Is time travel really possible?

According to a lot of well known scientists, including Albert Einstein have claimed that some time in future we can travel in time. He states that time is nothing but a scalar quantity which can be quantified according to our speed. He meant that time can be slowed down or fastened up according to your relative speed to the Earth's rotation/revolution or the light's speed.
Going in the past is actually possible if one can travel at Light's speed outside and come back. One hour of Light's speed could make us travel in time by around 50 years back in the time. Now, all us humans need to figure out is how to travel with the speed of light. Or maybe, something faster.