“The color of the emitted light depends on the relative heights of the starting and ending energy levels. A crash between closely spaced levels (such as two and one) releases a pulse of low-energy reddish light, while a crash between more widely spaced levels (say, five and two) releases high-energy purple light.”

American writer

Sam Kean is an American writer known for books that tell the story of scientific discoveries in a narrative style. He was born in Sioux Falls, South Dakota, and lives in Washington, D.C. He has written for The New York Times Magazine, Mental Floss, Slate, Psychology Today, and The New Scientist. He has also published eight books, and they have been reviewed positively by The Wall Street Journal, Library Journal, and The New York Times.