Looking in the rear view mirror at the 50 years of my journey in science, I see a life rich in scientific discovery as well as scientific colleagues, who have without a doubt enriched my life. No one can predict what path their career will follow. Mine began in 1970 at Penn State University as a biology major, where I became intrigued by recent findings of ancient life on Earth. The Viking space probes had landed on Mars, and impacted my curiosity about life on other planets, a theme that remained dormant for many years. I knew at an early...

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