For more than two centuries, astronomers have treated the Sun’s spectrum as a solved problem, a textbook example of how light reveals the chemistry of the cosmos. Now a fresh look at that familiar ...

For most of human history, darkness was a constant. The rhythms of nature, wildlife behavior, and even human sleep evolved under predictable cycles of day and night. In the past century, however, ...

When a laser experiment fails to produce the expected flash of light, most researchers would assume something went wrong with the hardware. In this case, the missing signal turned out to be the most ...