In thinking about the question and reading the various answers, I find myself agreeing most with lynn300k's post. If time travel were possible, how would we ever know for sure the "quality" of the timeline in which we lived? Would it be the original timeline, if there is one, or would it be an altered timeline?
Science fiction is indeed the place to go for this sort of discussion. A number of episodes from the Star Trek Enterprise series center around the playing out of a "Temporal Cold War," in which conflicting factions struggle to reshape the past (and, thus, the future) to fit their vision. The series didn't often get good reviews or ratings, but I sure liked it!
If interested, see the wikipedia links below. Wikipedia is a questionable source in many matters (there's no guarantee that contributors are qualified to make many of their contributions), but it's one of the best places to go to get an overview of developments in American popular culture.
Interesting question. I think it would make things an incredible mess. How could you ever know which reality you were in? If someone monkeyed with the past and changed things, only they would know--for the rest of us, it would seem as if things were the way they always had been. We would know no different. In addition to the Bradbury story mentioned above, you might want to read Haldeman's The Forever War. There is also a short story--can't recall the name--that makes the point of: when does the past start? Ten years ago? A month ago? Really, the past starts as from the moment we enter the next second, and if even the viewing of "the past" is possible, it totally removes everyone's privacy about anything. All I have to do is watch what you are doing one second ago, on a continuous basis....
There have been a LOT of SF stories on the time travel theme. I think you might be interested in them. Jack Finney's novels completely side-step the machinery that would be involved; his characters kind of just believe themselves into the past. But I'm a SF fan, and like most of the authors who take a stab at time travel.
If time travel were possible, there could be so many effects, both good and bad. However, it is hard to know what would be possible -- we don't know if people who went into the past could affect the present.
If people could go back and affect the present, that would be terrible. Imagine if some neo-Nazis could go back in history and warn Hitler about some mistakes he made. This could allow him to win WWII.
On the more positive side, you can imagine that people could go into the future and find out from them things like cures for diseases or green technology that could prevent global warming.
So it would be a mixed blessing for sure.
If time travel was a possibility, a million things would be different. Our imaginations would not be able to grasp even a drop in the bucket. Just imagine if one were to bring medical technology into the past. How many lives could we save? Or consider, if we brought military technology in the past and it fell into the wrong hands. This would spell disaster. The would would be a very different place, to say the least. Or consider if time travel itself was monopolized by a few people. Imagine the dynamics of power that would be in play. These are just a few suggestions to think about.
If Time Travel were possible, one must have to first begin in the present and concretely decide which consequences we would be able to tolerate should, by any chance, we chance the course of things (as we know them).
Yet, if it were possible, and humans were always well-behaved, we could use that unique resource to explore who we once were, and trace where we are heading. We could analyze our behavioral and cognitive patterns, and establish guidelines to the manners in which we have problem solved life's toughest times.
Unfortunately, greed, envy, and other things tend to get on our way, so these ideals may be null.
When I first considered the idea that time travel was possible, I thought it would be fantastic! Imagine being able to go back and see great events in history---while they happened! Imagine going back and meeting some of the great figures from the past! Imagine what would happen if you could go back and do something that you should have done in your past!
When that last idea hit me though, I started to think of the consequences of doing that. Just changing one minor event in your past life could change who you are now in ways that would be unfathomable. Everything that you are now would be different. It’s almost hard to comprehend.
So, I think time travel would not be a good thing---unless we could go back and not influence anything that was happening. It would be great just to see history being made, but not being able to change it.
As this is the subject of several works of science fiction, I would also posit that the discussion is highly interesting. The notion of how things could change with the slightest of alteration would be of critical and pressing importance in such a question. Ray Bradbury's work, "A Sound of Thunder," is an interesting work on the piece as it charts back through prehistoric times what happens if individuals go back in time and alter the events that compose the present. It might be wonderful to go back in time and right wrongs committed, but an equally perplexing situation would be how the present and the future are altered by the changing of what was in the past. It is almost beyond comprehension as to how events in the past link and connect those that come after it.
This question really depends on whether events are set in time or not. If events are set, basically if fate exitst, then no matter what I did if I travelled back in time, nothing would change. Things would occur just perhaps in different ways. For example, if i went back in time and saved someone from being killed in a car crash, they would die from choking or falling down the stairs if events were fixed.
If events are not fixed, and there is no such thing as fate, then a great deal of damage would probably be done to the world through the actions of the time traveller. For example, I could save a drowning child only for the child grow up to be a serial killer.
It's funny when thinking about possibly jepordising our own existance, like in Back to the Future. Surely, if you stop yourself from existing, then you wouldnt have existed to stop yourself, therefore you would still exist?
If time travel were possible it could bring many things to the world. However, I believe it would be more detrimental than helpful for humanity. Human beings have not been able to adjust to the technological and scientific changes that have developed over the last century. Imagine if humans could go into the future and bring back advanced technology. My biggest concern would be the use of weapons to assist in the destruction of our planet.
I think an advantage would be that a human could go back in time and repair his/her mistakes, but that may not fix their future just alter it. However, human nature being at its worst sometimes would most likely be used to create chaos instead of assistance for our society.
Good technology from the future such as medications could help prevent certain diseases and offer cures. On the other hand it could result in a population explosion that could result in dissolution of resources
As this concept is based on the theory of RELATIVITY,so acc to it time travel is possible only if we move with the speed of light,which is practicallynot possible till now.
This is based on REFLECTION of LIGHT as we see things due to reflection of light,so if we travel with the speed of light we can see the past eventsjust like a movie as the reflected rays remain going on.
But i think we cant bring about any change in past & prhaps its not possible to go in FUTURE AS LIGHT has not reflected yet.
These were my views for further details refer to EINSTEIN'S THEORY OF RELATIVITY .