If you are referring to the speed of light through any medium, then Jim Moor has your answer. If, however, you are referring to the speed of light through a vacuum, then it it impossible to travel faster than the speed of light, and here is why.

As an object's velocity approaches the speed of light, its mass actually increases. The equation for this is m = m0/sqrt(1-(v^2/c^2)), where m is the final mass, m0 is the "rest" mass (that is, the mass of the object when it not moving), v^2 is the object's velocity squared, and c^2 is the speed of light squared. As v approaches the speed of light, the ratio of the velocity squared to the speed of light squared approaches one, making the square root on the bottom approach zero. Therefore, as v increases, the total mass of the object approaches infinity. Since F = m*a (force equals mass times acceleration), and if the object's mass is infinity, then it would take a disproportionately large force to accelerate it to anything close to the speed of light.

If the velocity is greater than the speed of light (v > c), you will obtain sqrt(1-x) in the denominator of the function I mentioned above, where x is any arbitrary number greater than one. Since the square root of a negative number does not exist in the set of real numbers R (in fact, it involves imaginary numbers in the set C), what ends up happening is that the mass becomes imaginary, meaning that it would be physically impossible for that object to exceed the speed of light.

Hope this answers your question!

Source(s):
I have read a little about relativity and am in a college course that briefly touched on relativity.