Yes, traveling forward in time is definitely possible, but we're not sure about back. This has nothing to do with wormholes or anything, that probably wouldn't work.
Anyway, velocity distorts time. The faster you go, the slower time goes for you. This effect is negligible unless you are going very close to the speed of light. In fact the formula is:
t'= t/sqrt(1-v^2/c^2)
where t' is the time that has passed for a stationary observer, t is the time that has passed for you, sqrt means square root and ^2 means squared. As you can notice, when v is small, since c^2 is so huge, you get a miniscule decimal, and 1 minus that number is basically as small as .999999999999999 or something very very close to one, and so t' stays basically the same as t and time is not really affected. As v gets larger(it can never be the speed of light, then the denominator would be zero) that fraction becomes closer to 1, so when you subtract it from one, the denominator gets smaller and smaller, meaning t gets smaller(in order for t' to remain constant) this means that time slows down for the object moving at such velocities! time slows down, so it would feel like lets say This formula is correct, it is part of Einstein's theory of relativity, and I have had to derive it myself from ordinary mechanics formulas.
This proves the formula:
According to the same factor, length also contracts. It has been observed in certain tiny particles coming to the earth's surface. These particles have a certain lifespan before they become unstable and decay. They are also moving at a certain speed. (which is very fast; close to the speed of light.) You should simply be able to calculate v=d/t (velocity=distance/time) to find out how far they would travel. However, they somehow travel farther than that. When this calculated distance is put into that formula, we come up with the correct distance they actually travel!
So yes, as you get faster and faster, since time slows down for you, theoretically, you could be moving at these speeds for a short time and time will seem to be moving normally for you, but have years and years pass for everyone else, thus traveling forward in time. As far as back in time... well, if you think about it, if things travel slower and slower the closer you get to light, does that mean it would stop when you reached it? and what would happen when you went faster, would it go back in time? the only problem with this is that nothing can go faster than the speed of light, which has been considered "the ultimate speed limit of the universe." Plus, if you were to go faster, the v^2/c^2 would be greater than one, meaning you'd get a negative number after subtracting it from one and have a negative number under the square root in that formula. This is impossible. Also, the problem with even traveling forward in time is that it would require immense amounts of energy to accelerate objects that fast. It requires particle accelerators miles long just to get small sub-atomic particles to go that fast, imagine massive objects, it would be crazy. and distorting time by any reasonable amount would require going at least 90% the speed of light.. probably faster. The closer you got to the speed of light, the more time would slow down for you.
There are also some other methods described in the book "time travel in Einstein's universe" by Richard Gott, if you're interested.