Escape velocity is the speed required for a rocket to theoretically escape the gravitational pull of an object such as a planet or a moon, assuming it does not produce its own thrust. In order to escape the gravitational pull of the Earth, a bullet would need to leave the muzzle of a gun at a speed of over 11 kilometres (6.84 miles) per second.
In reality, a rocket that is producing a thrust needs a much lower speed to escape gravity, since the acceleration produced will cancel out some of the negative acceleration that this force causes.
However if your rocket is not travelling at 7.8 kilometres (4.8 miles) per second by the time it gets to LEO (low Earth orbit) altitude, and if it is not producing its own thrust at this point, gravity will pull it back down towards our planet’s surface.
Got a question for us? Send it into email@example.com and you could see it featured in All About Space – available every month for just £3.99. Alternatively you can subscribe here for a fraction of the price!