Argument: Humans should send a manned mission to Mars to find life
Neil deGrasse Tyson, director of the Hayden Planetarium at the American Museum of Natural History. "Why Go to Mars." 2004: "We learned in the 1960s that Mars's surface has features that, as far as we can tell, can only have been made in the presence of water: standing water, running water, deluging water. There are features that look like they're floodplains. There are riverbeds that are straight and riverbeds that meander. Combine all of this, and you consider how important water is to life on Earth, you can't help but speculate that Mars was once a really wet place, possibly even harboring life at one point. So much of what drives cosmic exploration involves the quest to learn whether or not we're alone in the Universe—as an intelligent species, or as life at all. Mars being so close compared with the rest of the cosmos—it's a slam dunk as a place you want to go visit."