While everyone is trying to go faster then light, no human will be able to go faster then light. If everything leaves a imprint in time space. Light does not leave a imprint only a magnetic or energy other then light must have this imprint. To move thru the signature or pinpoint a time you wish to travel too, you must find the signature of the time space. By bending time, as I like to call it, you warp the space timeline causing the line to curve opening a wormhole. The question is how big of a wormhole will you open based on how much "energy" force you apply to the environment of testing. Also to bend the timeline this would have to be a large amount of energy force, though much of the earth has very strong energy forces on the earth. I believe there are places on the earth that have these signutares in them. Just as a tree has rings when you cut it open. If the earth has a signature we have to bend the time signature to be able to see the past. The future is something that you can't travel too, I believe the signutare will only tell you the past and present. Also you can see the past yet you can't change it because of the space time will have to be rewriten. The possiblity of time travel has many great ideas for mankind yet many downfalls. The choices you make, are what make you. You can't physically exist in the same time space.