 Galileo 's astronomical discoveries and investigations into the Copernican theory have led to a lasting legacy which includes the categorisation of the four large moons of Jupiter discovered by Galileo ( Io , Europa , Ganymede and Callisto ) as the Galilean moons . Other scientific endeavours and principles are named after Galileo including the Galileo spacecraft , the first spacecraft to enter orbit around Jupiter , the proposed Galileo global satellite navigation system , the transformation between inertial systems in classical mechanics denoted Galilean transformation and the Gal ( unit ) , sometimes known as the Galileo , which is a non @-@ SI unit of acceleration . 
