If time travel is possible, why haven't people from the future come back to the present to meet us?
Considering time travel a possibility, people from the future could have come back, say to the world war period, and persuaded America not to drop the atom bombs in Japan. So does this imply that time travel is an impossibility, or does it imply that we can travel only into the future and not into the past?
Time travel is debated among scientists today. Relativity tells us, in a nutshell, that we can travel so quickly that time actually passes faster for us, and we essentially go "into the future." There is evidence suggesting that this is possible (through observations of things called muons), however, travelling BACK in time is something that many scientists think is impossible because of something called "the grandfather paradox."
This paradox essentially says that if a person were to be able to travel back in time, he could travel back in time and kill his own grandfather, meaning that he would never be born. However, if he did this, then he would have been unable to travel back in time to kill his grandfather, because he would have never been born. It's kind of confusing to put into words, but that's the reason that many scientists believe that travelling back in time is impossible.
theoretically we have the technology now to transmit data through time, but not physical objects. that would require teleportation as well as time travel. also, based on current theory, nothing could travel back before the time machine was invented. besides that, the worlds gonna end in 2012, so none of this is relevent
time travel is definately possible to the future, and is indeed possible as to travelling back in time, we just haven't got the technology yet. perhaps they know that messing with one's universe's history (ours) will greatly have an effect on us (i say this becus as far as we noe time travel into our exact past is impossible, time is another dimension and so you can go into another universe as to what may seem like your past but in reality it is not YOUR universe it is his). part of evolving and becoming the smarter cilivilization is learning from our mistakes in the past what not to do or how to handle situations next time we encounter similar ones. yes the bomb did kill many but we also gained the wisdom to use it as our last resort ONLY instead of, "we got the technology so lets just nuke em all." but thats not to say there hasn't been ANY whatsoever, look up john titor. he's claimed to come from the future and i dont doubt him.
This is entirely hypothetical of course but any change in the past will inevitably cause a change in the future. For example, if a time traveller persuades America not to drop the atom bomb on Hiroshima and Nagasaki, who is to say that the change in the course of history from that point onwards would not lead to a situation that the time traveller would not be existing in the future that he came from?
Let's consider a hypothetical situation where the time traveller is Japanese and he convinces America not to bomb Japan and Japan didn't get bombed. Maybe then Japan does not see the large scale industrialism that came about after the war and sticks to its feudal system. The feudal system suppresses free enterprise and scientific research. As time goes by, Japan gets left behind and the time machine doesn't get invented. Then where would the time traveller come from? This is a Causality Paradox and there are theories that work around it but that's another long story.
Maybe the folks in the future realise this and are happy to leave well enough alone. Hope this is useful.
We have been coming back and forth in time for hundreds of years.
We are here.
But you will never know.