The document discusses the celestial bodies in our solar system. It defines galaxies, stars, planets, satellites, asteroids, comets, and meteors. It describes the inner and outer planets and the movements of rotation and revolution that cause day/night and seasons on Earth. It outlines the parts of Earth including the atmosphere, hydrosphere, and geosphere. It also defines rocks, minerals, and the methods used to classify them. Finally, it provides details about the moon, noting it is Earth's only natural satellite and discusses its phases and the Apollo 11 mission.

1. Galaxy: Large system of stars held together by mutual gravitation (Solar System is in the
Milky way galaxy)
Star: A celestial body that generates light and other radiant energy and consists of a
mass of gas
Planets: Spherical bodies that emit neither heat nor light and revolve around a star (Sun)
Satellites: Celestian bodies (no light itself). They orbit around a planet
Asteroids: Celestian bodies . Orbit around the sun (but too small for being a planet)
Comets: “Space travellers”. Snow-ball that orbit around the sun
Meteors: Small rocks in our solar system. They travel in the space

2. VIDEO: The Universe and its celestial bodies (click it)

3. PLANETS:
Inner planets ( rocky planets): Mercury, Venus, Earth and Mars.
Outer planets (gaseous planets): Jupiter, Saturn, Uranus and Neptune.

4. Movements:
Rotation: The Earth moves around itself (rotate clockwise).
24 hours.- day and night
Revolution: The Earth moves around the Sun. It forms an ellipse called Orbit
365 days and 6 hours- Seasons (Spring, summer, autumn, winter)

5. VIDEO: The Earth movements , with exercises (click on it)

6. The Earth
Parts:
Atmosphere: Gaseous part. Essential for life
Hydrosphere: All the water on the planet
Geosphere: Solid part of our planets.

7. VIDEO: The Earth parts (click on it)

8. • Rocks: Combination of minerals and other compounds.
Classification:
 Igneous (volcanic rocks)
 Metamorphic (Formed when other rocks changed )
 Sedimentary (Formed when combinations of rocks are compressed)
• Minerals: Unique chemical structure
We classify them according to their properties:
 Hardness
 Texture ( smooth or rough ) ,
 Magnetism ,
 Luster ( vitreous or metal ),
 Shape (shaped or not)
 and color.

9. THE MOON.-
* It is the only natural satellite of the Earth.
* The moon has no light of its own.
* Its movements and phases have major consequences for life on our planet. (tides)
Stages:
Apollo 11.-(1969)- Amstrong, Aldrin and Collins.