Jill Tarter
Dr. Tarter, director of the Center for SETI Research, has devoted her career to hunting for signs of sentient life elsewhere. She says that being a scientist is a privilege -- it is almost like getting to remain a kid because she never needs to stop asking "why?"

Lynn Rothschild
Dr. Rothschild, an astrobiologist, studies how life, particularly microbes, evolved. She asks, "After all, how can we understand the evolution of life in the Universe, or discover whether we are alone in the cosmos, without a deep understanding of the one place we have data -- planet Earth?"

Richard Quinn
Chemist Dr. Quinn's research primarily focuses on evidence for ancient life that once existed on the planet. Based upon observational evidence in terms of the history of liquid water on Mars, it appears there were habitable environments in the past. He thinks the probability of ancient life existing on Mars is very high.

Margaret Race
Dr. Race's work addresses planetary protection: ensuring that missions to the Red Planet and other solar system bodies do not inadvertently bring terrestrial microbes along or return any microbes to Earth. She believes that no amount of science is able to tell us what it would mean to us as humans to know we're not alone.