Need a refresher on light and color? Latest episode of Cosmos unlocks the mysteries

by Liam McCabe

posted Monday, April 7, 2014 at 11:20 AM EDT

Photo: Dan Smith / FOX

As photographers, we think about light every time we pick up a camera. But the last time that most of us thought about the science behind light may well have been in a high-school physics lecture.

For those of us who could use a refresher, the latest episode of the Fox mini-series Cosmos, titled “Hiding in the Light,” takes a look at light, color, and the way humans see. Host Neil deGrasse Tyson, the astrophysicist and science-popularizer du jour, tells the stories of all the discoveries over the past few millennia that allowed us to understand, for instance, why grass is green and roses are red when they’re both lit by the same white light of the sun, or which properties of light make it necessary to have an aperture in order to focus an image.

Ever wondered how we can tell what distant stars are made of? The secret is in the color of the light. Photo: NASA

The episode isn’t all related to photography—it’s pretty tough to capture UV light or gamma rays with a Nikon, and we can’t use our point-and-shoots to discern the chemical composition of a star a few thousand light-years away. But anybody with a passing interest in the way that we see things, or the kinds of stories that light can tell us, should find something interesting here.

Cosmos: A Spacetime Odyssey is in the middle of a 13-episode run. Last night’s episode re-airs on Fox tonight at 9pm, various Fox and Nat Geo channels throughout the week, and is available for free online here. It's an eye-opener, for sure.