As a child growing up in the Buffalo area, Ariel Anbar was fascinated by the biggest of questions. Where did life come from? Is there life elsewhere in the galaxy?
Now it's Anbar's job to help find the answers. Anbar, an assistant professor of earth and environmental sciences at the University of Rochester, has been awarded a total of more than $800,000 from NASA and the National Science Foundation to search for evidence of life in far-off places. Anbar will be developing new techniques to analyze rocks and see what they reveal about life and the environment on ancient and remote spots on Earth as well as other parts of the solar system.
"Our definition of the conditions necessary for life is much broader than it was 20 years ago," says Anbar. "Scientists have been surprised to find micro-organisms that can survive temperatures close to the boiling point of water, and other organisms that can live with absolutely no light at the bottom of the ocean." Scientists know that life can even survive on the Moon: Bacterial spores from Earth that snared a ride on one of the moon landers survived for several years in space before their return to Earth on a subsequent mission.
"Life can grow in some pretty harsh conditions," says Anbar, a geochemist. He's been hooked on the search for life in the rock record since he was a college student at Harvard, cracked open a rock and found a fossil. "I was awe-struck: No eyes had gazed on this thing for 300 million years." Anbar began wondering about ways to study the life and environment of ancient Earth history, so long ago that there are few fossils or other physical clues to examine for answers. He turned to geochemistry. He went on to graduate school at the California Institute of Technology and joined the University in 1996.
Now he's involved in two five-year NASA projects, one run by colleagues at Harvard University and the other managed by scientists at NASA's Jet Propulsion Laboratory in California. He's also part of a three-year study managed by NSF's Life in Extreme Environments (LExEn) program. Anbar will use the funds to support graduate students and run experiments in his laboratory, which is designed to ferret out the tiniest amounts of select substances.
As part of the projects, Anbar and colleagues will examine ancient and remote rocks for traces of past life. They're developing new ways to look at metals like iron, copper and molybdenum, analyzing what the ratios of the different chemical forms of these elements tell us about life deep under the sea or elsewhere in the solar system. There is evidence that microbes sometimes prefer to munch on one form of an element over another, in a process known as fractionation; if true, their choices eons ago would be preserved in rocks today.
"Geologists have long studied carbon, nitrogen, and sulfur in rocks to learn more about biology in the past," says Anbar, an assistant professor of earth and environmental science and chemistry. "But this is the first study of the possibility that metals in rocks might also hold clues about ancient biological processes. "
The research will rely on scientists' ability to sort out atoms whose masses differ by the scant weight of a few subatomic particles. They'll use Anbar's new mass spectrometer facility, which includes an MC-ICP-MS (multiple collector inductively coupled plasma mass spectrometer), a device that can detect a single metal atom hidden among more than a million atoms of other substances. It's one of only five such machines at American universities.
It was just three years ago when the world was electrified by news that a meteorite from Mars may show evidence of ancient life. Since then scientists have argued vigorously about that evidence. Most expect to have rocks from Mars available for study within a decade or two, and they want to be ready when those rocks arrive.
"I've always been interested in using the tools of science to address the big questions, like what is the possibility of life elsewhere in the universe? It's only in the last 30 years or so that technology and our understanding have become sophisticated enough that we can approach this question from many scientific angles," Anbar says.