HONG KONG: New images from the Hubble space telescope show three of Jupiter’s largest moons moving across the face of the red planet at the same time, a rare occurrence that happens only once or twice a decade.
The Jovian lunar gathering, which happens only once or twice a decade, was captured on January 23 showing the unusual sight in a single frame.
The moon Io, which orbits significantly closer to Jupiter and so moves much more quickly, can be seen approaching the eastern limb of the planet.
While Callisto’s shadow seems hardly to have moved, Io’s has set over the planet’s eastern edge and Europa’s has risen further in the west.
Missing from this sequence is the Galilean moon Ganymede which was outside Hubble’s field of view.
Each moons of Jupiter have very distinctive colours. The smooth icy surface of Europa is yellow-white, the volcanic sulphur surface of Io is orange and the surface of Callisto, is a brownish colour.
The moons are bigger than all the dwarf planets, and Ganymede, Callisto and Io are all larger than Earth’s moon. Ganymede, meanwhile, is larger than the planet Mercury.
The images were taken with Hubble’s Wide Field Camera 3 in visible light.
While Hubble captures these moons in great clarity, Nasa says they can also be seen with a small telescope or even a strong pair of binoculars from home.
