It is impossible to travel at or above the speed of light, however you can get close. I believe that just as one quanta is the smallest unit, the speed of light is the maximum for velocity.
Retardation in Physics terms means to slow. Seriously. So the speed of slow is... -9.81ms^-2 on Earth if gravity is the retardation. To travel at 3x10^8 ms^-1, or the speed of light, you have to have a near-infinite constant acceleration. However, the closer you get to the speed of light, the slower time gets. They proved this with two exactly accurate atomic clocks; scientists put one atomic clock on a concorde and let it fly about. Then they left another on the floor. Afterwards, the clock that had been on the plane was slower... by 1/100000th of a second or something really negligible like that. So it is theoretically and physically impossible to get anywhere near the speed of light.
i think anyone who says that the speed of light is reachable clearly isn't taking retardation into account.
LMFAO I was looking at the news and how these people slowed light down to the point where it almost stopped moving, and only now have I realized, the only way to go faster than light is to slow light down!
I{f you slow down light, it becomes a rainbow. Not the colours from the poem though. Different order.