WASHINGTON, Feb. 5 (UPI) -- Jupiter hosts 67 confirmed moons, the largest lunar portfolio in the solar system. But even with so many moons, it's rare that a handful are all in the same place at once.
Last month, the Hubble Space Telescope caught one of these rare moments on camera. A snapshot of Jupiter revealed three of the gas giant's four largest moons -- Io, Europa and Callisto -- each making their way across the planet's striped surface. Only Ganymede is missing.
Scientists say seeing three of the four moons backed by Jupiter's glow is something only happens once or twice a decade.
Perhaps the most intriguing of the three moons appearing in the latest image is Europa. Any icy satellite which scientists say likely features salty, churning oceans under its frozen outer crust. NASA's newest budget proposal has offered the green light to plans for flying a probe mission to Europa.
Hubble is jointly managed by NASA and the European Space Agency. The James Webb Space Telescope, a next-generation observatory and Hubble's successor, is expected to launch in 2018.