Editing Solar system (section)

=== The Origin of the Solar System ===
The Solar System, which includes the Sun, eight planets, and countless smaller bodies, formed about '''4.6 billion years ago''' from a giant cloud of gas and dust known as the '''solar nebula'''. Understanding how it came into existence helps scientists learn not only about our cosmic neighborhood but also about the formation of other planetary systems in the universe.

'''1. The Solar Nebula Theory'''

The most widely accepted explanation for the origin of the Solar System is called the '''Nebular Hypothesis''' or '''Solar Nebula Theory'''. According to this theory, a large cloud of interstellar gas and dust began to collapse under its own gravity. This collapse may have been triggered by a nearby supernova explosion, which sent shock waves through the cloud, causing it to contract. As the cloud collapsed, it began to spin faster and flatten into a rotating disk. Most of the material gathered at the center to form the '''Sun''', while the remaining gas and dust spread out to create the '''protoplanetary disk''', from which planets and other celestial bodies eventually formed.

==== 2. Formation of the Sun ====
At the dense center of the nebula, gravity pulled gas together, increasing pressure and temperature until nuclear fusion began. Hydrogen atoms fused to form helium, releasing enormous energy. This process marked the birth of the '''Sun''', the star at the heart of our Solar System.

==== 3. Formation of Planets and Moons ====
In the surrounding disk, tiny dust grains began to stick together through static electricity and collision, forming larger clumps called '''planetesimals'''. Over millions of years, these planetesimals collided and merged to form '''protoplanets''', the early versions of planets.

* '''Inner Planets (Mercury, Venus, Earth, Mars):''' Closer to the Sun, where it was too hot for gases to remain, rocky materials combined to form small, dense terrestrial planets.
* '''Outer Planets (Jupiter, Saturn, Uranus, Neptune):''' Farther from the Sun, cooler temperatures allowed gases like hydrogen and helium to accumulate, creating massive gas and ice giants. Moons, asteroids, and comets also formed from leftover materials that did not become part of planets.

==== 4. Present Solar System ====
Over billions of years, the Solar System stabilized. The planets settled into their current orbits, and the Sun became the steady source of light and heat that sustains life on Earth. Today, scientists continue to study the Solar System’s origin through space missions and telescopic observations. By examining meteorites and distant protoplanetary disks, astronomers gain valuable insights into how the Solar System and possibly countless others came to be.