According to our current understanding of physics, the speed of light in a vacuum, denoted by "c," is considered to be the ultimate speed limit of the universe. In the theory of special relativity, proposed by Albert Einstein, it is postulated that nothing with mass can accelerate to or surpass the speed of light.
The reason why the speed of light is regarded as the cosmic speed limit is rooted in the fundamental structure of the universe. The theory of relativity shows that as an object with mass approaches the speed of light, its energy and momentum increase towards infinity, making it progressively harder to accelerate further. It would require an infinite amount of energy to accelerate an object with mass to the speed of light, which is considered impossible.
Light, being composed of particles called photons, does travel at the speed of light in a vacuum, as it has no rest mass. Photons are massless particles that always move at the constant speed of light, regardless of their energy. However, it's crucial to note that other forms of matter, including particles with mass, are subject to the speed limit imposed by the theory of relativity.
In summary, based on our current scientific understanding, it is not possible for any object with mass to exceed or even reach the speed of light. The speed of light in a vacuum is a fundamental limit in the fabric of our universe.