Solar System KS2

What is a solar system?

A solar system consists of a star and objects that orbit it, bound to the star by gravity.

In our solar system, we call the star the Sun. Orbiting the Sun in our solar system are four main groups of objects: planets, dwarf planets, satellites, and comets and asteroids.

How many planets are in our solar system?

Planets are the largest objects in the solar system (not including the star). There are eight in our solar system.

In order to be a planet, these objects need to conform to three rules:

• It must orbit around the Sun.
• It needs to be roughly spherical.
• It needs to be big enough to have cleared other objects of a similar size (except satellites) from its neighbourhood.

What are the planets in our solar system?

Here are the planets in order:

The planets of our solar system

There are three main types of planet in our solar system.

• Terrestrial planets - Mercury, Venus, Earth and Mars are terrestrial planets. They are mostly made of rock and metal.
• Gas giant planets - Jupiter and Saturn are gas planets. They are much bigger than the other planets and are made of hydrogen and helium.
• Ice giant planets - Uranus and Neptune have atmospheres of mainly hydrogen and helium but their interior is made of ice.

Why isn't Pluto a planet?

Pluto used to be considered a planet, but it doesn’t meet the third rule. It is not large enough to have cleared other large objects nearby. It was demoted to a dwarf planet in 2006. A dwarf planet is the name given to a celestial object that is similar to a planet, but hasn't met the criteria that would deem it a planet.

What is a satellite?

Satellites orbit planets. They can be natural, like the Moon, or man-made. Man-made satellites have been sent from Earth to orbit our planet or another in order to collect or relay information.

A weather satellite orbiting Earth

What is an asteroid?

An asteroid is an irregularly shaped object which orbits the Sun. Asteroids are usually made from rocks or metal. There is a large area filled with asteroids between Mars and Jupiter called the asteroid belt.

When an asteroid enters Earth’s atmosphere, we call it a meteor. Usually these burn up in the atmosphere, but on very rare occasions they can reach Earth’s surface, where they’re called meteorites.

What is a comet?

Just like an asteroid, a comet is also an irregularly shaped object which orbits the Sun. However, comets are made from ice and frozen gases like carbon dioxide. They are sometimes referred to as ‘icy dirtballs’. They orbit the Sun but most don’t come near Earth.

When should children learn about the solar system?

According to the National Curriculum Science objectives, children start to learn about the solar system in KS2. It is assigned as compulsory learning in Year 5 under the 'Earth and Space' strand of learning.

In Year 5, children should learn to:

• describe the movement of the Earth, and other planets, relative to the Sun in the solar system

In the non-statutory guidance, it is suggested that pupils should learn that the Sun is a star at the centre of our solar system and that it has eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune (Pluto was reclassified as a ‘dwarf planet’ in 2006).

In addition to our Year 5 Science scheme of work, Earth and Space, we also have an upper KS2 cross-curricular Space Topic, which includes 18 ready-to-teach lessons. If you are looking for space-themed English lessons, you might like our Stories from Space: Descriptive Writing scheme of work for Year 5.