Best accomplishment that had previously seemed impossible 2012: Todd Frazier's hands-free home run
Jamie Moyer has given up an all-time record 522 home runs in his major league career. I can't confirm this, but it seems a safe bet that 521 of those came off of baseball bats that at the moment of contact were held in at least one hand, and usually in both, of a professional baseball player. And then there was this one, which was hit by Todd Frazier in Cincinnati on May 27, the last game of Moyer's 2012 season and probably the last of his storied big-league career:
Yes, that was a home run (you can watch the video here), and yes, the bat appears to have completely left Frazier's hands by the time it made contact with the ball.
That doesn't seem like the kind of thing that should be allowed to happen. You hear hitting coaches talk about the importance of keeping both hands on the bat for as long as possible; no hands at all at the moment of contact seems like a really bad idea. One might be tempted (as Grant was) to proclaim Frazier the Strongest Man Alive, or to use it as yet another excuse to mock Moyer's age and velocity.
I know I'd have bought both of those explanations, but I talked to Alan Nathan, the University of Illinois professor who teaches a Physics of Baseball course and gave a talk at last summer's SABR conference regarding the physics of bat performance in which he explained this very event (here is a clip). Professor Nathan knows a lot more about this sort of thing than I do and, I'd guess, more than you do too. It turns out that while the no-hands home run is an unusual and surprising thing, it turns out it's neither a superhuman feat by Frazier nor a just-that-bad pitch by Moyer; it's just physics, really. According to Professor Nathan:
When the ball impacts the barrel of the bat, a vibrational wave is created that propagates down the length of the bat toward the knob, reflects off the end (or the hands, if they are there), then propagates back to the barrel again. However, by the time the reflected wave arrives back at the impact point, the ball has long since departed. So nothing on the handle end of the bat can possibly influence what happens to the ball: not the size or shape or weight or even the hands. So the batter could just as well let go of the bat just prior to impact and it would not make any difference to the fate of the ball.
A hitter needs a grip and handle he's comfortable with, and needs his hands to guide the bat to a very specific spot in order to make solid contact, which is probably very difficult to do while letting go of the bat (or else we'd see this kind of thing all the time). Once the bat's course is set, though, the hands' and handle's work is done; that part of the mechanism can't have any effect on the force with which the ball is struck. That would shock a lot of baseball fans (and players and coaches) and is a very cool thing to know, even if it's a bit disappointing from the perspective that we can't pretend that the ball would've gone 500 feet if Frazier had merely kept his hands in the game. All the power that swing had on it was the 370-ish feet the ball ultimately traveled; the hands knocked off a little earlier than they normally would, but they'd already done their job anyway, so no harm done.
So Frazier's hands-off home run seems like something that should be phisically impossible or an incredible human achievement; in reality, though, what it is (thanks to the insights of Professor Nathan) is a particularly striking example of a straightforward, if somewhat counterintuitive, principle of physics as applied to baseball. As such, it's one of my very favorite events of 2012.