The Solar System

The solar system consists of the Sun, planets, and other celestial objects such as comets.

The Sun, a part of our solar system, which is the closest star to Earth. It takes just over eight minutes for light from the Sun to reach Earth.

The 8 planets in the solar system are:

1. Mercury

2. Venus

3. Earth

4. Mars

5. Jupiter

6. Saturn

7. Uranus

8. Neptune

This is the order of the planets, starting with the one closest to the Sun. So, Mercury is closest to the Sun.

An easy way to remember the order is:

  • My Very Easy Method Just Speeds Up Naming

Scientists have debated Pluto’s status as a planet. Since its discovery in 1930, Pluto has been considered the ninth planet. But in 2006, it was downgraded to a dwarf planet.

Heliocentric Model

The diagram below depicts the heliocentric model of our solar system, with the Sun at the centre and the planets orbiting it.

It takes around 365 days for the Earth to orbit the Sun. However, the duration of each planet’s orbit varies.

Inner and outer planets

The inner planets are rocky, while the outer planets are gas giants.

Geocentric model

In the past, people didn’t always believe that the Sun was at the centre of the solar system. Initially, the geocentric model was more popular.

In the geocentric model, the Earth is at the centre, with the Sun, Moon, stars and planets orbiting the Earth. The geocentric model is the older, outdated model.

Observing the Sun move across the sky led people to believe in the geocentric model, which places the Earth at the centre. owever, we now know that the Sun is at the centre and the planets, including Earth, orbit around it.