Ronald Mallett thinks he has found a practical way to make a time machine. Mallett isn't mad. None of the known laws of physics forbids time travel, and in theory, shunting matter back and forth through time shouldn't be that difficult.
Leonhardt and his colleague Paul Piwnicki at the Royal Institute of Technology in Sweden have devised a way to create black holes in the lab. They are quick to point out that these aren't real black holes but 'optical black holes' that are created by slowing light down.