Firing off a string of snapshots like a sports photographer at a NASCAR race, NASA's Hubble Space Telescope captured a rare look at three of Jupiter's largest moons zipping across the banded face of the gas-giant planet: Europa, Callisto, and Io. Jupiter's four largest moons can commonly be seen transiting the face of the giant planet and casting shadows onto its cloud tops. However, seeing three moons transiting the face of Jupiter at the same time is rare, occurring only once or twice a decade. Missing from the sequence, taken on January 24, 2015, is the moon Ganymede that was too far from Jupiter in angular separation to be part of the conjunction.
Join Hubble Heritage Team members during the live Hubble Hangout event at 3:00 pm (EST) today (Thursday, February 5) to learn more about Jupiter's rare triple-moon conjunction. Visit https://www.youtube.com/watch?v=Pf6j6WJS8Ig.