Introductory Astronomy Syllabus

Spring 2008    Prof. Mack

Text: Bennett et al. "The Essential Cosmic Perspective"+ "Mastering Astronomy" disk. Disk  Required for assignments-Due 1 week from presentation.<>

Part I: Developing an Astronomical Perspective---Ch. 1-3

Introductory Presentation: First Week: Our Place in Space + Mastering Astronomy
READINGS: Ch. 1

Mastering Astronomy Assignment & Ch. 1 Assignments including Scale of the Universe Tutorial See Schedule (Allow 1-2 hours.)

Concepts: Understand astronomical distance scale, scientific notation for large/small numbers, arithmetic with powers of 10, scale model of the universe, cosmic abundances, hierarchy of structure: Stellar system (ours is the Solar System.)-galaxy-cluster or group of galaxies-supercluster. How do these objects move? The expanding universe.
Vocabulary: Astronomy, astrology, contract grade, hypothesis, theory, fact, symbols for equal, approximently equal, equal by definition, light-year.
Also: what to expect of the course.

The Celestial Sphere
READINGS: Ch.2

PLANETARIUM DEMONSTRATIONS: Locating the pole, reference systems, motions

Concepts: Understand direct motion (relative to us) and proper motion (relative to the stars), of the sun, moon, planets, and stars, angular size, angular measure, sidereal and solar day, prograde and retrograde  motions (proper motions), ecliptic circle,
Vocabulary: Celestial sphere, horizon, angular distance, zenith, celestial poles & equator, meridian, sidereal day, altitude & azimuth (horizon system of coordinates), declination & right ascension (equatorial system), latitude , superior & inferior planets, cardinal points (N,E,S,W), constellation, asterism (recognized star pattern), zodiac, precession.

The Sun and Seasons
READINGS: Ch. 2
Concepts: Proper motion of the "planets" (wanderers), changing declination of the sun, how the sun drives seasons.
Vocabulary: proper motion, solstice, equinox, ecliptic, prograde (& retrograde)

The Moon as we see it 
READINGS: Ch.2
Concepts: Lunar phases, solar & lunar eclipses
Vocabulary: waxing, waning, new, crescent, gibbous, full, synodic & sidereal month, umbra, penumbra, eclipse, node, line of nodes,synodic period

Heliocentric Copernican understanding
READINGS: Ch.3

Concepts: conjunction & opposition, heliocentric explanation of annual motion

Vocabulary: heliocentric, orbit, ellipse, AU

<>Part II: Key Concepts for Astronomy--Ch. 4,5
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Energy

READING: Ch.4

Concepts: Energy in several forms, conservation laws, speed, force and acceleration, heat vs. temperature, absolute temperature, rest mass erergy

Vocabulary: Kelvin, Celsius, Fahrenheit, kinetic, potential, thermal

Gravity
READING: Ch.4
Concepts: Proportional to masses. Inversly proportional to separation squared. bound and unbound orbits. Difference of gravitational pull causes tides. Gravity is the basis of Kepler's Laws of orbits. We use orbits to calculate masses.
Vocabulary: Kepler's Laws, mass, weight, ellipse, parabola, hyperbola, escape velocity, tide, tidal bulge, semi-major axis

Light
READING: Ch. 5
Concepts: Light as a wave. Speed C is a constant of nature. Light as quantum particles-photons. Electromagnetic spectrum - visible & invisible wavelenths (or photon energies) Matter-atoms and sub-atomic particles. Emission, absorption, scattering. Spectrum-continuous, emission, & absorption. Analysis of light. Indications of stellar composition, temperature, velocity, magnetic field, and pressure, wavelength, spectrum, spectroscope, black body spectrum, emission and absorption lines, Doppler effect.
Telescopes-Parts, function, and characteristics of telescopes, types of telescopes and mounts, magnification, limits on magnification, largest & smallest useful magnification, field of view, radio telescope, effects of the atmosphere, Hubble telescope.
Vocabulary: wavelenth, photon. radio, microwave, infrared, visible (wavelength as color), ultraviolet, x-ray, gamma radiation, aperature, focal length, magnification, eyepiece

Part III Learning From Other Worlds--Ch. 6-9

The Solar System-A Brief Tour

READING: Ch. 6.1

Concepts: Classification of planets, characteristics of the sun and individual planets, layout of the system, solar elemental abundances (original composition of the system), density and composition (allowing for compression)
Vocabulary: Density, composition, cloud (yes, cloud), asteroid belt, Kuiper belt, Oort cloud.

Formation of the system part 1 - Clues from observations
READING: Ch. 6.2
Concepts: Patterns in orbits and rotations, Terrestrial and Jovian types, asteroids, comets, satellites.
Vocabulary: prograde, ecliptic

Formation part 2 - Birth of the Solar System
READING: Ch. 6.3
Concepts: solar nebula, origins of H & He, & heavy elements, compression, contraction, heating, spinning, flattening, planetary systems in formation.
Vocabulary: Infrared

Formation of Planets
READING: Ch. 6.4
Concepts: Condensation sequence, metals, rock, ices (H compounds), accretion, nebula clearing (competes with accretion), asteroids, comets, Kuiper belt objests ("leftover" planetisimals), equitorial satellites, captured satellites, satellites from giant impacts, dating of rocks, age of system from common oldest meteorites. Discovery of other planetary systems (astrometric, Doppler, transits, infrared eclipses), other systems indicate planetary migration
Vocabulary: Grain, planetesimal, radioisotope
Concepts: Crust, atmosphere, core, plate tectonics, age of surface vs. age of planet

Earth & Terrestrial Planets
READING: Ch. 7

Earth: Concepts: planetary activity, structure (crust, mantle, core), heat and differentiation, convection and motions+stresses on the crust, surface modification (cratering, volcalism, erosion, tectonic effects), atmospheric processes, age of a surface, atmospheric greenhouse effect,

magnetic field.
Vocabulary: crater, basalt, volcanism

Moon and Mercury: Concepts: Cratering, basins, maria (moon), compression faults (Mercury), effect of asymetric crust (moon), age of surfaces (maria, Mercury, lunar highlands)
Vocabulary: maria, highlands

Mars: Concepts: No plate tectonics, volcanism is concentrated, water once was there but climate changed, carbon dioxide and water loss - linked to loss of magnetic field?
Vocabulary: Tharsis ridge, Olympus Mons, Vallis Marineris.

Venus:Concepts: Massive CO₂ atmosphere, (Earth's CO₂ is in carbonate rocks), enormous greenhouse effect, clouds of sulfuric acid droplets, almost no water (runaway greenhouse effect) difference between planetary greenhouse effect (a process) and runaway greenhouse effect, an event (process in past, can not repeat)
Vocabulary: Carbonate

Earth as a habitat: Earth has plentiful water, oxygen in its atmosphere, continents rising abobe ocean level, fairly stable climate. We will link these blessings with earth's size, distance from sun, magnetic field, plate tectonics.

The Jovian Planets
READING: Ch. 8
Concepts: Gas giants: compressed, structure: atmosphere-liquid hydrogen layer-liquid matellic hydrogen layer (all containing compressed gaseous He)-ice+rock+metal core (mixed-not differentiated)

Ice giants: less compressed, structure: atmosphere-outer core(ices)-inner core(rock+metal).
Magnetic fields and their sources. Internal heat sources (Jupiter, Saturn, Neptune)

Satellites: Over 150 known. Small (less than 300 km any axis)-irregular and often captured, medium-(300-1,500 km diameter)-round and usually formed with the planet, usually geologically inactive, large(diameter>1,500 km)-round, usually formed with the planet, geologically active now or in the past. Heat sources for the activity are sometimes known. Activity happens at lower temperatures in icy bodies with lower melting temperatures.

Io (Jupiter): Most active object of any sort! Heated by varying tidal deformation, from a slightly eccentric orbit. Silicate (ordinary) volcanos & sulpher geysers. Youngest surface anywhere.

Europa (Jupiter):  Thick ice crust over a liquid (mostly water) deeper layer, with a solid rock-metal interior. Most of the mass is the interior. The surface is young.

Ganymede and Callisto (Jupiter): Ganymede is differentiated. Both are ice-rock-metal composition with half ice, both show surface modification (Ganymede's is younger), both have evidence of subsurface water, requiring a heat source.

Titan (Saturn): Atmosphere 10 x Earth's per area. (methane), erosion, methane lakes and rivers. Needs internal heat.

Saturn's mid-size moons: Five of six have had activity, some strange. Encaladus is active now-water vapor fountains! Iapetus has a high, sharp equatorial ridge.

Triton (Neptune): Ridges, varied terrain. Triton was captured, an event which probably produced heat as energy was exchanged.
And: Three of five mid-sized moons around Uranus show evidence of past activity.

Rings: Ten's of thousands km in width (inner to outer), less than .05 km thick (Saturn's). Made of particles, mostly ice, from dust grain size to boulder size. Gaps are made by collisions induce by the gravity of certain moons. All Jovians have rings, three discovered in the past 30 years. Rings wear down their components, so they must form at intervals.
Vocabulary: push-pull tide, ice geology, shepherd moons

Asteroids, Meteorites, Comets & Dwarf Planets
READING: Ch. 9

Asteroids: Concepts: Orbits and characteristics of small solar system objects. Asteroids are leftover planetesimals. Jupiter's gravity caused a planet's mass of planetsimals to be lost rather than combine into a planet.

Meteorites: Parts of asteroids released by collisions.Iron-nickel,stony.  Primitive meteorites - mixed rock and metal or rock+metal+water+carbon compounds.  Primitives are 4.6 billion years old, solar system age. Processed meteorites -  younger, and derive from differentiated asteroids. Some are nickle-iron, others are deficient in these metals.

Comets: Ice-rich planetesimals left over from the formation of Jovian planet cores. They were scattered (by gravity of Jovian planets) to the Kuiper belt and Oort cloud.
Vocabulary:  coma, dust & ion tails, meteor shower

Part IV: Stars--Ch. 10-13

The Sun

READING: Ch. 10
Concepts: Structure and characteristics of the sun, solar activity, solar power,solar power source. Why does it shine? Must account for the luminosity (power) and total energy (luminosity x lifetime). Since lifetime is greater than age, the great age of the system demands a fantastic power source - nuclear fusion. Convection layer, magnetism, sunspots.

Vocabulary: limb, disk, photosphere, chromosphere, corona, convection zone, core, fusion - P-P cycle, opacity, sunspot, flare, prominence, solar cycle, granulation, neutrino.

Surveying the stars
READING: Ch. 11

Concepts: To measure luminosity: need apparent brightness, use inverse square law and measured distance, measure distance through stellar parallax. Magnitude scale-astronomical system for recording apparent brightness (magnitude) and luminosity (absolute magnitude), color/spectrum/temperature, color index, measuring stellar masses (in binary systems). The HR diagram (luminosity vs temperature). Luminosity is surface brightness (power/cm²) x surface area, and the surface brightness is a strict function of temperature. Therefore, temperature and luminosity can be used to find surface area, and thus diameter and volume. Several HR diagram regions are named for size.

Important sizes: red giants, white dwarfs

Main sequence: For 90% of stars, luminosity is strongly corollated with temperature, and both depend on mass. These are the stars like the sun, fusing H to He in their cores. The other 10% are in different stages of their lives.

Cluster ages: Stellar mass controls stellar H burning lifetime, so all stars of a certain lifetime are on the same place on the main sequence. In a cluster with hundreds or more stars of the same age, stars of a lifetime less than the cluster age have disappeared from the main sequence. We see the termination point, so we can deduce the age of a cluster. Most globulars have the same (ancient) age, so that is the age of the galaxy.
Vocabulary: Hertzsprung-Russell diagram, main sequence, red giant, white dwarf, mass-luminosity relationship, binary system, open clusters, globular clusters.

Lives of the Stars
READING: Ch. 12
Concepts: Molecular clouds, protostars, Protosteller disks  contract, spin, and issue jets of gas. Contraction heats them up, eventually resulting in H to He fusion in the core. Upper and lower limit to stellar mass (.08 to 150 solar masses). Stars with mass too low for fusion don't contract without limit, they become brown dwarfs about the size of Jupiter but nearly 100 times more dense. Brown dwarfs (and some other types) are stable because of electron degeneracy pressure, not conected with temperature, just by electron density.

Life of a "low mass" star. Main sequence star. Lifetime depends on mass (inversely and strongly) but always 90% on main sequence. Is main sequence until core H is exhausted. Then: core contracts, surrounding shell has a rapid and accelerating episode of H-He fusion, luminosity tremendously increases. The star expands to a red giant. Core continues to contract and heat up - He-C fusion. Mainly supported by electron degeneracy pressure, so fusion produces heat, not expansion. He-C fusion is rapid and accelerating for a few seconds. Then the core does expand, and the star gets dimmer. It is a horizontal branch star on the HR diagram. Low-mass stars can't burn C, so they are out of fuel.

Planetary nebula: Exterior is interesting too. Red giants emit gas in the stellar wind. This surrounds the star with a transparent gas and exposes the core. Ultraviolet from the core excites emission from the gas, producing a short-lived and beautiful planetary nebula.

End point: The core, supported by electron degeneracy pressure, begins to slowly cool. It's about earth size, solar mass, density about a million times that of water- a white dwarf.

Life of a high mass star. These stars mature fast - lifetimes in millions of years. They do burn any element that can produce fusion energy, up to iron, which can't. The electron degeracy pressure has a limit, and when the iron core exceeds the limiting mass, it collapses, producing a supernova.

Lives of close binaries: These exchange mass whenever one becomes a giant, making their evolution complicated.

Stellar Graveyard
READING: Ch. 13
Concepts: White Dwarfs: Core, exhausted of fuseable nucleii, supported by electron drgeneracy pressure, end product of low mass stellar evolution. Density: tons/cubic cm. Mass limit: 1.4 solar mass.

White dwarfs in binaries: They can accept mass from giant companions. The new gas is heated and compressed, sometimes causing nullear fusion expolsions-novas. Sometimes the new material can push the white dwarf over 1.4 solar mass, resulting in a Type Ia supernova-different from the kind seen in Ch. 12.

Neutron stars: Massive star cores collapse, producing type II supernova (Ch.12). The core is stiil there, but all electrons have reacted with protons and formed neutrons. The neutron star is as dense as an atomic nucleus, 100 million tons/cu. cm. It is supported by neutron degeracy pressure. mass limit uncertain, but less than 3 solar masses.

Black Hole: Concepts: A region of space closed by the gravitational curvature around a mass. Could result from the collapse of a very massive stellar core. event horizon, singularity, curved space, event horizon, singularity.

Part V: Galaxies and Cosmology--Ch. 14-17

The Milky Way Galaxy
READING: Ch. 14

Concepts: Structure & orbits. Why hard to determine, how determined. How mass is determined. Dark matter. Recycling of gas; enrichment of heavy elements. Spiral arms and star formation. nebulas-types. galactic history. Galactic center.

Vocabulary: extinction, galaxy, spiral arm, disk, halo, dust/grains, dark matter, dark halo

Galaxies and Cosmology
READING: Ch. 15
Concepts: Galaxiy types and clusters. Distance measurement on the million light-year scale, Hubble law, universality of Hubble law, free expansion time, age of universe. Formation. Active galactic nucleii and quasars.
Vocabulary: galactic interactions, standard candle, Cepheid variable, redshift, Hubble law, the expanding universe, galactic interactions, standard candle, Cepheid variable, redshift, Hubble law.

Dark Matter and Dark Energy: Is the Universe Eternal?
READING: Ch. 16
Concepts: Dark matter-detected by its gravity, unseen. Dark energy- The expansion of the universe seems to be expanding. Dark energy is the name of the cause. It is not understood and may be a bad name. Evidence for dark matter: rotation curve, motions of galaxy pairs, hot gas in clusters, gravitational lensing. Hypotheses. Formation of giant structures. Can we know the fate of the universe?

The  Beginning of Time:
READING: Ch. 17
Concepts: Big Bang: What it was and wasn't. Epochs in the first few minutes. Annihilations. Proton-neutron ratio. Element abundances. Cosmic background microwave radiation.
Cosmic inflation: A rapid, accelerated expansion, at a tiny fraction of the Big Bang age. Has a plausible explanation. Explains: horizon, flatness, amd smoothness problems.