Why did the terrestrial planets form close to the Sun while the Jovian planets formed far from the Sun?

The formation of our solar system is elegantly explained by the Early Solar Nebula Theory. Imagine the cosmos roughly 4.6 billion years ago with a giant, rotating cloud of gas and dust. This cloud, known as the solar nebula, was the nursery of our planetary system. Due to the force of gravity, this cloud began to collapse in on itself, spinning faster and flattening into a disk.

At the center of this whirling nebula, the majority of the material clumped together to form our Sun. With the new star at its heart, the remaining particles in the disk moved around it, colliding and sticking together. Over time, these aggregations grew, ultimately giving rise to the planets. This process exemplifies the concept of accretion, where small particles coalesce to form larger bodies, a fundamental mechanism of planet formation.

Understanding the solar nebula theory helps clarify why certain materials are found in specific regions of our solar system, influencing the characteristics of the emerged celestial bodies. As the nebula evolved, its inner regions remained hot due to proximity to the newly formed Sun, while the outer reaches were cooler, an essential factor in determining planetary composition.

Planetary differentiation refers to the process where a planet becomes layered internally based on density, with heavier materials like iron sinking to form a core, and lighter materials forming the outer layers. This phenomenon is akin to oil floating on water due to density differences.

In the early stages of a planet's development, it's often in a molten state due to the heat generated from frequent collisions and the decay of radioactive elements. During this molten phase, heavier elements can move towards the center, a process known as 'iron catastrophe' in the context of Earth, leading to the formation of our planet's layered structure: an iron core surrounded by a silicate mantle and crust.

Terrestrial planets, being closer to the Sun, formed from heavier elements that could withstand the intense heat, leading to solid surfaces and differentiated layers. In this way, understanding planetary differentiation is key to comprehending why Earth and our neighboring rocky planets have a core-mantle-crust structure, vastly different from the composition of the gas giants.

The concept of the condensation of planetary materials is at the heart of explaining why different types of planets formed at varying distances from the Sun. Within the protoplanetary disk, the temperature gradient from the hot inner regions to the cold outer spaces determined which materials could transition from a gaseous phase to a solid one.

Near the Sun, only materials with high melting points, such as metals and silicates, could solidify, leading to the formation of rocky terrestrial planets. These materials condensed into solid grains, which then accumulated through accretion to build up the terrestrial planets. On the other hand, farther from the Sun's warmth, volatile compounds like water, methane, and ammonia could also condense, either as ices or liquids, depending on the prevailing temperatures.

The jovian planets were born in these outer, cooler regions, allowing them to capture not just rock and metal but also a significant amount of these lighter materials, including hydrogen and helium, leading to their characteristic massive, gaseous compositions. This variance in temperature and resulting condensation zones in the early solar system disk are fundamental to understanding the dichotomy between terrestrial and jovian planets.