Test+Information+120

Former Test #1s[[file:Astro120-Test1-Spring2016.pdf]] [[file:Astro120-Test1-Fall2015.pdf]]
=== For this test you will be allowed to bring in a calculator (but only one that is not connected to the internet...no smartphone calculator apps allowed!) and one 4" x 6" index card. You can hand-write (your hand writing!) anything you like on this index card. Please note that as a result of allowing you index cards, there will be no equations, constants, or other information provided on the test itself. ===

__ Science __ :
 * The definition of astronomy
 * How astronomy differs from astrology
 * The scientific method

__Stars and Constellations__:
 * Definition of a star and a constellation.
 * Equatorial coordinate (Right Ascension and Declination) mapping system. When to use it and how to use it.
 * Which mapping system professional astronomers use and why.

__ Everything is in Motion __ :
 * Johannes Kepler wrote three laws of planetary motion.
 * Sir Isaac Newtons wrote three laws of motion and the Universal Law of Gravitation. He also explained orbits.

__Electromagnetic Radiation__:
 * Colors of the rainbow (ROYGBIV)
 * Refraction. What it is and when it happens.
 * Light as a wave (wavelength)
 * The whole electromagnetic spectrum (gamma, xray, UV, visible, IR, microwave and radio)
 * Speed of light (constant)
 * Frequency of light (in per second units, normally called Hertz: Hz)
 * Equations that relates wavelength to frequency
 * Light as a particle/photon: wave-particle duality
 * The energy of light, and the equation(s) that relates energy to wavelength and/or frequency.
 * Doppler Effect

__Optics and Telescopes__:
 * Lenses in refracting telescopes, though that does cause chromatic aberration.
 * Parabolic mirrors in reflecting telescopes.
 * Three reasons why we use telescopes: brighten, resolve and magnify. Least important is magnification.
 * Know how light travels through each type of telescope and where it ends up: the light collecting device and the light analyzing device: A photographic plate, CCD camera or a spectrograph.
 * The Universe emits light in all wavelengths, and in order to collect this light, some telescopes (radio and visible/optical) can be on the Earth, but most have to be above the atmosphere, which absorbs that light and keeps it from getting to Earth's surface

__Blackbodies and Spectra__:
 * Definition of a blackbody
 * Electromagnetic spectrum as described by a graph of intensity vs. wavelength
 * Wien's law and its implications
 * Color of stars (what we see vs. what the star emits at it's "wavelength max.")
 * Kirchhoff's three laws and which type of spectra is produced by which type of environment

__Atomic structure, the origin of light & spectral analysis__:
 * Examples of real spectra with Fraunhofer lines, and understanding/explanations of how these lines are formed.
 * Atomic structure (neutrons & protons in the nucleus, electrons orbiting the nucleus), and electron transitions.

__The Sun__:
 * Three atmospheric layers of the Sun, and their characteristic features, including sunspots and the Zeeman effect.
 * Thermonuclear fusion, the energy production caused by thermonuclear fusion and how that energy escapes the Sun.

Former Test #2: [[file:Astro120-Test2-Spring2015.pdf]]
=== For this test you will be allowed to bring in a calculator (but only one that is not connected to the internet...no smartphone calculator apps allowed!) and one 4" x 6" index card. You can hand-write (your hand writing!) anything you like on this index card. Please note that as a result of allowing you index cards, there will be no equations, constants, or other information provided on the test itself. ===

__Characterizing Stars__:
 * Distance to stars: Stellar parallax, spectroscopic parallax
 * Apparent vs. Absolute magnitude
 * Spectral Classification (O B A F G K M)
 * HR Diagram (spectral class vs. luminosity class). Know the diagram and how to label the axes.
 * Mass-Luminosity relationship

__Interstellar Medium__:
 * Emission nebula (pretty colors...why these colors are there, and which element these colors are representative of)
 * Reflection nebula
 * Interstellar reddening
 * Interstellar extinction
 * Atomic nebula and the 21 cm line!
 * Dark/molecular nebula. Those cold, dark places within which stars form.

__Star Formation__:
 * Star formation triggers: supernovae shockwaves, collisions of ISM clouds and the starlight of nearby O & B type stars (See figure 10-15, p. 278 for an excellent explanation of this last trigger method)
 * Formation of Bok Globules
 * The effects of spin on the forming star(s) of these Bok globules
 * Gravitational collapse leads to increased pressure in the core, which drives the core temperature up.
 * 10 000 000 K needed to ignite thermonuclear fusion.
 * hydrostatic equilibrium and ZAMS
 * Stellar populations and statistics...more little mass ones formed than very massive ones formed.
 * Lower limit = 8% solar mass, upper limit ~ 100 - 200 solar masses

__Stellar Evolution & Death__:
 * __Low Mass Stars (0.08 - 0.4 solar masses)__:
 * Long time to form, extremely long time on the MS, since they fuse H *VERY* slowly!
 * Fully convective stars. All H to the core, and all H eventually fused.
 * Final product = He ball, that cools and fades over time.
 * NONE of these stars have yet evolved off the MS.
 * __Medium Mass Stars (0.4 - 2 solar masses)__:
 * These stars have "chemically separate cores and shells."
 * When core hydrogen is used up, there is no outward radiation pressure to counteract the gravitation collapse, so the star collapses.
 * This increases the pressure throughout the star, and the temperature throughout the star increases.
 * H fusion begins in a shell surrounding the core and the star's outer regions expand due to this increase in temperature.
 * The star becomes a red giant (up and to the right of the MS on the HR diagram)
 * Meanwhile... in the core, due to electron degeneracy, the core cannot expand and cool, so the core superheats until the helium ignites explosively, in a "helium flash."
 * This red giant phase lasts about 10% the time that the star lasted on the MS
 * Once the He is used up in the core (fused to Carbon via the triple alpha process), the core collapses, and as there **isn't** enough mass to provide the pressure to drive the temperature up to what is needed for carbon fusion, the core collapses.
 * Next stage is He inner shell fusing/surrounded by outer H shell fusion (and expansion to red supergiant phase)
 * Then there is the final expansion of outer layers as a planetary nebula and exposure of the carbon-oxygen core (white dwarf).
 * A cooling white dwarf will eventually crystallize to a diamond.
 * __High Mass Stars (2 - 8 solar masses)__:
 * These stars have "chemically separate cores and shells."
 * When core hydrogen is used up, there is no outward radiation pressure to counteract the gravitation collapse, so the star collapses.
 * This increases the pressure throughout the star, and the temperature throughout the star increases.
 * H fusion begins in a shell surrounding the core and the star's outer regions expand due to this increase in temperature.
 * The star becomes a red giant (up and to the right of the MS on the HR diagram)
 * Since there is NO electron degeneracy, there is only gradual heating in the core, and NO helium flash
 * Once the He is used up in the core (fused to Carbon via the triple alpha process), the core collapses, and as there **isn't** enough mass to provide the pressure to drive the temperature up to what is needed for carbon fusion, the core collapses.
 * This collapsed core is a "white dwarf" ("white" hot) that ionizes the surrounding layers, which expand as a planetary nebula.
 * A cooling white dwarf will eventually crystallize to a diamond.
 * __"Neutron Star" Mass Stars (8 - 25 solar masses)__:
 * These stars have "chemically separate cores and shells."
 * When core hydrogen is used up, there is no outward radiation pressure to counteract the gravitation collapse, so the star collapses.
 * This increases the pressure throughout the star, and the temperature throughout the star increases.
 * H fusion begins in a shell surrounding the core and the star's outer regions expand due to this increase in temperature.
 * The star becomes a red giant (up and to the right of the MS on the HR diagram)
 * Since there is NO electron degeneracy, there is only gradual heating in the core, and NO helium flash
 * Once the He is used up in the core (fused to Carbon via the triple alpha process), there is no outward radiation pressure to counteract the gravitation collapse, so the star collapses.
 * This increases the pressure throughout the star, and the temperature throughout the star increases.
 * Since there **is** enough mass to (create the pressure to drive the temperature up high enough to) fuse carbon in the core, carbon starts fusing.
 * These successive fusion processes continue until iron is the fusion product in the core.
 * Iron can't fuse, so the core collapses.
 * This core environment is so hot, photodisintegration breaks up all the iron nuclei into protons, neutrons and electrons. The electrons fuse with the protons, making yet more neutrons, and a neutron core is formed.
 * The upper layers of the star collapse towards this neutron core, but rebound when they hit the non-compressible "surface" of the neutron core.
 * The material of these outer layers rebound and speed through space in a type II supernova explosion.
 * The neutron core, once exposed, is a neutron star.
 * A spinning neutron star is called a pulsar.
 * __"Black Hole" Mass Stars (more than 25 solar masses)__:
 * These stars have "chemically separate cores and shells."
 * When core hydrogen is used up, there is no outward radiation pressure to counteract the gravitation collapse, so the star collapses.
 * This increases the pressure throughout the star, and the temperature throughout the star increases.
 * H fusion begins in a shell surrounding the core and the star's outer regions expand due to this increase in temperature.
 * The star becomes a red giant (up and to the right of the MS on the HR diagram)
 * Since there is NO electron degeneracy, there is only gradual heating in the core, and NO helium flash
 * Once the He is used up in the core (fused to Carbon via the triple alpha process), there is no outward radiation pressure to counteract the gravitation collapse, so the star collapses.
 * This increases the pressure throughout the star, and the temperature throughout the star increases.
 * Since there **is** enough mass to (create the pressure to drive the temperature up high enough to) fuse carbon in the core, carbon starts fusing.
 * These successive fusion processes continue until iron is the fusion product in the core.
 * Iron can't fuse, so the core collapses.
 * This core environment is so hot, photodisintegration breaks up all the iron nuclei into protons, neutrons and electrons.
 * The upper layers of the star collapse towards this neutron core, and as there is SOOOOOO much mass, the pressure crushes the neutrons.
 * This crushed core is a black hole.
 * Some outer layers still rebound and speed through space in a type II supernova explosion.

__Variable Stars__:
 * RR Lyrae
 * Medium mass stars, post helium flash pass through the RR Lyrae variable star stage.
 * Light curves show periodicity of less than one day
 * Cepheid Variables
 * Leavitt law possible due to period-luminosity relationship. The longer the period, the luminous the star
 * Very bright, and can be seen in distant galaxies, used as a standard candle.

__Binary star evolution__:
 * In close binary star systems, mass (H) can be transferred from an evolved (bloated red giant) to it's companion.
 * If this companion is a white dwarf, the mass transfer causes layers to H to build up on the white dwarf.
 * This material can spontaneously fuse if/when enough mass (that creates the pressure, that drives up the temperature) builds up.
 * Novae, or sometimes type I supernovae can result.
 * A nova does not destroy the white dwarf, only the layers of added H.
 * A type I supernova completely destroys the white dwarf.
 * Type I supernovae are brighter than type II supernovae and the type I's are used a standard candles.
 * gamma ray bursts: long bursts and short bursts
 * different "sizes" of black holes, escape velocity of a black hole, what it would be like to go near a black hole (not recommended).

Former Final Exam (or parts thereof): [[file:Astro120-FinalExam-Spring2015.pdf]]
=== For this final exam you will be allowed to bring in a calculator (but only one that is not connected to the internet...no smartphone calculator apps allowed!) and one 8.5" x 11" sheet of paper. You can hand-write (__your__ hand writing!) anything you like on this sheet of paper. Please note that as a result of allowing you paper, there will be no equations, constants, or other information provided on the final exam itself. ===

__Galactic Content__:
 * Stars, stellar remnants ISM and dark matter.
 * Open clusters and globular clusters
 * Pop I, II & III stars
 * metallicity

__Milky Way__:
 * Shapley-Curtis debate
 * Edwin Hubble and the size of the universe
 * Galactic structures and motion of components (using the 21 cm line); disk & spiral arms, bulge, bar, nucleus (Sag A*) & halo
 * rotation curve; evidence for dark matter
 * spiral arm winding and density wave theory

__Galaxies__:
 * Normal Spirals and barred spirals; flocculent and grand design
 * Giant elliptical and dwarf elliptical galaxies
 * irregular galaxies and merging galaxies.

__Cosmology, the past__:
 * The universe is not static.
 * Hubble and Humason saw distant galaxies moving away. The more distant (cepheids, type Ia SN), the faster the recession (cosmological redshift)
 * Space is expanding. The universe is expanding.
 * The "Hubble constant" measures this rate of expansion: 67.8 +/- 0.9 km/s/Mpc
 * It started from a point, 13.799 +/- 0.021 billion years ago
 * The "big bang" theory seeks to describe what happened then
 * Evidence for the big bang is the Cosmic Microwave Background (CMB), which is measured at ~1 mm and 2.72548 +/-0.00057 K
 * Tiny fluctuations in the CMB are hypothesized to signify clumping of the energy/matter of the early universe leading the galaxy & star formation
 * Grand Unification Theories (GUT)/Theory of Everything

__Cosmology, the future__:
 * Observations and theories pre-1998 vs. observations and data after the "missing" 73% of the matter-energy density of the universe ("dark energy") was realized.
 * Dark energy is repulsive and is causing the expansion rate of the universe to increase.
 * Omega_0 = 1, so the universe is flat. It will expand forever.
 * The End