Jupiter’s moon, Ganymede takes 7.15 Earth days to orbit Jupiter. Ganymede is measured to be 7.1 X 10-3 AU from Jupiter’s center. A second moon of Jupiter, Callisto, takes 16.69 Earth days to orbit Jupiter. How far away is Callisto from the center of Jupiter?

0.0124 AU

Explanation:

Ganymede takes 7.15 Earth days to orbit Jupiter. Ganymede is measured to be 7.1 X 10⁻³ AU from Jupiter’s center.

We need to find how far away is Callisto from the center of Jupiter if a second moon of Jupiter, Callisto, takes 16.69 Earth days to orbit Jupiter. Let it is r₂. Using third law of Kepler.

i.e.

So, Callisto is 0.0124 AU from the center of the Jupiter.