Nebula (IMAGE) Royal Astronomical Society Caption Sketch of the nebula formed by a wind of electrons and positrons coming from the pulsar, and the interaction with interstellar gas. Geminga crossed the plane of the Galaxy (off to the bottom right) around 100,000 years ago. It is thought that the supernova explosion was not symmetric, causing the remnant to recoil at around 200 km per second from its birth location. Credit Credit: Jane Greaves / University of Cardiff 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.