Earth's Place In Space

Earth's Place In Space

Origin Of The Universe− Big Bang Theory − How our solar system formed

Earth's Early Atmosphere Evolution

Origin Of The Universe

Big Bang Theory− Scientists believe that there was a giant

explosion around 12-14 billion years ago.− Atomic particles from the explosion later

formed galaxies, stars, and planets.

Supernova

− 7 Billion years ago, a supernova occurred from one of the first generations of giant stars exploding.

− A supernova occurs at the end of a stars life, releasing huge amounts of energy.

Solar Nebula

− The energy released from the first generation of stars exploding, produced a solar nebula.

− A solar nebula is thought to be a spinning cloud of dust and gas.

Solar Nebula

Gravity caused the spinning could of dust and gas to collapse and condense forming our Sun in the center.

The other lumps of matter that formed from the contracting dust and gas became the planets.

Earth's Early Atmosphere

4.6 billion years ago, Earth was nothing more than a molten ball of rock surrounded by an atmosphere of hydrogen and helium.

As the Earth cooled

enough to form a

solid crust, it was

covered with active

volcanoes.

Earth's Early Atmosphere

These volcanoes spewed out gasses, like water vapor, carbon dioxide, and ammonia forming Earth's early atmosphere.

Earth's Early Atmosphere

Very little oxygen No ozone layer

− Early life could only survive in the ocean (UV radiation)

Early organisms used energy from the Sun for photosynthesis.

− Conversion of the suns energy into chemical energy by living organisms.

− Oxygen was released as a byproduct.

Earth's Early Atmosphere

As oxygen increased, the ozone layer was formed protecting Earth from harmful radiation.

This allowed for plant life to evolve and made it possible for the evolution of animal life on land.

Evolution

Precambrian: Multicelled organisms

Paleozoic: Reptiles− Ice Age

Mesozoic: Dinosaurs/Mammals

Cenozoic: Early humans/Modern Humans