In the grand body of the universe and even our own solar system the speed of light is incredibly slow on the cosmic scale. Why does it have this speed limit ? It is theoretically possible to go faster than light ? Or is light just the fastest thing we have observed thus far ?
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This is an artifact of how we measure the speed of light. Briefly, what we actually do is measuring patterns across moments in time. Doing so we divide spacetime (a single, unified entity) into space and time. It’s really hard to not fall in this trap, because the concept of time is so embedded in our perception. Velocities are not additive at high values close to the speed of light.
If you were to use the right tools to measure the “speed” of light, as is done in relativity, the answer would be infinity. This is the so called “rapidity”, which is a generalization of speed for relativistic speeds. There is no limit to the “rapidity” quantity. From our reference frame this is equivalent to say that light rays don’t experience time passing, but since we are measuring that process as beings experiencing time, the comparison leads us to infer a maximum speed limit. Again, this is simply an artifact of our limitations and the scale of the unvierse at which we exist.
Another issue with the speed of light is that in General Relativity is that the speed (as we mean in 3D space + 1D time, i.e. 300000 km/s) is not at all constant: it varies with gravitational potential as measured by distant observers, which in turn is the cause of gravitational time dilation. Light is slower, hence the speed at which information travels is slower, so everything happens in slow motion compared to other places where the speed is higher.
Back in 4D spacetime, we use 4-velocity, which doesn’t change and it is always equal to c^2 in magnitude.
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