According to our current understanding of physics based on Einstein's theory of relativity, it is not possible for an object with mass to travel at the speed of light in a vacuum. As an object with mass approaches the speed of light, its energy requirements become infinite, making it unattainable. However, let's consider a hypothetical scenario where an object could travel at the speed of light.
In this scenario, if an object were traveling at the speed of light, it would experience time dilation, which means time would pass differently for the object compared to an observer at rest. From the perspective of the object traveling at the speed of light, time would essentially stand still. This phenomenon is described by the theory of special relativity.
However, it's important to note that according to special relativity, an object with mass cannot reach or exceed the speed of light. As an object with mass accelerates towards the speed of light, its energy increases, and its relativistic mass also increases, making it more and more difficult to accelerate further. At the speed of light, an object with mass would require an infinite amount of energy, which is not possible.
In practical terms, for any object with mass, including humans, it is impossible to reach the speed of light. Therefore, the experience of traveling at the speed of light and its effects on time are purely hypothetical and not something that could be observed or experienced by a person.