1. Looking at the History….of EVERYTHING….

2. Origin of the Universe
Approximately 13.7 billion years ago, the universe began as a single point containing all matter and energy. This point suddenly expanded and has been expanding ever since. This is known as the Big Bang.

3. Origin of the Stars
Matter is not distributed evenly throughout the universe.
Gravity began attracting hydrogen (H) and helium (He) atoms together into large collections of gas and dust
These clouds of gas and dust are known as nebulas (97% H and 3% He)

4. Nebulas
Portions of the nebula begin to contract, forming clumps of spinning gas.
Gravity causes these clumps to condense into dense pockets of matter within the nebula
As it shrinks, it becomes hotter and when it is hot enough, nuclear fusion can start in the center…..and A Star is Born!
Crab Nebula

5. Origin of the Solar System – Solar Nebula Theory
Solar System – the Sun (a star) and all the planets and other bodies that travel around it The planets began to form by accretion, where pieces of leftover material stick together to form planets, comets, asteroids, etc.

6. Formation of the Planets
After the sun formed in the middle of our solar system, the rest of the matter began to combine….forming….
Planetesimal – small celestial body from which a planet originated in the early stages of our solar system
Some of these planetesimals collided and through the force of gravity became….
Protoplanet – larger ‘early planets’ formed from planetesimals and other matter

7. Origin of our Earth
Eventually, Protoplanets also began to collide and condense….forming the planets we know today. Earth continued to grow by accretion. The more mass on object has, the more gravity it will have causing more material to be attracted to the planet.

8. Origin of Earth
Earth’s layers formed through density differentiation – this means that the heavier elements sunk towards the middle. Iron and nickel sunk to the middle to form the core while oxygen and silicon, lighter elements, moved toward the surface.
The composition of the Earth’s core has not changed since its formation 4.6 billion years ago! 3

9. Origin of our Moon
The moon is believed to have formed when a small, Mars-size protoplanet collided with Earth and sent part of the Earth into space to form the moon. This occurred around the same time of Earth’s formation, 4.5 billion years ago.
Since the moon is a piece of Earth, its rocks are like those found on Earth….BASALT!!! 4

10. Interesting Fact
About 3 billion years ago, the moon was a lot closer to the Earth than it is now. As a result, the moon caused tides of up to 1000 feet!

11. Origin of the Atmosphere
Earth’s atmosphere evolved in stages : Stage 1 = Volcanoes formed the first atmosphere of CO2 H2S water vapor CH4 (methane) NH3 (ammonia)

12. Origin of the Atmosphere
Stage 2 - Water condensed to form clouds and produce liquid water. As soon as Cyanobacteria evolved, they added oxygen into the atmosphere….so that atmosphere is now Nitrogen CO2 Oxygen H2SO4 water vapor

13. Origin of the Atmosphere
Stage 3 - As life evolved, more and more oxygen was added until we reached our modern atmosphere levels Nitrogen – 78% Oxygen – 21% Argon – 0.9 % CO2 – 0.04%

14. Origin of the Atmosphere
In addition, oxygen in the atmosphere oxidized to produce ozone (O3) which formed our ozone layer. This layer protects Earth from harmful radiation, which allows life to move out of the ocean onto land.
The Ozone layer is found in the Stratosphere.

15. Eventual Origin of the Oceans
Comets and meteorites brought frozen water to Earth while Earth was forming. As the planet cooled, precipitation could occur and liquid water began to accumulate in the ocean.
Runoff brought dissolved ions from the continents to the oceans to make it salty.

16. Why the Seas Are Salty
1. Minerals and chemicals eroded and dissolved into fresh water and flowed into the ocean - Waves and surf also contribute by eroding coastal rock.
2. Hydrothermal vents also change seawater by adding some materials (sulfur) while removing others (salt)
Scientists believe these processes all counterbalance each other so the average salinity of seawater remains constant.

17. Origin of Life
The first life on Earth formed about 3.8 billion years ago. Life was anaerobic (no oxygen) and produce food through chemosynthesis. This is like photosynthesis, except instead of using sunlight, they use chemicals in the water to produce food.
Hydrothermal Vent communities are now considered to be the first life forms. They are called extremophiles because they live in extreme conditions.

18. Origin of Life - Photosynthesis
Stromatolites first appeared about 3 billion years ago and were photosynthetic. They produced oxygen for our atmosphere. More complex life didn’t appear on land until 450 million years ago, when oxygen became more abundant in the atmosphere.