Light has always been a fundamental component of our universe. It is our gateway into understanding the vast world around us and the history of our universe. But what exactly is light? And why is it a lot more significant to us than we know? Sure it's a group of photons that propagate through the universe in a wave-particle f0rmation but what does that mean exactly? And why is it directly related to our understanding of the universe and its workings (like Einstein's theory of relativity for example)?
It turns out that light in itself doesn't dictate the universal constant that is the speed of light. It just happens that the fastest speed anything can reach in the universe is 299,792,458 meters/second. And because light doesn't need a medium to spread, it isn't really limited by anything and thus can travel at the universal speed limit without any restrictions.
This amazing video from Youtube channel Kurzgesagt sheds some light (pun intended) on what exactly is light and where exactly it comes from in the universe, and why its speed considered a universal constant.