All of our scientific tools have limits. These limits ensure that we will never see the whole picture. We can never have complete knowledge of the universe. Above, the ESO's APEX radio telescope probes the heavens from its lonely perch on Chile's Chajnantor plateau. Gordon Gillet/ESO hide caption

itoggle caption Gordon Gillet/ESO

Will people in a couple of generations be unable to distinguish between real and virtual reality? What would it even mean to be able to experience false realities that feel true? Welcome to the world of holographic pink flamingos! Sven Hoppe/AFP/Getty Images hide caption

itoggle caption Sven Hoppe/AFP/Getty Images