Time travelling forward is easy, just do nothing and time goes forward. Want to travel into the future more rapidly? Park near a large mass or accelerate to massive speed and fast forward the surrounding time to your hearts content. Travelling backwards in time however is another matter. To travel somewhere, it has to exist. You cannot travel to a location that doesn't exist. The future exists as potential and thus can be travelled to. The past does not exist in the same way. Whereas the present will naturally progress to the future, and using relativity you can from your reference point get there faster, the past does not really exist in the same way. The only way that the past exists is by taking every piece of matter and energy in existence and somehow reversing the flow of all of it. Basically, to "travel" to the past, what you effectively have to do is turn back time, by extrapolating out every previous event using every piece of information existing in the present. cont.