According to our current understanding of physics, objects with mass cannot travel at the speed of light in a vacuum. This is because of the theory of special relativity proposed by Albert Einstein.
In special relativity, Einstein derived the famous equation E=mc², where E represents energy, m represents mass, and c represents the speed of light in a vacuum, which is approximately 299,792,458 meters per second. This equation shows that as an object with mass approaches the speed of light, its energy (and therefore its momentum) increases significantly. As the object's speed approaches c, its energy would theoretically approach infinity, requiring an infinite amount of energy to accelerate it further.
As an object with mass approaches the speed of light, its relativistic mass increases, making it more and more difficult to accelerate it. The energy required to accelerate a massive object to the speed of light would be infinite, which is practically impossible to achieve.
On the other hand, objects that are massless, such as photons (particles of light), travel at the speed of light in a vacuum. Since they have no rest mass, they can achieve and maintain the speed of light without violating the laws of physics.
It's important to note that these concepts are based on our current scientific understanding, and new discoveries or theories could potentially provide further insights or modifications to our understanding of mass, energy, and the fundamental laws of physics.