Some questions...

[Guest]

Dear scientists.
I'm a student of Medicine in Greece, and my greatest hobbies are computers and astronomy (well... astronomy of the paradox to be more precise). I would like to ask a few questions about certain things concerning astronomy and time travel.
First of all do you think that the theory of time travelling contradicts the laws of physics like thermodynamics (entropy always increases), so as to set a limit in wether we can travel towards only one direction (past or future)? In addition Einstein suggested that E=mc^2, but how do we know that matter does not respond differently under conditions of speed close to the speed of light? For example we know that matter does not respond similarly in our everyday world and in extreme conditions like in temperatures close to absolute zero (perhaps something like that happens with the speed of light). Moreover even if E=mc^2 is correct in every case, then what if we accelerate an object to a speed close to the speed of light, and then bring it close to a gravitational field (of Sun or of a black hole)? Wouldn't then the object accelerate even more to reach and surpass the speed of light? (remember that the acceleration of an object in a grvitational filed does not depend on its mass).
Suppose that I travel in the past and I prevent my parents from meeting each other. I think that I'm not wiped out of existence. I continue to exist but if i return to my starting point I will realise that myself has never existed (as my parents never had me). Then I automatically create another dimention in which I do not exist (but I come from the previous dimention). If I'm wiped out of existence then don't you think that we have a paradox? (I do not exist, so no one goes to the past to prevent my parents from meeting, so my parents meet normally and I am born, so I go back to the past and prevent them from meeting, and I never exist, and no one prevents them from meeting, and...). Now suppose that I invent a machine that can travel through time. I go to the past and I return 1 hour before my starting time (starting time=the time I started travelling to the past). I destroy any time machines existing. Am I stuck with myself? (as the other me never goes to the past).
As the universe expands, its temperature falls continuously. Shouldn't the expansion end when the universe's temperature reaches absolute zero?
What about time travelling with... our minds (I'm talking about people's abilities of seeing the future, and I know that they can't be all frauds).
When an aeroplane reaches the speed of sound, the plane tavels as fast as th sound it produces. The result is an extremely loud "bang" noise heard. What similar phenomenon can we expect when an object reaches the speed of light (that is when this object travels as fast as the photons emmited from it)?
I'm verry sorry if I tired you with all my questions. I'm really looking forward to receiving your answer, and I'll be very happy if you answer any of my questions.
Thank you very much for your time...
Anastasios Mylonas.

 

[Guest]

Good point on your mass/light speed issue. My speculations on this parallel yours.

Then...

The paradoxes inherent in the traditional concept of time travel are themselves the best evidence that it is not do-able. The laws of physics (Newtonian, Einsteinian or otherwise) do not lead to paradoxes in any way. Ergo, no-paradoxes=no-time-travel. (My application of Occam's Razor.) The paradoxes in backward time travel are obvious. The ones in forward time travel are not quite so obvious but they are there nonetheless. The initial error is in assuming that there is some else/when where events have "ALREADY" occurred that you are going to travel "to". (This in itself is an oxymoron.) If you accept that this future exists you have to suppose YOU played some role in it's unfolding in the manner it has. But, you decide to travel to it, and are therefore "not existant" during the intervening period to fullfill the role you "had" in creating it. Or you DON'T make the trip and THAT becomes contrary to the way it's supposed to unfold. Either way, this is not only a paradox, it is an oxymoron as stated earlier. I call this one "oxymoronic" thinking. The paradoxes go both ways.

And finally...

As far as the "esoteric" time travel of the mind, sure. Why not.