What primary components constituted the original solar nebula before condensation began?
Primarily hydrogen and helium, with trace amounts of heavier elements and rock-forming materials.
The composition of the initial material that collapsed under gravity to form the Sun and planets—the solar nebula—was dictated by the raw materials available in the interstellar medium. This cloud was overwhelmingly composed of the lightest elements: hydrogen and helium, which constituted the vast majority of the mass. Embedded within this light gas were trace amounts of heavier elements, including rock-forming materials (metals and silicates) and materials that would later form ices. This initial composition set the stage for the subsequent thermal differentiation process where the heavier, refractory materials condensed closer to the forming Sun, while the lighter gases remained farther out until trapped by growing outer planets.
