A recent Dornsife Dialogues conversation hosted by the USC Dornsife College of Letters, Arts and Sciences explored two big questions: How does life begin - and where else in the universe it might it exist?
The conversation, led by USC Dornsife Dean James Bullock, included alumnus Laurie Barge, a senior research scientist in astrobiology at NASA's Jet Propulsion Laboratory, and Karen Lloyd, Wrigley Chair in Environmental Studies and professor of Earth sciences.
Both are conducting research that's changing our understanding of what makes for habitable conditions. Life, they argue, may not require sunlight or even abundant energy, only the right chemical conditions.
Lloyd focuses on life deep beneath Earth's surface. Using modern DNA sequencing tools, she and her team have discovered entirely new branches of microbial life.
These "novel phyla" are thriving in extreme environments, from highly alkaline deep-sea mud volcanoes to ancient Siberian permafrost frozen for 120,000 years. Some microbes appear to survive on energy levels far below what scientists once thought possible. Her new book, Intraterrestrials: Discovering the Strangest Life on Earth, covers this journey of discovery.
In her lab, Barge is recreating hydrothermal vents, mineral "chimneys" similar to those on the ocean floor, to test how early chemical reactions could have generated energy and organic molecules on Earth - and possibly on worlds like Mars or Saturn's moon Enceladus. She's exploring whether life's building blocks can form without biology and what measurable "biosignatures" future space missions should seek when they look for life on other planets.
For Barge, who completed her PhD in 2009 at USC Dornsife, these emerging discoveries give her a sense of optimism. "It makes me feel less alone. We're less alone than we even thought we were here on our own planet," she says. "Spending all my time thinking about it really gives me a lot of hope, and I see a lot of possibilities and interesting questions."
