Neil DeGrasse Tyson: Science And 'Empire-Building Ambitions' Have Always Worked Hand In Hand

Physicist Neil deGrasse Tyson writes about the ways science has been put to use to help fight, conquer and expand in his new book "Accessory to War," which he co-authored with Avis Lang. In a special episode of the Here & Now podcast, Tyson joins host Jeremy Hobson to discuss the book and have a wide-ranging conversation about space — and, of course, aliens.