said it could happen. Although I think he also said that you would need to travel so fast that you could rip a hole in the space time continuum and thus destroy the universe.
On a similar note: You may have heard of the Large Hadron Collider
Well, its is also thought that time travel may work like a phone, you need someone els to have one for you to call them etc.
So, with the Large Hadron Collider thought to have the ability to create a 'wormhole' then perhaps someone in the future with the capability to travel from wormhole to wormhole, could travel to a wormhole created by the Large Hadron Collider.
with me? lol
So... What are your thoughts?