What is it like on the moons of Jupiter?

Answer 1

They are practically airless with frozen and cratered surfaces, although Europa is thought to have an underground ocean warmed by tidal friction with Jupiter. Ganymede, Callisto, and Io, the other three large moons, are rocky bodies. Io is covered in sulfur dioxide 'frost' and has numerous sulfur 'volcanoes' whose eruptions cover the surface and give the moon a yellow hue.

The other 63 known moons are much smaller, only 4 larger than 60 kilometers in any dimension. The largest of these four, Almathea, is reddish and oblong, about 250 by 150 kilometers. Amalthea is the third-closest moon to Jupiter, and circles the planet about every 12 hours. The sky view on the side facing Jupiter would be nearly half-filled by the giant planet, with a complete set of phases twice a day.

Answer 2

The moons of Jupiter have diverse landscapes, with Io being the most volcanically active, Europa having a subsurface ocean that may harbor life, Ganymede being the largest moon in the solar system with its own magnetic field, and Callisto having a heavily cratered surface. The environment on these moons is harsh, with extreme temperatures and radiation levels due to Jupiter's powerful magnetic field.