Above: An artist’s impression of the planets of our solar system, with the sun shown bottom middle (Credit: NASA).
8 – the number of planets in our solar system. We used to count 9, including Pluto, but this has now been reclassified as a Kuiper Belt object (KBO).
4 – the number of solid, terrestrial planets in our solar system – Mars, Venus, Earth and Mercury (planets comprised of rock and metal).
4 – the number of gaseous planets in our solar system – Jupiter, Saturn, Uranus and Neptune (planets with a solid core but whose greatest size is comprised of liquid gasses – hydrogen and helium – surrounded by rings of debris).
828,000 km/h – the speed at which our solar system is orbiting the centre of the Milky Way (514,000 mph).
230 km – the distance our solar systems travels every second (143 mi/s).
230 million years – the time it takes to complete one orbit of the Milky Way.
28,000 light years – the distance of the solar system from the centre of the Milky Way.
4 – the number of planets that have rings; Jupiter, Saturn, Uranus and Neptune.
99.8% – the amount of the total mass of the solar system that is contained within the sun alone.
99% – the amount of the remaining 0.2% of the mass of the solar system that is contained with the four giant gas planets (Jupiter, Saturn, Uranus and Neptune).