If you were making a bowling pin on a lathe and suddenly decided to make a baseball bat instead, the result would look something like the "torpedo bat" that is the talk of MLB's new season. After some New York Yankees used the unusual bats to launch a barrage of home runs on opening weekend, scientists who study baseball quickly took notice. "The same bat design has been in existence for a century and a half, maybe," says Alan Nathan, professor emeritus of physics at University of Illinois at Urbana-Champaign. "And to come up with something new, to me, is...