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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