1. The Origin of Earth

2. Creation of our Universe Our universe is believed to be created 15 billion years ago It is believed that 15 billion years ago the universe was a superdense mass that exploded throwing energy and matter into space The matter that was in space was pulled together to form galaxies, stars, moons and planets Even though the universe was created 15 billion years ago, it is still expanding BIG BANG

3. Creation of the Earth Believed that Earth formed 4.6 billion years ago Also believed that the Moon was formed at the same time as the Earth due to rocks found on the Moon The Moon could have been formed when a meteor crashed into Earth sending a piece of Earth into space

4. Geological Time Scale of the Earth EraMillion Years AgoFirst Evidence of Precambrian4,600 3,500 2,500 2,100 -Formation of the Earth -Prokaryotes -Free oxygen Eukaryotes Paleozoic520 430 400 360 300 -Vertebrates -Land plants -Land animals -Amphibians -Reptiles Mesozoic235 220 140 -Dinosaurs -Mammals -Flowering plants Cenozoic65 7-5 -Primates -Humanlike apes

5. Edwin Hubble It is believed that the universe is still growing Edwin Hubble wanted to test the idea that the size of the universe was stable He was a scientist in the 1920’s who studied light from distant galaxies The Hubble Telescope is named after him

6. How could he test that idea? Hubble studied light Light consists of waves and waves change depending on if the object producing the waves moves away or towards another object When a light source moves away from the observer the wavelength becomes longer and the visible light is more red

7. Theory of an Expanding Universe After Hubble studied the waves coming from different galaxies he found that those objects gave off red light Concluded that objects were moving away from Earth Also found that distant objects were moving away more quickly than closer objects

8. SUMMARY The universe was created 15 billion years ago due to a big explosion The Earth was created 4.6 billion years ago and from there life began to develop Edwin Hubble proved the theory of the expanding universe by observing light waves