Rattlesnakes, vampire bats, and James Webb Space Telescope have something in common: They can all detect the infrared — wavelengths of light that are too long for the human eye. That helps the snakes and bats find and catch prey. And it will help the telescope find some of the coolest and most remote objects in the universe. The light that’s visible to human eyes forms only a tiny sliver of the electromagnetic spectrum. Other forms range from radio waves — the longest and least energetic — to gamma rays — the shortest and most energetic. Infrared is right in the middle. Although we can’t see it, we do feel it — as heat. A fireplace and a pot of soup simmering on the stove both produce a lot of infrared. So do people and other mammals. Yet infrared is the main way to study some of the cooler objects in the universe. It’s produced in large amounts by cool stars, failed stars, and stellar nurseries. Many planets emit infrared as well. And the earliest stars and galaxies also glow mainly i
