syllabus & course expectations
Astronomy
Picture of the Day the
latest astrophysics discoveries
what's up in the sky
this week
Skywatcher's
Diary for this month
| Monday August 7 |
August 8 |
August 9 |
August 10 |
August 11 |
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no class |
final exam, 2 - 5 pm |
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(always done before class) |
27, galactic violence: quasars |
28, cosmology; how the universe will end |
29, the Big Bang; how the universe began |
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questions you should be able to answer after you've done the reading |
what are the competing theories of galaxy formation and evolution? are there genes that decide E or S? what environmental conditions favor E or S? |
what is the evidence for dark energy? how is dark energy different from dark matter (or bright matter)? what is the geometry of the universe? what is the likely future of the universe: expand forever? collapse on itself? how secure is our understanding of the future? |
what evidence is there for the Big Bang? is it circumstantial or ?? what happened during the main events in the first hour: the inflation era? the pair creation era? the fusion era? the radiation-dominated era? the matter-dominated era? the moment of decoupling? |
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| homework |
homework 5 |
homework 6
now posted |
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components
of the Milky
Way a new closest galaxy: the Canis Major dwarf the Sagittarius dwarf (discovered only in the last decade) is living inside the Milky Way Milky Way Past Was More Turbulent Than Previously Knownthe oldest
objects Star Formation Peaked Later than thoughtdeepest view ever unveils
earliest galaxies Hubble
Sees
Early Building
Blocks Of Today's Galaxies Hubble Identifies Primeval Galaxies |
the Supernova Cosmology project
is trying to measure how the expansion of the universe is changing (and
therefore what the future history of the universe might be) mass/energy inventory of the universe |
the Millenium
Cold Dark Matter simulation WMAP views the 3K background Beyond the Big Bang (" countless replicas of Earth, inhabited by our clones, are scattered throughout the cosmos...) |
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| Monday July 31 |
August 1 |
August 2 |
August 3 |
August 4 |
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test
emphasizes binary stars through stellar evolution |
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(done before class) |
finish chapter 22: how massive stars die: the supernova phenomenon |
23 |
24
(and 23 if you didnt read it for yesterday) |
25
and 26 [you should have already read sections 25(4-5) and 26 (1-5)] |
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| questions you
should be able to answer after you've done the reading |
what decides how a star dies? (what stellar property, what "event") what triggers the supernova explosion? why does the onset of complete degeneracy signal the end of a star's active life? |
why are supernovas important to your existence? why was supernova 1987A so important to astronomers? why don't all supernova remnants contain pulsars? why aren't all pulsars surrounded by supernova remnants? |
what's the difference between type I and type II supernovas? (which type have we been discussing in class?) what 5 things would you have done to decide if the LGM phenomenon was an astronomical object or the communication from some extraterrestrial civilization? what are the only 3 properties that black holes can have? what is the event horizont? what is the singularity? |
how do we think the Milky Way formed? what are population I and II objects, and how are they different? how does the origin theory of the Milky Way explain these differences? what's the difference between elliptical galaxies and spiral galaxies? |
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| homework |
homework
4 (assignment 5) |
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red
giant and planetary nebula evolution supernova events supernova implosion and explosion movies (best movies are the ones at the very top) |
the crab pulsar: on
and off pulsar physics type Ia SN happen in binaries |
Laser
Interferometer |
components
of the Milky
Way a new closest galaxy: the Canis Major dwarf the Sagittarius dwarf (discovered only in the last decade) is living inside the Milky Way Milky Way Past Was More Turbulent Than Previously Knownthe oldest
objects Star Formation Peaked Later than thoughtdeepest view ever unveils
earliest galaxies Hubble Sees Early Building Blocks Of Today's Galaxies Hubble Identifies Primeval Galaxies |
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lakes
on Titan? |
| Monday July 24 |
July 25 |
July 26 |
July 27 |
July 28 |
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(done before class) |
assuming you have finished reading 18(1-4); new = essay on "searching for neutrinos ... " at end of chapter 18 21(1) |
finish chapter 18 on the outer parts of the sun |
chapter 20 [remember that you have already read section 20-2] starbirth steps starbirth summary table |
21(2,3) on stellar old age 22(1-4) on the death phase of stars like the sun 25(7) on spiral shock waves |
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| "next-day" assignment; bring completed to class | 1)
what would the power in the mass-luminosity relation (in other words,
what is p in Luminosity = Mass^p or Mass raised to
the power of p) have to be in order that the least massive stars were
also the shortest lived (and the massive stars were the ones to live
the longest?) explain. (yesterday's reading in chapter 21 should be helpful) (is there more than 1 answer?) 2) how do we know -- just from observations, not theory -- that the O stars live the least long of all the stars and that the M stars are the longest lived? after all, we have never seen a single star leave the main sequence (and evolve to become a giant/supergiant because it ran out of hydrogen in the core) stars' main sequence lifetimess are millions of years at least -- we won't see one leave the main sequence in your lifetime either! |
see
email that i sent wednesday afternoon, 2:15 pm |
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questions you should be able to answer after you've done the reading |
what is the source of energy of the sun (and all main sequence stars? (i.e., what form is the energy in before it is light?) why do we think hydrogen --> helium fusion is the energy source at the cener of the sun, even though we apparently can't "see" this happening? (4 separate answers here!) what property of a star determines its lifetime? |
why can neutrinos tell us that nuclear reactions are occurring in the sun's core? how can we be sure that the neutrinos we detect are coming from the sun (and not from somewhere else)? how did sunspots get to be cool? |
ow does the energy generated via nuclear fusion reach the surface? (by what processes) why does the energy leave the center and reach the surface?a star's life is a long-term fight between the pressure forces pushing outward and gravity pulling inward...what causes an intersellar cloud to begin the collapse toward starhood? in what part(s) of the spectrum do astronomers have to look to see starbirth? why? |
the H-R diagram on p. 450 shows the evolution of pre-main-sequence stars on their way to the main sequence... what part of stars' pre-main sequence evolution did they leave out? why do you think they did that? notice that the times given for pre-main-sequence evolution on this H-R diagram are much shorter than for main-sequence evolution.... why is that? |
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homework assignments |
homework 3 (assignment 4) due today |
homework 4 (assignment 5) due tuesday |
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the active sun in the
ultraviolet close-up of magnetic coronal
loops the magnetic corona hear the sun quake see what helioseismology tells us see the sun quake the
most amazing coronal mass ejection sunspot loops in the UV CMEs on the active sun |
shockwaves
star formation: star formation propagation(grav collapse induced by shock wave from O/B stellar winds) M16 before
hubble shock-wave
triggered starbirth star
death/supernova: Cygnus
loop shock wave spiral shock waves in galaxies: M51 as seen by
Hubble 2005 M83's emission nebulae
and its spiral arms a bow shock near LL Orionis molecular clouds & cooling the GMC at the heart Of Orion Dark Bok
Globules in IC 2944 Stellar
Disks Set Stage for
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interstellar sugar provides clue to origin of lifestatistics of exoplanetsjk's summary of extrasolar planets properties brown dwarfs, planets, and superplanets the brown dwarf smoking gun gif |
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| Monday July 17 |
July 18 |
July 19 |
July 20 |
July 21 |
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(always done before class) |
H-R diagram leftovers: 19(8): how do you tell the difference between a main sequence, giant, and white dwarf star spectroscopically? [from last friday: 26(1-3,5)] new 26(4): how we get distances to galaxies? [please do not read box 26-2!!] Kepler's 3rd law (plus his other two laws, where it came from, and why it's equivalent to the law of gravity): 4(3-7), particularly boxes 4-2 and 4-3 |
19(9-11): spectroscopic, eclipsing, and visual binaries: how astronomers get masses |
one
more example of the doppler effect: finding the mass of a galaxy: 25(4), including box 25-2 18(1), the beginning of "how stars work" |
18(2-4): stellar structure, stability, and energy transfer |
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| assignment
to bring completed to class |
5(39) |
after
reading box 26-2: why does the interpretation of a galaxy's redshift as
a recession velocity from us (in a universe of finite age, the time
since the Big Bang) violate the "no one is special" principle? for the yellow handout in class today: 1) which star (A or B) is more massive? 2) by how many times? 3) which star is eclipsed at phase = 0? how did you know? (hint: think about how the stars are moving right before and after the eclipse at phase = 0) |
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| questions you
should be able to answer after you've done the reading |
what are the main classes of galaxies? what do galaxies contain? how do we know that the universe is expanding? what is the implication of Hubble's observation that the furthest galaxies are moving away from us the fastest? how do we get distances to galaxies so that we can plot a Hubble diagram? |
be able to distinguish between various book versions of Kepler's 3rd laws how astronomers find the masses of stars in a binary system |
how is Kepler's 3rd law used to find the mass of a galaxy? |
Why doesn't the sun collapse under its own gravity? Why does the gas pessure increase with depth in the sun? Why does the gas temperature increase with depth in the sun? How did the temperature get to be so high at the center of the sun? Why does the temperature and density need to be high for fusion to occur? |
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| homework |
homework 2 (assignment 3) due |
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I did not make up buckyballs shock waves from bullets and jets a bow shock in the Orion nebula the Supernova Cosmology project is trying to measure how the expansion of the universe is changing (and therefore what the future history of the universe might be) mass/energy inventory of the universe |
the spectroscopic
binary applet the eclipsing binary applet |
HD 209458 velocity curve HD 209458b transit first image of an extrasolar planet Cygnus X-1 velocity curve: first case for a black hole |
typical MACHO micro-lensing event typical macro-lensing behavior due to galactic-scale dark matter for your leisure reading: are periodic
extinctions
The
Great Dying: the |
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| Monday July 10 |
July 11 |
July 12 |
July 13 |
July 14 |
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(done before class) |
7
(6-7) 19 (1-3_& boxes 19(1-3) |
19(2-3) boxes 19(2-3) 5(7-8): line spectra & energy levels |
start
with 5(7-8) [unless you are already read it for yesterday] 19(5-7) on spectra and the H-R diagram |
still
working on 19(5-7) |
20(2):
red nebulas, blue nebulas, and fluorescent lights 5(9): the Doppler effect 26(1-3): what's a galaxy? 26(5): the expansion of the universe and how we know that the universe had a beginning |
questions you should be able to answer after you've done the reading |
the handout on planetary
temperatures how do we know how old the solar system is? how did the (2) major "events" (planetary melting/differentiation and the bombardment era) that occurred after planetary formation change the face and interiors of the planets? how do astronomers find the distance to a nearby star? |
what does apparent magnitude measure? what does absolute magnitude measure? what are the two basic rules of magnitudes? |
why does the existence of energy levels explain why transparent gases have line spectra? why do opaque gases have continuous spectra? what happens in fluorescence? |
why
are hydrogen lines strong (dark) in A stars (of temperature 10,000 K)? why [in terms of the hydrogen energy level diagram -- see 5(8)] do the hydrogen lines get weaker in cooler stars? in hotter stars? why are lines due to neutral metals (such as Fe, Na, Ti, Ca) very strong/dark only in cool stars? why are lines due to helium very strong/dark only in the hottest stars? |
why are red fluorescing nebulas ONLY found around the bluest stars? |
homework |
collective list of answers to the "list of 10 properties of stars to find from spectra" |
homework 1 due today |
homework 2 (assignment 3) due next tuesday |
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evidence
for ancient
life on Mars ? meteorites we saw in class |
Orion's Great Nebula & the Trifid Nebula are starbirth sites; note that red- fluorescing nebulas can only surround BLUE (uv-emitting stars) The Helix Nebula
& spectrum of a planetary
nebula fluorescing H II regions in
the M51 galaxy help us trace the spiral arms and places of recent
stellar birth The Crab Nebula
& [these
two supernovas left behind neutron stars (stars made entirely of
neutrons that are about the size of durham)] the eclipsed sun shows a red fluorescing atmosphere (which reveals the flash spectrum ) flash spectrum with lines identified A Perseid Aurora
& Comet tails
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spectrum of an A0V star spectrum of a G2V (sun-like) star |
doppler
effect applet |
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| Monday July 3 |
July 4 |
July 5 |
July 6 |
July 7 |
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(always done before class) |
5(5-6): know the three basic types of spectra and what physical states of matter produce them |
light: behavior & characteristics |
5(3-4); be familiar with the 2 blackbody laws (Wien's and Stefan's) |
finding the radius of a star: box (19-4) intro to planets: 7 (1 - 5) the solar system's planets can be divided into two classes: what are the names of these 2 classes are what are some properties that distinguish these two classes of planets? |
how the planets
got their properties: the formation of the solar system: 8 (1-5) & 7(6-7) |
questions you should be able to answer after you've done the reading |
what are the 3 ways that a
hotter blackbody curve differs from a cooler blackbody curve? what does Wien's law relate the temperature of a star to? what does Stefan's law relate the temperature of a star to? how do Wien's and Stefan's laws show up on the blackbody curve graphs? what is a blackbody, anyway? |
what are the units of flux? of luminosity? what else is different about them? what instruments can measure flux? (how) can luminosity be measured? |
what are the basics of our present (the "condensation-accretion" theory) of how the planets formed and acquired their properties? which came first, condensation or accretion, in planetary formation? why? what were the major events that occurred in planetary history after planetary formation? how do we know how old the solar system is? |
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homework |
to hand in: 10 properties (of stars) to find from spectra due in class today to think about (not to hand in): based on the physical state of a fluorescent light bulb, what type of spectrum would you predict the light would have? |
homework 2 due tuesday, July 11 blackbody applet for homework (the applet requires java, so that must be enabled on your computer; if you can't find a computer that it works on, let me know) clicking on the link above should open 2 new windows -- be patient... it could take 30 seconds -- a useless one and one containing intensity/wavelength axes; in this window, click on the "blackbody" button to add a blackbody, type in the temperature below the thermometer, and you'll find the %s emitted in uv. vis, and ir in another new, tiny window that opens |
image processing lab due |
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images for the lab stellar evolution summary CCDs and how they work |
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discovered last year the status of the Voyager satellites |
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summer
discovery highlights: two dust disks (& a planet?) around nearby star black hole paradox answered |
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| what
we did in class |
saw
examples of different types of spectra (continuous, bright-line, and
dark-line) what astronomers can observe and what they can deduce |
what flux means and how
astronomers measure it the image processing lab: how astronomers manipulate data |
what
blackbodies are and why stars are good blackbodies the first blackbody law: Wien's law & how the color of a star is determined by its temperature why the sun looks yellow even though it's really blue-green (effects of the eye sensitivity and scattering by the sky) |
the
second blackbody law: Stefan's
law: how the flux in a blackbody is determined by temperature differences between flux and luminosity the differences between terrestrial and jovian planets |
measured
the luminosity, radius, and temperature of the sun using only a meter
stick, a 200-watt light bulb, and a wax photometer the condensation-accretion theory of planet building why condensation is necessary for accretion what determines the temperature of a planet how temperatures in the proto-planetary disk around the sun determined the composition, size, mass, density, etc of the planets |
