Formation and Structure of the Solar System
Ever wondered why the Solar System is flat even though planets are round? About 4.6 billion years ago, gravity pulled together a giant cloud of gas and dust called a nebula. As this material collapsed, it flattened into a spinning disc, much like a pizza dough being tossed and spun.
In the center of this disc, tremendous pressure created our Sun. The remaining materials collided and stuck together, eventually forming the planets and other objects. This whole collection of the Sun and orbiting objects makes up our Solar System.
The eight planets in our Solar System are divided by the asteroid belt, which sits between Mars and Jupiter. The inner planets (Mercury, Venus, Earth, and Mars) are smaller and rocky. The outer planets (Jupiter, Saturn, Uranus, and Neptune) are much larger gas giants.
Fun Fact: Beyond Neptune lies the Oort cloud, which is filled with comets - icy objects that develop beautiful tails of gas when they approach the Sun!