Energy Drives earthquakes and volcanic eruptions Drives earthquakes and volcanic eruptions Concentrated at certain tectonic settings Concentrated at certain tectonic settings Associated with the Earth’s formation Associated with the Earth’s formation

Driving Forces on and within the Earth?

Heat formation: Heat formation: –Impact of asteroids and comets in Earth’s early history –Decay of radioactive elements –Gravitational contraction –Differentiation into layers Driving Forces within the Earth Artist Impression, NASA

Earth’s internal heat Earth’s internal heat –Flows within the mantle (largest volume of Earth) –Release in terms of volcanic activity and earthquakes –Long-term: continents, oceans and atmosphere –Movement of tectonic plates Driving Forces on and within the Earth? Greg Houseman, University of Leeds

Gravity: the attraction between bodies Gravity: the attraction between bodies –Segregating elements within the Earth –Movement along the Earth’s surface  landslides –Movement within the Earth  Subducting oceanic slab moving into the mantle Driving Forces on the Earth Landslide, China

The Sun The Sun –¼ of the Sun’s energy reaches the Earth –Evaporation –Warming of atmosphere and hydrosphere –Weather: movement of air from warm to cooler areas Driving Forces on the Earth

Formation of Solar System What happened in the past and how is this currently reflected? What happened in the past and how is this currently reflected? –Gravitional force –Variations of temperatures –Rotation –Composition of material –Different states of matter

A nebula is formed from a collection of gases (98%) and dust (2%) A nebula is formed from a collection of gases (98%) and dust (2%) The mass rotates and is held together by gravity. The mass rotates and is held together by gravity. The Nebular Hypothesis The solar system formation

Where do we see this in our sky? Third star down on Orion’s belt Third star down on Orion’s belt Star nursery Star nursery 100 light years across (1 light year equals 6 trillion miles) 100 light years across (1 light year equals 6 trillion miles) Reflection of dust and hydrogen Reflection of dust and hydrogen

Orion Constellation Winter sky constellation Winter sky constellation Hunter in Greek mythology Hunter in Greek mythology New stars in several hundred million years New stars in several hundred million years

Nebula: Step I Nebula exists and through time: Nebula exists and through time: –Contracts causing the nebula to increase temperature in center and increase speed of rotation

The Nebula collapses: step 2 The collapsed mass forms a proto-sun and disc-shape rotating mass of gas and dust. The collapsed mass forms a proto-sun and disc-shape rotating mass of gas and dust. The Orion nebula contains about 153 visible protoplanetary disks The Orion nebula contains about 153 visible protoplanetary disks 2-17 times larger than our solar system 2-17 times larger than our solar system

Rotation increases Rotation increases Temperature increases: 1,800,000 degrees Fahrenheit Temperature increases: 1,800,000 degrees Fahrenheit Fusion begins Fusion begins Protosun

Fusion What does “to fuse” mean? What does “to fuse” mean? Remember, what is the composition of the nebula? Remember, what is the composition of the nebula? Look on the periodic table Look on the periodic table What is the relation or difference between Hydrogen and Helium? What is the relation or difference between Hydrogen and Helium? Can you predict what fuses? Can you predict what fuses?

Fusion Hydrogen (1 proton) fuses with another Hydrogen (1 proton) = Helium (2 protons) Hydrogen (1 proton) fuses with another Hydrogen (1 proton) = Helium (2 protons) E = mc 2 E = mc 2 E = energy E = energy m= mass (very small) m= mass (very small) c squared =speed of light (186,000 miles/second) c squared =speed of light (186,000 miles/second)

Step 3: Sun Forms Step 3: Sun Forms The disk is “cleared out” due to the immense amount of energy released. The disk is “cleared out” due to the immense amount of energy released. Dust and gases cool, condense and accrete forming planetesimals. Dust and gases cool, condense and accrete forming planetesimals. Defined orbits around the sun Defined orbits around the sun

Earth’s internal heat from formation formation

Our Sun Sun Collapsed disk not shown Collapsed disk not shown Sun is about 5 billion years old Sun is about 5 billion years old 5 billion years until a red giant is formed 5 billion years until a red giant is formed

Temperature differences with respect from the sun Temperature differences with respect from the sun Terrestrial planets (closer) Terrestrial planets (closer) Jovian or gaseous planets (farther away) Jovian or gaseous planets (farther away) Step 4: Material Cools and Condenses; planet formation

Solar System The first four planets are terrestrial (iron and silicate) The first four planets are terrestrial (iron and silicate) The last planets are composed of gases The last planets are composed of gases

Moon’s Formation Formation A large size planet, thought to be the size of Mars, collided with Earth- 4.4 billion years ago A large size planet, thought to be the size of Mars, collided with Earth- 4.4 billion years ago The debris formed the moon The debris formed the moon The impact, set the Earth on its axis The impact, set the Earth on its axis 23 degrees 23 degrees 5:20

The Earth tilted on its axis in response to the collision

The Early Earth Hot Hot Homogenous Homogenous Crust as we know it, not developed Crust as we know it, not developed 4.6 billion years ago 4.6 billion years ago Melted again due to the collision of the Mars size planet Melted again due to the collision of the Mars size planet

Transitional Earth Segregation of elements by density Segregation of elements by density Iron moves to the center Iron moves to the center Gravitational pull and rotation Gravitational pull and rotation

Chemically distinct layers Crust: oxygen and silicon (70%) Crust: oxygen and silicon (70%) Mantle: iron, magnesium, lower % Si, O Mantle: iron, magnesium, lower % Si, O Core: iron and nickel Core: iron and nickel

Physically Distinct Layers Inner core: solid Inner core: solid Outer core: liquid Outer core: liquid Mantle: capable of flow Mantle: capable of flow Asthenosphere: acts like a hot plastic Asthenosphere: acts like a hot plastic Lithosphere: rigid Lithosphere: rigid

Lithosphere Rigid layer that lies between the surface and miles Rigid layer that lies between the surface and miles “Floats” on the asthenosphere “Floats” on the asthenosphere The tectonic plates are composed of lithosphere The tectonic plates are composed of lithosphere Contains crust and upper mantle Lithosphere

Continental Crust Less dense Less dense Higher % of silicon and oxygen Higher % of silicon and oxygen Lower % of iron and magnesium Lower % of iron and magnesium Thicker (15-25 miles) Thicker (15-25 miles) 30 % of Earth’s surface 30 % of Earth’s surface

Oceanic Crust Crust More dense More dense Higher % of iron and magnesium Higher % of iron and magnesium Lower % of silicon and oxygen Lower % of silicon and oxygen Thinner (5-7 miles) Thinner (5-7 miles) 70 % of Earth’s surface 70 % of Earth’s surface

Asthenosphere Relatively soft layer capable of flow that lies below a depth of miles (upper mantle) Relatively soft layer capable of flow that lies below a depth of miles (upper mantle) Dr. Railsback, University of Georgia

The Mantle Largest portion of the Earth Largest portion of the Earth Very rich in iron and magnesium Very rich in iron and magnesium Very poor in silicon and oxygen Very poor in silicon and oxygen The mantle is solid but because of high temperatures and pressures, it is soft enough to flow The mantle is solid but because of high temperatures and pressures, it is soft enough to flow The asthenosphere is part of the upper mantle The asthenosphere is part of the upper mantle

The Core Outer core-liquid which can flow and generates the Earth’s magnetic field Outer core-liquid which can flow and generates the Earth’s magnetic field Inner core- solid and rotates faster than the Earth Inner core- solid and rotates faster than the Earth Mostly iron, some nickel Mostly iron, some nickel Complex fields in the core contribute to the dipole field at the surface (UC Berkeley)

The magnetic field protects the Earth from solar radiation

External Source of Earth’s Water The collision of comets with the Earth’s surface The collision of comets with the Earth’s surface As the ice hits the warm Earth, the ice melts to water As the ice hits the warm Earth, the ice melts to water Gravity holds the water to the surface Gravity holds the water to the surface Haley’s comet contains ices and dust. The tail is created by ice to sublimate to steam.

Water vapor is released during volcanism Water vapor is released during volcanism Cooling of the hot Earth involved intense volcanism Cooling of the hot Earth involved intense volcanism Water condenses Water condenses Internal Source of Earth’s Water

Formation of Atmosphere Gas is expelled from magma during volcanic eruptions Gas is expelled from magma during volcanic eruptions Nitrogen, carbon dioxide, hydrogen, sulfur dioxide and water Nitrogen, carbon dioxide, hydrogen, sulfur dioxide and water Early Earth’s atmosphere did not contain which gas? Why? Early Earth’s atmosphere did not contain which gas? Why?

History of the Earth 4.6 billion years old 4.6 billion years old 4.4 bya, formation of moon 4.4 bya, formation of moon 3.9 bya, oldest rock (sedimentary rock) 3.9 bya, oldest rock (sedimentary rock) –sedimentary rocks are made-up of fragments of preexisting rocks –Sediments are carried and deposited by water and wind –implies the existence of weather and water 4.1 bya, age of particles within the sedimentary rock 4.1 bya, age of particles within the sedimentary rock Early Earth

3.5 bya, first bacteria 3.5 bya, first bacteria 3.2 bya, algae (product?) 3.2 bya, algae (product?) plants plants –photosynthesis, by-product is oxygen worms and jelly fish worms and jelly fish 500 million years ago, Cambrian (life) explosion: marine fauna; modern phyla: sponges, mollusks (clams and snails), echinoderms (sea urchins and stars), anthropoda -trilobites(crabs, lobsters) 500 million years ago, Cambrian (life) explosion: marine fauna; modern phyla: sponges, mollusks (clams and snails), echinoderms (sea urchins and stars), anthropoda -trilobites(crabs, lobsters) History of the Earth Fossil Worm, Cambrian Sponge Trilobite

Earth as an evolving system Creation and early Earth Creation and early Earth Earth’s chemically and physically distinct layers Earth’s chemically and physically distinct layers Atmosphere (air) Atmosphere (air) Hydrosphere (water) Hydrosphere (water) Biosphere (plants and animals) Biosphere (plants and animals)

Summary The Nebular Hypothesis The Nebular Hypothesis Earth’s heat sources Earth’s heat sources –Radioactive decay –Initial heat produced by collision of other objects Moon, water and gas formation Moon, water and gas formation Earth’s layers, differences and locations Earth’s layers, differences and locations Importance of gravitational pull Importance of gravitational pull Think Quest