Solar System

The word "solar" is derived from the Latin word for sun, Sol, leading to the term solar system, or the system of the sun.

Our particular solar system is believed to be more than 4.6 billion years old. It is home to the sun, nine planets including ours, the Earth, 158 known moons that orbit those planets and countless other celestial bodies like asteroids, comets and meteoroids that exist throughout its vast space.

Our solar system is comprised mostly of open and empty space. In fact, the largest body of matter in our solar system is the sun itself. Our sun contains 99.85% of the matter in our solar system.

Our solar system had very humble beginnings. It was formed from a simple cloud of gas consisting of 75% hydrogen, 25% helium and 1% heavier elements. These three main elements condensed into the gas cloud which in turn continued to condense into solid objects. These objects later came to be called our Sun and the planets Earth, Mercury, Mars, Venus, Jupiter, Saturn, Neptune, Pluto and Uranus.

In addition to the sun and nine planets, our solar system also consists of small bodies. These small bodies are asteroids, meteoroids, comets, satellites of the planets, and interplanetary medium. Interplanetary medium is considered the gas and dust that floats around in our solar system. Comets are known as solar system "leftovers" or "dirty snowballs" - lumps of frozen gas and dust.

Our solar system is divided into two parts: an inner solar system and an outer solar system. The inner solar system consists of the Sun and the planets closest to it - Mercury, Venus, Earth and Mars. These planets are known as terrestrial planets due to their rocky surfaces. The outer solar system is comprised of those planets furthest from the Sun - Jupiter, Neptune, Saturn, Pluto and Uranus.

Our solar system is vast and fascinating to study. At night, when you gaze up into the dark sky, know that our solar system is not the only one to exist. The star that gives our solar system its name is, after all, only a star. There are literally billions of stars in our galaxy alone! And there are 40 billion galaxies known to us at this time in our observable universe.