Iconic picture of scientist. Who’s he, and what makes this image special?

Cracked by shrik, Thejas V R, Raghuvansh, Rogi, Aparna, varuns88, krudebox, sidsen, Dibyo, udupendra, googboog, Nihar, Gowri, reddevil_ani, Shwetha Maiya, Manish Achuth, Raison, v.chandrashekar, Arun Krishnamoorthy, Anubhav, AmK, wanderlust, shenoyvarun86, Logik, Qbrain, lanu, Bharath, dineshk, Rahulk and Sourya