Time travel is not possible. The universe is expanding, and getting larger every second, and it is carrying the galaxies along with it as it expands. That means that there is not a location that is stationary in our universe. To travel backwards in time would mean that you would have to find the previous location where our galaxy was once located, within a smaller universe. The distortion in location would make it impossible, because not only would you need a time machine, but also a very fast transport that could get you to your location safely. Just think if you could create a pocket of stopped time for just yourself alone. The earth would continue to move, and so you would see yourself ripped from off it's surface as it speed away on it's journey. The galaxy would speed away. The universe would continue to expand while you stayed stuck in one location.
Traveling forwards through time would create the same issues. Another thing to consider is that if time travel were possible, then why haven't we seen any time travelers? The absence of time travelers is another major reason to consider it impossible.
Yes, I believe time travel is possible, with future scientific knowledge and inventions that is. Look at our world now. Years ago, we would have never even DREAMED about all these cars and phone brands. :) x)