Dimensional AnalysisDimensional Analysis

It is 93,000,000 miles to the sun. If a It is 93,000,000 miles to the sun. If a spaceship can travel 18,000 m/s how long spaceship can travel 18,000 m/s how long would it take to get there?would it take to get there?

Welcome to EarthWelcome to EarthThird Rock from the SunThird Rock from the Sun

What do we know What do we know

about our planet?about our planet?

Some Facts about Some Facts about EarthEarth

Earth is covered with 71% Earth is covered with 71% oceansoceans

Densest Rocky planet in Densest Rocky planet in our solar systemour solar system

Our Atmosphere is 77% Our Atmosphere is 77% Nitrogen and 21% Nitrogen and 21% Oxygen. Oxygen.

Earth’s Composition Earth’s Composition (what is it made of)(what is it made of)

34.6% Iron mostly in core34.6% Iron mostly in core 29.5% Oxygen 29.5% Oxygen 15.2% Silicon in most surface rocks, QUARTZ15.2% Silicon in most surface rocks, QUARTZ 12.7% Magnesium 12.7% Magnesium 2.4% Nickel 2.4% Nickel 1.9% Sulfur 1.9% Sulfur 0.05% Titanium 0.05% Titanium Other elements…Other elements…

The parts of Earth’s The parts of Earth’s interior are interior are

Inner CoreInner Core Outer CoreOuter Core Mantle Mantle Outer Mantle or AthenosphereOuter Mantle or Athenosphere Lithosphere Lithosphere Crust (includes oceanic and Continental Crust (includes oceanic and Continental

Crust)Crust)

The Theory of Plate The Theory of Plate TectonicsTectonics

The surface of the earthThe surface of the earth is is brokenbroken

The pieces are large The pieces are large (continent size and larger)(continent size and larger)

The plates move on a plastic layer of rock in The plates move on a plastic layer of rock in the upper mantlethe upper mantle

Movement is very slow, but can be Movement is very slow, but can be measured measured

Types of Plate movementTypes of Plate movement

Converging Converging (compression)(compression)

Diverging Diverging (extension)(extension)

Transform FaultsTransform Faults

Converging PlatesConverging Plates

Two plates move together Two plates move together and collide and collide

One plate moves under One plate moves under the the other plateother plate

Oceanic crust sinks under the continental crust Oceanic crust sinks under the continental crust in the in the subduction zonesubduction zone

The oceanic crust melts back into magmaThe oceanic crust melts back into magma Volcanoes are often found above subduction Volcanoes are often found above subduction

zoneszones

Convergent Plate Convergent Plate BoundariesBoundaries

Are Plate boundaries Are Plate boundaries Dangerous?Dangerous?

Mountains, earthquakes, and volcanoes form where plates Mountains, earthquakes, and volcanoes form where plates collide. Millions of people live in and visit the beautiful collide. Millions of people live in and visit the beautiful mountain ranges being built by plate collisions. For mountain ranges being built by plate collisions. For example, the Rockies in North America, the Alps in Europe, example, the Rockies in North America, the Alps in Europe, and the Himalayas in central Asia were formed by plate and the Himalayas in central Asia were formed by plate collisions. Each year, thousands of people are killed by collisions. Each year, thousands of people are killed by earthquakes and volcanic eruptions in those mountains. earthquakes and volcanic eruptions in those mountains. Occasionally, big eruptions or earthquakes kill large Occasionally, big eruptions or earthquakes kill large numbers of people. In 1883 an eruption of Krakatau numbers of people. In 1883 an eruption of Krakatau volcano in Indonesia killed 37,000 people. In 1983 an volcano in Indonesia killed 37,000 people. In 1983 an eruption-caused mudslide on Nevada del Ruiz in Columbia eruption-caused mudslide on Nevada del Ruiz in Columbia killed 25,000 people. In 1976, an earthquake in Tangshan, killed 25,000 people. In 1976, an earthquake in Tangshan, China killed an astounding 750,000 people. China killed an astounding 750,000 people.

Converging of Two Converging of Two ContinentsContinents

Formation of the Formation of the Himalayas Himalayas

Divergent Plate Divergent Plate BoundariesBoundaries

Two plates move apart and create a gapTwo plates move apart and create a gap The center of the gap is called a The center of the gap is called a Rift ValleyRift Valley Magma fills the edges of the Rift valley and Magma fills the edges of the Rift valley and

forms new lithosphere, forms new lithosphere, Mountains can form next to the Rift ValleyMountains can form next to the Rift Valley These largest of these Divergent Plate These largest of these Divergent Plate

Boundaries is the Boundaries is the Mid-Atlantic RidgeMid-Atlantic Ridge

See the formation of See the formation of mountains and valleysmountains and valleys

Transform Fault Transform Fault BoundariesBoundaries

Two plates move horizontally Two plates move horizontally past each otherpast each other

The most famous in the The most famous in the United United States is the San Andreas FaultStates is the San Andreas Fault

Since the plates move horizontally, Los Since the plates move horizontally, Los Angeles is in no danger of “falling into the Angeles is in no danger of “falling into the ocean”ocean”

The San Andreas FaultThe San Andreas Fault

Los Angeles is Los Angeles is moving north 6 moving north 6 cm per yearcm per year

In 10 million In 10 million years Los years Los Angeles will be Angeles will be next to San next to San Francisco!Francisco!

Location of plates and directions of movements on those plates in western United States

Evidence for Plate Evidence for Plate TectonicsTectonics

The most convincing The most convincing evidence is standing on a evidence is standing on a fault line and seeing fences, fault line and seeing fences, buildings, and other man-buildings, and other man-made objects breaking apart made objects breaking apart from the movement. In San from the movement. In San Francisco you can still see Francisco you can still see evidence of the 1906 evidence of the 1906 earthquakeearthquake

Evidence of Plate Evidence of Plate TectonicsTectonics

In the 1960s, evidence was In the 1960s, evidence was discovered on discovered on the rock on the the rock on the ocean floor ocean floor surrounding the surrounding the Mid-Atlantic Ridge: Mid-Atlantic Ridge: Alternating Bands Alternating Bands of rock showed of rock showed changes in magnetic orientationchanges in magnetic orientation

When magma cools, it’s iron minerals align with the When magma cools, it’s iron minerals align with the Earth’s magnetic fieldEarth’s magnetic field

Earth’s magnetic field has reversed direction many Earth’s magnetic field has reversed direction many times, about once every 200,000 years.times, about once every 200,000 years.

The youngest rock was found near the center of the The youngest rock was found near the center of the ridge, older rock farther awayridge, older rock farther away

Modern EvidenceModern Evidence GPS systems can now GPS systems can now

accurately measure small accurately measure small movements on the earth’s movements on the earth’s surface. surface.

Large scale experiments have measured Large scale experiments have measured continents moving togethercontinents moving together

Small scale experiments have measured Small scale experiments have measured movement on individual faults like the San movement on individual faults like the San Andreas Fault in California. They can Andreas Fault in California. They can measure 0.1mm movements.measure 0.1mm movements.

50 million years from 50 million years from now…now…

If we continue present-day If we continue present-day plate motions the Atlantic will plate motions the Atlantic will widen, widen, Africa will collide with Africa will collide with Europe closing Europe closing the Mediterranean, Australia will collide the Mediterranean, Australia will collide with S.E. Asia, and Southern California will with S.E. Asia, and Southern California will slide northward up the coast to Alaska.slide northward up the coast to Alaska.

This is the way the World This is the way the World may look like 50 million may look like 50 million

years from now!years from now!