The “possible” discovery of Martian life made headlines again in March 2001. In a strained effort to uphold the evolutionary paradigm, secularists seize any hope of a Martian origin-of-life scenario with gleeful enthusiasm.1 According to one popular hypothesis, Earth might have been seeded with life from Mars carried here by meteorites a few billion years ago. More importantly, the spontaneous appearance of life on Mars would seem to indicate that life is abundant throughout our galaxy and perhaps throughout the cosmos.
The highly publicized Martian meteorite ALH84001 serves as the focal point of research.2 This meteorite, ejected from the surface of Mars roughly 16 million years ago, arrived on Earth 13,000 years ago and was discovered in Antarctica in 1984.3 Since then, it has been studied intensely. In 1996, when NASA scientists announced that its oval-shaped mineral deposits could be the fossilized “leftovers” of bacteria, it sparked huge media excitement. 4
Several scientists put a damper on that excitement in 1998. One group of researchers pointed out that the oval structures (within carbonate globules) of ALH84001 are too small to be fossilized microorganisms.5, 6 Another demonstrated that the oval-shaped deposits are identical to those produced inorganically.7 These challenges, of course, received little media attention.
Recent excitement was stirred by the findings of two Finnish scientists, who claimed to have produced evidence for bacteria so small that they could possibly account for the oval structures. 8, 9 These hypothetical bacteria, called nanobacteria, are said to be one-tenth the size of typical bacteria cells. Though they defy the lower size limit for living systems, the case for their existence seemed airtight at first.
The Finnish scientists, using biomineral deposits as the indicator for nanobacteria’s presence, seemingly cultivated nanobacteria from a number of sources. They developed subcultures of nanobacteria by transferring a portion of the biomineral deposits to fresh growing sites. Examination of the various mineral deposits revealed spherical particles about 0.1mm in size—presumably nanobacteria encased in mineral deposits. When the researchers found DNA associated with the biomineral deposits, their case seemed certain. Going one step further, they succeeded in amplifying and sequencing a 16s rRNA gene from the “nanobacterial” DNA.
However, when scientists from the National Institutes of Health (NIH) attempted to repeat and extend the Finnish scientists’ work on nanobacteria, they could not. 10, 11 Instead, they uncovered experimental artifacts and contamination that may have misled the Finnish scientists into thinking they had discovered nanobacteria. The NIH scientists showed that mineralization in culture media (growing sites) is caused not by bacteria but rather by nonliving molecules that serve as initiation sites for mineral deposition. As it turns out, the self-propagating nature of the biomineral deposits explains how a subculture of the supposed nanobacteria developed. The 16s rRNA gene amplified and sequenced by the Finnish scientists appears to have come from an environmental bacteria, Phyllobacterium mysinaceareum, that commonly contaminates DNA amplification and sequencing experiments.
The NIH study raises serious doubts about the existence of nanobacteria in the Martian meteorite. Thus, research again argues against, rather than for, the discovery of life on Mars.
- Fazale R. Rana and Hugh Ross, “Life From the Heavens? Not This Way… An Inside Report on ISSOL ’99,” Facts for Faith 1 (Q1 2000), 11-15.
- David S. McKay et al., “Search for Past Life on Mars: Possible Relic Biogenic Activity in Martian Meteorite ALH84001,” Science 273 (1996), 924-30.
- Everett K. Gibson et al., “The Case for Relic Life on Mars,” Scientific American (December 1997): 58-65.
- McKay et al., 924-30.
- Richard A. Kerr, “Requiem for Life on Mars? Support for Microbes Fades,” Science 282 (1998), 1398-400.
- Gretchen Vogel, “Finding Life’s Limits,” Science 282 (1998), 1399.
- Kerr, 1398-400.
- E. Olavi Kajander and Neva Ciftcioglu, “Nanobacteria: An Alternative Mechanism for Pathogenic Intra- and Extracellular Calcification and Stone Formation,” Proceedings of the National Academy of Sciences, USA 95 (1998): 8274-79.
- Dennis A. Carson, “An Infectious Origin of Extraskeletal Calcification,” Proceedings of the National Academy of Sciences, USA 95 (1998): 7846-47.
- John O. Cisar et al., “An Alternative Interpretation of Nanobacteria-Induced Biomineralization,” Proceedings of the National Academy of Sciences, USA 97 (2000): 11511-15.
- J. T., “Study Casts Doubt on Minibacteria,” Science News 158 (2000): 328.