Jupiter’s moon Io has active volcanoes that spew a continuous jet. How is this volcanism powered?
PREMCHAND
Coimbatore, Tamil Nadu
Io is the innermost of Jupiter’s five major moons. It is about the same size as Earth’s moon. But unlike our moon, Io has many active volcanoes. In fact, it now known that Io is the “most volcanically active body in the solar system”, notes US Geological Survey (USGS).
Jupiter is several times bigger than the Earth. In terms of surface area, the blue planet is about 120 times smaller than Jupiter, and in terms of mean circumference, Earth is 11 times smaller than Jupiter. While Jupiter is several times bigger than the Earth, Jupiter’s moon Io is many times smaller than ours. Also, unlike our moon, Jupiter has a few natural satellites orbiting it. It is sandwiched between two of Jupiter’s large moons — Europa and Ganymede.
Much like the tidal bulge that is experienced by the solid Earth, Io too experiences it at several times higher magnitude. According to USGS, the tidal bulge experience by Io due to the gravitational force exerted by Jupiter and the two bigger moons is about 100 metres high. In other words, the solid rocky crust of Io is stretched and pulled about 100 metres high by the gravitational force. With the rotation of Io around the massive Jupiter, the tidal bulge too moves. “Io’s crust is flexed, and tremendous heat is generated — much like the heat generated in a piece of wire when it is quickly bent back and forth. This heat drives the volcanic activity so prevalent on Io,” states USGS.
S. SURESH
Chennai
