Question

Why are the inner planets made of denser materials than the outer planets?

A) The Sun's gravity pulled denser materials toward the inner part of the solar nebula, while lighter gases escaped more easily.
B) Denser materials were heavier and sank to the center of the nebula.
C) In the inner part of the nebula only metals and rocks were able to condense because of the high temperatures, whereas hydrogen compounds, although more abundant, were only able to condense in the cooler outer regions.
D) When the solar nebula formed a disk, materials naturally segregated into bands, and in our particular solar system the denser materials settled nearer the Sun while lighter materials are found in the outer part.
E) In the beginning, when the protoplanetary disk was spinning faster, centrifugal forces flung the lighter materials toward the outer parts of the solar nebula.

Answer 1

The inner planets are composed of denser materials because only metals and rocks could condense in the high temperatures near the Sun. In the cooler outer regions, lighter materials like hydrogen compounds could also condense, leading to less dense compositions.

Step-by-step explanation:

The inner planets are made of denser materials than the outer planets primarily due to the temperature conditions present in the early solar system. During the formation of the solar system, the first materials to condense into solid grains were metals and rock-forming silicates. High temperatures in the inner part of the solar nebula prevented less dense materials, such as ice or carbonaceous organic compounds, from condensing. This resulted in inner planets largely composed of rock and metal. In contrast, the cooler temperatures of the outer solar system allowed for the condensation of ices, in addition to rocks, which are the building blocks of the gas giants and their moons.

The correct answer to the student's question is option C and here's why: In the inner part of the nebula, only metals and rocks were able to condense because of the high temperatures, whereas hydrogen compounds, although more abundant, were only able to condense in the cooler outer regions.