Pulsar Dwarf (IMAGE) National Radio Astronomy Observatory Caption A 21-year study of a pair of ancient stars -- one a pulsar and the other a white dwarf -- helps astronomers understand how gravity works across the cosmos. The study was conducted with the NSF's Green Bank Telescope and the Arecibo Observatory. Credit B. Saxton (NRAO/AUI/NSF) 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.