Linkage

These stories made me smile (because I'm a nerd like that):

Time machine design made simpler
"No exotic matter needed ... just the power of a black hole"

Time-travel physics: stranger than fiction
"Physicists say future tests could tell whether we can change the past"

One great theory: the "chronology protection conjecture", which basically says if you go back in time and try to change history, the universe will conspire to against you. So, for example, if you tried to shoot your father before you were concieved, the gun wouldn't go off.

...Or if you try to stop the Glencoe massacre, you fall in a loch and get hypothermia. *g* On that note, I think I'll go work on the rest of that scene...