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

Detail of a Turing Bombe machine in Bletchley Park Museum in Bletchley, central England. The device, the brainchild of Alan Turning, was instrumental in cracking the German code during World War II. Alessia Pierdomenico/Reuters /Landov hide caption

itoggle caption Alessia Pierdomenico/Reuters /Landov