Final answer:
The solar nebular theory states the solar system formed from a solar nebula, which collapsed to form a hot dense center that became the Sun. Solid materials condensed into planetesimals, the precursors to planets and moons, in the cooler areas of the rotating disk. Over time, these planetesimals coalesced to form the planets and other celestial bodies we observe today.
Step-by-step explanation:
The solar nebular theory describes the formation of our solar system. According to this theory, the solar system was born 4.5 billion years ago from a solar nebula, a large rotating cloud of gas and dust. As the nebula collapsed due to its own gravity, the material within started to fall toward the center, forming a hot, dense region that would eventually become the Sun.
With the collapse of the nebula, it began to flatten into a disk due to its rotation, leading to concentrations of material at the center where temperatures soared. This heat caused most of the solid materials to vaporize. Meanwhile, in the cooler regions of the disk away from the center, solid particles began to condense, eventually forming planetesimals. These planetesimals are the building blocks of what would become the planets and moons in our solar system.
Following the formation of planetesimals, many of these bodies gathered together through a process called accretion. This accretion of materials caused the newly forming planets to heat up, leading to their differentiation into layers. The largest of these planets were also able to attract and retain gas from the solar nebula, possibly explaining the formation of the gas giants in our solar system. After a period of violent collisions and impacts, most of the debris was either included in the formation of larger bodies or ejected from the solar system, with only asteroids and comets remaining as remnants of this intense period of solar system formation.