The Voyager probes used to be moving much faster, but as they've fought the gravity of the Sun they've slowed down, that's the price they pay for leaving the So

The Voyager probes used to be moving much faster, but as they've fought the gravity of the Sun they've slowed down, that's the price they pay for leaving the Solar System. The result is that now the Earth moves faster than the Voyager probes, relative to the Sun.