How did our Universe first begin?

The Big Bang Theory• According to the Big Bang

theory, the universe expanded from an extremely dense and hot explosion and continues to expand today. A common analogy explains that space itself is expanding, carrying galaxies with it, like raisins in a rising loaf of bread. The graphic scheme to the right is an artist's concept illustrating the expansion of a portion of a flat universe.

Our Solar System…

• Astronomers believe the Solar System is about…. The Earth too is 4.6 billion years old!– How do we know it’s that old?

• Through the study of meteorites and• “radioactive dating” of these objects

4.6 billion years old!

Solar System Formation So…how did the Solar System form and

end up with all these different types of objects?

Currently the best theory is the…

Solar Nebular Theory

The Solar Nebular Theory:

The Solar Nebula Theory states:– Explains how the Solar System first

developed out of an interstellar clouds of dust and gas

• Cloud of dust and gas also called a Nebula• A nebula is where stars are formed

– This theory best accounts for the objects we currently find in the Solar System and the distribution of these objects

Earth’s Structure• The crust

• The mantle• The outer core• The inner core

How could scientists even know

that?

Wave Motion

Scientists study earthquake waves as they move through the Earth. This has enabled them to make detailed maps of the Earth’s interior.– When S-waves are produced on one side

of Earth due to an earthquake, there is a large area on the other side where the waves can’t be detected.

– Scientists know that secondary waves do not pass through liquids.

Earth’s StructureThe crust (Types = oceanic and continental)

the “shell” of the Earth 5 to 25 miles thick

the coolest layer (about 1,600 oF)

* Continental is thicker but less dense than Oceanic crust is thinner but denser.

Earth’s CrustOxygen 46.1 %Silicon 28.2 %Aluminum 8.23 %Iron 5.63 %Calcium 4.15 %

Earth’s StructureThe mantle takes up 80% of the

volume of the earth1,800 miles thick

warmer than the crust about 8,000 oFTop layer of the mantle is the LithosphereBottom layer of the mantle is the Asthenosphere litho - rock, stone

astheno - weak (soft)

The Center of the Earth

• The Outer Core• very hot (about 11,000 oF)• 1,400 miles thick• made of liquid metal• Magma is found here!

• The Inner Core• 800 miles thick • hottest layer (about 13,000 oF)• made of solid metal (iron and nickel)• Lots of pressure here!

Earth’s Temperature vs. The Sun’s Temperature

• Scientists believe that the Earth’s surface heats up to about 1,600 0F where as the Earth’s Core is about 13,000 0F.

• Scientists believe that the Sun’s surface is only 10,000 0F where as the core is believed to be around 1,000,000 0F.

• The Earth’s core is additionally heated by the breaking down of isotopes into radioactive material which helps to keep the Core very hot.

• This is called radioactive decay!

What are three reasons why you could never dig your way to the center of the Earth like in movies?

• It’s way too hot!• Way too much pressure down there.• Too much radiation down there!

Earth’s Density

• Scientists believe that Earth was formed from the gas and dust that surrounded our young sun.

• At first, Earth’s surface was made of the same materials as its center. Later, the materials melted and became fluid.

• More dense materials settle toward the center of the Earth (inner core and outer core).

• Less dense materials rose toward the surface (continental crust and Lithosphere).

Alfred Wegener

• Alfred Wegener was a German climatologist and arctic explorer.

• He suggested the concept of the…

Continental Drift Theory

Continental Drift Theory

A theory that explained how the continents floated and moved along.

Are the continents still moving or sitting still?

The continents are still moving!Even though it was a great theory, Wegner had a difficult time convincing others of his theory.

Movement of Continents

• Wegener believed that the continents we know today had once been part of an earlier supercontinent.

• He called this great landmass Pangaea.

• (means single landmass)

Evidence that supports the Continental Drift Theory

1. The continents look like they “fit” together like puzzle pieces.

(Pangaea the “Super Continent)2. Similar fossils of plants and

animals have been found on continents that are oceans apart.

3. The same types of rocks and minerals have been found on continents that are oceans apart.

4.* Magnetic orientation of rocks on the ocean floor.

Evidence that supports the Continental Drift Theory

5. Matching coal deposits found on continents that are oceans apart.

6. Matching mountain ranges found on continents that are oceans apart.

7. Similar Glacier deposits on different continents that are oceans apart.

Plate Tectonic TheoryMany scientists did not believe Wegners theory

of Continental Drift.• Wegner had a lot evidence but had a difficult

time explaining how the plates move.• Plate-Tectonics Theory…A theory that explains how large plates, moving underneath the continents, cover the Earth and fit together like a puzzle.

North American

Plate

South American

Plate

Eurasian PlateEurasian

Plate

African Plate

*Pacific Plate*

Antarctic Plate

Australian Plate

NazcaPlate

Scotia

Indian

ArabianPhilippine

Juan de Fuca

Cocos Caribbean

Aust.

Let’s Review!!! What are the 4 layers of the Earth? A: crust, mantle, outer and inner core What layer of the Earth is the hottest and most

dense? A: the inner core Which crust is thinner but very dense? A: oceanic crust What theory supports the movement of the

continents? A: continental drift theory What is the theory that is widely used today?

A: Plate Tectonics

Why are the tectonic plates moving?

Okay… we know that the plates are moving, but what is making them move?

Convection Currents and gravity are making the plates move!

This is what Alfred Wegner couldn‘t explain or prove to other scientists.

Convection Currents

Hot magma cools and

sinks

Magma riseswhen heated

Cooler magma

isheated

Think of Lava lamps Earth is

very good at

recycling itself!

Plate BoundariesWhat is a plate boundary?A: Where two plates come in contact with each other.

(Like two puzzle pieces)

There are three major types of plate boundaries.

Divergent, Transform Fault, Convergent

The type of boundary depends on how the plates are moving with each other…

Plate Boundaries:

1. Divergent Boundaries:

These plates aremoving away from eachother or dividing.

•

Example:Sea FloorSpreading

At Divergent Boundaries, these Geological Formations occur–

Sea floor spreading, Mid-oceanic ridges, Islands and Volcanoes form

Old Sea floor

New

Sea

floor

Old Sea floor

Rift valley

Divergent Boundaries

Magma Chamber

Sea floor movingSea floor moving

Plate Boundaries:

2. Transform FaultThese plates are sliding along side

each other.

Pacific Plate

NA Plate

Transform Fault2. Transform FaultThese plates are sliding past each

other.

Example: San Andres Fault

San Andreas Fault

• Extends almost the entire length of the state of California.

• What two plates are sliding past each other here?

• Pacific and NA plate.

At Transform Faults, these Geological Formations occur– Small earthquakes, tremors, and fault

lines.

Convergent Boundaries

3. ConvergentThese plates are moving into each

other.

Types of Convergent Boundaries:

Different things can happen at Convergentboundaries because of the crust.Remember there is continental crust

(crustthat is mostly above water: land)

AndThere is oceanic crust...that is under the

water.Scientists know that the continental crust is less dense and thicker than the oceanic crust… so what happens when the two different crusts collide at a convergent boundary???

Convergent Boundaries

with SubductionA: Since the Oceanic crust is more dense it dives beneath the Continental crust = SUBDUCTION ZONE

* Most dangerous boundary *

Convergent Boundarieswith Subduction

Geological Formations that occur here are– Volcanoes, Small Mountains (Andes), and Deep Oceanic Trenches ex. (Marianas Trench)

Convergent Boundaries

With NO subductionContinent to Continent collisionThe crust buckles UP and forms large mountains.Geological Formations= large mountains form ex.

Himalayas Mts.

When the Indian Plate crashed

into the Eurasian Plate, it created

the…

Himalaya Mountains

Himalayas

Rocky Mts.

Appalachian Mts.

Andes Mts.

Alps

Himalaya’s

Let’s Find Some plate boundaries

D

Transform Fault

Mid-Atlantic Ridge

Divergent

Convergent w/o

Subduction

Convergent with

subduction

Divergent

Himalaya's

Andes

App. Mts.Rockies

Alps

Question?• We now know that new rock is

created at divergent boundaries because of seafloor spreading.

• Explain why the Earth’s mass is NOT increasing as a result.

• Use the Law of Conservation of Mass in your answer.

• Answer: The Earth is very good at recycling itself and it’s crust b/c mass cannot be create or destroyed!

• Divergent Mid-Oceanic Ridge occurs at the Mid-Atlantic Ridge between the NORTH AMERICAN, AFRICAN, EURASIAN and SOUTH AMERICAN PLATE.

(Sea floor spreading, Mid-oceanic ridges, Islands and Volcanoes form here.)

• Transform Fault occurs at the San Andreas Fault (in California!!!) between the NORTH AMERICAN and PACIFIC PLATE.

(Small earthquakes, tremors, and fault lines occur here.)

• Convergent with Subduction occurs at the Peru-Chile Trench and Andes Mts. between the NAZCA and SOUTH AMERICAN PLATE (forms the Andes Mts.) (*most dangerous*)

(small Mts.(Andes) and deep ocean trenches form)

• Convergent (NO subduction)

occurs at the Himalaya Mts. between the INDIAN and EURASIAN PLATE.

(large Mts. (Himalaya’s) form here)

The RING OF FIRE occurs around the edge of the entire PACIFIC PLATE. The largest earthquakes, most dangerous volcanoes and tsunami’s occur here often.

Earthquakes and plate boundaries

• Earthquakes commonly occur at plate boundaries.

Earthquakes• The second longest ever

recorded earthquake occurred in 1964 in Alaska and lasted for four minutes.

• The longest recorded earthquake was in Sumatra on December 26 2004.

• It had a magnitude of Size: 9.1 - 9.3 and lasted about 10 minutes! The energy released equaled the power of a 100 gigaton bomb!!!!

Seismographs• Seismologist

study earthquakes.

• Seismographs are instruments that record earthquakes.

• Richter Scales are used to measure the magnitude or strength of the earthquake.

Tsunami Waves• Tsunami means “Harbor Wave”• A Tsunami is a series of ocean waves

caused by an erupting volcano, earthquake or landslide.

• A tsunami is not a single wave but a series of waves, also known as a wave train.

• The first wave in a tsunami is not necessarily the most destructive.

• Tsunamis are not tidal waves. They actually have nothing to do with tides.

Tsunami WavesWhat do you think can causes a Tsunami to happen?

• Underwater earthquakes• Underwater volcanoes erupting• Underwater landslides

Tsunami Waves• Tsunami waves can be very long (as

much as 60 miles) and be as far as one hour apart.

• They are able to cross entire oceans without great loss of energy (500-600mph).

The Indian Ocean Tsunami

• The Indian Ocean tsunami traveled as much as 3,000 miles (nearly 5,000 kilometers) to Africa, arriving with sufficient force to kill over 250,000 people and destroy property.

The Indian Ocean Tsunami

Tsunami Disaster

Earth Exam Focus• Know the structure of the Earth.• Know the supporting evidence of plate

tectonics.• Know where the major tectonic plates are.• Know the best possible explanation for the

movement of the plates.• Know what Pangaea is. • Know the different plate boundaries and

what happens at each plate boundary.• Know Earthquakes and why they happen.• Know what seismometers are.• Know what the Ring of Fire is.