What's the Science of Invisibility?

Sure, invisibility is about magic cloaks and invisible inks. But it's so much more than that! From the way butterflies see a secret world of light that humans can't, to the real reason polar bears are completely undetectable to infrared cameras, there's a whole big world you ought to hear about… even if you can't see it. Featuring author Bob Berman. This episode originally aired on September 1,…