"If the United States commits to the goal of reaching Mars, it will almost certainly do so in reaction to the progress of other nations - as was the case with NASA, the Apollo program, and the project that became the International Space Station." - Neil deGrasse Tyson
"Are physical forces alone at work there, or has evolution begotten something more complex, something not akin to what we know on Earth as life? It is in this that lies the peculiar interest of Mars." - Percival Lowell, Mars, 1895.
The planet Mars -- crimson and bright, filling our telescopes with vague intimations of almost-familiar landforms -- has long formed a celestial tabula rasa on which we have inscribed our planeto-logical theories, utopian fantasies, and fears of alien invasion or ecological ruin. - David Grinspoon, Scientific American, Nov. 2005