which of jupiter’s moons is believed to be covered with water ice
Galilean moons Some models predict that there may have been several generations of Galilean satellites in Jupiter's early history. Each generation of moons to have formed would have spiraled into Jupiter and been destroyed, due to tidal interactions with Jupiter's proto-satellite disk, with new moons forming from the remaining debris. By the time the present generation formed, the gas in the proto-satellite disk had thinned out to the point that it no longer greatly interfered with the moons' orbits.[14][15] Other models suggest that Galilean satellites formed in a proto-satellite disk, in which formation timescales were comparable to or shorter than orbital migration timescales.[16] Io is anhydrous and likely has an interior of rock and metal.[14] Europa is thought to contain 8% ice and water by mass with the remainder rock.[14] These moons are, in increasing order of distance from Jupiter:
Triton (moon) Triton is one of the few moons in the Solar System known to be geologically active (the others being Jupiter's Io and Europa, and Saturn's Enceladus and Titan). As a consequence, its surface is relatively young with few obvious impact craters, and a complex geological history revealed in intricate cryovolcanic and tectonic terrains. Part of its surface has geysers erupting sublimated nitrogen gas, contributing to a tenuous nitrogen atmosphere less than 1/70,000 the pressure of Earth's atmosphere at sea level.[6] It is the second-largest planetary moon in relation to its primary, after Earth's moon.