People can only see the light of your body, and not your body itself. Because we move slower than the speed of light ( which is approximately 300,000 kilometres per second ), our body's are visibly synchronised with our physical state. But what would happen if you were to move faster than the speed of light? well first, you wouldn't be able to see anything. It would all be black. That is because light can not catch up to you. So lets say your speed is twice that of light, and you travel for 1 hour
... ... Your physical position : >>>>>>>>>|
Your body's light's position : >>>>|
The speed of light is about 1,079 million kilometres per hour. So if you travelled in a rocket constantly going twice the speed of light to a point 534.5 million kilometres from earth and returned, it would take you one hour to physically arrive back on earth. But because you were going at twice the speed of light, your body's light (or your "visible being") will arrive back on earth two hours after your departure. If as soon as you got back to earth, you have a coffee and sit down to watch a bit of television then leave, people will see you having a coffee and watching television an hour after you actually do it. You will not physically be there, but your visible being will. If someone touched your visible being, their hand would go straight through your visible being like it would a ghost. While people are fascinated by your "ghost" you would be somewhere one hour in the future. As soon as you stop travelling faster than light, your body will become visible. You will have a ghost though, sort of like a clone. The ghost will do anything you do, only an hour later. It would be impossible to go back in time, and your 1 hour delayed clone/ghost will remain for ever, even after you die.
notes : after you stop travelling faster than light, you should be able to see things again.
In this example you have travelled one hour into the future. Feel free to comment if you are confused by anything. I even confused myself while coming up with this.