When Christopher Columbus set sail from the port of Palos de la Frontera on Aug. 3, 1492, no doubt there was some peasant standing on the wharf, muttering to himself, “A fine waste of royal escudos. As if we don’t have enough problems at home. Why are their stinkin’ majesties funding a voyage to nowhere?” Fortunately for Spain, those benighted views did not prevail. If they had, Spain would not have gained one of the most lucrative empires in history. Unfortunately for us, the sentiments of that apocryphal peasant seem to be the dominant reaction to President Bush’s bold vision for colonizing the moon and visiting Mars, which may be why he didn’t mention it in the State of the Union speech. A chorus of critics is demanding that, instead of exploring brave new worlds, we perfect the one that we already have.