Does altitude explain the Rockies’ hot hitting? We ask a physicist

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Photo: Baseball at Coors field (stock image)With more than a third of the major league baseball season in the books, one of the biggest stories so far is the strong hitting of the Colorado Rockies.

Through the end of May, the Rockies led Major League Baseball in almost every offensive category including batting average and home runs. Shortstop Troy Tulowitzki is on a tear, hitting a monster .521 at home, and third baseman Nolan Arenado has had a 28-game hitting streak.

But any national news story about the Rockies’ hitting inevitably uses high altitude to explain the team’s success. It’s a story as old as the Rockies franchise: Baseballs fly farther at Coors Field than anywhere else, giving the Rockies an unfair advantage over other teams, none of which play 82 games a year at high altitude.

But is it true? And if so, why?

Alan Nathan, a professor emeritus of physics at the University of Illinois, has studied the physics of baseball for 15 years, and he's analyzed the advantages -- and disadvantages -- of playing at a mile high.

The primary benefits: the air at a mile high is drier and thinner. But the Rockies have taken steps to reduce those benefits.

To mitigate the dryness, the team installed a humidor and started using it regularly in the early 2000s. Nathan says the humidor makes baseballs bigger, heavier and less bouncy -- meaning they don't fly as far off the bat. Nathan says his research shows that the humidor is doing its job: Home runs at Coors Field decreased by about 25 percent after the Rockies started using it.

But the Rockies have had a harder time accounting for how thin the air is at a mile high. Thin air makes baseballs fly farther. It also makes pitching harder since pitching is mostly about how balls break and spin, and thin air gives the pitcher less control.

Nathan says that in response the Rockies have moved the fences back, meaning a ball has to travel longer distances to be a home run. But Nathan thinks that approach is counterproductive because it spreads the outfielders out farther, resulting in more hits overall.

Nathan says the best solution would be to move the walls in and make them bigger, resembling something like Fenway Park's Green Monster.

As for the Rockies' pitching -- which is historically poor -- Nathan recommends stocking up on hurlers who entice hitters into a lot of ground balls. He's even pitched the idea to the team's brass.