Nebula Theory is a scientific explanation for the formation of stars and planetary systems. It suggests that these celestial bodies form from large clouds of gas and dust, known as nebulae. Over time, gravity causes the material in a nebula to clump together, leading to the creation of stars. As a star forms, it can also gather surrounding material, which may eventually coalesce into planets, moons, and other objects. This process is fundamental to understanding the structure of our solar system and the formation of other systems throughout the universe.