The Sirens of Mars
A planetary scientist details the remarkable history of humankind’s efforts to find signs of life on Mars. Speculation on the nature of Mars, and whether it could harbor life, goes back to the early days of astronomy, when thinkers such as Galileo and Newton peered into the night sky using primitive technologies to examine Mars’ surface. For centuries, theories of what existed there ran rampant. “The idea that Mars was like our planet only drove the quest to see it better,” writes Johnson, who teaches at Georgetown.