The Solar System

The Solar System

Several planetary systems are present in the universe, with planets taking orbits around a host star. Our planetary system is named the Solar System because the Sun is named Sol, after the Latin word “sols”. Therefore, anything related to the Sun is called Solar. The solar system consists of our star- the Sun – and all other things bound to it by gravity, including eight planets, millions of asteroids, comets, meteoroids, dwarf planets like Pluto, and dozens of moons. This planetary system is present in the outer spiral arm of the Milky Way. 

Sun 

The Sun, occupying the centre of the solar system, is a 4.5 billion-year-old star. Positioned 93 million miles away from the Earth, it is a hot, glowing ball composed of hydrogen and helium. Without the presence of the Sun, life on Earth would not be possible. 

The Sun is the largest object in the entire solar system. If we compare it to Earth, we would need about 1.3 million Earth to fill up the volume of one Sun. It is the primary part of the solar system since the gravitational pull of the Sun keeps everything in the solar system, ranging from the biggest to the smallest objects, orbiting around it.  

With its powerful eruptions and the steady stream of charged particles, the Sun directs the nature of all the objects in the solar system. The hottest part of the Sun is its core, having a temperature of 15 million degrees Celsius. 

NASA and other space agencies monitor this yellow dwarf star 24×7. They research and study its atmosphere, surface, and other characteristics. The spacecraft used for exploring the Sun are Solar Orbiter, ACE, Parker Solar Probe, STEREO, Hinode, WIND, and IRIS. 

The Planets In Order 

Our galaxy comprises more planets than stars. Currently, there are eight planets in the solar system after the exclusion of Pluto. Mercury, Venus, Earth, and Mars are categorized as inner, rocky planets. Jupiter and Saturn are identified as gas giants, while Uranus and Neptune are known as ice giants. Besides, there are dwarf planets such as Pluto that reign beyond Neptune.

These are the planets in order along with their unique characteristics: 

1. Mercury: The smallest planet in the solar system, Mercury’s size is only slightly larger than Earth’s Moon. This planet has the closest orbit to the Sun and is the fastest planet in the entire system. Mercury has no moons and rings. 

2. Venus: Venus is the second planet from the Sun and Earth’s closest neighbour. Venus is often known as “Earth’s twin” because of its similar size and structure as Earth. It is always shrouded in thick clouds that smell of rotten eggs. 

3. Earth: Earth is the only planet home to human life. A day on Earth is 24 hours long, and it takes 365 days for this planet to complete an orbit around the Sun. Earth has only one Moon and no rings. The Earth’s atmosphere protects it from the meteoroids that get broken and burnt in the atmosphere before reaching the surface.   

4. Mars: Mars is the fourth planet from the Sun. Several missions are being conducted to discover the possibility of life on Mars. There are two moons of Mars, known as Phobos and Deimos. The atmosphere of Mars is thin and made up of carbon dioxide, nitrogen, argon, oxygen, and water vapour. 

5. Jupiter: Jupiter is the fifth planet from the Sun and the largest planet in the solar system. Being the largest planet, Jupiter also has more than 75 moons. 11 Earth would be needed to fill up the space of Jupiter’s equator. Jupiter takes a time of 12 years to complete one orbit around the Sun. 

6. Saturn: Sixth in line from the Sun, Saturn is the second-largest planet in the solar system. With its thousands of ringlets, Saturn is a distinguished planet of the solar system. Being a gas giant planet, Saturn does not have a solid surface like Earth. 

7.Uranus: Seventh in line from the Sun, Uranus is the planet with the third-largest diameter in the solar system. Uranus has 13 wings, narrow inner rings, and bright-coloured outer rings. Besides, it has 27 moons named after the characters of William Shakespeare’s and Alexander Pope’s work. 

8. Neptune: The most distant planet from the Sun, Neptune is the 8th planet of the solar system. It is the only planet in the solar system which cannot be seen with the naked eye. This planet is approximately four times wider than our home planet. Neptune has 14 moons named after the nymphs and sea gods of Greek mythology. 

Moons

Moons, also referred to as natural satellites, orbit around the planets and asteroids. There are over 200 moons in our solar system, one of which is the Earth’s Moon. The only two planets that do not have moons are Mercury and Venus. Even dwarf planets and several asteroids have individual moons orbiting around them. 

Different moons have varied shapes and sizes. Some moons even have atmospheres and hidden oceans beneath the surface. Most moons have been formed by the gas and dust around the planets in the initial solar system. The number of moons that different planets have are:

Asteroids, Comets, and Meteors

Before the formation of planets and moons, there were swirling clouds of gas and dust encircling the Sun. These dust particles became bigger pieces of rock by constantly colliding with each other. This process of collision, also known as accretion, eventually formed all the planets of the solar system. 

However, billions of such small pieces never evolved into huge planets, and they are now known as asteroids, comets, and meteors. The number of these bodies in the solar system are: 

• Asteroids- 1,113,527
• Comets – 3,743

Conclusion

Thus, our solar system is rich with stars, planets, moons, and meteors. There are billions of galaxies like our Milky Way in the universe. Within the galaxy as well, there are around 100 billion stars with at least one planet orbiting around it. Our Sun is just one of these 100 billion stars present in the universe by which you can ascertain how big the universe is. 

We still do not know the exact size of the universe since scientists believe that it is still expanding outwards. Everything that we know of, the planets, stars, meteors, and moons, are a part of the big universe.