SdA 71 The blue

Apuntes

SdA 7: The blue planet , the Earth INDEX 1. The Earth: our planet 2. The Earth’s movements 3. Orientation 4. The Earth’s representation Blue planet : the most of its surface is composed of oceans and seas, contrasting with green and brown colours of the continents The Earth is special because it is the only planet with liquid water which makes life possible Human society has transformed the Earth breaking the balance of its ecosystems, risking our survival. If we don’t change our actions, we can destroy our planet. L et’s build a sustainable world. Ecosystem : community of living organisms and the physical environment where they interact with each other and their surroundings 1. The Earth: our planet The Earth was formed about 4,600 million years ago , at the same time as the Sun and the Solar System . The Earth has a size of 510 million km 2 and an imperfect sphere shape , wider at the equator than at the poles. Real Earth’s shape Earth is the only planet in the Solar System where ...