Artist's Impression of a Pulsar (image) International Centre for Radio Astronomy Research Caption The densely packed matter of a pulsar spins at incredible speeds, and emits radio waves that can be observed from Earth, but how neutron stars emit these waves is still a mystery. Credit Image Credit: Swinburne Astronomy Productions/CAASTRO. Usage Restrictions With credit as above, thank you. 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.