If you were to throw a ball in outer space, say, like when you were doing a extravehicular walk outside your spacecraft flying beyond earth's orbit, it would just continue going due to inertia. However, other planets have their own gravity, and their own drag force depending on the atmosphere. Planetary scientist James O'Donoghue made us a visualization of how far a ball thrown at a 45 degree angle would go in the conditions of different planets in our solar system, plus the moon.
Well, baseball fans, you watched this and thought about how nice it would be to have a league playing on Mars. But then, there's the moon! And the moon is easier to get to than Mars, anyway. Oh, but what about Pluto? That's pie in the sky, so to speak, because it's going to be very hard to get to Pluto, and I hear it's pretty cold there, too. -via Laughing Squid