syllabus
& course
expectations
safety,
tardy, classroom computer use, and honesty
Universe/publisher link: register as a student to use the resources
Astronomy
Picture of the Day
the
latest astrophysics discoveries
what's up in the sky
this week
|
September 29 |
September 30 |
October 1 |
October 2 |
October 3 |
|
|
|
|
|
now that I think about it, there is probably a better than average chance that we will start the lab by mid-block |
|
|
|
(always done before class) |
|
(why not??) |
|
AND Box 4-2 4(6,7) should be a review sections 4(1-3) provide a nice historical background |
|
| things you should know the answer to before coming to class | bring to class: 1) a calculation of the age of the universe in YEARS, given that H = 71 km/s/Mpc 2) a calculation of how much you would grow IF you were participating in the expansion of the universe a) first calculate how fast (in km/s) your head would be receding from your foot by using the Hubble law b) then, assuming that this speed remains constant during your lifetime, calculate how much you would grow during your remaining lifetime due to the expansion of the universe (which of course doesnt apply to you, as we discussed earlier in class last week) |
know Kepler's 3 laws and what physics is hiding behind each of them |
|||
| homework (written assignments to be turned in) |
homework
on magnitudes due Tuesday: 1) a) using only the apparent magnitude (vs time) graph on page 480, determine how many times delta Cephei is at brightest than when it is faintest (on this and all future parts, make sure you show me what you did; do not just announce the answer) b) determine the period of delta cephei (the figure caption has an incorrect period) and use it to determine the average luminosity (it's a log scale! treat accordingly!) using the period-luminosity diagram on the adjacent page (delta Cephei is a type I cepheid); then use this luminosity (relative to the sun) to determine its average absolute magnitude c) finally, find the distance to delta Cephei 2) a) advanced question 19(40) AND also find the difference in the b) their apparent magnitudes c) their absolute magnitudes 3) the 4th-brightest appearing (and nearby) star in the sky, alpha centauri, is actually a double star with components cleverly named A and B.... the stars are so close that they cannot be seen indiviudally by the eye... using the data in Appendix 4, find the apparent magnitude of the combined light of the alpha Centauri AB system |
||||
|
|
|
|
|
the eclipsing binary applet |
|
|
|
|
|
|
|
|
|
|
and here's the real article |
Major Hubble Failure to delay shuttle mission |
|
|
| Monday, September 22 |
September 23 |
September 24 |
September 25 |
September 26 |
|
|
|
lab quiz on
the Doppler effect so bring your "sun" lab book to class bring your computer to use on the applet quiz (assuming it displays the applet) |
jit due by noon it's ready in moodle! |
|||
|
(always done before class) |
spend
30 minutes reading the fluorescence links below |
19(3) |
19
(4,6-7) (this means we have now read all of chapter 19 up through section 7) "come as your star day" wear the color of YOUR star bring to class something that is roughly the size of your star (if the sun were represented by a closed fist) or be able to point something out in the classroom |
5(9) Walker discusses the doppler effect in sound in sction 14(6) spend sufficient time with the doppler applet below so that you understand 1) what it's showing (e.g., what do the circles represent) 2) that the doppler effects explained in 5(9) match what you're seeing the applet |
|
things you should know the answer to before coming to class |
in each case, make a decision about what is driving the fluorescence: is it KE from collision or uv energy from photons? |
know the 2 rules of magnitudes know how to convert from luminosity and flux to absolute and apparent magnitude |
|||
homework (written assignments to be turned in) |
homework
on energy level diagrams due at noon at 6:30 pm |
||||
|
|
fluorescence in the image processing lab: fluorescing hydrogen regions around hot stars in M100 help us trace the spiral arms and places of recent stellar birth
spectrum
of a planetary
nebula 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 fluorescing things in the solar system we DIDNT see in the image processing lab: Comet tails both fluoresce and reflect... can you tell which is which? A Perseid Aurora
& |
Mars Rover
heads to a new crater 2 of this year's 25 Macarthur Fellowships ("genius grants") go to astronomers |
doppler
effect applet |
||
|
|
|||||
|
of the week |
|
September 15 |
September 16 |
September 17 |
September 18 |
September 19 |
|
|
|
|
|
|
to moodle |
|
|
(always done before class) |
we start line spectra: Walker 31(1-3), up to the bottom of p. 1042) |
|
also Universe 5(7 & 8) bring Walker (but not Universe) to class |
box 7-2 (again) page 2, yellow Astrophysics book |
|
things you should know the answer to before coming to class |
bring to class a list of: 1) new physics (new laws, new formulas), not accounted in previous physics 2) wrong (or incomplete or approximate) physics 3) connections to spectra lab |
perhaps take the lists to the left a bit more seriously, especially (1) and (2) what is the ratio of the electric force to the gravitational force for a proton/electron pair in the hydrogen atom? |
why did we invent a new unit of energy (the electron volt) for atoms? Find the expression for electric energy that we taught you last year! how do the energy levels of the hydrogen atom determined by Walker (page 1044 ) compare to those claimed by Universe (page 112)? how can the energy level values be different if we are talking about the same thing???? |
answer this before AND after you do the reading in 19(5): why is it that the spectra of A stars have the strongest (i.e., darkest) hydrogen lines of any stars? why would the lines be weaker in other stars? what is the energy range of visible light? |
|
| homework (written assignments to be turned in) |
|||||
|
|
|
|
|
|
the 5 dwarf planets now all have names!
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Monday, September 8 |
September 9 |
September 10 |
September 11 |
September 12 |
|
|
|
bring
your lab book to class: I will check your calculation of your group's solar luminosity and your prediction of the light bulb's wavelength of maximum intensity/flux |
calculate the
temperature of YOUR planet.... check with table partner TONIGHT! to make sure that you agree.... (it should be fairly close to the actual temperature in the book EXCEPT in a couple cases) |
or last day on
planets, their origin and their properties |
bring
computers to class if you have HOU installed for today's asteroid lab |
|
|
(always done before class) |
8(3)
and associated box 8(1) 17(1-6) |
re-read
8(5) |
your
choice of planetary readings.... the goal is to find two IMPORTANT sources of energy
that we left out of our calculation for planetary temperatures (remember we have done sunlight & the greenhouse effect so far) box 19-6 and associated box for homework below box 7-2 on what it means to be hot |
you
may have read some of these sections as part of what you chose to read
for wednesday.... but if not, please read hopefully you find the 3 missing energies to add to the table of what melted the planets: 7(7) 8(5) again (where the 2nd most important energy source is), 9(2), 9(7), 10(4), 30(1) |
|
things you should know the answer to before coming to class |
which of the properties in the list of terrestrial-vs-Jovians lists helps us understand/explain all of the other properties? what is the origin of the meteorites and asterloids? what didn't their material form into planets? |
why the terrestrial planets are made of rock and metal, have high density, and are small in both radius and mass |
2 (not 3 as I said in class) IMPORTANT sources of energy that could heat either the planet's surface or its interior |
which planets melted (or which planets are easier to melt) and which didn't? why? |
|
homework (written assignments to be turned in) |
you
will determine many of your star's properties from what we observe (its spectral class, distance -- obtained from parallax, and absolute magnitude_ a) identify your star's name & the spectral/luminosity class listed in the Appendix 5 table b) determine your star's temperature (in K).... from your star's spectral class by using the decoding graph , figure 19-12.... note that each lettered spectral class (for example, B, has 10 subclasses: B0 followed by B1, B2, .... B9, which is followed by A0, A1, A2...) c) determine the wavelength of max flux for your star AND what color your star would appear to humans d) determine your star's luminosity relative to the sun by using the secret formula Lstar/Lsun = 2.512(4.7 - M) where M is your star's absolute visual magnitude (your luminosity ratio should also match that given in Figure 19-14a) e) the flux of your star at Earth in SI units (check that the distance listed is properly computed from your star's parallax.... there is at least one mistake in the table, but I've forgotten whic star is wrong)) 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) |
||||
|
|
meteorite
classification |
parents'
jit available on the Astrophysics moodle site.... login name for parents is astroguestl ditto for the password |
|||
|
|
spectra
lab due |
are
you working on your lab for tomorrow? |
sun
lab due today's lab: asteroid parallax we will use the HOU software... it would be a good idea to bring your computer if you have the HOU software installed; otherwise, bring a flash drive to save your intermediate images images are here: asteroid1.fts asteroid2.fts |
sun lab due | |
|
of the week |
| Monday, September 1 |
September 2 |
September 3 |
September 4 |
September 5 |
|
|
|
deadline for picking your star (from Appendix 5) in class; first come, first choice what is the flux of the sun at earth? |
jit2 due by
noon today it's on moodle |
|||
|
(always done before class) |
5(3,4) (which you have already read) |
19(2) and then 19(1) |
box
5-4 box 19-2 box 1-1 & lab below |
7(1,4)
& 8(1,2,4,5) |
|
things you should know the answer to before coming to class |
hopefully you still remember the differences between flux and luminosity |
how astronomers use parallax to measure distance where the formula d = 1/p came from? be ready to present a derivation in class |
why is the parallax method limited by some maximum distance? what planet (in the solar system) would astronomers like to be living on to measure parallaxes? |
||
homework (written assignments to be turned in) |
collective list of stellar properties |
||||
|
|
red sky on Mars red sky on Earth (due to volcanic eruptions).... and also responsible for the red sky in Edvard Munch's "The Scream" Rayleigh scattering and blue sky, blue water, and ... relfection nebulas are blue but not due to rayleigh scattering and the blue of blue jays was thought to be due to Rayleigh scattering until 4 years ago when someone checked.... full details from Journal of Experimental Biology |
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 |
|||
|
|
solar
luminosity lab: we measure the luminosity and temperature of the sun with a meter stick, a light bulb, and two pieces of paraffin |
spectra
lab data collection must be finished since we are putting equipment away spectra lab due Monday |
|||
|
of the week |
