Instrument to Go Back in time?

Unfortunately, since time, space, "space-time," m, energy and gravity are all related...I don't see mankind ever being able to harness the power needed to create such a device. I think the closest we'll come, given enough time, would be to create a transportation device which will approach light speed (of couse, not exceed it); and that will, for the penger, slow time down. This will give him/her the experience of moving quickly into the future. But I think that's as far as it could ever go.