We humans have always believed that we have a good understanding of time, space and technology. We consider ourselves to be an "intelligent life". Perhaps we are, however, it is just as possible that from the perspective of the rest of the Universe we are a very primitive life, just as we see ants, for example. So, is time travel possible? I don't know. I would certainly say that based on our current understanding I would say no. On the other hand; it may be very easy!