Heres some stuff you might want to include if you don't already have it.
PAST
In terms of the past you may want to consider the 'Grandfather Parodox' ie: A man steps in a time machine and goes back in time to when his own grandfather was 10 years old. He kills his grandfather. His grandfather is now dead, therefore your mother/father can't be born and in turn, you won't be given birth to. If you are not born then you won't step into the time machine, you won't go back in time and kill your grandfather, and your grandfather lives! Your parents exist, you are born, you can go back and kill him .........and it goes on and on. Total paradox. This is why if time travel was possible, and we did go back it would have to be professionals who were only there to observe and document. In the wrong hands this technology could have disastrous consequences and could split the STC (Space Time Continuum) right down the middle! As far as past time travel is concerned, I believe that if the technology existed, we certainly could, because the past is something that has already occurred. So in essence, we are just 'rewinding' and having another look at something that has happened. Just imagine how many unsolved mysteries and crimes we could unravel by just going back and having a look!
Also, if you left at a certain time you would have to return at that exact time, otherwise (if you came back earlier) you may risk bumping into yourself or living in a world with another you! You can probably come up with a few ideas of your own on the disasters this would cause.
FUTURE
I have two personal theories on future time travel;
1. If it was possible: Here is a theory I like to call the "Future Self Observation Problem" My theory relies on the following notion;
Scenario: A person steps into a time machine and decides that they want to see what they look like in 10 years time. They do this, and once there, decide to track themselves down. Instead of finding themselves in a future existence, they come across a newspaper which, in the small print, tells of how this same person mysteriously dissappeared 10 years ago.
The idea behind this is simple. As soon as this person is projected 10 years into the future they instantly skip over that 10 years. This being the case, they obviously haven't been present for this length of time and therefore haven't even created a future. To them, they arrived 10 years later instantaniously. Everyone else, however, had to live out those 10 years, without that person there!
2 Reasons for an impossibility:
This is quite simple. I beleive that if something hasn't been done, then you cant see it. KE-SERA-SERA.
If it was possible then another theory of mine is that you would be sent into a limbo for the amount of time you selected, and then emerge at the required destination. You will have lived in this 'limbo' and will have aged properly, therefore making the journey pointless.
THANKYOU FOR YOUR TIME, HOPE YOUR LECTURE GOES WELL.
P.S: You might want to contact me for my theories on Atom/Particle Acceleration, a possible way to age and de-age matter( could possibly be the missing link in time travel) MY E-MAIL:
[email protected]