syllabus
& course
expectations
safety,
tardy, classroom computer use, and honesty
Astronomy
Picture of the Day
the
latest astrophysics discoveries
what's up in the sky
this week
| Monday, February 15 |
February 16 |
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make sure that you have green book in class today |
final exam sometime today make sure that you have checked the exam schedule so that you know where it is you can use YOUR notes (in your handwriting), your past assignments (homework and labs), any official handouts (green book, particle sheet) bring your textbook, but you will likely not be using it amnesty hour is 10 - 11 am today you can bring in assignments (labs and homework) that were done sort of on time but were not turned into the black box before grading started (this does not include assignments that were not done until today) |
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(always done before class) |
nothing new we didnt finish last friday's stuff |
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see friday questions |
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homework (written assignments to be turned in) |
absolute last chance to turn in any assignments is today |
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web stuff |
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 the Antennae, a galaxy-galaxy collision molecular clouds & cooling molecules in space how stellar disks form and evolve (theory in pictures) the first observations of jets and
disks during stellar
birth Stellar
Disks Set Stage for
disks without
jets: planet
building?:
Protoplanetary Disks |
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of the week |
| Monday, February 8 |
February 9 |
February 10 |
February 11 |
February 12 |
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short classes |
last (or 2nd
last?) jit of
the trimester is now available in moodle... due by 1 pm remember that you are to use no other source besides articles contained within the JIT or the text make sure that you haev your green book & calculator |
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(always done before class) |
21(3), especially figure 21-9 |
neutrinos: 18(4) pp. 407 - 408 & the atmospheric-neutrino article |
20(1,2) did you do tuesday's reading? 21(3) <------ 21(1) |
20(7,8) |
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things you should know the answer to before coming to class |
see the questions in last friday's slot.... we didnt make much progress how do astronomers KNOW (with observational evidence to back it up) that massive main-sequence stars live less long than less massive stars? you (with your table partner) will get to calculate the red giant lifetime based on the calculation we did in class friday (for main-sequence lifetime) be prepared! it's a quiz! |
how can tell the age of a star? how would we calculate lifetimes of other phases of a star's life? (we've already done main sequence and red giant in class) have we proved that chemical burning cannot have powered the sun for its lifetime? |
questions imspired by yesterday's class: so what is the charge of the weak force? (what is that you have to have to participate?) how did Mr. Davis collect the handful of Ar atoms from the huge chlorine tank? not something i want you to look up, but use your chemistry knowledge: what bonds best with argon? look again at the 3 tables we looked at in class today on page 21 green book: why is it that one of the reactions in the middle table, has a target area (cross sectional area) of zero? how can that be? (hint: the answer is in the 3rd table!) the big question: what are the 3 generic explanations for why experiments on earth have not detected the expected number of solar neutrinos? how are the atmospheric neutrinos (in the weighing the neutrino article) produced? what process makes them? stellar birth questions: what are some on the objects out there that seem to be in the process of star making? |
what's
in the interstellar medium? what are the 3 types of nebulas present? how do each of them show themselves? how do we know they are there?: what are 3 pieces of evidence for the presence of interstellar dust? ditto for interstellar gas? what condition(s) would require a star to contract? to expand? (hint: it's an inequality!) what controls each side of the inequality? |
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homework (written assignments to be turned in) |
"your fusion" reaction assignment due sign up for your reaction on the bulletin board OUTSIDE the physics hallway (just around the corner from the elevator) [the sign-up sheet is page 25 in your green book; follow exactly the procedure i showed you in class! 1) name & show the three integer conservation laws 2) calculate the KE/light released (or absorbed?) in Mev in the nuclear reaction, following the same steps we did in class 3) calculate the efficiency of the reaction if any of your nuclei are not in Appendix F in Walker, find the mass (in u) here (type your isotope, for example C-12, in the box at the upper left) start EARLY, so that if you end with questions, you can come get help! |
show and tells we would really like to see answers to before the course ends: how hot does it have to be for fusion in the sun? we know the energy of the coulomb barrier at the protons' closest approach to each other.... how much KE is needed to get over it? how long could the sun have lasted on all the gravitational energy it has released in its lifetime? how long can the sun last on chemical energy? how big is the orbit of Nemesis, the sun's possible companion? would it be visible in binoculars? a small telescope? |
bring to class a circular cutout representing your extrasolar palnet with diameter = 10 cm*(Myp/MJ) with color of the cutout determined by the temperature of your planet black = 0 - 300 K violet = 300-500K blue = 500 - 700 K green = 700-900 K yellow = 900 - 1100 K orange = 1100 - 1300 K red > 1300 K also write on your circle: 1) your extrasolar planet's orbit radius in au 2) your extrasolar planet's star's luminosity relative to the sun |
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the first neutrino image
of the sun
Super-Kamiokande and its photomultipliers surrounding the water (before it was destroyed in a chain reaction) |
are
periodic extinctions really caused by a companion to the sun? A Scientific American debate A UC-Berkeley discussion |
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binary
star lab due have you entered you star radii in moodle? (moodle slots opens at 6 am saturday) |
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of the week |
| Monday, February 1 |
February 2 |
February 3 |
February 4 |
February 5 |
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canceled |
also, bring to
class TOMORROW (wednesday) a printed copy of your
extrasolarplanet's (starr's) radial velocity curve start early, because some curves are harder to find than others as instructions say, first try clicking on the data links to your extrasolar planet star in either of the two encyclopedias... if that doesnt work, there is always google if after 15 minutes, you still havent found it, write me (although not later than 9 pm tonight).... |
jit is now
available in moodle due by
10:45 am today |
in addition to
your green book & calculator, make sure you have your
particle physics handout AND your radial velocity curve bring to class today your binary star lab book which contains everything up through part C of the lab (radii of the two stars) also, please think carefully about (because no one came up with the correct answer last time) the deeper eclipse is always the eclipse of the __________ star by using the star cutouts and thinking carefullly about the answer to the question: in which eclipse (primary = deeper or secondary) is more area covered? (are you using your star cutours?) |
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(always done before class) |
the search for dark
matter moodle readings include a different search for dark matter article (Scientific American March 2003) plus The Universe's Invisible Hand on dark energy (Scientific American February 2007) plus Did Dark Matter Power Early Superstars? (Sky and Telescope March 2010) |
18(2) a new topic: the interior of stars, particularly the sun Walker 15(2 on Pascal's principle.... how does pressure vary with depth?) Walker bottom of p. 549-551 on the derivation of the perfect gas law |
18(1)
for the JIT 18(2) since we didnt get to it yesterday |
18(4)
and pages |
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things you should know the answer to before coming to class |
the first questions I will ask in class: how does pressure vary with depth in an incompressible fluid? where does the perfect gas law come from? why does pressure depend on temperature and on particle density? |
see questions <------ |
what is the strong force's strength (relative to the electric force)? what tells us? from Universe: how did the temperature get to be so high at the center of the sun so that fusion could start? what if fusion slowed down in the sun (compared to its present rate); what would happen? what if fusion sped up and produced more energy than presently; what would happen? (for both questions, connect the dots) why doesn't the sun collapse under its own gravity? why does the gas pressure increase with depth in the sun? why does the gas temperature increase with depth in the sun? why does high density and high temperature produce high pressure? (what's the physics?) how does the energy released in fusion get to the surface? by what processes? |
from the end of yesterday's class what were the 3 mistakes we made in sun's main-sequence lifetime calculation that we did right at the end of yesterday's class (in making each mistake, we allowed the sun to live longer than it actually does) new questions from the new reading: what are the 2 or 3 DIFFERENT ways that we can detect neutrinos? what is the flux of solar neutrinos at earth? why isn't it easy to detect neutrinos? questions we didnt get to yet: how did the temperature get to be so high at the center of the sun so that fusion could start? what if fusion slowed down in the sun (compared to its present rate); what would happen? what if fusion sped up and produced more energy than presently; what would happen? (for both questions, connect the dots how does the energy released in fusion get to the surface? by what processes? |
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homework (written assignments to be turned in) |
have you selected your extrasolar planet and posted your choice in moodle? |
extrasolar planet homework due (start early... it's fairly long) moved to friday---> |
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European catalog of
extrasolar planets Princeton catalog of extrasolar planets for help in your homework due thursday |
here's
another extrasolar
planet catalog I found that has more direct links to the original
data and is organizable (clickable) by different parameters (period,
orbit size, mass, etc) by clicking on the column headings at the top of
the page |
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binary star lab due monday | ||||
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of the week |
january pages
december pages
november pages