What does the future hold for America’s space program? Astrophysicist Neil deGrasse Tyson argues that space exploration is vital for our economy, our security — and our morale. "Audacious visions... have the power to change assumptions about what is possible," he says. In his most recent book, "Space Chronicles," Tyson challenges lawmakers to invest in NASA and once again put a priority on the nation's space program. Neil deGrasse Tyson joins us to talk meteors, aliens and thinking big about exploring the universe.