The Rock From Mars (45 page)

Romanek, in this case
• Goldsmith,
Hunt for Life on Mars,
pp. 49–57. As noted earlier, people study stable isotopes not to find out the age of something but to pinpoint its birthplace. Various places, on Earth, Mars, and elsewhere in the universe, have varying ratios of isotopes of a given element—an isotopic signature.

In the course of the
• Author interviews with Romanek.

CHAPTER FOUR:
e.t.’s handshake

Everett Gibson, the
• Author interviews with Gibson.

For sport, Gibson
• Every fall, Gibson (although he had not served in the military) coordinated the military portion of the fourth-largest air show in the country, Wings over Houston, at nearby Ellington Field.

These attributes
• E-mailed list from office of NASA/JSC meteorite curator Carlton Allen (compiled by database analyst Terrie Bevill) at author’s request (April 22, 2002); also, Romanek provided to author a list of sample numbers, recipients, and issue dates sent by Robbie Score to Romanek (Aug. 8, 1994).

Gibson considered
• More on the story told by the isotopes in the rock: the carbonates held a signature of the gases (the carbon dioxide atmosphere of Mars, presumably) that had interacted with the fluids that flowed through the rock. Over time, as the chemical interactions reached equilibrium, they should have set up a particular ratio of the carbon isotopes and a particular ratio of the oxygen isotopes—like fingerprints of sorts. The carbon isotopes told one part of the story, and the oxygen isotopes another.

THE OXYGEN ISOTOPES

From the oxygen ratio, researchers could get a handle on the temperature at which the carbonates formed. (If you cool water down it becomes enriched in the light isotope. If you boil water, the light isotope escapes, leaving the water enriched in the heavy isotope.) Romanek and Gibson, and their British colleagues, found that the sample was enriched in the lighter oxygen isotopes. Using a computer model to reveal the conditions that likely would have produced this particular isotopic signature, they concluded that the rock was probably formed between freezing and boiling temperatures—a range within which life could exist. Later, others would interpret the same evidence differently, sometimes concluding the temperatures were much too high for life. Eventually, the consensus would settle toward the milder end of the temperature scale and the Gibson-Romanek position.

Romanek and Gibson initially assumed there was a state of equilibrium. (If you “cooked” the material at a certain temperature and pressure over time, the stuff should assume a certain stable mineral composition because there were no longer chemical reactions going on.) It later became clear that the minerals had formed under conditions decidedly
out of
equilibrium. One way to achieve such a state is to more or less freeze the ingredients very quickly. You “catch them in the act,” as McKay would put it later, of changing from one set of minerals to another set of minerals. Another way to achieve it is biologically. Biological systems are typically out of equilibrium. They can manipulate their environment. The McKay team, investigating this possibility, looked at experiments done by Henry Chafetz, of the University of Houston, who had been growing carbonates out of equilibrium. He proposed that the carbonates grew only when bacteria were present. The McKay group found the Chafetz evidence remarkably similar to what they were seeing in the Mars rock.

THE CARBON STORY

When the researchers measured the carbon 12–to–carbon 13 ratio, they found out it was enriched in the carbon 13 fraction—heavy carbon. Until then, researchers had not known very well the carbon isotopic composition for Mars’s atmosphere (which had reacted with the fluids in the rock).

The ratio was measured in parts per thousand (“mils,” in the jargon). As the number deviated from the terrestrial standard of zero, it showed that a given mix was either enriched in heavy carbon (a “plus” value) or depleted in heavy carbon (a “minus” value). The range for Earth carbonates went only as high as about plus 20 parts per thousand—and that was only in very unusual situations. What Romanek and Gibson (and the group in England) saw in the Mars specimen was a value of “plus 40” parts per thousand—well beyond the range of anything resulting from natural processes on Earth. The way the carbonates were enriched in heavy carbon suggested that the light carbon—carbon 12—had perhaps been stripped out of the Martian atmosphere early in the planet’s history.

But the carbon also told another story. From the carbon, it was possible to find out whether a substance was associated with life or not by the way carbon atoms were known to be used by living systems, whether plants, critters, or something else. The numbers told the investigators that this particular fraction of the carbonate was
not
a type of carbon associated with any known living matter, because living systems on Earth produced ratios that were typically down around minus 25 to 30 parts per thousand.

So the carbon in these measurements did not reflect biological origins, but did signal that it was Martian.

He knew that a
• Author interviews with Gibson: In 1984–85, when Gibson wanted to learn more about stable isotopes, he was awarded a Leverhulme Fellowship for study in England. He sought out Colin Pillinger, of Britain’s Open University, whose strong suit was isotopic analysis. Gibson studied with Pillinger for more than a year.

The journal
Nature
• In July 1994, after the transatlantic phone conversation, Gibson and Pillinger and their coworkers decided to work together to publish the isotope findings.

Not many people
• J. H. Alton, J. R. Bagby Jr., and P. D. Stabekis, “Lessons Learned During Apollo Lunar Sample Quarantine and Sample Curation,”
Advanced Space Research
22, no. 3 (1995): pp. 373–82.

In the mid-1980s
• Author interviews with Gibson. In the season of 1979–80, Gibson joined the meteorite hunt in Antarctica. But he was yanked out of the field in midseason when word came that his infant son had been diagnosed with spinal meningitis. Gibson and his wife, a biologist, turned much of their focus to their son’s health.

Gibson and the others
• See H. R. Karlsson, R. N. Clayton, E. K. Gibson, Jr., and T. K. Mayeda, “Water in SNC Meteorites: Evidence for a Martian Hydrosphere,”
Science,
vol. 255 (1992): pp. 1409–11. Haraldur Karlsson had worked with Gibson as a postdoctoral fellow. And it was the expertise of one of the paper’s coauthors, Robert Clayton of the University of Chicago, that also confirmed Duck Mittlefehldt’s discovery of the strange new Martian meteorite the following year.

Romanek had in mind
• Author interviews with Romanek; see also Michael Ray Taylor,
Dark Life
(New York: Scribner, 1999), p. 104.

When Folk had
• Taylor,
Dark Life,
pp. 20, 37–45. (Folk preferred the term
nannobacteria,
but that spelling didn’t catch on.)

Led by a single
• Steven J. Dick,
Biological Universe
(Cambridge: Cambridge University Press, 1996), pp. 462–70. After years of struggle for money, NASA’s SETI began operations in October 1992, and in September 1993, Richard Bryan of Nevada successfully led a move to terminate what he called (misleadingly) “the Great Martian Chase.” SETI’s supporters soon revived remnants of the project by enlisting private-sector money. In the early 1990s, NASA had sponsored a series of workshops where a group of some twenty historians, scientists, behavioral scientists, and government policy experts discussed the implications of actual contact. But the report appeared only in preprint form and was not widely seen. (Steven Dick, in a talk delivered at George Washington University symposium, Nov. 1996, referencing “Social Implications of Detecting an Extraterrestrial Civilization: A Report of the Workshop on the Cultural Aspects of SETI” [Mountain View, Calif.: SETI Institute preprint, 1994]. The report was published in 1999 as
Social Implications of the Detection of an Extraterrestrial Civilization,
available for purchase at: http://www.seti.org/site/pp.asp?c=ktJ2J9MMIsE&b=180343.

Legitimate research
• Dick,
Biological Universe,
pp. 141, 354–55, 370, 377–78. U.S. life sciences research relating to the possibility of extraterrestrial life (as opposed to astronaut health and survival issues) since 1960 had been centered at NASA’s Ames Research Center in Mountain View, California, and the effort attracted the support of prominent scientists. (The Ames program included studies of the origins of life on Earth.) But the research was assailed repeatedly over the years, and even more so after the Viking probes for biology on Mars showed no persuasive signs. Evolutionary biologist George Gaylord Simpson, in 1964, had said exobiology was a “science” that “has yet to demonstrate its subject matter exists.” Physicist Frank Tipler in 1987 compared bioastronomy to parapsychology, calling it a “pseudoscience” that should not be given institutional respectability.

In 1977, three
• Victoria A. Kaharl,
Waterbaby: The Story of Alvin
(New York: Oxford University Press, 1990), p. 173, cited in William J. Broad,
The Universe Below
(New York: Simon & Schuster, 1997), pp. 105–06.

People learned from these
• In May 2002, on the twenty-fifth anniversary of the discovery of hydrothermal vents with associated life-forms, the Woods Hole Oceanographic Institute, the National Oceanographic and Atmospheric Administration, and the National Science Foundation summarized the significance on a CD-ROM,
The Discovery of Hydrothermal Vents.
The author derived some descriptions from her own descent aboard
Alvin,
in the summer of 1998 with researchers on an expedition to the Juan de Fuca Ridge in the Pacific. Under the auspices of the National Science Foundation’s Life in Extreme Environments program, the researchers were studying extreme life-forms around the vents and potentially below the seafloor.

The microorganisms at
• Instead of photosynthesis, they used chemosynthesis.

In the last quarter of the
• Woods Hole Oceanographic Institute et al., May 2002 summary.

(More than a decade later
• See Glennda Chui, “Study Surveys Human Intestines,” San Jose
Mercury News
wire service, posted April 15, 2005, at: http://www.miami.com/mld/mercurynews/news/local/states/california/peninsula/11401088.htm.

Some of these organisms
• The traditional system of naming and classifying species (kingdom, phylum, class, order, etc.) has been evolving to take advantage of advances in evolutionary biology. The new, improved system is based on the comparison of the sequences of information-bearing molecules, such as DNA or proteins, from different organisms in which the molecules carry out the same function. See Christian de Duve,
Life Evolving: Molecules, Mind, and Meaning
(Oxford: Oxford University Press, 2002), pp. 100–04. The three domains of life are Archaea (discovered late in the twentieth century), Bacteria, and Eucarya. The first two are made up of prokaryotes, whose cells lack nuclei. Of all the domains, only a small fraction of the Eucarya branch is made up of “the subject matter of a conventional biology course, organisms large enough to be visible without a microscope,” as noted by Donald Goldsmith and Tobias Owen,
The Search for Life
(Sausalito, Calif.: University Science, 2002), p. 214, Figure 9.1 (illustration of the three domains).

One was the emerging
• J. William Schopf,
Cradle of Life
(Princeton, N.J.: Princeton University Press, 1999), pp. 166–67.

Just months before Romanek
• Schopf published articles in 1992 and 1993 describing the discovery of the oldest known fossils. See J. W. Schopf, “Times of Origin and Earliest Evidence of Major Biologic Groups,” in J. W. Schopf and C. Klein, eds.,
The Proterozoic Biosphere: A Multidisciplinary Study
(New York: Cambridge University Press, 1992), pp. 587–93; and J. W. Schopf, “Microfossils of the Early Archean Apex Chert: New Evidence of the Antiquity of Life,”
Science,
vol. 260 (April 30, 1993), pp. 640–46.

Many people had
• Dick,
Biological Universe,
p. 331.

What Mittlefehldt had
• Mittlefehldt told the author that he believes this initial allotment contained two different types of samples: four chips (which would be destroyed by such methods as Romanek’s acid etching) and a thin section that could be used over and over, like a library book, for nondestructive microscope viewing. Records provided to Romanek by Robbie Score from the curation lab (faxed Aug. 8, 1994) indicate that Mittlefehldt had received twenty samples of the rock by this time, the first one in 1987 and all the rest between November 1993 and March 1994.

Mittlefehldt and meteorite curator
• Author interviews with Mittlefehldt and McKay.

In most cases
• Author interview with Mittlefehldt.

This afternoon in the late
• Author interviews with Gibson, Romanek, and McKay.

When the staff tried
• Charles Meyer,
Mars Meteorite Compendium
(Washington, D.C.: NASA/JSC, 2001), p. 126; illustrations, pp. 120–22. (See also online site: http://www-curator.jsc.nasa.gov/curator/antmet/mmc/84001.pdf.) With photo and graphics, the curators have depicted the sequence in which samples were chipped or sawed out of the main body of the meteorite.

But by the end of
• Curators records, as of August 8, 1994 (list faxed from Score to Romanek).

It was only a few
• Author interviews with McKay and Gibson. Also McKay interview with Dick, NASA archives. Both McKay and Gibson had received NASA exobiology funding before this, and as they set up their collaboration they applied for a new grant to look for signs of biology in the Allan Hills rock and other meteorites from Mars. NASA rejected the proposal the first time but in the summer of 1996 approved the group’s second request.