Astrophysicist Says He Knows How to Build a Time Machine

The CNN article has more details and it makes it clear that the effect depends on general relativity. With special relativity, it's clear that you can't travel back in time.

Without a veeeeeeeery strong gravitational field the universe is approximated so well by special relativity, that makes time travel to the past impossible. Nearby a rotating charged black hole, I have doubts, so ask an specialist.

But a device with just a bunch of lasers and no strong gravitational field will not make this happen.

Extract: Astrophysicist Ron Mallett believes he’s found a way to travel back in time — theoretically.

The tenured University of Connecticut physics professor recently told CNN that he’s written a scientific equation that could serve as the foundation for an actual time machine. He’s even built a prototype device to illustrate a key component of his theory — though Mallett’s peers remain unconvinced that his time machine will ever come to fruition.