240903-Hirata-Ganymede-Ganymede (IMAGE) Kobe University Caption On large parts of its surface, the Jupiter moon Ganymede is covered by furrows (right) that form concentric circles around one specific spot (left, red cross), which led researchers in the 1980s to conclude that they are the results of a major impact event. Credit HIRATA Naoyuki Usage Restrictions Credit must be given to the creator. License CC BY 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.