This is your morning dose of heady reading: a ten section thesis on the implications of the grandfather paradox, from the perspective of modern physics.
The essay starts off by considering what would happen if you stuffed a pistol in your pocket and traveled back in time to pump a few rounds into your grandfather's belly. The logical loop is obvious and fun: if you kill your grandfather, you can't travel back in time to kill him, which, in turn, means he'll live and you will go back in time to kill him.
But some of the other wrinkles are less obvious, though just as fascinating: consider, for example, sending an atomic particle back in time to collide with its younger self. The collision would send the younger particle in a reactionary trajectory, different from the trajectory in which it traveled through the time hole to collide with its younger self. There is also an interesting thought experiment on what would happen if you took a photograph of a photograph sent through a time machine, then sent that photograph into the past for you to take a photograph of.
The real question, of course, is not whether or not I can go back in time and kill myself: it's whether or not there's anything preventing me from traveling back in time and teaching myself to make out. Because, quite frankly, a lustful heavy petting session with a younger me is the only way I can think of that will allow me to ever cure myself of my rumored inadequacies as a french kisser.
Time Travel and Modern Physics [Stanford Encyclopedia of Philosophy]
