Why massless particles can go at such high velocity?
I know that we will travel time if we go faster than light.
As you approach the speed of light, time will slow down for you as compared to an outside observer (although time will seem to be going at a normal rate to you). If you reach the speed of light, time would apparently stop. This does necessarily imply that you could travel backwards in time.
Although, as you reach the speed of light, your mass becomes infinite, therefore it would take an infinite amount of energy to keep accelerating (which is impossible to have an infinite amount of energy). Only massless particles, like photons can travel at the speed of light.
And no, we would not become energy.