What is the Solar System? | Types, Definition, Structure, Function & Facts
What is the Solar System?
The center of the solar system is the Sun. The Solar System is made up of the Sun and all the planets, asteroids, and other objects that orbit the Sun.
The Planets
There are eight planets in our solar system. Start with the planets closest to the sun, which are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The four closest planets (Mercury, Venus, Earth, and Mars) are called terrestrial planets, which means they have hard rocky surfaces. The four outermost planets (Jupiter, Saturn, Uranus and Neptune) are called gas giants. These planets are much larger and their surfaces are composed of gaseous elements (mostly hydrogen).
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Other Objects
In addition to the Sun and eight planets, there are other objects that are part of the solar system.
Dwarf Planets – Dwarf planets are objects that are similar to planets in the solar system, but they are defined as not large enough to “clear their orbits from other objects”. Some of the dwarf planets in the solar system include Pluto, Ceres, Eris, Haumea, and Makemake.
Comets – Comets are objects made of ice, dust, and rock that orbit the sun. They usually have a visible “tail” of gas coming from solar radiation and solar wind. Comets come from the Kuiper belt and the Oort cloud.
Asteroid Belt – The asteroid belt is the region between the planets Mars and Jupiter. In this region, thousands of rocky objects orbit the Sun. They range in size from microscopic dust grains to the dwarf planet Ceres.
Kuiper Belt – The Kuiper Belt is a region of thousands of small objects that exist outside the orbits of planets. Objects in the Kuiper Belt are made up of “ice” such as ammonia, water, and methane.
Oort Cloud – The Oort Cloud exists far beyond the Kuiper Belt. About a thousand times farther than the Sun. So far, scientists have only speculated about the existence of the Oort cloud, which they believe is made up of thousands of small icy objects. The Oort Cloud is located on the outskirts of the solar system.
Milky Way
The solar system is part of a larger group of stars called galaxies. Our galaxy is the Milky Way. The solar system orbits the center of the Milky Way.
Interesting Facts about the Solar System
Because Uranus and Neptune contain a lot of “ice” such as water, methane, and ammonia, they are often referred to as “ice giants”.
Scientists estimate there are about 200 billion stars in the Milky Way galaxy.
Pluto was once considered a planet in its own right, but was redefined as a dwarf planet in 2006.
About 99.85% of the solar system’s mass is the Sun. All other planets, asteroids, moons, etc. together make up less than 0.15% of the solar system’s mass.
The area around the Sun that the solar wind from the Sun affects is called the heliosphere.
All the planets orbit the Sun in the same anti-clockwise direction.
Scientists who study the solar system and outer space are called astronomers.