Engineering News

Nathan presents the physics behind America's favorite pastime

3/12/2010 12:41:00 PM

“The trajectory of a baseball moving through the air is very different from the one we teach in our introductory classes in which the only force is that due to gravity,” explained Alan Nathan, a professor of physics and expert on the physics of baseball. “In reality, the aerodynamic drag force (which retards the motion) and the Magnus force on a spinning baseball (which causes the ball to curve) play very important roles that are crucial to many of the subtleties of the game.”

Physicist and baseball researcher Alan Nathan
Physicist and baseball researcher Alan Nathan
Over the past several years, Nathan has successfully combined his understanding of nuclear physics with his love of the game. At the March meeting of the American Physical Society, Nathan presented his findings about the science behind America’s favorite pastime.

“These forces are governed by three phenomenological quantities: the coefficients of drag, lift, and moment, the latter determining the spin decay time constant. In past years, these quantities were studied mainly in wind tunnel experiments, whereby the forces on the baseball are measured directly.

More recently, new tools have been developed that focus on measuring accurate baseball trajectories, from which the forces can be inferred. These tools include high-speed motion analysis, video tracking (the so-called PITCHf/x and HITf/x systems), and Doppler radar tracking via the TrackMan system. According to Nathan, these new tools have the potential to revolutionize the analysis of the game itself.

"The PITCH f/x tracking system relies on several fixed cameras to record the complete 3D trajectory of pitched baseballs in Major League Baseball games," he explained. "The HIT f/x system uses the same cameras to track the initial part of batted ball trajectories. For data-hungry baseball analysts, the data from these new systems are revolutionizing the way the game is studied,” Nathan added. Next up: FIELD f/x, in which the movement of every player on the field is tracked along with the full-batted ball trajectory.

"These data will lead to new insights about the nation's pastime, including new metrics for fielding, the long sought holy grail of baseball analysis.”

Nathan presently serves on the editorial board of the journal Sports Engineering and serves on panels advising major league baseball, USA Baseball, and the NCAA. His 2003 American Journal of Physics paper (A.M. Nathan, “Characterizing the performance of baseball bats,” Am. J. Phys. 71, 134–143 [2003]) serves as the basis for present efforts to regulate the performance of non-wood bats.

At Illinois, Nathan’s current research focuses on the study of the nucleon using medium energy probes. Most recently, he has been working on an exciting new experiment to measure the electric and magnetic polarizability of the neutron. These are fundamental properties of the neutron that teach us about its underlying quark structure.

In addition to his research accomplishments, Nathan is an enthusiastic and highly regarded teacher. He is a regular member of the University's list of "Teachers Ranked as Excellent by their Students."
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Contact: Alan M. Nathan, Department of Physics, 217/333-0965.

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