The Dragonballs are powerful balls(marble-like) created by the Namek elders. The Dragonballs were originally created by Guru, the eldest Namic. The other elders created Dragonballs too, then they hid them accross the plains of Namic. Dragonballs got on to Earth with the arrival of Kame, an eldest Namic. He made 7 Dragonballs, but they were smaller than the ones on Planet Namek. The dragonballs on Earth are about the size of your fist