Op ch01 lecture_earth3

Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 1: Cosmology and the Birth of Earth

Chapter 1Cosmology and the Birth of Earth

©2008 W. W. Norton & Company, Inc.

Portrait of a PlanetThird Edition

earthearth

LECTURE OUTLINE

Cosmology and the Birth of Earth

Cosmology and the Birth of Earth

Prepared by

Ron Parker, Earlham College, Department of Geosciences

Richmond, Indiana

Prepared by

Ron Parker, Earlham College, Department of Geosciences

Richmond, Indiana


Our Island in SpaceOur Island in SpaceOur Island in SpaceOur Island in Space We pass our lives on our one planet Earth. We pass our lives on our one planet Earth. Earth may seem endless; it isn’t.Earth may seem endless; it isn’t. Viewed from space, Earth is a small, shiny globe. Viewed from space, Earth is a small, shiny globe. It is truly our island oasis in space.It is truly our island oasis in space.

We pass our lives on our one planet Earth. We pass our lives on our one planet Earth. Earth may seem endless; it isn’t.Earth may seem endless; it isn’t. Viewed from space, Earth is a small, shiny globe. Viewed from space, Earth is a small, shiny globe. It is truly our island oasis in space.It is truly our island oasis in space.


Our Island in SpaceOur Island in SpaceOur Island in SpaceOur Island in Space The Earth is a very special and unique planet. The Earth is a very special and unique planet.

Its temperature, composition and atmosphere favor life.Its temperature, composition and atmosphere favor life.

It is dynamic and ever-changing. It is dynamic and ever-changing. It has a long and complex history.It has a long and complex history.

The Earth is a very special and unique planet. The Earth is a very special and unique planet. Its temperature, composition and atmosphere favor life.Its temperature, composition and atmosphere favor life.

It is dynamic and ever-changing. It is dynamic and ever-changing. It has a long and complex history.It has a long and complex history.


CosmologyCosmologyCosmologyCosmology Conscious thought distinguishes humans.Conscious thought distinguishes humans.

Developed across thousands of generations. Developed across thousands of generations.

Earth Flat Disk>>Geocentric Model>>Heliocentric ModelEarth Flat Disk>>Geocentric Model>>Heliocentric Model Lends us curiosity, insight, and the ability to learn. Lends us curiosity, insight, and the ability to learn.

As a result, we seek to explain our surroundings. As a result, we seek to explain our surroundings. Where do we come from?Where do we come from? Where do we fit in the Universe?Where do we fit in the Universe? Why are we here?Why are we here?

Conscious thought distinguishes humans.Conscious thought distinguishes humans. Developed across thousands of generations. Developed across thousands of generations.

Earth Flat Disk>>Geocentric Model>>Heliocentric ModelEarth Flat Disk>>Geocentric Model>>Heliocentric Model Lends us curiosity, insight, and the ability to learn. Lends us curiosity, insight, and the ability to learn.

As a result, we seek to explain our surroundings. As a result, we seek to explain our surroundings. Where do we come from?Where do we come from? Where do we fit in the Universe?Where do we fit in the Universe? Why are we here?Why are we here?


CosmologyCosmologyCosmologyCosmology Study of the structure and evolution of the Universe. Study of the structure and evolution of the Universe.

Cosmology is a complicated science. Cosmology is a complicated science.

Requires thinking in unfamiliar scales of space and time. Requires thinking in unfamiliar scales of space and time. Spatial scales. Spatial scales.

Attometers (10Attometers (10-18-18 meters), to meters), to 10s of billions of light years (9.4610s of billions of light years (9.462222 meters +). meters +).

Temporal scales.Temporal scales. Attoseconds (10Attoseconds (10-18-18 seconds), to seconds), to 10s of billions of years (3.1510s of billions of years (3.151717 seconds +). seconds +).

Study of the structure and evolution of the Universe. Study of the structure and evolution of the Universe.

Cosmology is a complicated science. Cosmology is a complicated science. Requires thinking in unfamiliar scales of space and time. Requires thinking in unfamiliar scales of space and time.

Spatial scales. Spatial scales. Attometers (10Attometers (10-18-18 meters), to meters), to 10s of billions of light years (9.4610s of billions of light years (9.462222 meters +). meters +).

Temporal scales.Temporal scales. Attoseconds (10Attoseconds (10-18-18 seconds), to seconds), to 10s of billions of years (3.1510s of billions of years (3.151717 seconds +). seconds +).


CosmologyCosmologyCosmologyCosmology Ideas about the Universe have a rich history. Ideas about the Universe have a rich history.

These ideas are often culturally determined.These ideas are often culturally determined.

The Greeks believed that the mediterranean was at the center The Greeks believed that the mediterranean was at the center of the universeof the universe

Commonly include supernatural forces. Commonly include supernatural forces.

The Greeks believed that earth was a flat disk, below it was The Greeks believed that earth was a flat disk, below it was the underworld governed by the fearsome god Hadesthe underworld governed by the fearsome god Hades

The Western tradition applies scientific discovery.The Western tradition applies scientific discovery.

Ideas about the Universe have a rich history. Ideas about the Universe have a rich history. These ideas are often culturally determined.These ideas are often culturally determined.

The Greeks believed that the mediterranean was at the center The Greeks believed that the mediterranean was at the center of the universeof the universe

Commonly include supernatural forces. Commonly include supernatural forces.

The Greeks believed that earth was a flat disk, below it was The Greeks believed that earth was a flat disk, below it was the underworld governed by the fearsome god Hadesthe underworld governed by the fearsome god Hades

The Western tradition applies scientific discovery.The Western tradition applies scientific discovery.


ScienceScienceScienceScience The systematic analysis of natural phenomenon.The systematic analysis of natural phenomenon. Has evolved as the most significant human Has evolved as the most significant human

development for understanding the natural world. development for understanding the natural world. Rationally explains cosmological evolution.Rationally explains cosmological evolution. Scientific understanding can evolve and change. Scientific understanding can evolve and change.

The systematic analysis of natural phenomenon.The systematic analysis of natural phenomenon. Has evolved as the most significant human Has evolved as the most significant human

development for understanding the natural world. development for understanding the natural world. Rationally explains cosmological evolution.Rationally explains cosmological evolution. Scientific understanding can evolve and change. Scientific understanding can evolve and change.


Earth’s Changing PlaceEarth’s Changing PlaceEarth’s Changing PlaceEarth’s Changing Place 3,000 years ago, humans knew the heavens well. 3,000 years ago, humans knew the heavens well.

They knew that stars were fixed relative to other stars.They knew that stars were fixed relative to other stars. They knew that stars moved predictably across the sky.They knew that stars moved predictably across the sky. They saw retrograde motion separating planets from stars.They saw retrograde motion separating planets from stars. They did not think of Earth as a planet, however.They did not think of Earth as a planet, however.

Movement in the heavens was attributed to deities.Movement in the heavens was attributed to deities.

3,000 years ago, humans knew the heavens well. 3,000 years ago, humans knew the heavens well. They knew that stars were fixed relative to other stars.They knew that stars were fixed relative to other stars. They knew that stars moved predictably across the sky.They knew that stars moved predictably across the sky. They saw retrograde motion separating planets from stars.They saw retrograde motion separating planets from stars. They did not think of Earth as a planet, however.They did not think of Earth as a planet, however.

Movement in the heavens was attributed to deities.Movement in the heavens was attributed to deities.


An Evolving Image of EarthAn Evolving Image of EarthAn Evolving Image of EarthAn Evolving Image of Earth The ancients thought the Universe was geocentric. The ancients thought the Universe was geocentric.

Heavenly bodies circle around a motionless central Earth. Heavenly bodies circle around a motionless central Earth. Proven by Ptolemy (100-170 Proven by Ptolemy (100-170 C.E.C.E.), the idea was still wrong. ), the idea was still wrong. Yet it held as doctrine for 1,400 years during the dark ages.Yet it held as doctrine for 1,400 years during the dark ages. It became religious dogma supporting the importance of It became religious dogma supporting the importance of

Earth in the scheme of heaven. Earth in the scheme of heaven.

The ancients thought the Universe was geocentric. The ancients thought the Universe was geocentric. Heavenly bodies circle around a motionless central Earth. Heavenly bodies circle around a motionless central Earth. Proven by Ptolemy (100-170 Proven by Ptolemy (100-170 C.E.C.E.), the idea was still wrong. ), the idea was still wrong. Yet it held as doctrine for 1,400 years during the dark ages.Yet it held as doctrine for 1,400 years during the dark ages. It became religious dogma supporting the importance of It became religious dogma supporting the importance of

Earth in the scheme of heaven. Earth in the scheme of heaven.


The RenaissanceThe RenaissanceThe RenaissanceThe Renaissance A rebirth of rational thinking in 15A rebirth of rational thinking in 15thth-century Europe.-century Europe.

Copernicus – Published evidence for heliocentricity.Copernicus – Published evidence for heliocentricity. Kepler – His elliptical planetary orbits refuted Ptolemy.Kepler – His elliptical planetary orbits refuted Ptolemy. Galileo – Observed moons orbiting Jupiter. Galileo – Observed moons orbiting Jupiter.

These ideas were considered to be heresy. These ideas were considered to be heresy. Earth didn’t center the Universe.Earth didn’t center the Universe. Planetary orbits weren’t circular.Planetary orbits weren’t circular. Not all bodies orbited Earth.Not all bodies orbited Earth.

A rebirth of rational thinking in 15A rebirth of rational thinking in 15thth-century Europe.-century Europe. Copernicus – Published evidence for heliocentricity.Copernicus – Published evidence for heliocentricity. Kepler – His elliptical planetary orbits refuted Ptolemy.Kepler – His elliptical planetary orbits refuted Ptolemy. Galileo – Observed moons orbiting Jupiter. Galileo – Observed moons orbiting Jupiter.

These ideas were considered to be heresy. These ideas were considered to be heresy. Earth didn’t center the Universe.Earth didn’t center the Universe. Planetary orbits weren’t circular.Planetary orbits weren’t circular. Not all bodies orbited Earth.Not all bodies orbited Earth.


The EnlightenmentThe EnlightenmentThe EnlightenmentThe Enlightenment Sir Isaac Newton (1642-1727) devised…Sir Isaac Newton (1642-1727) devised…

The Law of Universal Gravitation.The Law of Universal Gravitation. The Three Laws of Motion. The Three Laws of Motion. The mathematics of change (calculus).The mathematics of change (calculus).

He proved that natural law governs natural events.He proved that natural law governs natural events. Geocentricity faded away.Geocentricity faded away.

Sir Isaac Newton (1642-1727) devised…Sir Isaac Newton (1642-1727) devised… The Law of Universal Gravitation.The Law of Universal Gravitation. The Three Laws of Motion. The Three Laws of Motion. The mathematics of change (calculus).The mathematics of change (calculus).

He proved that natural law governs natural events.He proved that natural law governs natural events. Geocentricity faded away.Geocentricity faded away.


Earth as a SphereEarth as a SphereEarth as a SphereEarth as a Sphere A flat Earth was dispelled by ~ 250 A flat Earth was dispelled by ~ 250 B.C.E.B.C.E.

Abundant evidence suggested a spherical Earth.Abundant evidence suggested a spherical Earth. A curved shadow crossed the Moon during eclipses.A curved shadow crossed the Moon during eclipses. Only the tops of distant sailing ships were visible.Only the tops of distant sailing ships were visible.

In 1520, Magellan circumnavigated this sphere.In 1520, Magellan circumnavigated this sphere.

A flat Earth was dispelled by ~ 250 A flat Earth was dispelled by ~ 250 B.C.E.B.C.E.

Abundant evidence suggested a spherical Earth.Abundant evidence suggested a spherical Earth. A curved shadow crossed the Moon during eclipses.A curved shadow crossed the Moon during eclipses. Only the tops of distant sailing ships were visible.Only the tops of distant sailing ships were visible.

In 1520, Magellan circumnavigated this sphere.In 1520, Magellan circumnavigated this sphere.


Earth’s RotationEarth’s RotationEarth’s RotationEarth’s Rotation How do we know that Earth rotates about Polaris?How do we know that Earth rotates about Polaris?

Clearly visible in a time-lapse photograph of the night sky.Clearly visible in a time-lapse photograph of the night sky. Foucault’s pendulum (1851) proved Earth’s rotation.Foucault’s pendulum (1851) proved Earth’s rotation.

How do we know that Earth rotates about Polaris?How do we know that Earth rotates about Polaris? Clearly visible in a time-lapse photograph of the night sky.Clearly visible in a time-lapse photograph of the night sky. Foucault’s pendulum (1851) proved Earth’s rotation.Foucault’s pendulum (1851) proved Earth’s rotation.


Earth’s CircumferenceEarth’s CircumferenceEarth’s CircumferenceEarth’s Circumference Eratosthenes calculated ~25,000 miles in ~ 200 B.C.Eratosthenes calculated ~25,000 miles in ~ 200 B.C. He measured shadows in deep wells 800 km apart. He measured shadows in deep wells 800 km apart.

Measurement taken at noon on the same day. Measurement taken at noon on the same day. Syene – Shadow absent (directly overhead). Syene – Shadow absent (directly overhead). Alexandria – Shadow at 7.2Alexandria – Shadow at 7.2oo..

He calculated that 800 km was He calculated that 800 km was

1/50th of Earth’s circumference.1/50th of Earth’s circumference. He was correct!!He was correct!!

Eratosthenes calculated ~25,000 miles in ~ 200 B.C.Eratosthenes calculated ~25,000 miles in ~ 200 B.C. He measured shadows in deep wells 800 km apart. He measured shadows in deep wells 800 km apart.

Measurement taken at noon on the same day. Measurement taken at noon on the same day. Syene – Shadow absent (directly overhead). Syene – Shadow absent (directly overhead). Alexandria – Shadow at 7.2Alexandria – Shadow at 7.2oo..

He calculated that 800 km was He calculated that 800 km was

1/50th of Earth’s circumference.1/50th of Earth’s circumference. He was correct!!He was correct!!


Distances from Earth Distances from Earth Distances from Earth Distances from Earth The dimensions of the Universe are staggering!The dimensions of the Universe are staggering! We must consider huge expanses of space and We must consider huge expanses of space and

time.time. The speed of light (The speed of light (cc) is 186,000 miles/s (300,000 km/s).) is 186,000 miles/s (300,000 km/s).

The Moon is 1.3 light seconds (~237,000 miles) away.The Moon is 1.3 light seconds (~237,000 miles) away.The Sun is 8.3 light minutes (~93 million miles) away.The Sun is 8.3 light minutes (~93 million miles) away.

A light year measures a distance of 5.87 trillion miles. A light year measures a distance of 5.87 trillion miles. Alpha Centauri, the closest star, is 4.3 light years away. Alpha Centauri, the closest star, is 4.3 light years away. The visible Universe is > 13 billion light years awayThe visible Universe is > 13 billion light years away

The dimensions of the Universe are staggering!The dimensions of the Universe are staggering! We must consider huge expanses of space and We must consider huge expanses of space and

time.time. The speed of light (The speed of light (cc) is 186,000 miles/s (300,000 km/s).) is 186,000 miles/s (300,000 km/s).

The Moon is 1.3 light seconds (~237,000 miles) away.The Moon is 1.3 light seconds (~237,000 miles) away.The Sun is 8.3 light minutes (~93 million miles) away.The Sun is 8.3 light minutes (~93 million miles) away.

A light year measures a distance of 5.87 trillion miles. A light year measures a distance of 5.87 trillion miles. Alpha Centauri, the closest star, is 4.3 light years away. Alpha Centauri, the closest star, is 4.3 light years away. The visible Universe is > 13 billion light years awayThe visible Universe is > 13 billion light years away


Modern View of the UniverseModern View of the UniverseModern View of the UniverseModern View of the Universe Current concepts differ wildly from 100 years ago.Current concepts differ wildly from 100 years ago.

Earth is one of nine planets in the solar system. Earth is one of nine planets in the solar system. The solar system is on an arm of the Milky Way galaxy.The solar system is on an arm of the Milky Way galaxy. Our Sun is one of 300 billion stars in this galaxy.Our Sun is one of 300 billion stars in this galaxy.

Current concepts differ wildly from 100 years ago.Current concepts differ wildly from 100 years ago. Earth is one of nine planets in the solar system. Earth is one of nine planets in the solar system. The solar system is on an arm of the Milky Way galaxy.The solar system is on an arm of the Milky Way galaxy. Our Sun is one of 300 billion stars in this galaxy.Our Sun is one of 300 billion stars in this galaxy.

You are HERE!You are HERE!You are HERE!You are HERE!


Modern View of the UniverseModern View of the UniverseModern View of the UniverseModern View of the Universe Current concepts differ wildly from 100 years ago.

The vastness of the Universe is almost incomprehensible. Andromeda, the next galaxy, is 2,200,000 light years away.

The Universe contains more than a billion galaxies.

Current concepts differ wildly from 100 years ago. The vastness of the Universe is almost incomprehensible. Andromeda, the next galaxy, is 2,200,000 light years away.

The Universe contains more than a billion galaxies.


QuestionsQuestionsQuestionsQuestions Science is the basis for addressing hard questions.Science is the basis for addressing hard questions.

How did the Universe form?How did the Universe form? Do galaxies move with respect to each other?Do galaxies move with respect to each other? Is the Universe expanding? Contracting?Is the Universe expanding? Contracting? How do we know anything about these matters?How do we know anything about these matters?

The Doppler Effect permits us to detect star motion. The Doppler Effect permits us to detect star motion.

Science is the basis for addressing hard questions.Science is the basis for addressing hard questions. How did the Universe form?How did the Universe form? Do galaxies move with respect to each other?Do galaxies move with respect to each other? Is the Universe expanding? Contracting?Is the Universe expanding? Contracting? How do we know anything about these matters?How do we know anything about these matters?

The Doppler Effect permits us to detect star motion. The Doppler Effect permits us to detect star motion.


The Doppler EffectThe Doppler EffectThe Doppler EffectThe Doppler Effect Waves compress or relax with relative motion. Waves compress or relax with relative motion. Applies to waves of both sound and light. Applies to waves of both sound and light.

The stopped train sounds the same to Anna and Bill.The stopped train sounds the same to Anna and Bill. The moving train sounds different to Anna and Bill.The moving train sounds different to Anna and Bill.

Anna hears a higher pitch from compressed sound waves. Anna hears a higher pitch from compressed sound waves. Bill hears a lower pitch from expanded sound waves.Bill hears a lower pitch from expanded sound waves.As the train passed Anna, the pitch would drop (higher to lower). As the train passed Anna, the pitch would drop (higher to lower). This is commonly heard as cars whiz by on a road.This is commonly heard as cars whiz by on a road.

Waves compress or relax with relative motion. Waves compress or relax with relative motion. Applies to waves of both sound and light. Applies to waves of both sound and light.

The stopped train sounds the same to Anna and Bill.The stopped train sounds the same to Anna and Bill. The moving train sounds different to Anna and Bill.The moving train sounds different to Anna and Bill.

Anna hears a higher pitch from compressed sound waves. Anna hears a higher pitch from compressed sound waves. Bill hears a lower pitch from expanded sound waves.Bill hears a lower pitch from expanded sound waves.As the train passed Anna, the pitch would drop (higher to lower). As the train passed Anna, the pitch would drop (higher to lower). This is commonly heard as cars whiz by on a road.This is commonly heard as cars whiz by on a road.


The Doppler EffectThe Doppler EffectThe Doppler EffectThe Doppler Effect Light waves behave like sound waves. Light waves behave like sound waves. Visible light is electromagnetic radiation.Visible light is electromagnetic radiation.

Visible wavelengths range from 400 to 700 nanometers.Visible wavelengths range from 400 to 700 nanometers.400 nm – Blue = Higher frequency400 nm – Blue = Higher frequency700 nm – Red = Lower frequency700 nm – Red = Lower frequency

Light waves behave like sound waves. Light waves behave like sound waves. Visible light is electromagnetic radiation.Visible light is electromagnetic radiation.

Visible wavelengths range from 400 to 700 nanometers.Visible wavelengths range from 400 to 700 nanometers.400 nm – Blue = Higher frequency400 nm – Blue = Higher frequency700 nm – Red = Lower frequency700 nm – Red = Lower frequency


The Doppler EffectThe Doppler EffectThe Doppler EffectThe Doppler Effect A moving star displays Doppler-shifted light. A moving star displays Doppler-shifted light.

Light from an approaching star is compressed.Light from an approaching star is compressed.This causes a shift to higher frequencies, so that…This causes a shift to higher frequencies, so that… Stars moving toward Earth are shifted toward blue. Stars moving toward Earth are shifted toward blue.

Light from a receding star is expanded.Light from a receding star is expanded.This causes a shift to lower frequencies, so that...This causes a shift to lower frequencies, so that...Stars moving away from Earth are shifted toward red.Stars moving away from Earth are shifted toward red.

A moving star displays Doppler-shifted light. A moving star displays Doppler-shifted light. Light from an approaching star is compressed.Light from an approaching star is compressed.

This causes a shift to higher frequencies, so that…This causes a shift to higher frequencies, so that… Stars moving toward Earth are shifted toward blue. Stars moving toward Earth are shifted toward blue.

Light from a receding star is expanded.Light from a receding star is expanded.This causes a shift to lower frequencies, so that...This causes a shift to lower frequencies, so that...Stars moving away from Earth are shifted toward red.Stars moving away from Earth are shifted toward red.


The Expanding UniverseThe Expanding UniverseThe Expanding UniverseThe Expanding Universe Light from distant galaxies appeared “red shifted.” Light from distant galaxies appeared “red shifted.” In 1929, Hubble recognized this as a Doppler shift. In 1929, Hubble recognized this as a Doppler shift.

He concluded that galaxies were moving away rapidly. He concluded that galaxies were moving away rapidly. No galaxies were found to be moving toward Earth.No galaxies were found to be moving toward Earth.

This led to the development of the Expanding This led to the development of the Expanding Universe Theory, analogous to expanding bread. Universe Theory, analogous to expanding bread.

Light from distant galaxies appeared “red shifted.” Light from distant galaxies appeared “red shifted.” In 1929, Hubble recognized this as a Doppler shift. In 1929, Hubble recognized this as a Doppler shift.

He concluded that galaxies were moving away rapidly. He concluded that galaxies were moving away rapidly. No galaxies were found to be moving toward Earth.No galaxies were found to be moving toward Earth.

This led to the development of the Expanding This led to the development of the Expanding Universe Theory, analogous to expanding bread. Universe Theory, analogous to expanding bread.


Big BangBig BangBig BangBig Bang When did the expanding Universe begin?When did the expanding Universe begin?

The best answer so far? The big bang.The best answer so far? The big bang. All of the mass and energy in the Universe was packed into All of the mass and energy in the Universe was packed into

a single small point.a single small point. It exploded 13.7 Ga and has been expanding ever since.It exploded 13.7 Ga and has been expanding ever since.

When did the expanding Universe begin?When did the expanding Universe begin? The best answer so far? The big bang.The best answer so far? The big bang. All of the mass and energy in the Universe was packed into All of the mass and energy in the Universe was packed into

a single small point.a single small point. It exploded 13.7 Ga and has been expanding ever since.It exploded 13.7 Ga and has been expanding ever since.

The Modern Universe

The Modern Universe



Big BangBig BangBig BangBig Bang Rooted in the Laws of Physics.Rooted in the Laws of Physics. Started as a rapid cascade of events.Started as a rapid cascade of events.

Protons and neutrons formed within 1 second.Protons and neutrons formed within 1 second. Hydrogen atoms formed within 3 minutes.Hydrogen atoms formed within 3 minutes. Hydrogen fused to form new light elements (He, Be, Li, B) Hydrogen fused to form new light elements (He, Be, Li, B)

via big bang nucleosynthesis. via big bang nucleosynthesis. The Universe continued to… The Universe continued to…

Expand. Expand. Cool.Cool.Decrease in density.Decrease in density.

Rooted in the Laws of Physics.Rooted in the Laws of Physics. Started as a rapid cascade of events.Started as a rapid cascade of events.

Protons and neutrons formed within 1 second.Protons and neutrons formed within 1 second. Hydrogen atoms formed within 3 minutes.Hydrogen atoms formed within 3 minutes. Hydrogen fused to form new light elements (He, Be, Li, B) Hydrogen fused to form new light elements (He, Be, Li, B)

via big bang nucleosynthesis. via big bang nucleosynthesis. The Universe continued to… The Universe continued to…

Expand. Expand. Cool.Cool.Decrease in density.Decrease in density.


After the Big BangAfter the Big BangAfter the Big BangAfter the Big Bang With expansion and cooling, atoms began to bond. With expansion and cooling, atoms began to bond.

Hydrogen formed HHydrogen formed H22 molecules - The fuel of stars. molecules - The fuel of stars.

Atoms and molecules coalesced into gaseous nebulae.Atoms and molecules coalesced into gaseous nebulae.

Gravity caused collapse of gaseous nebulae.Gravity caused collapse of gaseous nebulae. Collapse resulted in increases in…Collapse resulted in increases in…

Temperature.Temperature. Density.Density. Rate of rotation. Rate of rotation.

With expansion and cooling, atoms began to bond. With expansion and cooling, atoms began to bond. Hydrogen formed HHydrogen formed H22 molecules - The fuel of stars. molecules - The fuel of stars.

Atoms and molecules coalesced into gaseous nebulae.Atoms and molecules coalesced into gaseous nebulae.

Gravity caused collapse of gaseous nebulae.Gravity caused collapse of gaseous nebulae. Collapse resulted in increases in…Collapse resulted in increases in…

Temperature.Temperature. Density.Density. Rate of rotation. Rate of rotation.


After the Big BangAfter the Big BangAfter the Big BangAfter the Big Bang Condensed nebulae formed flattened accretion discs.Condensed nebulae formed flattened accretion discs. Heat and mass from collapse ignited nuclear fusion.Heat and mass from collapse ignited nuclear fusion. These 1These 1stst-generation stars consumed H-generation stars consumed H22 fuel rapidly. fuel rapidly.

As the stars became HAs the stars became H22 starved, they initiated… starved, they initiated… Collapse and heating.Collapse and heating. Heavy element production.Heavy element production. Catastrophic explosion Catastrophic explosion

(supernova).(supernova).

Condensed nebulae formed flattened accretion discs.Condensed nebulae formed flattened accretion discs. Heat and mass from collapse ignited nuclear fusion.Heat and mass from collapse ignited nuclear fusion. These 1These 1stst-generation stars consumed H-generation stars consumed H22 fuel rapidly. fuel rapidly.

As the stars became HAs the stars became H22 starved, they initiated… starved, they initiated… Collapse and heating.Collapse and heating. Heavy element production.Heavy element production. Catastrophic explosion Catastrophic explosion

(supernova).(supernova).


NucleosynthesisNucleosynthesisNucleosynthesisNucleosynthesis Stars are truly “element factories.”Stars are truly “element factories.” BigBig bangbang nucleosynthesis formed lighter elements. nucleosynthesis formed lighter elements.

Atomic #s 1, 2, 3, 4 and 5 (H, He, Li, Be, and B).Atomic #s 1, 2, 3, 4 and 5 (H, He, Li, Be, and B).

Heavier elements are from Heavier elements are from stellarstellar nucleosynthesis. nucleosynthesis. Atomic #s 6 - 26 (C to Fe).Atomic #s 6 - 26 (C to Fe).

Elements with atomic #s > 26 Elements with atomic #s > 26

form during supernovae.form during supernovae.

Stars are truly “element factories.”Stars are truly “element factories.” BigBig bangbang nucleosynthesis formed lighter elements. nucleosynthesis formed lighter elements.

Atomic #s 1, 2, 3, 4 and 5 (H, He, Li, Be, and B).Atomic #s 1, 2, 3, 4 and 5 (H, He, Li, Be, and B).

Heavier elements are from Heavier elements are from stellarstellar nucleosynthesis. nucleosynthesis. Atomic #s 6 - 26 (C to Fe).Atomic #s 6 - 26 (C to Fe).

Elements with atomic #s > 26 Elements with atomic #s > 26

form during supernovae.form during supernovae.


NucleosynthesisNucleosynthesisNucleosynthesisNucleosynthesis The mass of a star governs its element production.The mass of a star governs its element production.

Smaller-mass stars (like the Sun).Smaller-mass stars (like the Sun).““Burn” slowly.Burn” slowly.Live longer (10 Ga).Live longer (10 Ga).Create lighter elements up to carbon (C).Create lighter elements up to carbon (C).

Larger-mass stars (10-100x the mass of the Sun).Larger-mass stars (10-100x the mass of the Sun).““Burn” rapidly.Burn” rapidly.Are shorter lived (10s of Ma).Are shorter lived (10s of Ma).Create heavier elements up to iron (Fe).Create heavier elements up to iron (Fe).

The mass of a star governs its element production.The mass of a star governs its element production. Smaller-mass stars (like the Sun).Smaller-mass stars (like the Sun).

““Burn” slowly.Burn” slowly.Live longer (10 Ga).Live longer (10 Ga).Create lighter elements up to carbon (C).Create lighter elements up to carbon (C).

Larger-mass stars (10-100x the mass of the Sun).Larger-mass stars (10-100x the mass of the Sun).““Burn” rapidly.Burn” rapidly.Are shorter lived (10s of Ma).Are shorter lived (10s of Ma).Create heavier elements up to iron (Fe).Create heavier elements up to iron (Fe).


NucleosynthesisNucleosynthesisNucleosynthesisNucleosynthesis When fuel dwindles, stars heat by inward collapse. When fuel dwindles, stars heat by inward collapse. This leads to a cataclysmic explosion (a supernova).This leads to a cataclysmic explosion (a supernova). The supernova creates heavier elements. The supernova creates heavier elements.

Uranium (atomic # 92) is the heaviest natural element. Uranium (atomic # 92) is the heaviest natural element.

When fuel dwindles, stars heat by inward collapse. When fuel dwindles, stars heat by inward collapse. This leads to a cataclysmic explosion (a supernova).This leads to a cataclysmic explosion (a supernova). The supernova creates heavier elements. The supernova creates heavier elements.

Uranium (atomic # 92) is the heaviest natural element. Uranium (atomic # 92) is the heaviest natural element.

Earth shares the solar system with 7 other planets.

Planet – A precise definition developed in 2006. A planet…

Is a large solid body orbiting a star (e.g., the Sun).

Has a nearly spherical shape.

Has cleared its neighborhood of other objects.

Thus, Pluto, previously defined as a planet, is excluded.

Moon – A solid body locked in orbit around a planet.

Earth shares the solar system with 7 other planets.

Planet – A precise definition developed in 2006. A planet…

Is a large solid body orbiting a star (e.g., the Sun).

Has a nearly spherical shape.

Has cleared its neighborhood of other objects.

Thus, Pluto, previously defined as a planet, is excluded.

Moon – A solid body locked in orbit around a planet.

The Solar System



The Planets: An Overview The Planets: An Overview Two groups of planets occur in the solar system.

Terrestrial (Earth-like) - Small, dense, rocky planets.Mercury, Venus, Earth, and Mars.

Jovian (Jupiter-like) - Large, low-density, gas-giant planets.Jupiter, Saturn, Uranus, and Neptune.

Two groups of planets occur in the solar system. Terrestrial (Earth-like) - Small, dense, rocky planets.

Mercury, Venus, Earth, and Mars. Jovian (Jupiter-like) - Large, low-density, gas-giant planets.

Jupiter, Saturn, Uranus, and Neptune.



The Solar SystemThe Solar System Our solar system also includes…Our solar system also includes…

The Sun – An average star.The Sun – An average star. Asteroids – Rocky or metallic fragments.Asteroids – Rocky or metallic fragments. Comets – Fragments of ice orbiting the Sun.Comets – Fragments of ice orbiting the Sun. Kuiper Belt and Oort Belt objects.Kuiper Belt and Oort Belt objects.

Planetary systems have been found near other stars. Planetary systems have been found near other stars.

Our solar system also includes…Our solar system also includes… The Sun – An average star.The Sun – An average star. Asteroids – Rocky or metallic fragments.Asteroids – Rocky or metallic fragments. Comets – Fragments of ice orbiting the Sun.Comets – Fragments of ice orbiting the Sun. Kuiper Belt and Oort Belt objects.Kuiper Belt and Oort Belt objects.

Planetary systems have been found near other stars. Planetary systems have been found near other stars.


Solar System FormationSolar System FormationThe Nebular Theory A 3rd, 4th or nth generation nebula forms 4.56 Ga.

Hydrogen and helium left over from the big bang. Heavier elements produced by stellar fusion and supernovae.

The nebula condenses into an accretion disc.

The Nebular Theory A 3rd, 4th or nth generation nebula forms 4.56 Ga.

Hydrogen and helium left over from the big bang. Heavier elements produced by stellar fusion and supernovae.

The nebula condenses into an accretion disc.



Solar System FormationSolar System Formation The ball at the center grows dense and hot. Fusion reactions begin; the Sun is born. Dust in the rings condenses into particles.

Particles coalesce to form planetesimals.

The ball at the center grows dense and hot. Fusion reactions begin; the Sun is born. Dust in the rings condenses into particles.

Particles coalesce to form planetesimals.



Solar System FormationSolar System Formation Planetesimals accumulate into a larger mass. An irregularly-shaped proto-Earth develops.

Planetesimals accumulate into a larger mass. An irregularly-shaped proto-Earth develops.

The interior heats and becomes soft.

Gravity shapes the Earth into a sphere.

The interior differentiates into…• a nickel-iron core, and

• a stony (silicate) mantle.

The interior heats and becomes soft.

Gravity shapes the Earth into a sphere.

The interior differentiates into…• a nickel-iron core, and

• a stony (silicate) mantle.



Solar System FormationSolar System Formation Soon, a small planetoid collides with Earth.

Debris forms a ring around the Earth.

The debris coalesces and forms the Moon.

Soon, a small planetoid collides with Earth.

Debris forms a ring around the Earth.

The debris coalesces and forms the Moon.



Solar System FormationSolar System Formation The atmosphere develops from volcanic gases. When the Earth becomes cool enough,

moisture condenses and accumulates, and the oceans are born.

The atmosphere develops from volcanic gases. When the Earth becomes cool enough,

moisture condenses and accumulates, and the oceans are born.



Solar System FormationSolar System Formation

Synopsis



Solar System FormationSolar System Formation The Nebular Theory of Solar System Formation is

supported by the configuration of planets.

• The orbital planes of the planets lie within 3° of the Sun's equator.

The Nebular Theory of Solar System Formation is supported by the configuration of planets.

• The orbital planes of the planets lie within 3° of the Sun's equator.



Chapter 1Cosmology and the Birth of Earth

©2008 W. W. Norton & Company, Inc.

Portrait of a PlanetThird Edition

earthearth

LECTURE OUTLINE

This concludes the

Op ch01 lecture_earth3

Education

Transcript of Op ch01 lecture_earth3