1.32 Understand gravitational field strength, g, and recall that it is different on other planets and the moon from that on the Earth

All objects have an attracting force. The Earth attracts you and you attract the Earth. The larger the object, the larger the attracting force. Planets are large enough to have a gravitational field, and we measure this and call it g. 

On earth, g is approximately 10 n/kg

On other planets, it varies with their mass.