Stephen Hawking defied the odds to explore the universe

Stephen Hawking overcame the loss of his working limbs and voice to become the best-known theoretical physicist of his era, upending the scientific consensus that nothing escapes the intense gravity of black holes. Earning countless honors, he used his fame to appeal for saving the Earth. Science correspondent Miles O'Brien joins Hari Sreenivasan to remember Hawking, who died Wednesday at 76.