reports, it is important to remember the overarching concepts which may motivate some researchers: validation of the old age of the universe; promotion of the cosmic and organic evolution paradigm; and, as a corollary to these, the need to find life elsewhere in the universe. It is necessary, therefore, that all claims be very closely examined. This obviously includes presentations in the popular media, but more importantly, those reports made in technical literature. Diligent and tenacious examination of all such claims, assertions, and references is critical for this subject which has enormously profound philosophical and theological importance.

References

Anders, E. 1996. Evaluating the evidence for past life on Mars. Science 274:2119-2120.

Ash, R.D., S.F. Knott, and G. Turner. 1996. A 4-Gyr shock age for a Martian meteorite and implications for the cratering history of Mars. Nature 380(7):57-59.

Becker, L., D. Glavin, and J. Bada. 1997. to be published in Geochimica et Cosmochimica Acta.

Bradley, J.P., R.P. Harvey, and H.Y. McSween. 1996. Magnetite whiskers and platelets in the ALH84001 Martian meteorite: Evidence of vapor phase growth. Geochimica et Cosmochimica Acta 60(24):5149-5155.

Folk, R.L. 1993. SEM imaging of bacteria and nannobacteria in carbonate sediments and rocks. Journal of Sedimentary Petrology 63(5):990-999.

Jagoutz, E., A. Sorowka, J.D. Vogel, and H. Wanke. 1994. ALH84001: Alien or progenitor of the SNC family? Meteoritics 29:478-479.

McKay, D.S., E.K. Gibson Jr., K.L. Thomas-Keprta, H. Vali, C.S. Romanek, S.J. Clemett, X.D.F. Chillier, C.R. Maechling, and R.N. Zare. 1996. Search for past life on Mars: Possible relic biogenic activity in Martian meteorite ALH84001. Science 273:924-930.

McSween, Jr., H. Y. 1994. What we have learned about Mars from SNC meteorites. Meteoritics 29:757-779.

Miura, Y.N., N. Sugiura, and K. Nagao. 1994. New SNC meteorite ALH84001: Evidence for SNC meteorite from noble gases (abstract). Lunar Planetary Science 25:919-920.

Nishiizumi, K., M.W. Caggee, and R.C. Finkel. 1994. Exposure histories of ALH84001 and ALHA77005 (abstract). Meteoritics 29:511.

Pal, D.K., C. Tuniz, R.K. Moniot, W. Savin, T. Kruse, and G.F. Herzog. 1986. Beryllium-10 content of shergottites, nakhlites and Chassigny. Geochimica et Cosmochimica Acta 50:2405-2409.

Shearer, C.K. and J.J. Papike. 1996. Evaluating the evidence for past life on Mars: in Technical Comments, Science 274:2121.

Treiman, A. H. 1995. A petrographic history of Martian meteorite ALH84001: Two shocks and an ancient age. Meteoritics 30:294-302.

Tucker, M. E. and V.P. Wright. 1990. Carbonate Sedimentology. Blackwell Scientific Publications, Oxford. London, England. p. 307.

Wood, T.C.. 1996. Was there really life on Mars? Creation Matters, Sept./Oct.

Zheng, Y. F. 1989. Influences of the nature of the initial Rb-Sr system on isochron validity. Chemical Geology 80:1-16.

[Editor's note added in proof: As this article went to press, two more articles appeared in the 14 March 1997 issue of Science. Both provide additional indirect evidence of low temperature formation of the carbonate globules in the meteorite. One line of reasoning is based on remnant magnetization. The other article cites evidence from stable isotopes and mineralogy.]

 


Planets or Preconceptions?


by Gary Locklair, M.S.

Gary Locklair's Master of Science degree is in Computer Science.

Extrasolar planets are all the rage in the astronomical community these days. Until very recently in recorded history, only planets which revolve around our own star, the Sun, have been known. Astronomers and just-plain-folks have speculated about the existence of other planets around other stars in the universe possibly since the dawn of time.

For the evolutionist, planets orbiting other stars in the universe fit perfectly within their worldview. If the evolving cosmos produced our solar system, then surely the same evolving cosmos has produced a vast array of other planetary systems around other stars, the evolutionist reasons. In the evolutionary worldview, there is nothing special or unique about life, planet Earth, or our solar system. Since all origins are the result of non-directed, natural processes, having a unique earth and solar system is anathema to the evolutionist. Uniqueness conveys "specialness;" and this smacks of a dangerous competing model for origins: creation.

"Objects" in orbit

In the last 10 years astronomers have identified "objects" in orbit around other stars. In 1988, David Latham's group at Harvard identified an object orbiting the star HD 114762. Because of the mass of the object (minimally 9 times the mass of the planet Jupiter, the largest in our solar system), many astronomers refer to it as a "brown dwarf" rather than a true planet. In 1991 Wolszczan and Frail discovered "objects" orbiting pulsars (presumably a type of collapsed star). Until 1995, the identity of these objects orbiting other stars were debated among astronomers, with many preferring to label them as "other" (a dark, small, or collapsed companion star, for example) rather than a true planet. It should be mentioned that there are many examples of binary star systems; that is, a system with two stars orbiting each other (remember the scene in Star Wars: A New Hope, on Luke Skywalker's home planet Tatooine, with the two setting suns? Oh, wait, that's science fiction - sorry).

Planetary proof?

For many astronomers, the shroud of uncertainty over the existence of extrasolar planets was lifted on 6 October 1995 when Mayor and Queloz of Geneva Observatory announced the discovery of a "planet" orbiting the star 51 Pegasi. Shortly after this find, American astronomers Marcy and Butler announced finding 3 other similar "planets" in orbit around 3 distinct stars. Shortly after the initial finding, Ron Cowen of Science News stated, "Forget speculation. It's no longer a matter for debate. As of last month [October 1995], astronomers have proven they're out there - planets orbiting ordinary stars within a stone's throw of our solar system." Headlines in the popular media heralded the discovery in similar tones, leaving any lay-reader with the impression that astronomers have actually seen extrasolar planets.

Actually, astronomers have not seen any of these planets. What actually happened provides an instructive look into the "workings" of science, and into the role assumptions and worldviews play in the "doing" of science.

Indirect methods required

Discoveries of extrasolar "planets" have been made indirectly. Of course, the possibility of observing a planet in orbit around another star is extremely small. Planets do not generate their own light and are much smaller than stars. So, rightly, astronomers are forced to use indirect means to search for extrasolar planets. In order to detect the "planet" around 51 Pegasi, astronomers used an indirect spectroscopic technique. Spectroscopy was used to analyze the light from 51 Pegasi over time. Variations in the spectroscopic signals led astronomers to conclude that a "planet" was in orbit since the variation in spectra might result from the gravitational pull of an unseen planet.

If the interpretation of the spectroscopic signals is correct, the "planet" around 51 Pegasi isn't exactly like Earth! The interpretation suggests that a "planet" of at least 50% the mass of Jupiter is in orbit only 0.05 AU (Astronomical Unit - 1 AU is the distance from the Sun to the Earth) from the star. It is so close that it orbits the star once every 4.2 days, as compared to once every 365.4 days for the Earth to revolve around the Sun. Also, it is so close to its star (only 1/8 the distance of the Sun to Mercury, the Sun's closest planet) that it gives new meaning to the phrase "a hot time on the old planet tonight."

Interestingly, the current interpretation techniques cannot determine an extrasolar object's maximum mass; they can only set a lower limit to the mass. All of the "planets" discovered so far are much more massive than earth, suggesting gaseous makeup with high temperatures, strong magnetic fields, and other nasty conditions inhospitable to life.

A problem for evolution?

Behind the astronomical scenes, the existence of such planets has caused problems for evolutionists. Until now, astronomers "knew" that giant planets could only form at a certain (far) distance from the star. Evolutionary models of system formation demanded this. Now, evolutionists must revise their models of solar system formation to allow for close giant planets, such as the "planet" around 51 Pegasi.

There's another problem: the "planet" around 51 Pegasi may not really exist. Last month, Canadian astronomer David Gray claimed that the previous interpretation of the 51 Pegasi spectra is wrong. There is not a planet orbiting the star; instead, there is a "complex sloshing" (analogous to ocean waves) on the star's surface, Gray maintained. His paper in the journal Nature has caused quite a fuss among astronomers. AP science editor Matt Crenson began his press release with "[t]he first world ever found beyond the solar system is but an illusion ...", while Washington Post correspondent Kathy Sawyer wrote, "A Canadian astronomer claims he has, in effect, made a planet vanish."

The current debate about extrasolar planets is instructive for creationists for several reasons. First of all, scientific findings are built upon philosophical foundations and assumptions. If evolution is true, then the predictions of the model must be true also. The evolution model predicts a vast number of extrasolar planets. (Again, there can be nothing special about our solar system in the evolutionary model.) If it turned out that ours was the only solar system in the universe, evolutionists would be confounded. Given that foundation, it makes perfect sense for an evolutionist to "see" extrasolar planets when examining the spectra of stars. Do the biases and presuppositions of scientists creep into their work? Absolutely.

Other interpretations

Secondly, there are other valid interpretations for the data. Observing a "planet" in orbit around another star in the present does not give conclusive evidence for its origin. A creationist can interpret the data as evidence for the degradation of the universe. Are we witnessing the birth of planets, or are we witnessing the death of stars? Is it possible for a star to burn out and be captured by another star?

Actually, evolutionists have a much more difficult task of explaining where stars came from. All current evolutionary models require the existence of stars in order to produce other stars! The question "where did the first star come from?" is extremely difficult for an evolutionist. If Gray's interpretation is correct, 33% of the current extrasolar objects are disqualified from "planethood" since they were discovered using similar techniques aimed at 51 Pegasi. Additionally, Gray's work casts serious doubts on the validity of all current candidates for extrasolar planets.

When I'm asked, "are there extrasolar planets?" I confidently answer "I don't know." Seriously, though, I am aware of no astronomical data that conflicts with the creation model. The creation model does not rule out the existence of extrasolar planets. Yet, the Bible is clear concerning the uniqueness of planet Earth. If extrasolar planets exist, they certainly won't be anything like home! God declared that He created the universe fully formed and functional during the creation week. God uniquely created planet Earth as the home of His creation. Has the universe changed since then? Absolutely! We do not find evidence for the "building up" of the universe as predicted by the evolution model; instead, we see data consistent with an initially perfect creation which has since decayed. Yet, still "the heavens declare the glory of God."



ISSN 1094-6632
A publication of the Creation Research Society
Volume 2, Number 2
March/Aprilt 1997

Copyright 1997 Creation Research Society
All rights reserved.

General Editor: Glen Wolfrom

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Articles published in Creation Matters represent the opinions and beliefs of the authors, and do not necessarily reflect the official position of the Creation Research Society.

 


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