Astro 4 - Key Themes in My Test Bank
This is a generic list. I made this by looking at all the
~ 400 questions in my test bank. Remember that I make my quizzes and finals
fresh each semester, and you'll see roughly 120 questions drawn randomly from
this master test bank. For more help
in studying for your particular questions, refer to the study guide I handed
out and which is on-line for the Monday/Wednesday, and for the Monday evening
classes, which focuses in a different way on your particular exams. Looks
like a lot to learn here, right? But before you get depressed, realize that
your particular exams will only sample a small part of this, and all you need
is a 75% for an "A". You can do it!
Chap 0: Scientific Thinking
of “Chap 0” is important! Read it thoroughly and ask for any clarifications
steps of the scientific method
nature and psychological issues of pseudo-science.
of representing reality in our minds
fatal flaws with supernaturalism
Our Place in the Universe
of this material we will cover in more detail later so I have not written
questions on it. But, I do have a few introductory ideas for you to focus
definition of a light year, the general distance order of things out
there; planets, stars, galaxies.
Universal Motion, Relativity
Kepler’s 3 laws and their meaning
Newton’s Laws of Motion and their meaning
as more than water at the beach – the cause of tides via gravity and what
aspects of a gravitating system will increase or decrease tidal force
tides and neap tides and how they relate to the position of sun, moon.
meaning of angular momentum and conservation of angular momentum
as electromagnetic waves in a particle form
two ways to produce photons.
electromagnetic spectrum and the names of the different energy or
wavelength bands in the spectrum. Which bands will pass through earth’s
structure of the atom: nucleus and electrons in quantized orbits. Don’t
memorize the names of atoms and how many protons! I want concepts.
and absorption of photons via electrons changing orbits in atoms, and how
these processes make the spectral “lines” in astronomical objects.
lines: produced by cool gas in front of a hot object
lines: produced by gas lit up from the side against a black background.
Doppler effects; photons “redshifted” to longer wavelength if source /
observer are moving apart; “blueshifted” if moving towards each other
the shape of a thermal spectrum, and the two thermal radiation laws:
Hotter objects are bluer. Hotter objects give off more total light.
- Special Relativity follows from the fact that the speed of light in a vacuum is measured to be the same no matter how the observer is moving
- General Relativity follows from the Equivalence Principle: Effects of gravity are identical to the effects of being in an accelerating coordinate frame.
relativity = modern gravity; paths follow curvature of space, determined
by mass and energy density.
structure of the sun; layers, temperatures, densities, and why
cause and nature of sunspots
basics of nuclear fusion; hydrogen into helium, electromagnetism
vs. the strong nuclear force
– tiny interaction rate with other matter, the solar neutrino problem
– balancing gravity, energy production, pressure. How changing one will
affect the structure of the star
relation to the solar corona, magnetic fields
- The 3
mechanisms of heat transfer and which dominate in which layers of the sun
Properties of Stars and How We Measure Them
know how we measure it to determine distances to stars
H-R Diagram main features; main sequence, red giants, white dwarfs
- Mass –
luminosity relation for main sequence stars
types – really a temperature sequence. Hotter stars have fewer absorption
lines. Know the sequence!
– all main sequence stars burn hydrogen into helium in their core
eclipsing binaries; allow measurement of most stellar properties
demographics; most stars are low mass, but a brightness-limited sample
will be dominated by high mass stars – they’re far more luminous
Star Formation and Evolution
the mass limits for a star and why
- The 2
“fuel tanks” of a star; gravitational potential energy, and fusion
formation requirements; high density and low temperature, shock waves
dwarfs – too little mass to allow core fusion
always born in star clusters, how age of a cluster determined
the evolutionary sequence of a low mass star, medium mass star, and high
mass star, and relative lifetimes for each
pulsating stars which change their brightness
– know the two types; ‘carbon bomb’ and iron core, and why
iron core supernovae produce all of the elements in the universe heavier
the nuclear energy curve; which nuclear reactions produce, and which
consume, energy. This determines the evolution of stars.
The Stellar Graveyard
fusion explosions on the surface of binary star white dwarf
type I = “carbon bomb” supernovae. Know why
the 3 end states of a star - white dwarf, neutron star, black hole – and
the mass limits of each
the typical sizes of white dwarfs, neutron stars, and black holes
pulsars; flashing lights in the sky due to rapidly spinning neutron stars
Our Milky Way Galaxy
arms – density waves sweeping
through the interstellar medium initiating star formation
vs. open star clusters; their different ages and origins, and where they
are in the galaxy
populations: the definition, explanation, and distribution of Pop I vs.
the evidence for a massive black hole in the center of our galaxy
the structure; disk, bulge, halo, nucleus, dark matter
is (vertically) centered in the disk, where dust is concentrated. Affects
our ability to see the rest of the galaxy
the prime evidence for dark matter in our galaxy
formed from agglomeration of smaller proto-galaxies soon after Big Bang
Galaxies, Galaxy Evolution
variables and period/luminosity relation; importance in measuring galaxy
general star formation history; in spirals vs. ellipticals
stars, most galaxies are low mass and low luminosity, but
brightness-limited photographs will be dominated by large galaxies –
spirals and giant ellipticals
of Ellipticals; how determined by observing twisted isophotes
collisions -> irregulars, more common in early universe when it was
the Hubble Law and its uses and pitfalls in measuring distances to
galaxies, and in estimating the age of the universe
distance ladder: different methods have to be pieced together in order to
measure the distances across the universe
travel time, how it allows us to study the early universe
we measure mass in galaxy clusters and star clusters using velocity
don’t know exactly what it is, but we’ve ruled out all ordinary forms of
matter. Know what class of material it must be
Dark Matter vs. Hot Dark Matter, which is the dark matter? Why?
Collaboration has ruled out all dark matter candidates the size of planets
the rotation curve of a galaxy is; used to determine the mass
distribution, and evidence for an extended dark matter halo around all
only hydrogen and helium emerged from the cooling matter after the Big
difference between the “universe” and the “observable universe”
evidence that the Big Bang really happened; CMB, abundances of the
redshifted light from the time when hydrogen , helium cooled from ionized
“cosmological constant” and relation to the acceleration of the expansion
of the universe; it dominates the mass/energy density of the universe.
Know what current observations support it.
Olber’s Paradox – proof that the universe can’t be both
eternal and infinite
the basic idea of “inflation”. Postulated to solve what problem in the
“standard” Big Bang? New evidence strongly supports it really happened.
and anti-matter in the early universe, and how ratio is preserved in the
Life in the Universe
Miller-Urey experiment created amino acids out of the chemistry, conditions
of the early Earth
K main sequence stars most likely to have living planets
– the only element permitted by the laws of physics which can be used to
make complex molecules, why needed for life.
arguments for searching for radio communications near the main spectral
lines for water
- theories of the origin of
the Big Bang also predict a near-infinite number of alternate universes;
if so, we are self-selected to be a univers suitable for life. This kabosh's
the supernatural argument.