There's always been this debate of whether we can travel in time. There has been no end to it, almost 99% of people would conclude, oh, we just don't have the technology now, we would be able to do so in the future, perhaps year 2100.
Ok, what is time? It's actually a scheduling tool used by homosapiens to delegate our daily chores, its a dividing of a process we go through. On a smaller scale, hours, on larger scales, years. But is there a definite relativity to our natural world? Does nature comprehends or response in the way we, homosapiens divide our time? NO.
We cannot relate year 1950 to a state where the earth's temperature is 2 degrees celcius colder on average, it's just our recording of a process that nature went pass, and we're in it; not above it. This theory of time travel is based on the same concept that we, homosapiens living on this third rock from the sun, is actually the middle of the universe, and that everything rotates around our sense of understanding.
Time travel is impossible. There is no way we can travel our selves in space and dimension to a world where we have been. The theory of time travel is based on our believing of everything is destined, and that we can change it if technology allows, it is so near to reality because we can perceive the 'benefits' that could be obtained, it is also based on our imaginations, our thinking power which renders us almost 'free' from our basic instincts, to gain a higher level of self consciousness whereby we are able to change destiny.
Let me explain abit, if it is destined that if YOU crossed the road and thus both your legs were decapitated by that truck, and that if you are able to travel in time to stop your own self from crossing the road, or if earlier, sabotaging the truck to not allow it to start, it would be also destined, that time travel would definitely happen !
If the timeline of activities were of a constant line that we humans believe what destiny are to be, then time travel would also be included in this time line, perhaps at a later stage, and this, would literally means time travel would not be able to change destiny after all because it is in it.
Now let's move to a slightly deviated topic, looking into the past. As we all know, light travels at 299,792 Kilometers per second. The vision of something happened at 299,792 KM away will reach you at 1 second later. We also know that by looking up to the Sun, we're actually looking at history because light needs 8 minutes and 20 seconds to reach us, and if you have a powerful enough telescope to take a glimpse into, you'd be able to see the surface of the sun, albeit 8 mins and 20 seconds slower to what was happening there RIGHT NOW, because the vision which could only be comprehended by light, needs that amount of time to reach our very eyes.
Now bring this to Proxima Centauri, the nearest star (Another SUN, closest from earth) is 4.22 light years away from us; now what are lightyears? A light year, is the amount of distance light travels in a year's time, 365 days. Hence light needs 4.22 years to reach us from there, meaning we're looking at something 4.22 years ago, however we do not know what was happening to it NOW.
Ok, vice versa, if some alien being was looking at us thru their high powered telescopes, and they are able to zoom to the surface and see what's actually happening, perhaps on someday in year 2005 (maybe near September) these aliens were shocked by what they actually saw, 2 planes crashing to the twin towers in New York City. Ok, imagine you were there as well, looking back from the very telescopes these ETs were looking thru, are you looking back in time?
Hence to conclude, if we are able to invent something that travels faster than light, say, we could reach a planet 100 million light years away, in 1 year, ok perhaps immediately reaching there, (not much difference ain't it?) and when we looked back thru some portable hubble telescope, what can we see? You'd guessed it, 100 million years ago, T-Rex, from Jurassic
You can see the past, you can never go back.
Image used taken by Photographer Yitzhak Avigur, hosted at TrekEarth.
No intention for commercial purposes.