The theory says that objects in space developed from cooling condensing and contracting nebular gases?

The theory you’re referring to is known as the Nebular Hypothesis, which posits that the solar system formed from a rotating cloud of gas and dust, known as a nebula. As the nebula cooled, it contracted under gravity, causing it to spin faster and flatten into a disk. Within this disk, particles collided and coalesced to form larger bodies, eventually leading to the creation of planets, moons, and other celestial objects. This process highlights the role of gravity and thermodynamics in shaping the structure of our solar system.