I have thought about time travel and I would like to see the comments about it, both sides are welcome to comment so I can think some more!
First of all, as I assume the most common thought about time travel is that a body travelling back in time to experience and act with old actions of the same or another body.
Or travel forward in time to act and experience an action of a body before the action occurs later on.
(It might be a bit complicated but I tried to contain everything in the text, ask for a more longer but simpler explanation if you wish).
But as I think the explained time travel above is impossible is because you can't travel before an action is committed from a source or travel back and do more then just observe a committed action, let me explain.
Let's say we are in a room and we have a source, lets say the source is a lamp emitting light. You can stand in 3 places, the first one is close to the source, the second is twice as far from the first and the third is three times as far from the first. From these positions you can see the light. And you currently stand on the second and you can move faster then the light. As light has a speed you can move faster then that. Lets say it takes 100 seconds for the light to reach you, if you move to the position closer to the light then it takes 50 seconds for the light to reach you. You have the possibility to see an action before your last position could and if you would move to the 3 position then you would be able to see the action again but the action would still be committed. But you can't move to the place that is imaginary as a action can't be committed before it reaches you. An action can be committed without your experience of it but you wouldn't know. The closest you can get to an source is the distance 0 and even that is hard. If you move past 0 and goes -0 then you wouldn't face the source in a 3d environment but current actions would still be committed.
Let's take another example to simplify: You have a bottle on a table, it falls off the table when you see it on your current position, but then you move backwards faster then the light and see that the bottle is reversing back onto the table and when you stop to the position were the bottle is on the table again just to see it fall to the ground. But as you move forward you meet both the light coming against you and your own speed, you then see the bottle fall faster until you reaches it and it is on the floor. The way to prevent the bottle falling to the ground is to stand as close as you can and see it move about to fall and catch it as it tries. but you can't see more then the sensation coming from the bottle, you can only assume the bottle is going to fall but assuming something isn't time travel.
So that's what why I think time travel doesn't work IN A SPACE, your current space.
But there are other options. Some say wormholes to another universe but that ain't time travel that is if you take my example, taking the door to another room. That (if you are lucky) act's the same as the last room you were in or act's like your room acted like (if you want to travel back), or act's like your last room presumably is going to act like. The more possible thing that is going to happen when you travel in a wormhole is that it's going to act completely different as there are a assumed infinitive number of universes. So to find the universe that is going to act like the one that you want it to act like is VERY hard to find.
That is some deep #$%@ man.
Given these scenarios and the ability to accelerate your mass to the point where you would skip over time, perhaps you could travel in time, sort of, but, could you interact?
If the bottle falls off the table and you witness the event then travel backwards in time to catch the bottle, and succeed, that puts you in another time altogether from the one you left because in the time you witnessed first, no body caught the bottle. The event already happened....the time sequence is written and cannot be changed unless the time event is rewritten entirely.
having caught the bottle, you would now exist in a time when the bottle was caught.
the time when the bottle was not caught doesn't have time travel in it. The time when it WAS caught does.
there is a problem with having a time line where time travel is possible...actually tow really large problems...
the first, in a time line that allows for travel, nothing can actually happen because no event can be rwitten with certainty. Anything could happen. The bottle could be caught. It could hit the floor and break. It could be transported to the surface of another planet. There would be no certainty, no causality. Time would have to exist as a single point.
Second, if multiple time lines exist, one where the bottle is caught, one where it isn't, just two small examples, then the entire universe as it exists the moment either thing happens must also be recreated with each event.
nothing exists in a vacuum. Time maybe linear in this universe but there are multiple lines occurring together, running parallel to each other. If other time universes exist, then all the things in this time universe occurring when the bottle isn't caught must also exist in the universe where the bottle is caught.
so, continuity and causality must be maintained or these other universes are so strange as to be...barely knowable for even the smallest of time travel events
The thing is time doesn't have a speed, it doesn't have a limit for wich you can reach. But the way we experience things by light for example. You could travel before an event but that is just traveling before the light that gave you that event/experience. light isn't instant and traveling faster then the light wouldn't be more diferent then running faster then a flying ball that is going to hit you but ofcourse with some limitations... like the laws of fysics.
You would need to move in a space to perceive that your moving backwards in time, that would (if I still use my old example) just move yourself further from the bottle, you wouldn't be able to save the bottle from the floor no matter how fast you are.
Both the light and your speed would meet and sum up and give you the sensation that you are traveling ahead in time but the bottle would get the speed of both you and the light plus the speed of which it's falling with.
To reply with time travel thoughts: I agree, if time travel would be possible then nothing would be certain.
But as our space not universe just have a linear time line time travel makes itself impossible.
Space is infinitive our universe in the space isn't.
Space contains an assumed infinitive and growing number of universes in our shared space.
Though these universes might have a bottle left on the table might be possible but improbable.