First of all, my background: I am an engineer interested in physics; so I am not very well versed with the nitty-gritty details and the math of physics. These are my thoughts and would like your comments: In some sense, time travel, being able to move back and forward in time is the ultimate dream to be solved by scientists. Many people, including physicists compare time travel to space travel and say that since we are able to move back and forth in space, why not in time. I have an issue with this comparison. The question I have is, are we really moving back and forth in space in a manner analogous to what we want to achieve in time travel? I don’t think so. Here’s why: As we know, the universe is expanding continuously. In particular, space is being created and we are all moving away from each other at the large scale. The new space is being inserted between galaxies and clusters of galaxies. That is the space into which we should be able to move to. Are we able to do that? Are we able to go back to the spot in hyperspace where we were, say last year? This too may not make sense because our space (or location) has not really moved due to the expansion of the space; it is just that it got shoved out due to new space being created. That’s why I used the term hyperspace. Similarly, just like space, time also is being created always. The one difference compared to the expanding space is that the newly created time is inserted to the edge, to the present, and we go into the future; the new time is not “inserted into the past.” We are all “travelling” in spacetime, clutching to our personal space and time. Moving back in time is comparable to moving back in hyperspace. We know that moving back in hyperspace is humanely impossible, unless the universe were to collapse on itself – the big crunch. Therefore we should not be surprised that it is impossible to do time travel. When the big crunch happens (if it does happen), space will contract and time will reverse itself and everything will happen backwards. We just have to wait for Mother Nature to be able to go back to the past. We will then re-live our lives backwards, from the grave to old age to middle age to youth to birth to non existence. Still, we will not be able to see outside of our living duration. From special relativity, we know that by travelling close to speed of light and coming back to earth, we are travelling into the future. So is there an analogous hyperspace travel? (I am not contradicting myself; we have a theoritical way to travel to future which may be humanely impossible. For space travel, there is no theoritical way even) The moving around in space that we indeed do is a movement in local space. The equivalent to that in time is probably remembering the past? Am I totally lost? Vibhu.