2.2. THE SOLAR SYSTEM

- COMPONENTS OF THE SOLAR SYSTEM (AGE: 4500 million years)

YouTube: Paxi ESA Kids “Solar system”

1 STAR

• The Sun

It is a yellowish medium-sized star.

YouTube: National Geographic “Sun 101”

Nuclear reactions take place in its interior and they produce huge amounts of energy: the temperature of the surface is about 6000 ºC and emits light and heat.

8 PLANETS (number of satellites in brackets)

• Rocky planets: Mercury (0), Venus (0), the Earth (1: the Moon) and Mars (2).
  They are located between the Sun and the asteroid belt.
  Their surface is solid and they have 3 layers:
  • Crust: the outermost layer; made of rocks.
  • Mantle: the layer under the crust; made of rocks.
  • Core: metallic.

YouTube: National Geographic “Mercury 101”

YouTube: National Geographic “Venus 101”

YouTube: National Geographic “Earth 101”

YouTube: National Geographic “Mars 101”

• Giant planets: Jupiter (63), Saturn (61), Uranus (27) and Neptune (14)
  They are located beyond the asteroid belt.
  Their surface and composition are gases, mainly H and He.
  They have solid cores.
  

YouTube: National Geographic “Jupiter 101”

YouTube: National Geographic “Saturn 101”

YouTube: National Geographic “Uranus 101”

YouTube: National Geographic “Neptune 101”

CELESTIAL BODIES

• Satellites
  They can be very large or very small and their shape can be spherical or irregular.
• Dwarf planets
  Their orbit around the Sun is not clear (Pluto, Ceres...).
• Asteroids
  They are rocky and irregular shaped bodies of different sizes. There is an asteroid belt between the orbits of Mars and Jupiter. There is a Kuiper belt beyond the orbit of Neptune.
• Comets
  They are small and irregular bodies which travel around the sun in highly elliptical orbits and have a nucleus of ice, dust and gas.
  They are formed in a very far region of the Solar System (the Oort cloud) and when they travel close to the Sun, the ice starts to evaporate creating a long and bright tail.