Has there ever been--or could there
still be--life on the red planet?
UC Davis alumnus and NASA scientist
Jack Farmer is working to answer
that question.

By Meg Gordon

espite its polar ice caps, apparent "canals" and the frequent appearance of Martians in science fiction, no signs of life have ever been found on Mars. But NASA scientist and UC Davis alumnus Jack Farmer is hoping to change that. Farmer hopes to apply what we've learned about the evolution of life on Earth to find fossil evidence of bacterial life on the red planet.

Farmer is compiling terrestrial evidence about Earth's Precambrian era, the time when the Earth's oceans and atmosphere first appeared and life originated. He will use this information to devise a strategic search for past life at similar sites on Mars over the course of a new round of Mars exploration missions scheduled to begin this November.

Farmer studies the geological past off-Earth as an "exopaleontologist" at NASA Ames Research Center in Mountain View. He coined the term "exopaleontology" to describe the blossoming field of research that melds classical paleontology with solar system exploration.

Working with the exobiology division at NASA, which is primarily concerned with space science and the search for life in the solar system, Farmer realized that, if early evolution of life occurred on Mars, planned Mars exploration missions could present a unique opportunity to bag some evidence of fossilized Martian microbes.

Water and carbon-based molecules are essential components to life as we know it here on Earth. Mars is the only planet in our solar system believed to have had liquid water on its surface for any part of its geologic history.

The 1978 Viking missions detected evidence of ancient running water and of glaciers that once scoured the surface of Mars. But the Viking landers also confirmed that harsh surface conditions present on the planet today do not allow for liquid water or life-forming compounds to exist.

Water remains near the surface only as ice. Mars' atmospheric pressure is less than a hundredth of that on Earth, which causes any liquid water to vaporize immediately. But fossil evidence of life that could have evolved when Mars still had a substantial atmosphere could be hidden in the surface rocks.

"If we run the clock backwards, it is likely that the atmosphere was denser on Mars, entrapping heat and warming the planet's surface above the freezing point. If there had been life on Mars at that time, a fossil record would most certainly exist," Farmer explains.

"Three and a half billion years ago when life first emerged on our planet, liquid water also existed on Mars," Farmer says. If Mars was warmer and wetter in its early days, it is conceivable that microorganisms evolved.

armer's initial project with NASA, studying thermal springs, laid a foundation for the fossil hunt on Mars. Geothermal hot spots, such as those found in Yellowstone National Park, are home to ancient bacterial families and fossilized ancestors that could play a significant role in understanding the early evolution of life on Earth.

Bacterial fossils continually form in Yellowstone's geothermal hot springs. Living Cyanobacteria colonize portions of these springs, residing in flumes of boiling hot water flowing from vents. "They sit in the hot spring effluents mining the sunlight for energy," Farmer explains. More ancient Archaea have been found living among these hot spring populations. Archaea are a group of bacteria-like organisms linked to Earth's earliest known life forms.

Farmer explains, "As the hot spring water cools at the surface, minerals previously dissolved begin to precipitate out, entombing the microorganisms." He calls this the "Jurassic Park effect" because--just as tree sap entombed and preserved ancient insects then hardened into amber, as depicted in the popular movie--opaline silica, calcium carbonate and iron oxides in Yellowstone create bacterial "micro-sarcophagi," forming a fossil record that is far more robust than one preserved in amber.

Farmer has been comparing the modern-day fossilization processes observed in Yellowstone's hot springs with similar ancient deposits, including a 350 million-year-old deposit in North Eastern Queensland, Australia, and a 1 billion-year-old hot spring near White Sulfur Springs, Montana.

For the upcoming Mars mission--dubbed Pathfinder--Farmer's exopaleontology group is helping to pinpoint Mars sites similar to those Farmer has studied on Earth where fossil evidence might be preserved among Martian surface rubble.

Since these fossils exist here on Earth, the theory goes, they might well exist on Mars if life has ever emerged on our closest planetary neighbor. It is also possible that deeper, closer to Mars' still warm core, liquid water could persist and with it, bacterial life. But a search beneath the frozen Martian crust is for future missions to undertake because drilling may require a human presence on the planet surface.

The Pathfinder mission will use a lander that will descend to the planet's surface, landing on giant air bags much like the ones in automobiles. On board will be a "micro-rover," a small vehicle that will take several tours around the landing site and search for the kinds of rocks that could have formed in association with water. It will be left to future launches over the decade-long program and to more discerning microinstrumentation to actually search for ancient biosignatures in rocks.

When the first portion of the Mars Pathfinder mission blasts off this November, it will initiate the era of "faster, better, cheaper" exploration of the solar system, employing the latest and greatest small-scale technologies. "Missions must be low-cost so we can deliver many smaller, higher-risk missions, lose some and still get lots of information," Farmer explains.

armer's interest in extraterrestrial fossils stems from a passion about collecting rocks and fossils that stretches back to when he was 5. "By the time I was 10, the collection was so big my parents had to hide portions of it when we moved," says Farmer, who grew up in Northern California's Central Valley.

At California State University, Chico, Farmer declared himself a geology major, selecting, on his father's advice, a subject he'd liked best since childhood. He became a member of the school's first graduating class of geology majors, the class of '69.

Farmer then continued his education at the University of Kansas, where he began work on a master's degree, initially studying statistical applications, geochemistry and volcanology. But funding problems plagued his field and this, coupled with the stimulating influence of paleontologist Bert Rowell, now professor emeritus at the University of Kansas, prompted his interest in the study of life from the geologic past.

The study of paleontology exposed Farmer to work done at the time by UC Davis faculty members Jim Valentine (now at UC Berkeley) and Richard Cowen. "These two were at the cutting edge of paleobiology and were actually looking at fossils as once-living organisms," Farmer says. They folded biology, ecology and oceanography into classical studies of geology. Farmer chose UC Davis to complete his Ph.D., working within the paleobiology program unique to Davis at the time.

Following completion of his degree in 1978, Farmer remained at UC Davis as a geology museum scientist, building and managing the teaching and research collections housed on campus. But in 1981, the deep pockets of the Exxon Corp. and its big oil exploration and extraction projects enticed Farmer away from Davis.

Farmer later returned to academia, accepting a position as visiting professor at UCLA. He spent five intense years with a rigorous schedule teaching oceanography, paleontology, an introductory course in Earth science, as well as a graduate seminar in sedimentology.

Farmer's work at NASA grew from his participation in an international study group of experts looking at the early evolution of Earth's biosphere. The group's efforts culminated in a reference book titled The Proterozoic Biosphere, A Multidisciplinary Study, edited by J.W. Schopf at UCLA and published in 1992. The book summarizes "the whole spectrum of what is known about that earlier part of the Earth's history, with focus on the biology," Farmer explains. The compilation received an Award for Excellence in Professional and Scholarly Publishing from the Association of American Publishers.

The interactions resulting from that publication effort solidified into the core group Farmer works with today, including David Des Marais, a geochemist at NASA Ames who prompted Farmer to secure a senior postdoctoral fellowship position from the National Research Council. That brought him to the NASA Ames Research Center in 1991.

Farmer, whose great-grandparents were Chickasaw-Cherokee, also makes time between his exopaleontological endeavors for the earthly concerns of the here and now. He is currently vice chair of the Native American Advisory Committee at NASA Ames Research Center. This role involves him in outreach programs that help bring state-of-the-art science into Native American universities like D.Q. University located between Davis and Winters. He is also an active member of the American Indian Science and Engineering Society.

he clues Farmer has collected from Earth's ancient sites and the modern geothermal systems like those in Yellowstone will hopefully lead the Pathfinder mission to discoveries in ancient and undisturbed equivalents on Mars. "Evidence of fossil life would be a discovery that would revolutionize biology as well as how we view our place in the cosmos," Farmer points out.

Even if life never developed on Mars, the mission will provide an opportunity to gaze back in time and learn still more about our own planet. Geologic features preserved on Mars can give us a more concrete idea of what Earth was like when our seas were gigantic hot springs, before volcanic action and earthquake activity changed the planet's prehistoric face forever.

Photos: NASA Hubble Space Telescope photo of Mars; photo of Farmer by Michael Milstein