Why Does Every Animal Look Like This?

Nothing can travel faster than light — in a vacuum. But when light slows down, sometimes matter can blaze past that speed limit, creating a stunning glow called Cherenkov radiation. We can see this glow in a nuclear reactor as high-energy particles speed by. It offers us a window into a realm of the universe that is usually invisible to us.

In the race to survive, both predators and prey use visual tricks to get ahead. One nearly universal trick is countershading, a color pattern that helps animals erase their own shadows or blend into different backgrounds. It’s worked well enough that nature has produced this pattern over and over again, all over Earth, for at least tens of millions of years.

500 years before the Scientific Revolution, the mathematician Al-Hassan Ibn al-Haytham spent hours in a dark room studying the light that filtered in. Not only did he revolutionize how we literally see the world, he pioneered the scientific method that is now the backbone of modern science.