What is the relationship between gravity and the motions of the objects in the solar system?

The force of gravity affects all objects on Earth by pulling them towards the centre. The Earth is close to spherical in shape as this is the geometry gravity prefers. Without gravity, objects would be floating in space. The atmosphere would not exist as the air particles would have no force pulling them towards the planet. Gravity means when you throw something up, most of the time it will come down. It is a force, which causes objects to accelerate when they fall.