• The universe is large, and the distances within it are often measured in light years. 
• The universe consists of many star systems or galaxies, which in turn each consist of billions of stars.
• The central star of our solar system is called the Sun.
• Eight planets orbit around the sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
• Planets can be divided into rocky planets and gas planets based on their composition.
• Our solar system consists of a central star (the Sun), planets (as well as their moons and satellites), and small asteroids.
• Key words: universe, galaxy, light year, solar system, rocky planets, gas planets.