Tpt> Yep, I think Hawking is right. However, time-travel is not based on the fact that the future is set.
That is exactly the definition of the future. All those choices that have NOT been made, events that have not yet happened, and may occur in various different ways.
The past is somehow settled. Information on all events that have happened, are all around us – not only on photos, in memory, on tape etc. Light (EM radiation) from those events penetrate the Universe (hence why we can see what happened at Alpha Centauri 4,3 years ago), and this emission of information somehow “locks” the past.
Imagine the following scenario. Some aliens, with a mega-hyper-super tech telescope 15 lightyears away are watching Earth. That means they’re hearing and seeing Earth anno 1989.
The light from the events back then have travelled to them during the past 15 years and reach our aliens now – in our 2004.
Should I go back in time, to 1989, you, the rest of the world, light from 1989 and our Aliens would still be here – in the present. If I were to start changing things, an incredible faster-than-light change would have to occur with the light that had just travelled to the aliens.
Lady Eowyn> That continuos movement of the present into the future is MOVING through time. It’s not how time-travel is defined.
Alpha Centauri> And I bet you no one IS trying to invent time-travel. For the simple reason that we don’t even have the beginnings of the physics required to do so.
Shaber> On the subject of Black holes? Or on wormholes? Or on time-travel in general?