If you’ve ever watched part of a professional football game, you’ve probably seen a tight spiral pass. They’re those perfect throws where the football leaves the player’s hand and neatly spins as it arcs through the air.
But those passes seem to defy fundamental physics.
And for a long time, scientists couldn’t figure out exactly why — until experimental atomic physicist Tim Gay cracked the case just a few years ago. His answer comes after two decades of hobby research and more than a couple of late-night shouting matches with two other physicists over Zoom.
Accidentally kicking off a mystery
Gay has always loved both football and physics. As a high schooler, he couldn’t help thinking about the sport through a scientific lens, asking questions about the shape of the football and how players were able to execute passes seamlessly.
He loved the sport so much that, as a physics professor at the University of Nebraska-Lincoln, Gay gave one-minute lectures for packed stadiums in the middle of football games.
These lectures caught the attention of Nobel Laureate Bill Phillips, who invited Gay to give a lecture on physics and football at the National Institute of Standards and Technology in 2000.
After Gay finished his talk, Phillips stood up to ask a question.
“I have been to enough meetings with Bill that I knew that if he stood up and asked a question, the speaker had probably screwed something up,” Gay says. “So I was a little petrified.”
Phillips wanted to know why, in a tight spiral pass, the front nose of the ballpoints up when it leaves the quarterback’s hand and then tilts down when it lands in the hands of a receiver. It was puzzling because fundamental physics suggests that the ball should either rotate in the air or just stay mostly upright.
But it doesn’t.
So when Gay heard the question, he racked his brain for an answer until he finally looked at Bill and said, “I have no idea!”