<Table> <Tr> <Td> </Td> <Td> This article is an orphan, as no other articles link to it . Please introduce links to this page from related articles; try the Find link tool for suggestions . (April 2014) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article is an orphan, as no other articles link to it . Please introduce links to this page from related articles; try the Find link tool for suggestions . (April 2014) </Td> </Tr> <P> Tidal heating (also known as tidal working) occurs through the tidal friction processes: orbital and rotational energy are dissipated as heat in the crust of the moons and planets involved . Io has a similar mass and size as the Moon, but Io is the most geologically active body in the Solar System . This is caused by the heating mechanism of Io . The major heating source of Earth and its moon is radioactive heating, but the heating source on Io is tidal heating . As Jupiter is very massive, the side of Io nearest to Jupiter has a slightly larger gravitational pull than the opposite side . This difference in gravitational forces cause distortion of Io's shape . Differently from the Earth's only moon, Jupiter has several moons (i.e. Io, Europa, Ganymede and Callisto). As Io is the innermost moon of Jupiter, Jupiter pulls Io inward and other moons pull Io outward . This causes Io's orbit to be elliptical and eccentric . The distance between Jupiter and Io changes all the time and the distortion of Io likewise changes all the time . The constant change in the shape of Io results in a large amount of friction in the moon and the friction - induced heating drives strong volcanic activities on the surface of Io . </P>

Tidal heating is stronger for io than for europa because