Why can't anything travel faster than light?

The answer

According to Einstein's special relativity, as an object with mass accelerates toward the speed of light (299,792,458 m/s), its relativistic mass increases without bound. Reaching light speed would require infinite energy, making it physically impossible for anything with mass. Additionally, the speed of light is woven into the fundamental structure of spacetime - it is not just a speed limit but defines the relationship between space and time. Massless particles like photons always travel at exactly this speed. This is not merely a technology limitation but a fundamental law of the universe.