Asgard (crater)
Asgard is the second largest impact crater on Jupiter's moon Callisto . It has a bright central region 300 km in diameter, and concentrically around this central region are rings up to a distance of 800 km from the center. The ring system was likely formed when semi-liquid material fell to the center of the impact crater and cooled in the process. The crater is named after Asgard, the place where the gods lived in Norse mythology .
