Astronomy 115 - Daily Outline of Lectures

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Note: This outline is for the course as offered in the fall 2003.

Part I

Lecture 1 - 3 September 2003

1. Questionnaire

2. Announcement concerning sections and WebText (book).
Relevance of internet: Text has many links. Online reading encouraged.
My HomePage - NEWS and other links.
Hardcopies of WebText: Get a few chapters at a time. New edition in preparation.

Lecture 2 - 5 September 2003

Theme: Questionnaire, Night Sky

1. Results of the questionnaire.

2. Current sky as seen from Ann Arbor. How to tell east from west on the sky. Astronomical Coordinates. Phases of the Moon.

3. Scope of the lectures - Two main branches of astronomy. Meaning of the word astrophysics.

4. This course will deal primarily with the structure and history of the solar system. What is "out there," what is it made of, and how did it evolve--what is its history?

5. Tools of the trade: elementary algebra, concepts from physics and chemistry, geology and some biology. The astronomy will be at college level, the tools used will be at high school level of sophistication (don't underrate the latter!).

6. Cosmochemistry deals with the composition and chemical history of cosmic materials.

Lecture 3 - 8 September 2003

Theme: A Quick Tour of the Universe Part I: Solar System

1. The Earth and Meteorites: samples of the universe. Four chemical mixtures.

2. The Moon and mercury: superficially similar surfaces. Different chemistry and history.

3. To the snow line: Venus, Mars, and the asteroids. Densities and decompressed densities.

4. The Titius-Bode law. The Jovian planets.

5. Satellites and rings. Comets. New views of Pluto and Charon.

6. Densities as a clue to the history of the planets. Condensation of materials from an SAD mix.

Lecture 4 - 10 September 2003

Theme: A Quick Tour of the Universe Part II: Stars, Galaxies, and the Universe.

1. Models and their use in science. Models of the universe.

2. Structure appears in the universe. Galaxies, and clusters of galaxies. Large-scale structure of the universe. The deepest probes.

3. Classification of galaxies. Spirals and ellipticals. Interactions between galaxies. Cannibalism, and star bursting.

4. Stars and star clusters. Multiple and binary stars. Planetary systems.

5. Gas and dust in the planes of spiral galaxies.

Lecture 5 - 12 September 2003

1. Modern solar system research is dominated by results from the space program.

2. We need a broader base in general science to understand the modern developments in the solar system than for classical astronomy. Much of the solar system is cold, and chemistry is highly relevant. Some planets and many satellites have solid surfaces, so geological methods are relevant.

3. The nature of science and the scientific method. Induction and deduction. What some philosophers mean by the scientific method.

4. Scope and purposes of the four physical sciences. Physics is the basic science. What is meant by an understanding "in principle." The concept of reductionism. Can biology be reduced to physics and chemistry? Vitalism.

Lecture 6 - 15 September 2003

Theme: Some analytical tools.

1. Powers of ten

2. Logarithms

3. Proportions and the skinny triangle

4. Amount = rate x time. Many applications, a Golden Rule.

5. units in physics and chemistry: examples of

4.

Lecture 7 - 17 September 2003

Theme: The sun--its structure and history.

1. The sun's mass and energy output.

2. The sun's energy. The sun's age and lifetime.

3. The structure of the sun. Interior and surface. Solar phenomena. Solar-terrestrial relations. Neutrinos from the sun.

Lecture 8 - 19 September 2003

Theme: The History of Astronomy and Astrophysics

1. The oldest science: why? Omit ideas that didn't pan out.

2. Four ancient astronomers. Hipparchus, Eratosthenes, Aristarchus, and Ptolemy

3. Four pre-modern astronomers. Copernicus, Tycho, Kepler, and Galileo

4. Kepler's laws.

5. Synodic and sidereal periods give rough structure of the solar system.

6. The stellar parallax, and the Tyconic universe.

7. Kepler finds the orbit or Mars.

Lecture 9 - 22 September 2003

Theme: Astronomy of position and the birth of astrophysics.

1. Newton, and the transition to modern astronomy.

2. Newton's form of Kepler's harmonic law.

3. Newton's law of gravitation.

4. Astronomy of position and astrophysics: contrast.

Lecture 10 - 24 September 2003

Theme: Resume of Concepts from Chemistry

1. Structure of atoms: planetary electrons and nucleons (protons and neutrons. Quarks and the standard model not a part of this course. Isotopes. The nuclide chart.

2. Subshells and the structure of the periodic table.

3. Molecular bonding: ionic and covalent. Oxidation and reduction.

4. Inorganic and organic chemical compounds. Acids, bases, and salts. The periodic table is the key. Simple hydrocarbons. Other organic molecules.

5. Molecular weights. Weight per cent and per cent by atom or molecule.

6. Weaker chemical bonds: essential for life. The properties of water.

Lecture 11 - 26 September 2003

Theme: Resume of Newtonian Physics: mechanics

1. Newton's mechanics as a paradigm science. Inductive foundation, deductive exploration of consequences.

2. Undefined terms avoid circular definitions: mass, length, and time.

3. Derived dynamical quantities: velocity, acceleration, momentum, force.

4. Vectors. Newton's second law includes his first and third.

5. Energy: kinetic and potential. The falling body as an illustration. A potential energy curve, and how it depends on the force law.

6. Conservation of energy and the behavior of simple systems: balls on a curved surface, planets and molecules. 7. Angular momentum. An effective potential curve for a planet.

Lecture 12 - 29 September 2003

Theme: Light and the Electromagnetic Spectrum: The astronomer's tools

1. Electromagnetic waves and photons

2. The Electromagnetic spectrum: Gamma rays to radio waves

3. Astronomical telescopes: reflectors and refractors.

4. Detectors: eye, photographic and electronic detectors.

5. Radio telescopes

6. x-ray and gamma-ray telescopes

Lecture 13 - 1 October 2003

Theme: Laboratory analysis of cosmic materials

1. General remarks

2. Wet chemical analysis

3. The mass spectrograph

4. Chromatography

5. Neutron activation

6. The spectrograph

7. The geologist's polarizing microscope

8. Electron and ion probes

First Hour Quiz - 3 October 2003

Part II

Lecture 14 - 6 October 2003

Theme: Down to Earth I - minerals

1. The earth is made mostly of rock and minerals. This is also true of Mercury, Venus, Mars, and probably most asteroids. We need to understand this material.

2. A mineral is...

3. A simplified classification of minerals. Native elements, oxides, silicates, carbonates, miscellaneous (sulfides, sulfates)

4. Important mineral families: olivines, pyroxenes, feldspars, amphiboles, carbonates, hydrated and clay minerals.

5. The Bowen series - mineral content as a clue to the history of earth materials. Weathering and weathering products.

6. The physical properties of these minerals.

Lecture 15 - 8 October 2003

Theme: Down to Earth II - rocks

1. Rocks are made of minerals. "We came to Mars to study rocks."

2. Six important rock types -

3. Rock type as an indication of history of the material. Mafic and felsic; volcanic and plutonic types. Lunar and martian rocks.

4. Rocks are made when magma solidifies. Ocean rifts and volcanos.

5. Kinds of volcanos on earth and other bodies in the solar system.

Lecture 16 - 10 October 2003

Theme: Down to Earth III - Earth structure

1. The earth's interior. Seismic waves.

2. Earth models. Core, mantle, and crust. Volatiles.

3. Heat flow. Plate tectonics. History of continental drift. Source of heating to come later in course.

4. The age of the earth: Uniformitarians and catastrophists.

5. Time's arrow and time's cycles: Hutton, Lyell, and their error. Deep time. Reinterpretation of the scriptures of Hutton and Lyell.

6. Radioactive dating.

Lecture 17 - 15 October 2003

Theme: Earth and its nearest cosmic neighbor, the Moon

1. Physiographic provinces of the earth and the Moon

2. The simplified petrology of the Moon. Anorthosites, a kind of gabbro?

3. Plate tectonics and erosion modify the earth's surface. Deep time written on the face of the Moon.

4. Geological eras, periods, and epochs. Lunar periods.

5. Stratigraphic nomenclature: group, formation, (member). Illustrations from the Grand Canyon and the Moon.

6. Cayley and Fra Mauro formations and their histories.

Lecture 18 - 19 October 2003

Theme: The Grand Canyon and the Moon - An independent essay

1. The concept of lunar and planetary geology

2. The Geological column

3. Stratigraphy of the Grand Canyon

4. Lunar nearside features

5. Geological Maps of the Moon

6. Simple lunar stratigraphy, some lunar groups and formations

Lecture 19 - 20 October 2003

Theme: Histories the Earth and Moon

1. Lunar-like surfaces. The nature of explosion craters. History of our understanding.

2. Crater density as a clue to the age of a surface. Calibration with lunar rates. Application to highlands and lowlands, to planets and satellites.

3. Histories of the earth and Moon.

4. The Moon's origin.

Lecture 20 - 22 October 2003

Theme: The direction of chemical reactions; the laws of thermodynamics.

1. Equilibrium and nonequilibrium. Systems that can do no useful work and those that can. A simple example.

2. The first law of thermodynamics: conservation of energy.

3. Entropy and the second law. Some specific examples.

4. We don't need the third law in this course.

5. The Gibbs energy as a kind of inverse to entropy. How to use it to tell the direction of a chemical reaction. For most of the reactions we will need to consider, the relevant Gibbs energies can be looked up in a big book.

Lecture 21 - 24 October 2003

Theme: Application of thermodynamics. Condensation in the solar nebula.

1. Formation of the solar nebula from an interstellar cloud.

2. Processes in the cooling nebula. Condensation of solids.

3. The relation between condensation temperatures and densities. Anorthite - an important exception.

4. The role of decompressed densities. How they are calculated. Predicted density gradient of condensed solids in a model nebula.

5. Comparison of theory and observation: homogeneous and inhomogeneous condensation.

6. Difficulties with the simple condensation hypothesis. Alternate explanation of Mercury's high density.

7. The condensation model today.

Lecture 22 - 27 October 2003

Theme: Lunar and terrestrial chemistry and the origin of the Moon.

1. A cosmochemical classification of the elements: easily oxidized metals in mantle and crust, reduced metals in core. Siderophiles and lithophiles.

2. Lunar rocks are dry. Lunar rocks contain reduced metal.

3. Lunar and terrestrial rocks are both depleted in siderophiles.

4. Oxygen and its isotopes. Isotopic abundances of oxygen in solar-system materials.

5. Historical theories of the origin of the Moon.

6. The modern Big Whack hypothesis.

Lecture 23 - 29 October 2003

Theme: Mars - the most earthlike planet.

1. Early speculations, canals in the late 1900's, vegetation on in 1950.

2. Mariner 4 reveals a moonlike surface.

3. Mariner 9 and the Viking results. Four physiographic provinces. with old and relatively young terrain.

4. The martian volcanos.

5. River beds.

6. Martian craters.

7. Meteorites from mars--evidence for past life.

Second Hour Quiz - 31 October 2003

Part III

Lecture 24 - 3 November 2003

Theme: Mercury: A moonlike planet. Contrast with lunar and martian surfaces.

1. Physical characteristics of the planet; ice at the pole?

2. The unusual rotation of mercury, and its discovery.

3. The Mariner 10 flyby.

4. Two physiographic provinces. Lava flows or Cayley formation?

5. Evidence of crustal foreshortening.

6. Caloris basin, and double-ringed craters. 7. Formation and evolution scenario.

Lecture 25 - 5 November 2003

Theme: Venus: Like the earth in mass, but very different on the surface.

1. Physical characteristics. Retrograde rotation.

2. Thick CO atmosphere. The Urey reaction. 2

3. Penetrating the clouds: landers, probes, and radar maps.

4. Three physiographic provinces. Intermediate-age surface. No evidence of plate tectonics.

5. No evidence for life. The greenhouse effect.

Lecture 26 - 7 November 2003

Theme: Transition to the Jovian planets: the asteroids

1. Discovery of the asteroids. A bookkeeping nuisance.

2. Eros and the astronomical unit.

3. Orbital properties, families, Trojans and Apollo asteroids.

4. Astroblemes, dinosaurs, chaotic orbits, and modern fears.

5. Astrophysical investigations: remote sensing techniques.

6. New classifications, meteorites from an asteroid?

Lecture 27 - 10 November 2003

Theme: The snow line and formation of the Jovian planets

1. Water condensation in the model solar nebula.

2. Early core formation and gravitational collapse.

3. Jovian planets must form prior to expulsion of solar nebula gas. H₂ the dominant mass.

4. Models: Uranus and Neptune require rocky cores. Jupiter and Saturn have them too.

5. Metallic hydrogen over the rocky cores.

6. Heat flow from Jovian and terrestrial planets. Sources of internal heat.

Lecture 28 - 12 November 2003

Theme: Temperatures and heat flow in solar system

1. Heat flow and energy: review of concepts. Units and conversions.

2. Heat received and emitted by a black body at a distance from the sun. Emission and albedo.

3. Heat flux from the interiors of planets: measurements.

4. Internal sources of heat: Radioactivities, gravitational energy, phase changes.

5. What the experts think of an ambiguous picture. Occam's razor?

Lecture 29 - 14 November 2003

Theme: Cosmic magnetic fields

1. Planetary magnetism - the Jovian planets have strong fields.

2. The sun's magnetism and the interplanetary magnetic field.

3. Magnetic stars.

4. Magnetic fields in cosmic clouds.

5. Plasmas and magnetic plasmas. Magnetic fields as a source of energy and pressure.

6. The origin of magnetic fields: fossil fields or the dynamo.

Lecture 30 - 17 November 2003

Theme: Jupiter and it's satellites

1. Jupiter's zones and belts. Differential rotation.

2. A passel of satellites. Inner, intermediate, outer.

3. Io

4. Europa

5. Ganymede and Callisto

Lecture 31 - 19 November 2003

Theme: Planetary rings and satellites

1. The Roche limit -

2. Saturn's extensive ring system.

3. Resonances and shepherding satellites.

4. Orbits in and out of the equatorial plane.

Lecture 32 - 21 November 2003

Theme: Saturn, Uranus, and Neptune; Pluto and Charon

1. 1970's and 80's Two Pioneer and Voyager flyby's to Jupiter, Saturn, Uranus, and Neptune.

2. Galileo mission in 1990's; Orbiter, probe of Jupiter's atmosphere. Still (1999) functioning.

3. Discovery of Uranus, Neptune, Pluto.

4. Pluto and Charon--Possible relation to Neptune. Capture? Kuiper Belt Objects? More big whacks?

Lecture 33 - 24 November 2003

Theme: Comets, their nature and origin.

1. Description of comet orbits.

2. The Oort and Kuiper clouds.

3. Pluto and Charon: Kuiper-belt objects?

4. Heads and tails: structure and composition.

5. Remnants or ejecta; interstellar comets?

Lecture 34 - 26 November 2003

Theme: Meteorites and the SAD (Combined Lecture)

1. Stones that fall from the sky

2. Stones, irons, and stony irons

3. Chondrites and chondrules

4. Achondrites

5. The carbonaceous chondrites

6. Quest for the SAD (Holy Grail). Type I Carbonaceous chondrites.

7. Volatile content of carbonaceous meteorites.

8. Relation to condensation temperatures.

9. Spectroscopic analysis of the solar photosphere

10. Dealing with the super-volatiles

11. Cosmic abundances: history and empirical rules.

12. Mystery of the Type I's.

Lecture 35 - 1 Decmber 2003

Theme: Isotopic anomalies in the solar system

1. For a long while it looked like isotopic abundances were constant.

2. Allende falls, and oxygen anomalies discovered.

3. Mass dependent and mass independent fractionations.

4. CAI's, extinct radioactivities, Al-26 and I-129.

5. Presolar grains, burning down the haystack.

Lecture 36 - 3 December 2003

Theme: Other stars and other planets

1. The sun among the stars. Stellar masses and luminosities.

2. Upper and lower main sequence, brown dwarfs.

3. Stellar evolution

4. The spectrum of stellar masses.

5. Astrometric searches for planets; Barnard's star

6. Modern searches using radial velocities.

7. No earthlike planets to date.

Lecture 37 - 5 December 2003

Theme: The early earth and Life

1. The oldest rocks

2. The earth's volatiles - outgassed or brought by comets?

3. The oceans are old.

4. The earth's original atmosphere.

5. Transition to an oxidizing atmosphere--life

6. The astronomer's job

7. Understanding life.

8. The building blocks.

9. Water and molecules in solution.

10. Running uphill--ATP

12. Conditions for life

Lecture 38 - 8 December 2003

Theme: Life on our world and on others

1. Racemic Mixtures and Meteorites

2. Catalysts and enzymes

3. The problem of origins

4. Life on other worlds

5. Spontaneous generation of life: Spallanzani and Pasteur

6. The Miller-Urey experiment and deep time. 7. The Drake equation.

Lecture 39 - 10 December 2003