How does the gravitational field gX at the surface of Planet X compare with the gravitational field gY at the surface of Planet Y

In empty space, there's nothing to exert force on the ball after it leaves
her hand.  It sails away in a straight line, at constant speed of 13 m/s. 
If it doesn't sail too close to a planet, a star, an asteroid, or a moon, it
may travel 6 billion light years and still be moving at 13 m/s.