the Solar System, although it is possible to use other nearby planets such as Venus or even the Moon as slingshots in journeys to the outer planets.

This maneuver can only change an object's velocity relative to a third, uninvolved object, - possibly the "centre of mass" or the Sun. There is no change in the velocities of the two objects involved in the maneuver relative to each other. The Sun cannot be used in a gravitational slingshot because it is stationary compared to rest of the Solar System, which