Internationally renowned scientist Stephen Hawking has died at the age of 76. His children say their father passed away peacefully at his home in Cambridge, England. Hawking was diagnosed with A-L-A at age 21, but stunned doctors by living with the normally fatal illness for more than 50 years. The British native was best known for his groundbreaking work with black holes and relativity, and was the author of several popular science books including “A Brief History of Time.”