Astronomy Exam #2 (3. Jovian Planets and Moons)

composition of jovian planets

four jovian planets are jupiter, saturn, uranus, and neptune

much larger than terrestrial planets and have thick atmospheres or envelopes containing hydrogen compounds

hydrogen compounds

refers to molecules containing hydrogen combines with other elements

in planetary science, water, methane, and ammonia are commonly grouped as ices because they can freeze under cold solar system conditions

jupiter and saturn

gas giants

composed primarily of hydrogen and helium, with smaller amounts of other materials

their interiors contain hydrogen under extremely high pressure

uranus and neptune

ice giants

contain hydrogen and helium in their outer atmospheres, along with larger proportions of hydrogen compounds such as water, methane, and ammonia in their interiors

magnetic fields of the jovian planets

planetary magnetic fields are generated by the motion of electrically conducting material inside a planet

jupiter magnetic field

generated primarily by moving metallic hydrogen deep inside the planet

extremely strong magnetic field

Saturn magnetic field

also generated by metallic hydrogen inside planet

uranus and neptune magnetic fields

associated with electrically conducting fields inside their interiors, including high pressure water rich mixtures containing other hydrogen compounds

magnetic fields have unusual orientations compared with those of jupiter and saturn

jupiter and saturn vs. uranus and neptune magnetic fields

jupiter and saturn = have metallic hydrogen layers that help generate their magnetic fields\

uranus and neptune = have different interior structures, with electrically conducting water rich fluids playing an important role

Tidal Heating

Gravity can stretch and compress a moon as it orbits a planet

when a moon’s orbit is elliptical, the strength of the tidal forces changes throughout its orbit

repeated deformation generates internal heat through friction

Io

one of jupiter’s moons and is exceptionally volcanically active

its volcanic activity is primarily powered by tidal heating caused by jupiter’s gravity

gravitational interactions with other moons help maintain the orbital conditions that sustain this heating