You have probably already heard, or at least heard of, white noise. Maybe you grew up when televisions were still analog. If so, you might remember the shhh that accompanied “snow” on a cathode-ray tube screen. It lived in special place between the few channels on the dial that actually had programming. And in that snow, you could see—and hear—residual cosmic radiation born in the big bang.

Or maybe you grew up in the age of apps and downloaded one of the many designed for relaxation or helping people focus. Perhaps you have even purchased a white noise machine to lull your newborn—or yourself—to sleep.

But what is white noise, exactly? Why does it affect humans the way it seems to? And what, for that matter, is pink, violet, brown or blue noise? What does color even have to do with it at all? Watch this video, and you may find that the hues of noise are all around you—and that you never recognized what you were hearing.