Thor—Norse god, Marvel superhero, and Hollywood eye candy—presents those of us living in the real world with a few problems. Thor is a “demigod,” and any attempt to scientifically explore his otherworldly abilities can be dismissed as such. But with his resurgence in The Avengers last year, and seeing that today is Thor’s Day, the time has come to discuss in real terms his most prized possession: Mjolnir (literally, "that which smashes")—his hammer.