Jim Dey | Baseball's physics guru provides 'seamless' analysis

Jim Dey | Baseball's physics guru provides 'seamless' analysis

Incoming calls have slowed to a trickle, but last Friday, University of Illinois Professor Emeritus Alan Nathan was talking by phone to reporters "virtually all day."

He said he's "not complaining." Indeed, Nathan accepts it as part of the responsibility that comes with being the "Unofficial Physicist of Major League Baseball."

"I kind of like that title," said Nathan, who received his doctorate in physics from Princeton.

The monicker, of course, is officially unofficial. But the fact is, when Major League Baseball has a question that can be answered through scientific inquiry, Nathan usually gets a call.

That's why he was in the news again last week.

Concerned about the reasons for an increased number of home runs and plagued by allegations that MLB baseballs are "juiced," baseball Commissioner Rob Manfred appointed a blue-ribbon committee of scholars — mathematicians, physicists, statisticians and engineers — chaired by Nathan to look into the matter.

They came, they studied, they narrowed the field of suspects to one — aerodynamics. But the academics could not reach a hard-and-fast conclusion.

The report, which is revealing about the hows and whys of home runs, is written in the non-fan-friendly style of the academy.

For example, here's a brief excerpt.

"One oft-repeated theory has been that the home run surge may be due to a 'juiced ball.' Since a large fraction of the impact energy is lost during ball-bat collision, small changes in energy dissipation can have a large effect on ball performance."

Got that? Didn't think so.

Nathan, who's 71, didn't grow up with the ambition to become a baseball physicist. A native of Maine and an avid Boston Red Sox fan, he was a conventional academic doing traditional brainiac stuff when he was asked about 20 years ago to give a public lecture about physics.

Nathan had a book on his shelf that he hadn't read — "The Physics of Baseball" — and he decided, figuring that it would motivate him to actually read the book, to give a lecture on that topic.

As luck would have it, Nathan's lecture, which was covered by The News-Gazette, drew widespread interest and calls for more talks of that nature.

What Nathan expected to be a "one-shot deal" turned into a "new career for me" that he said allowed him to "seamlessly step into the next phase of my life."

He enjoys the challenge of trying "to understand what is going on the game" and brags — with one substantial caveat — that he is tops in his field.

"It's easy to be the best person who's doing it if nobody else is doing it," Nathan conceded.

For example, Nathan is currently studying "the effects of the new (baseball) humidor" at Chase Field in Phoenix. He predicts storing baseballs in a temperature- and humidity-controlled environment in the otherwise "very dry climate" of Arizona will cause the baseballs to be "less bouncy" and decrease home run production at the park "by a lot, maybe 35 percent."

He said a similar baseball humidor at Coors Field in high-altitude Denver, Colo., led to the number of home runs there dropping 25 percent. Coors Field has long been considered to be a slugger's paradise because of the altitude.

"There's less air drag because there's less air," Nathan said. "The typical 400-foot homer at sea level would carry 425 feet in Denver. That's an enormous difference."

Major League Baseball is awash in statistics these days because of StatCast, a high-speed, high-accuracy, automated tool developed to analyze player and ball movements. Introduced to all 30 MLB stadiums in 2015, the numbers it generates are manna from heaven for sabermetrics and physics purposes.

Nathan's panel focused on three issues to determine why the percentage of batted balls turned into home runs jumped by one-third between 2008 and 2017:

— Livelier balls?

— Batter behavior?

— Aerodynamics?

The report states that 3.6 percent of batted balls were home runs in 2008 compared to 4.8 percent in 2017.

Examination of the "bounciness" of Major League Baseballs at Washington State's Sports Sciences Laboratory showed "no evidence" that bounciness — known as "coefficient of restitution" — played a "major contributing role" in the home run increase.

So what of batter behavior, specifically whether "batters are swinging the bat harder to obtain larger exit velocity" or doing so "with an elevated plane to produce launch angles conducive to home runs"?

Once again, they found "little evidence" that the much-vaunted "launch angles" and "exit velocities" — baseball's new buzz words — "contributed to an increase in home run hitting."

Finally, there's aerodynamics. It's the guilty party, but it's a mystery as to why.

They found "better carry" in the baseballs that "result in longer fly distances" because there is "reduced drag on the baseball."

Committee members concluded it was not due to the weather or the size, weight and seam height of the baseball.

The committee speculates that "manufacturing advances" are producing a "more spherically symmetric ball" that has an "unintended consequence of reducing the ball's drag."

"... if a ball has a center of gravity that is offset from its geographic center, the ball will wobble as it spins, increasing its effective surface roughness and potentially increasing its drag," the report states.

Now readers know as much as Professor Nathan and his colleagues have learned. But he says they're not licked yet — that studies are ongoing to solve the mystery of "better carry."

"We're going to continue to study this, partly because we hate to admit defeat," he said. "We think if we work hard enough on it, we can figure it out."

Jim Dey, a member of The News-Gazette staff, can be reached by email at jdey@news-gazette.com or by phone at 217-351-5369.

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