How do planets form?

Planets form through a process called **planetary formation**, which takes place within a rotating disk of gas and dust surrounding a young star, known as a **protoplanetary disk**. This process generally occurs over millions of years and involves several key stages. Initially, small particles of dust and ice within the protoplanetary disk collide and stick together through electrostatic forces, creating larger and larger clumps called **planetesimals**, which can be a few kilometers across. These planetesimals continue to collide and merge due to their mutual gravity, gradually forming **protoplanets**—larger bodies that can attract more material. In the inner regions of the disk, where it’s hotter, rocky planets form from metal and silicate materials. Farther out, where it’s cooler, ices and gases accumulate, leading to the formation of gas giants and ice giants. As protoplanets grow, their gravity can clear nearby debris, and in the case of gas giants, they can gather thick atmospheres of hydrogen and helium. Over time, the disk material is either accreted into planets or blown away by stellar winds, leaving behind a stable planetary system. This gradual accumulation and differentiation explain the diverse types and sizes of planets observed in our solar system and beyond.

Planets form through a process called **planetary formation**, which occurs within large clouds of gas and dust surrounding young stars, known as protoplanetary disks. This process typically unfolds over millions of years and involves several key stages. Initially, small particles of dust and ice within the disk collide and stick together due to electrostatic forces, gradually growing into larger clumps called **planetesimals**, which can be a kilometer or more in size. These planetesimals then attract each other through gravity, leading to further collisions and mergers. Over time, this accumulation forms **protoplanets**, which are large enough to clear their orbits of debris. Depending on their location in the disk, these protoplanets may become rocky terrestrial planets (closer to the star) or gas giants (farther out, where ices can condense and massive gas envelopes can be captured). Throughout this process, factors such as the composition of the disk, the distance from the star, and the disk’s lifetime influence the types of planets that form. Eventually, the star’s radiation and stellar winds blow away remaining gas and dust, leaving behind a stable planetary system. This general framework explains how diverse planetary systems, including our own solar system, come into existence.

Planets form through a process called **planetary formation**, which occurs within the rotating disks of gas and dust surrounding young stars, known as **protoplanetary disks**. This process typically unfolds over millions of years and involves several key stages. Initially, tiny dust grains in the disk collide and stick together, forming larger and larger clumps in a process called **accretion**. These small particles gradually build up into kilometer-sized bodies known as **planetesimals**. Through gravitational attraction, planetesimals continue to collide and merge, growing into **protoplanets**. In the inner regions of the disk, where temperatures are higher, rocky planets form from metal and silicate materials. Farther out, where it’s colder, ices and gases accumulate, allowing the formation of gas giants like Jupiter and Saturn. As protoplanets grow, their gravity can attract surrounding gas, especially in the outer disk, leading to the formation of thick atmospheres around giant planets. Over time, leftover debris is cleared out through collisions, ejections, or by being swept up by growing planets, leaving behind a mature planetary system. This gradual process explains the diversity of planets observed both in our solar system and around other stars.