We've already done time travel in the large hadron collide, just with molecules or atoms or something. You send tlthrm round fast enough and they go forward in time. Stephen hawking explains on the time travel documentary all this, and obviously far better than me! But yea we've already done it (to an extent) and we know you just need to go fast, or knock about near something big (talking a fuck off planet big). Give it a watch if you are even questioning whether time travel exists (as did I) and you watch thay it's one hell of a fucking eye opener and explained brilliantly so even people like m ewho know fuck all about physical, can understand