According to our current understanding of physics, as described by the theory of relativity, nothing with mass can travel at or exceed the speed of light in a vacuum (299,792,458 meters per second). This limitation is known as the "speed of light barrier" or "light speed limit."
The theory of relativity postulates that as an object with mass accelerates, its energy and momentum increase, and its mass appears to increase as well. As an object with mass approaches the speed of light, the amount of energy required to accelerate it further becomes infinite. This implies that it would take an infinite amount of energy to reach or exceed the speed of light, which is not feasible within our current understanding of physics.
Moreover, as an object with mass approaches the speed of light, its relativistic mass increases, and time dilation occurs. Time dilation means that time appears to pass more slowly for the moving object relative to a stationary observer. This effect becomes more pronounced as the object's speed approaches the speed of light.
It's important to note that the theory of relativity has been extensively tested and validated by various experiments. The speed of light barrier is a fundamental aspect of this theory and is considered a well-established principle in modern physics.
That being said, there are theoretical concepts and phenomena that can appear to "travel" faster than light within certain frameworks. For example, in the field of cosmology, the expansion of the universe can cause two distant objects to move away from each other faster than the speed of light. However, this expansion is a property of spacetime itself and not a movement of objects within spacetime.
Additionally, there are hypothetical particles called tachyons that have been postulated in some theories. Tachyons are hypothetical particles that are claimed to always travel faster than the speed of light. However, tachyons are not confirmed to exist, and their properties remain purely speculative.
In summary, based on our current understanding of physics, nothing with mass can travel at or exceed the speed of light in a vacuum. The speed of light barrier is a fundamental principle in the theory of relativity. While there are theoretical concepts and phenomena that can seemingly surpass the speed of light within certain frameworks, they do not violate the speed of light barrier as they are either intrinsic to spacetime or remain speculative.