"We stand on a great threshold in the human history of space exploration. On the one side of this threshold, we know with certainty that planets orbiting stars other than the Sun exist and are common. ... On the other side of this great threshold lies the robust identification of Earth-like exoplanets with habitable conditions, and with signs of life inferred by the detection of "biosignature gases" in exoplanetary atmospheres."
"Even today, children wonder, where did I come from? Astrobiology seeks to answer this enduring question."
"During my time as NASA Chief Historian, everywhere I went people of all ages wanted to know about life on other worlds. Astrobiology raises fundamental questions and evokes a sense of awe and wonder as we realize perhaps there is something new under our Sun, and the Suns of other worlds."