But learning as much as possible about the earliest life on Earth is probably the best starting point for trying to find life somewhere else, said Roger Buick, a paleontologist who became the first faculty member hired specifically for the University of Washington's pioneering graduate program in astrobiology. He also is an associate professor of earth and space sciences.
"The earliest organisms were presumably very simple, both in their structure and their chemistry," he said. "The evidence we're used to seeing for modern life may not be a good guide for what to look for in earliest life."
As a doctoral student nearly two decades ago, Buick discovered stromatolites, or mounds of sedimentary rock, formed by microbes 3.5 billion years ago in western Australia. Those mounds remain the oldest visible evidence of life on Earth.
Buick suggested that using basic techniques to search for the simplest evidence of ancient life on Earth is the best approach to finding evidence of life elsewhere. That is a message he delivered today at the American Astronomical Society's annual meeting in Seattle during a session called "The Biology of Astrobiology for Astronomers." There are a variety of difficulties associated with searching for early life based on what we know of biology and geology, he said, yet both disciplines must be involved if we are to be successful in the search for life elsewhere.
"We have to go from what we know, but we also must have an open mind because we might be surprised by what we find," he said. "We have to be hypercritical so that we're not misled by superficial resemblances to what we know."