Why is light speed the limit? Why is the light speed a limit? Why can't anything go faster than light? Not even a single atom?
 A: Because not until now that scientists discovered laws that can be applied on objects attaining even the speed of light .. actually no one knows what happens when an object attains the speed of light
A: There's no answer to this "Why". This is what we observe in nature. Nothing* can travel faster than light.
*Note: Denizens of the Quantum World like atom may not be agree with this. For example, information of quantum states of two entangled entities are shared between them faster than light. It has been tested with polarized light beams. Understand it this way: Suppose, two electrons are in Quantum Entanglement and both are in Quantum Superposition possessing up & down spin at the same time. You separate both electron to the opposite edge of the Galaxy and break the superposition of one electron. The other electron will know about it exactly at the same time faster than light. If one electron is ended up with Up Spin, Other one would start possessing Down spin instantly even if nothing's there to break the superposition.
Einstein called this faster than light Quantum interaction "Spooky action at a distance."
