(12 points) Recall that the gravitational force that object 1 exerts on object 2 is given by the field: .. 2 F2:9, 2) --- Gimme " + = " (* ) y (, yz= (x2 + y2 + z2)3/2' (x2 + y2 + z2)3/2' (x2 + y2 + z2)3/2 Note that G is the gravitational constant. Show that a gravitational field has no spin. (Hint: Compute the curl of F)