the earth and other planets. our solar system –sun / terrestrial planets / jovian planets...

The Earth and Other Planets


• Our Solar System

– Sun / Terrestrial Planets / Jovian Planets

– TERRESTRIAL PLANETS• Mercury• Venus• Earth• Mars

• The terrestrial planets all tend to be fairly small, have few moons, and are solid and rocky.


• JOVIAN PLANETS– Jupiter– Saturn – Uranus– Neptune

The jovian planets all tend to be quite large, have several moons, are primarily made of layers of gases which become denser further down, and may have a small solid core.


• NEBULAR THEORY

Theory re formation of solar system: As dust and gas clouds collected due to gravitational forces, they

began to rotate and flatten into a disk. The majority of mass collected in the center, and the planets began as mass concentrations orbiting the dense central body.

Where did the dust and gas clouds come from?Many believe the dust and gas originated in the events that occurred when the universe first formed.

How old is our solar system?Approximately 4.5 billion years old.


• DEBRIS THAT DID NOT BECOME PLANETS – Asteroids

• Small• Rocky• In a “belt” between Mars and Jupiter

– Comets• Ice and dirt• Circle the sun outside of Pluto• Halley’s comet is best known

– Meteors• Small pieces of debris• Orbit the sun• Burn if fall into earth’s atmosphere

– Meteorite• A piece of rock big enough to reach earth’s surface

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• THE EARTH’S MOTION– Revolves around sun

– Travels in an elliptical orbit – Takes approximately 365 days to complete 1 orbit

– Rotates on axis– Angle of rotation tilts 23°– Takes approximately 24 hours to complete 1 spin

– Precesses– Spinning on axis in a circular pattern– Completes circular pattern once every 23,000 years

• THE EARTH’S MOON– Orbits earth

– Has synchronized rotation and revolution with earth– Takes approximately 1 month to complete 1 orbit– Phase of moon is based on how mush of lighted side we can see

– Has 1/6 of the gravitational pull of the earth– Mutual gravitational influence– Pull on earth’s surface waters creates tides


• THE EARTH’S INTERIOR– CRUST

• Outer layer• 6 to 45 miles thick• Made of lightest materials• Solid• Approximately 70% covered with water

– MANTLE• Below crust• High temperatures• Solid in upper region, thick liquid of melted rock below• Widest layer

– OUTER CORE• Below mantle• Very high temperatures• Liquid• Iron – nickel

– INNER CORE• At the earth’s center• Extremely high temperatures• Solid due to tremendous pressure• Primarily iron, some nickel


• HOW “LIFE” ON EARTH BEGAN– GEOLOGIC TIME FRAME (see Time Scale shown in text, p. 631)

• Covers the 4.5 billion years of Earth’s existence• Life not possible initially due to high temperatures, lack of proper atmosphere,

no available water, continuous bombardment from space• As earth cooled and impacts lessened, land and sea formed• First living organisms appeared in oceans about midway through the earth’s

history• Gradually oxygen began to accumulate in atmosphere• Ozone layer began to form• Life forms appeared on land less than 500 million years ago• Principal vertebrate life froms on earth were reptiles fro 65 million to 250 million

years ago• Mammals began to dominate the earth in the last 65 million years• Human ancestors first appeared less than 2 million years ago

– HUMAN TIME FRAME• Modern human species less than 50,000 years old• Recorded human history available for past 4000 years only• Human influence on the earth’s ecosystems which support life insignificant until

the Industrial Era beginning 250 years ago

the earth and other planets. our solar system –sun / terrestrial planets / jovian planets...

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