On Wednesday, March 14, the renowned and respected scientist, Stephen Hawking, passed away at 76-years-old.

Hawking was born in Oxford, England, and enrolled at Oxford University at age 17. He later went on to earn his doctoral degree from Cambridge University.

While at Cambridge, Hawking began experiencing signs of physical health problems. In 1963, at just 21-years-old, he was diagnosed with ALS, more commonly known as Lou Gehrig’s Disease.

After being diagnosed with ALS, it is rare the person diagnosed will live past 5 years. However, Hawking’s case lasted nearly 55 years due to the slow progression of the disease. While his muscles were slowly deteriorating over time, his brain never faltered, and Hawking was able to use a computer to communicate his thoughts to the world.

Hawking’s most famous book, “A Brief History of Time,” sold more than 10 million copies and focused on his idea that the universe began with a big bang, and that it would eventually end in black holes. Hawking also proved that black holes can never get smaller but only expand. However, in the years that followed, he proved himself wrong and concluded that indeed black holes can get smaller.

Hawking is credited with explaining time, or even more importantly, explaining our existence. For most of his life, Hawking was an atheist, relying only on his scientific evidence for proof of human existence. But as he got older, Hawking left open the possibility that there may be a creator God, but never dismissed science.

One of Hawking’s most famous quotes was made to CNN in 2010 saying, “God may exist, but science can explain the universe without the need for a creator.”

In 2014, James Marsh directed “The Theory of Everything,” the biographical movie about Hawking’s life. The movie earned $123.7 million, making millions aware of the intellectual and intriguing life of Stephen Hawking.