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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October 30 |
October 31 |
November 1 |
November 2 |
November 3 |
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students return from extended faculty have countless meetings |
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and questions |
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(always done before class) |
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matching the steps on page 25 (green book) to 1) those pictured in the starbirth summary table & 2) the figures in Chapter 20 of the text |
and pages 172, 177 |
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<---- 25(5): the origin of the spiral shock wave in galaxies |
things you should know the answer to before coming to class |
see above |
figures in chapter 20 and pages 172, 177 & those listed on page 25 of green book matched to the 5 starbirth steps ("step 6" could be main sequence stars with, perhaps, planets) in the starbirth summary table what two "things" can a non-contracting, non-expanding interstellar cloud do (or have done to it) so that its energy (presently zero) can become negative and therefore begin collapsing? (looking at the terms in the calculation of total energy should immediately tell you! further hint: if the cloud were an isolated, closed system, its energy would remain the same (i.e., be conserved) and thus not change its expanding/constracting/sitting still status.... therefore these two "things" must involve an interaction with the outside world) how in practice do these two "things happen" ? I want details! |
why do starbirth objects end up
shaped like disks? why do they produce jets? what are the sources of shock waves that squeeze the clouds? what is the energy source of protostars? how long do the various phases of starbirth last and how do we know? |
see yesterday's questions <---- plus what does the H-R diagram of a young cluster (with star birth still going on) look like? what is the difference between protostars and pre-main-sequence stars? (behavior? state of matter? appearance?) |
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| homework (written assignments to be turned in) |
see ---> |
bring
to class (on paper, ready to hand in at the beginning of class), a) the name of your "starbirth-related" object b) its properties (T, M, R, and composition) including page number references to text ore elsewhere and/or how they were calculated c) the kinetic energy d) the gravitational energy e) the total energy f) whether it is collapsing or expanding & why g) does the theoretical calculations you did fit expectations? |
last chance for corrections to your board presentations on starbirth objects (there are still some incorrect entries on the board) |
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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 interstellar and circumstellar molecules 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 life |
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interstellar lab due |
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stellar sorting in a globular cluster HII regions and star clusters in the Antennae peeling back layers in Cas A |
Hubble views rare light echo |
(NY Times editorial) Hubble will be fixed (yes, NASA finally decides in favor of science!) |
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October 24 |
October 25 |
October 26 |
October 27 |
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jit due by 8am |
we do a lab on
interstellar matter; bring your lab book |
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(always done before class) |
Weighing
in on the Neutrino Mass --
the experiment that won the other half of the 2002 Nobel
Prize in Physics & 18(8-10) on sunspots |
20(1,2,8) 22(3) about different kinds of nebulae and their colors and spectra |
finish
reading chapter 18 check out at least 3 of the web links below |
20(3,7,8) |
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| things
you should know the answer to before coming to class |
what
the differences are between an emission nebula, a reflection nebula, a
planetary nebula, and a supernova remnant |
how
is that a portion of the interstellar medium begins its journey toward
starhood? to help answer this: before the collapse begins, what two forces are in balance? what property (or properties) of the nebula (protostar-to-be) must change (and how?) so the collapse of the nebula can begin? what are the (generic) names of the various kinds of clouds or nebulas that show signs of incipient or recent starbirth? answers are all in the reading! |
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homework (written assignments to be turned in) |
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the first neutrino image
of the sun
Sudbury Neutrino Observatory detection physics |
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
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of the week |
what the space shuttle has done to science funding in the US |
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October 16 |
October 17 |
October 18 |
October 19 |
October 20 |
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(always done before class) |
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in the sun: 18(3,5) on earth: boiling water: p. 188 in the oceans: p. 188 in the atmosphere: p. 187-188, 202, 250 in the mantle: p. 194-195 |
and pages 407-408 the neutrino section |
the
Mystery of the Missing
Neutrinos -- this
experiment won half of the 2004 Nobel Prize in Physics
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| things you should know the answer to before coming to class | how did the temperature get to be so high at the center of the sun so that fusion could start? 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 does the energy released in fusion get to the surface? by what processes? |
why does the sun switch from photon diffusion to convection about 70% of the way to the surface? what kind of problem would we do to find the time it takes for convection to move the energy through the outer 30% of the sun? why does convection occur in boiling water on the stove? why doesn't photon diffusion work? why not conduction? |
how
do we detect neutrinos? what are the various ways? why does the neutrino interact weakly with matter? have we solved the problem of the sun's missing neutrinos? how? |
be
able to talk sensibly about the different ways of detecting neutrinos how did we figure out that neutrinos made in the atmosphere were decaying (changing into something else) before they got to the ground (second reading above)? how did the affair of the atmospheric neutrinos (second reading above) help us with the first issue (the missing solar neutrinos, first reading above)? what was special about the sudbury detector (with heavy water) that allowed it to nail down the solution to the missing solar neutrinos? |
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| homework (written assignments to be turned in) |
for
your nuclear reaction: write the reaction and balance the three quantum numbers, Q, B, Le find the energy released in Mev (make sure that you start with Ei = Ef, and no numbers until the end) find the efficiency of your reaction find out how long the sun would last (in years) if the sun's core were made completely of the initial reactants of your reaction |
find the average acceleration of a convective cell we derived this in class; you have to find/justify the numerical value also find the time it takes the cell to reach the surface and the velocity it has when it gets there |
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statistics of exoplanets jk's summary of extrasolar planets properties brown dwarfs, planets, and superplanets |
(properties, including mass of atoms.... just type in the box, for example to find the mass of the C12 atom, type C12) |
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weather on an extrasolar planet |
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| Monday, October 9 |
October 10 |
October 11 |
October 12 |
October 13 |
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make sure that
you have your green book and the particle physics handout with you today jit due by 8 am |
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(always done before class) |
25(4) & 26(8) |
read
the captions on green book, p. 14, so you know the evidence for
Nemesis, the sun's binary companion big bang day: in honor of the Nobel prize award this year, I will answer questions about the 3 K background radiation and its importance if you have them (if not, we'll just go onto the next topic) from the reading 29(3-4) (also, see web stuff below) |
18(1)
on the fusion going on inside the sun |
read
about nuclear physics in Walker: 32(1, 4) |
Walker
32(6) a short section on fusion but block D hasn't covered binding energy yet |
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you should know the answer to before coming to class |
other ways to detect dark matter
besides the rotation curves of spiral galaxies see mass/inventory of universe link below |
find
the power law that relates luminosity to mass, using figure 19-20 |
what things are in the nucleus?, what things feel the nuclear force? what is the range of the strong force? is there a formula for the magnitude of the force? how big is a nucleus? how big is a proton? are the protons/neutrons touching? why are some nuclei stable and some not? what is binding energy? |
what physics principle was used to calculate binding energy of tritium? what physics principle was used to calculate the energy released during fusion? bring an example of a bound gravitational system, a bound electrical system, and a bound nuclear system to class.... maybe you even know the binding energies of each? |
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homework (written assignments to be turned in) |
make a table summarizing the results of friday: column 1: orbital speed dependence on r (e.g., linear, constant, etc) 2: where that dependence occurs in the galaxy (near center, near edge, most of galaxy) 3: mass inside dependence on r 4: shape of mass distribution (e.g., spherical, with uniform density, ...) |
5
pm homework: for your planet ((and using ONLY the observable quantities: period, radial velocity plot, and spectral/luminosity class of the star)) 1) attach a printed copy of your planet's star's radial velocity curve 2) find the lower limit to your planet's mass 3) % difference between your value and the accepted value (it should be less than 2% unless your orbit is noticeably elliptical) d) the planet's orbit size e) % diff f) a range for the planet's surface temperature (using a reasonable range for albedo) g) the likely composition of your planet based on its formation temperature (with justification!) |
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mass/energy inventory of the universe | first
image of
an extrasolar planetare periodic
extinctions
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RW Mon lab due | RW Mon lab due | |||
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of the week |
Nobel prize cosmology
for beginners Nobel prize cosmology for astronomers-to-be |
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October 2 |
October 3 |
October 4 |
October 5 |
October 6 |
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(always done before class) |
19(9-11) |
24(3) on finidng black holes in binary systems |
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(basic stuff about what's our galaxy and how we figured out that we live in a galaxy) the key sections are 25(4) and box 25-2 |
+ we still have to discuss the galaxy's rotation and dark matter |
| things you should know the answer to before coming to class | know the different types of binary stars and how to detect them | how to determine the mass of a
galaxy why/how the shape of the rotation curve -- figure 25-16, page 566 -- tells us that the galaxy contains dark matter |
how to tell the difference between a main sequence star, a giant star, and a supergiant star |
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| homework (written assignments to be turned in) |
bring
to class: from the physics equations we had in class today (N's version of K's 3rd law, with special units; the center of mass condition, the formula for speed in a circular orbit), show that mB3/(mA+mB)2 = PvA3/(8p)3 hint: start with N's version of K3 and then eliminate aB using the seesaw condition; then eliminate aA in favor of vA for star A |
bring
to class: a printed copy of your planet's star's radial velocity curve see the catalogs below |
bring
to class: 1) your grade record (4 homework scores and 2 lab scores) 2) RE-DO the calculation for the mass of the galaxy in box 25-2, EXCEPT you do it for the mass inside distance d (in kiloparsecs) where d (in kpc) = 0.7 x (number that the first letter of your last name is in the order of the alphabet).... e.g., if my last name is Kolena, the first letter of my last nameis K; K is the 11th letter of the alphabet, so I would find the mass inside the distance d = .7 x 11 kiloparsecs = 7,700 pc... you will of course need the orbit speed that goes with that distance from the graph on page 566 3) block D only: how your knew the units of G in the special units (not just the answer please) |
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the eclipsing binary applet |
Nobel prize cosmology for astronomers-to-be |
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France catalog of extrasolar planets |
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september pages for astro 06