@CNN: Stephen Hawking overcame a debilitating disease to publish wildly popular books probing the mysteries of the universe. But what is ALS, the condition he lived with for over 5 decades? https://t.co/lZjOAN2f4b https://t.co/4c2EwSiGn2

@CNN: Stephen Hawking overcame a debilitating disease to publish wildly popular books probing the mysteries of the universe.

But what is ALS, the condition he lived with for over 5 decades? https://t.co/lZjOAN2f4b https://t.co/4c2EwSiGn2