Cosmic Distance Ladder (IMAGE) Carnegie Institution for Science Caption An artist's conception of what's called the cosmic distance ladder -- a series of celestial objects, including type Ia supernovae that have known distances and can be used to calculate the rate at which the universe is expanding. Credit NASA/JPL-Caltech. Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.