Lab 3: The Moons of JupiterAstronomy 141Due at the end of class one week from todayName: ______________________________Date: ________Partner(s): ______________________________________________________In this exercise you will work in pairsat the computer to record the motions oftwoof Jupiter’sfour bright moons to determine the mass of Jupiter using Kepler’s third law.We will address thefollowing questions:How do we measure the orbits of distant, astronomical objects?How can we use orbits to “weigh” astronomical objects?Kepler’s Third LawKepler’s Third Law is usually expressed for planets as P2= a3.This equation isvalid only if:1.The semi-major axis, a, is measured inAstronomical Units(AUs),2.AND the period, P, is measured inyears,3.AND the object is orbiting theSun.For the moons of Jupiter, we need the more general form of Kepler’s third law:P2= a3/M,orM = a3/ P2where M is themassof the object being orbited, in this case,Jupiter, measured insolar masses.The period and semi-major axis must still be in years and AUs.