In $1610,$ Galileo used his telescope to discover four moons around Jupiter, with these mean orbital radii $a$ and periods $T :$ (a) Plot log $a(y$ axis) against log $T(x$ axis) and show that you get a
straight line. (b) Measure the slope of the line compare it with
the value that you expect from Kepler's third law. (c) Find the mass
of Jupiter from the intercept of this line with the $y$ axis.