Our Planet

How does Earth differentiate itself from other planets?

• contains life

  • (we) modified Earth & made it different from other planets

What would you need for intelligence life?

• A star that is just the right size (0.75-1.5 as big as the sun)

  • too large: burns too fast/too small: produces less heat (gradually cools down)

• A planet about the size of ours

• Has to be terrestrial: has to be made up of rock (for chem. reactions & things to grow upon), not gas

• Lots of water: liquid water (between 0 & 100C)

• Planet has to be just the right distance

  • too close: water will turn to steam/too far: water will be ice

• Needs to be a relatively circular orbit

  • reason: planet is evenly warmed up

• Rotate on its axis relatively frequently

  • 24 hours

    • spin of planet: constant temp.

What are the components of Earth & briefly describe each one.

• Hydrosphere - The world’s ocean (covers 55% of surface)

• Atmosphere -The gas that is held to the surface by gravity

  • ex: Mars has a thin atmosphere; weight down

• Lithosphere: the rock

• Biosphere: The area of the 3 above that contains life

Planetary Atmosphere: Sun

Hydrogen: 89%

Helium: 11%

Planetary Atmosphere: Venus

CO2: 96%

N2: 4%

Planetary Atmosphere: Earth

N2: 78%

C2: 21%

Ar: 0.9%

Planetary Atmosphere: Mars

CO2: 95%

N2: 3%

Planetary Atmosphere: Jupiter

Hydrogen: 90%

Helium: 10%

Planetary Atmosphere: Saturn

Hydrogen: 96%

Helium: 4%

Planetary Atmosphere: Uranus

Hydrogen: 85%

Helium:15%

Planetary Atmosphere: Neptune

Hydrogen: 85%

Helium:15%

Big Bang

Occurred approximately 13.9 billion years ago.

Sun Formation

Occurred approximately 5 billion years ago.

Earth Formation

Occurred approximately 4.6 billion years ago.

Oldest Fossil and Start of Photosynthesis

Occurred approximately 3.7 billion years ago

Vertebrates in Fossil Record

Occurred approximately 500 million years ago

Ozone Formation

Occurred approximately 400 million years ago, making life on land possible

Mammals and Reptiles

Occurred appear approximately 350 million years ago

Dinosaur Extinction (except birds)

Occurred approximately 65 million years ago

Early Homo Ancestors

Occurred approximately 2.5 million years ago

Homo Sapiens

Occurred appear approximately 50,000 years ago

Recorded History

Occurred approximately 10,000 years ago

High Technology

High technology advancements, such as the transition from horse and buggy to space shuttles, occur approximately 100 years ago

Large-Scale Environmental Issues

Occurred approximately 40 years ago