What is light? by Kurzgesagt
Adam Rifkin stashed this in Science!
Top Reddit comment:
We evolved eyes because visible light permeated water. We discovered additional wavelengths through science.
Just imagine everything we can't detect because we don't know how to find it.
Another Reddit comment:
Fun fact: Light is invisible - in the sense that you can't observe any light other than that which collides with your eye's retina (or any other light measurement device of your choice) but you can not see any light as it travels through space.
For example, if you shine a laser pointer somewhere (please not into your eyes) you can not observe any traveling photons that end up hitting whatever thing you point the laser at. The beam that you do see is light hitting dust in the air and this light is then reflected directly into your eyes.
If you could observe traveling light, the world would look extremely foggy as you'd observe all light from all directions.