On this day in space! Nov. 5, 2002: NASA's Galileo spacecraft flies by Jupiter moon Almathea only to find it's a 'pile of icy rubble less dense than water'

On November 5, 2002, the NASA Galileo spacecraft executed a close flyby of Jupiter’s fourth-largest moon, Amalthea, as part of its mission trajectory. During this encounter, scientists discovered that Amalthea was composed primarily of ice and debris, exhibiting a surprisingly low density. The findings indicated that the moon is significantly less dense than water, representing a substantial deviation from earlier models of its composition. This discovery prompted a reevaluation of the processes shaping the inner solar system and the formation of small moons around giant planets. Data collected during the flyby provided valuable insights into the geological characteristics of Amalthea and contributed to our understanding of Jupiter's system.