Cepheid distances are determined through the so-called inverse-square law of light, which tells astronomers how a star’s apparent brightness diminishes with distance. If a star appears to have a ...

Cepheid variables are a type of star that undergo regular pulsations. The length of a Cepheid’s pulsations is always related to its intrinsic, or absolute, brightness in a simple way: The longer its ...

LIGHT is the bedrock of astronomy, so it may come as a surprise that astronomers don’t have a very good handle on measurements of brightness. That is set to change, however, as the antiquated ...