Space

1. The sun

1.1. Getting bigger

1.2. Getting hotter

1.3. At the center of the solar system

2. Facts

2.1. 8 planets

2.2. 200-400 billion stars

3. Planets

3.1. Mercury

3.2. Earth

3.3. Jupiter

3.4. Uranus

3.5. Venus

3.6. Mars

3.7. Saturn

3.8. Neptune

4. Astronauts