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
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September 25 |
September 26 |
September 27 |
September 28 |
September 29 |
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no class only faculty have school |
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(always done before class) |
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26(4) on distances to galaxies 26(5) on the expanding universe |
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4(4 - 7) on Kepler's laws and gravity: key sections are 4(4 and 7) box 4-4 is important also |
| things you should know the answer to before coming to class | is the doppler shift in wavelength a significant fraction of the wavelength of starlight? what is the doppler shift formula in terms of frequency (the book only writes the one for wavelength) |
why do we think the universe is
expanding? what are the implications of hubble's law? (what IS Hubble's law?) (why is it that the farthest galaxies are farthest away?) how do astronomers get distances to galaxies? |
why can't galaxies' redshifts be doppler shifts? (i.e., due to the motion of the galaxies relative to us)? so what is the redshift is due to? |
KNOW Kepler's 3 laws and their implications (be able to state them from memory and be able to describe in english what they mean) what physics laws are Kepler's 3 laws hiding in disguise? know how to get Kepler's 3rd law from Newtonian laws |
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| homework (written assignments to be turned in) |
bring to class: determine the value of 1/H (in years) (2 units changes and an inverse) |
1) find the distance to delta Cephei (given the data on page 480 and using the period-luminosity graphs on page 481... delta cephei is a type I cepheid (we outlined the method in class; 2 digit accuracy is sufficient 2) find out how much taller you would grow during your future lifetime IF your body participated in the expansion of the universe; to do this a) first calculate the speed of the top of your head as "seen" by your feet; use the value of H given in the text b) assuming that this speed remains constant during your future, how much taller will you grow during the rest of your life? |
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a bow shock in the Orion nebula |
mass/energy inventory of the universe |
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if clear weather by the hour |
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September 19 |
September 20 |
September 21 |
September 22 |
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luminosity,
radius, and temperature of the sun lab (assuming it's clear) |
bring PINK Bohr-atom handout to
class |
jit due by 8
am today |
look at the
calcium energy level diagram and answer the following: 1) what temperature ionizes neutral calcium? 2) in what temperature range is calcium singly ionized 3) at what temperature will visible-light neutral calcium lines be strong? 4) what temperature will allow for strong visible light emission in a fluorescing nebula? |
bring
spectra/sun properties lab book to class (so I can grade it this
weekend) |
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(always done before class) |
FK
5(8) |
FK
19(5) but ONLY after you have answered JIT questions 2a also box 7-2 which can be read anytime! |
19(6,7): what is the story behind the H-R diagram? what is being plotted? why are stars in different places on the diagram? |
5(9): know the doppler effect |
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| things
you should know the answer to before coming to class |
see the JIT |
can
human experience the doppler effect in sound? (can we hear a change in pitch due to moving objects?) examples? can humans experience the doppler effect in light? (can we see a change in color due to moving objects?) examples? |
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| homework (written assignments to be turned in) |
to
be brought to class today: a) calculation of the luminosity of the sun (using lab guide expectations: no numbers till end, units, etc) b) a prediction of the color of the bulb-side wax (starting with a temperature of the bulb, a calculation, and corrections for human interpretation) c) ditto for color of sun-side wax |
estimate
of solar corona temperature brought to class (on paper, to hand in;
show work) today use the FeXIV line in the flash spectrum for your temperature estimate |
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fluorescing hydrogen regions
around hot stars help us trace
the spiral arms and places of recent
stellar birth fluorescence in the
solar
system: A Perseid Aurora
& the fireballs
in Jupiter's atmosphere created by comet Shoemaker-Levy Comet tails
spectrum
of a planetary
nebula starbirth nebula: Orion's Great
Nebula & the Trifid
Nebula are
starbirth sites; note that red- fluorescing nebulas can
only surround BLUE (uv-emitting stars) The Crab Nebula
& [these
two supernovas left behind neutron stars (stars made entirely of
neutrons that are about the size of durham)] gas
in the Coma Cluster of galaxies |
doppler
effect applet a bow shock in the Orion nebula |
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try
to finish this week's lab while it's fresh in your mind |
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of the week |
Xena
becomes Eris |
oldest
recorded supernova remains |
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September 11 |
September 12 |
September 13 |
September 14 |
September 15 |
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we will do the
luminosity of the sun lab as soon as the sun makes its appearance (be ready for appropriate dress) weather is here |
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(always done before class) |
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[it's assumed that you have already read 7(1,4) and 8(1-2,4-5)] |
& Walker 31(1,2) |
go through line-by-line making sure you understand where are the equations and ideas come from... there will be a) old physics laws put together in a new way b) new physics that you have never studied before (and we will have to stop and take the time to learn) c) wrong or omitted physics that you should notice annotate your pink sheet with examples of (b) and (c) above |
I think some of us can do a bit better job also BROWSE the following in Walker to get a taste of angular physics: 10(1,2 up to mid p. 287) moment of inertia at the bottom of p. 296 torque (or how wrenches work) on p.316 center of mass and balance on p. 330 conservation of angular momentum and ice skaters in example 11-9 on p. 339 see below |
things you should know the answer to before coming to class |
what 4 additional sources of energy have contributed to raising a planet's surface or interior temperature beyond that calculated from the one we obtained by assuming only absorption of sunlight?) |
what are 3 ways that astronomers or geolgists can tell that the interior of a planet is hot (see Tuesday reading!) review yesterday's question (4 sources of energy for heating planetary or surface temperatures) |
be able to fill in all the missing algebra steps that were omitted on the pink sheet as you browse Walker, create a two-column table, where you write down ALL the first-semester-physics quantities that you learned last year (about 12?), e.g., displacement, velocity, acceleration, mass, etc in the left column.... and then find and name the corresponding quantity in angular physics |
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| homework (written assignments to be turned in) |
bring
to class (on a piece of paper that can be handed in): calculated temperature of your planet (using last Friday's derived formula) & the real temperature of your planet (look it up in your planet's chapter) |
ratio of electric force between the proton and electron in a hydrogen atom to the gravitational force ; bring on a piece of paper to hand in |
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make sure you follow the communication guidelines! be prepared for luminosity of the sun lab on the first clear day of the week |
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(and how/why the planets have migrated a bit since formation) today's NY Times (requires NYT registration) |
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September 5 |
September 6 |
September 7 |
September 8 |
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no
class Labor Day |
you may want
to bring your computer today to do the asteroid image processing lab see below for software |
jit due by 8
am |
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(always done before class) |
19(1) |
19(3) [remember that you have already read 19(2)] |
7(1,4) and 8(1,2,4,5) | ||
things you should know the answer to before coming to class |
how
astronomers use parallax to measure distance where the formula d = 1/p came from |
class
presentation: know the derivation of the formula d = 1/p what planet (in the solar system) would astronomers like to be living on to measure parallaxes? |
important
differences between terrestrial and jovian planets basic features of the condensation-accretion theory of planetary formation why terrestrials and jovians ended up so different in size/mass and composition |
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homework (written assignments to be turned in) |
now
due sunday noon for your star: a) identify your star's name & the spectral/luminosity class listed in the Appendix b) determine your star's temperature (in K) c) determine the wavelength of max intensity for your star AND what color your star would appear to humans d) use your star's apparent magnitude (along with the sun's apparent magnitude and sun's known flux) to determine your star's flux e) determine your star's luminosity relative to the sun.... show work! (your luminosity ratio should also match that given in Figure 19-14a) f) the radius of your star (relative to sun) [see box 19-4 and follow the procedure exactly] (your answer should also match that given in Figure 19-14b) g) if we define the sun as fist-sized, what real life object (either bring one or have a classroom object identified) that approximately matches your star's size h) determine what fraction of your star's luminosity is emitted in the uv, in the visible, and in the ir (using the spectrum explorer applet) |
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spectrum
explorer (launch the explorer; it requires java, so that must be enabled; 2 new windows should open in a minute or 2-- a useless one and one containing axes; on the latter, click on the "blackbody" button to add a blackbody, type in the temperature below the thermometer, and you'll find the %s in another new, tiny window that opens |
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software
for today's asteroid
parallax lab: we will use the HOU software go to the following path on the T drive: T:\Software\HOU\PC_Installer you should be able to double click on the setup.exe icon to install (alternatively, you can just run it from the T drive) images for asteroid parallax lab: asteroid1.fts asteroid2.fts |
spectra lab now due Monday | |||
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of the week |
SMART-1 hits
moon |
planet or failed star? |
| Monday, August 28 |
August 29 |
August 30 |
August 31 |
September 1 |
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prepare lab
book for spectra lab (see below) |
JITdue by 6
am today although only 80% of JITs are required, everyone should plan to do the first one, if only to try out the process; if you do extra JITs, you will get extra credit |
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(always done before class) |
5(3,4) |
Walker
28(1,2,6) look at how the real formula is different than the on we came up with in class look at some of the examples, qualitative and quantitative |
5(6):
know what kind of source (solid, liquid, transparent gas, opaque gas, etc.) produced what kind of spectrum: there will be a short quiz at the beginning of this lab on the reading |
19(2) [yes, we skipped 19(1)]: how to distinguish between flux and luminosity |
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you should know the answer to before coming to class |
6
or more "behaviors" of light that are post-1800 of course you not only want to know the names but also what the behavior means and be able to give an example know how to draw blackbody curves.... how does a hotter blackbody curve differ from a cooler one's curve.... and what is a blackbody? |
still
doing post-1800 behaviors of light be ready! to describe these |
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homework (written assignments to be turned in) |
tally of star properties from both classes combined |
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| web
stuff |
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| lab |
bring 2nd lab book to class | image
processing lab due spectra lab begins |
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| news/discoveries of the week |
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August 22 |
August 23 |
August 24 |
August 25 |
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and image processing |
more about light detectors |
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(always done before class) |
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all of the lab guide |
the Fabulous CCD (TURQUOISE handout) 5(1): what is light? |
you should know some properties of light (e.g. wavelength or frequency) and some behaviors of light (e.g., reflection, refraction) see the Walker references on the syllabus (but it doesn't have to be Walker) perhaps you will learn some laws that go with the behaviors as you read? maybe two sides of a page of notes while you're reading? |
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you should know the answer to before coming to class |
what
are the three pieces of info astronomers can record about an incoming
photon? (block D only got "color" or "wavelength" or "energy" there are two more obvious, simpler answers) |
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homework (written assignments to be turned in) |
number the odd pages of your lab book |
list
of 10 properties of stars that
can be obtained from the light we receive (you can't use the example that came up in class) |
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download ds9 (the software necessary for tomorrow's lab) images for the lab stellar evolution summary |
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continues |
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of the week |
'Proof of Dark Matter' (front page, today's Washington Post) 'Planets Askew in Heavens, and Here on Earth, A Mess' (today's NY Times) the IAU debate: is Pluto a planet? (go to pages 4 and 5 after pdf opens) |
'the
day we
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the new proposal is to demote Pluto from planethood |
