The solar system is a fascinating and complex structure consisting of the Sun and all the celestial bodies bound to it by gravity. The gravitational collapse of a section of a massive molecular cloud created the solar system some 4.6 billion years ago. It is located around 26,000 light-years away from the core of the Milky Way galaxy and is one of the countless solar systems in the cosmos.
The inner solar system, which includes the four terrestrial planets—Mars, Venus, Earth, and Mercury—and the outer solar system, which includes the ice giants Uranus and Neptune and the gas giants Jupiter and Saturn, are the two main divisions of the solar system. Each of these planets has unique characteristics that make it distinct and intriguing.
How to Identify the Planets and What Are the Solar System Planets in Order?
Here’s a simple guide to help you recognise each planet based on their order from the Sun:
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Mercury
- Distance from Sun: Closest planet
- Characteristics: There are many craters on the surface of Mercury, the smallest planet in our solar system. It completes an orbit around the Sun in just 88 days, experiencing extreme temperature fluctuations—up to 840°F (450°C) during the day and dropping to -290°F (-180°C) at night.
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Venus
- Distance from Sun: Second planet
- Characteristics: Venus is often referred to as Earth’s twin due to its similar size but has a thick atmosphere composed mainly of carbon dioxide and sulphuric acid clouds. Its surface temperature can reach up to 900°F (475°C), making it the hottest planet in our solar system.
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Earth
- Distance from Sun: Third planet
- Characteristics: Our home planet, Earth, is unique for its liquid water and life-supporting atmosphere. It has a diverse climate and ecosystems, making it distinct among the solar system planets.
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Mars
- Distance from Sun: Fourth planet
- Characteristics: Known as the Red Planet due to its iron oxide-rich soil, Mars has two small moons, Phobos and Deimos. It features the largest volcano in the solar system, Olympus Mons, and has been a focal point for exploration regarding potential past life.
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Jupiter
- Distance from Sun: Fifth planet
- Characteristics: Jupiter is the largest planet in our solar system, more than twice as massive as all other planets combined. It is known for its Great Red Spot—a giant storm—and has at least 79 moons, including Ganymede, which is larger than Mercury.
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Saturn
- Distance from Sun: Sixth planet
- Characteristics: Saturn, a gas giant mainly consisting of hydrogen and helium, is well-known for its beautiful rings formed of ice and rock fragments. It has over 80 moons, with Titan being its largest.
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Uranus
- Distance from Sun: Seventh planet
- Characteristics: Uranus stands out for its blue color due to methane in its atmosphere and its unique sideways rotation. It orbits on its side, leading to extreme seasonal variations.
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Neptune
- Distance from Sun: Eighth planet
- Characteristics: Neptune is known for its striking blue colour and supersonic winds reaching over 1,200 miles per hour (2,000 kilometres per hour). It was discovered through mathematical predictions before being visually confirmed.
Composition of the Solar System
In addition to planets, our solar system is made up of a wide range of other celestial objects:
- Dwarf Planets: Pluto was reclassified as a dwarf planet in 2006 due to its size and orbital characteristics.
- Asteroid Belt: There are several stony bodies in this area, which is situated between Mars and Jupiter.
- Comets: Composed largely of ice and dust, comets originate mainly from two regions—the Kuiper Belt and Oort Cloud.
- Moons: Many planets have natural satellites or moons that orbit them; for example, Earth has one moon while Jupiter boasts over 79.
