In the context of special relativity, the theory developed by Albert Einstein, the fastest possible velocity in space is the speed of light in a vacuum, denoted by the symbol "c." The speed of light is approximately 299,792,458 meters per second (or about 299,792 kilometers per second).
According to the theory of special relativity, as an object with mass accelerates, its relativistic mass increases, and the energy required to continue accelerating it also increases. As the object approaches the speed of light, its relativistic mass becomes infinite, and it would require an infinite amount of energy to accelerate it further.
Thus, based on our current understanding of physics, no object with mass can reach or exceed the speed of light. This concept is encapsulated in the principle known as the "cosmic speed limit" or "Einstein's cosmic speed limit," which states that information, energy, or matter cannot travel faster than the speed of light.
It's worth noting that special relativity applies to objects with mass. However, there are hypothetical particles called "tachyons" that are sometimes discussed in physics, which, if they exist, would always travel faster than the speed of light. However, tachyons are purely speculative and have not been observed or confirmed in any experimental context.