Light is probably more interesting than you think. For thousands of years light was just one of those things that people knew was there, they knew it was important, but never really thought too much about it. Without light you can’t see, that’s all they knew. It wasn’t until later that people realized light is unique. In the last several hundred years scientists have discovered just how unique light really is. For one, it is unlike any other substance in the universe. That’s right, it can be defined as a substance. How can that be? It’s because light can be both a wave and a particle…at the same time! Moreover, scientists found that light always travels the same speed, even if you shine it off of a moving object. This may not be immediately obvious, but if you shoot or launch anything else off a moving object then it’s velocity will be affected by the velocity of the object you are launching it from. For example, try throwing a tennis ball out of a car window. Not only will it be moving perpendicular to your car but it will also continue moving in the direction of your vehicle as well. Light doesn’t do that. These are 25 enlightening facts about light and vision.