Stephen Hawking, the brilliant Cambridge University theoretical physicist and cosmologist, liked to note that he was born 300 years to the day after the death of Galileo. It seems a fitting bookend that he passed away on the 139th anniversary of Albert Einstein’s birth — Pi Day.

Although Hawking lived with amyotrophic lateral sclerosis for a remarkable half century, his death came as a shock to several of my peers and me. One could hardly help feeling that a brilliant and extraordinary mind like Hawking, who inspired people all over the world to look beyond our little blue and green marble, would always be around as an inexhaustible life force. But it’s undeniable that his ideas will be around as long as there are scientists, and assuming that Hawking was right about the lifespan of the universe, his legacy will live for another twenty billion years.

It’s difficult for the 99.9 percent of us who aren’t theoretical physicists to wrap our minds around Hawking’s discoveries, but it’s fair to say that they upended previously-unquestioned assumptions of the scientific community. As with many of the best scientific discoveries, they resulted in many more big questions about the universe and how it works. Based on Einstein’s theory of relativity alone, black holes were once thought of as places in which things are irretrievably sucked in. But by integrating Einstein’s theory with quantum mechanics — which describes nature at the energy levels of atoms and subatomic particles — Hawking discovered that black holes are not completely black. They are, in fact, wellsprings of energy, slowly leaking particles and radiation. Over eons they eventually explode, returning to the cosmos all the mass and energy that had once disappeared. Succinctly, Hawking showed us that black holes, like almost every other object in our universe, can shrink and die. “Black holes ain’t as black as they are painted,” he once said. “They are not the eternal prisons they were once thought. Things can get out of a black hole, both to the outside, and possibly, to another universe. So, if you feel you are in a black hole, don’t give up. There’s a way out.”

But in addition to Hawking’s universe-shaking theoretical work, many who knew him have remarked on his plucky wit and light-hearted outlook on life. When he appeared on John Oliver’s late-night comedy show Last Week Tonight, Oliver commented on Hawking’s belief that there exist an infinite number of parallel universes. “Does that mean that there’s a universe out there where I’m smarter than you?” Oliver asked. “Yes, and also a universe where you’re funny,” Hawking replied. He also had a mischievous way of getting back at people he didn’t especially like: deliberately running over their toes with his wheelchair. Hawking once said that one of his regrets in life was never having the chance to run over former British prime minister Margaret Thatcher’s toes. He was also said to have a remarkable way of relating to others. For example, his daughter Lucy recalled that at her son’s ninth birthday party, a child asked Hawking what would happen if he fell into a black hole. “You would turn into spaghetti,” Hawking said, and all the children immediately understood. He also wanted his book, A Brief History of Time, to be so understandable and accessible by the general public that it would be sold in airports.

The world has lost one of the smartest and most notable intellectuals that we’ve ever had and ever will. As we remember his life and extraordinary work, I urge us all to be careful not to express well-meaning but strikingly ableist sentiments, especially remarking how he is now “free” of his wheelchair and disability. The fact of the matter is that Hawking did all of his amazing work with his disability, not in spite of it. To forget that is to erase a part of who he was, simply because it was something that couldn’t be easily understood. Indeed, he did not need to be freed from his disability to change the way we think about our universe forever, so why must we think he needs to be freed from it in death? Hawking once said that he accepted that there were some things he couldn’t do. “But they are mostly things I don’t particularly want to do anyway,” he continued. “I seem to manage to do anything that I really want.”