The statement "light goes at the speed of light" is tautological because the speed of light in a vacuum is defined to be exactly 299,792,458299,792,458299,792,458 meters per second, denoted as ccc. This is a fundamental constant of nature and forms the basis of our understanding of space and time in the universe.
When we say "time travel" in the context of physics, we typically refer to the idea of moving backward or forward in time to visit different points in time. Time travel in this sense involves traveling along timelines and experiencing events at different moments. According to our current understanding of physics, particularly in the theory of special relativity, time travel in this manner is not possible for material objects with mass, including light.
One of the key insights of special relativity is that the speed of light (ccc) is constant in all inertial reference frames. This means that no matter how fast an observer is moving relative to the source of light, they will always measure the speed of light to be ccc.
For an object with mass to approach the speed of light, its energy would need to increase exponentially, and as it gets closer to the speed of light, its relativistic mass would become infinite. Objects with mass cannot reach or exceed the speed of light because it would require an infinite amount of energy.
However, photons, which are particles of light, are massless. Since they have no rest mass, they can indeed travel at the speed of light. From the perspective of a photon, time effectively stands still. This phenomenon is a consequence of special relativity and is often expressed by the concept of "time dilation."
So, while light (photons) travel at the speed of light and experience time differently compared to objects with mass, it does not enable time travel in the conventional sense where objects can move backward or forward along timelines. The "time travel" of light is more of a perspective related to how time is experienced by massless particles.