On the most recent edition of his "Star Talk" radio show and podcast, astrophysicist Neil deGrasse Tyson answered the question, "What is gravity?"
"I have no idea," he joked. "Okay, next question."
Then, he went on to explain, "Here's the difference. We can describe gravity, we can say what it does to other things."
"We can measure it, we can predict with it," he continued, "but when you start asking, like, what it is? I don't know."
His cohost Leighann Lord said, "So I accidentally asked a deeper question than I meant to?"
"No, no," replied Tyson, "you were meant to ask deep questions in life. So...in an Einstein-ian answer, we'd say gravity is the curvature of space and time, and that objects will follow the curvature of space-time and we interpret that as a force of gravity. That's probably the best answer I can give to a 'What is gravity?' question."
"And that's a good start," he said, before adding the formula: "Einstein noted that matter tells space how to curve and space tells matter how to move."
Watch the video, embedded below via StarTalk: