PHY 102 1st EditionOutline of Last LectureI. Big Bang ReviewII. The First Epocha. Temperature, not timeb. PredictionsIII. Standard Model’s Cosmic Zooa. Quarksb. RadiationIV. The Second EpochV. The Third EpochVI. The Fourth EpochVII. The Fifth EpochVIII. Proton-Proton ReactionIX. The Sixth EpochX. The Seventh EpochXI. SummaryOutline of Current LectureI. Cosmic Structure FormationII. Star FormationIII. Wrinkles In SpacetimeThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.IV. Problems with the Standard form of CosmologyV. Inflationary CosmologyVI. Galaxy Formation UncertaintyVII. Death of a Stara. White Dwarfsb. Black HOlesCurrent Lecture I. Cosmic Structure Formationa. Today we have a matter-dominated universe ruled by the force of gravityi. The formation of stars and the organization of stars in clusters raise questions about the formation of the universeii. Some variations need to be accounted forb. Slight variations in density produce formation regions for stars and galaxiesc. 1st generation stars and galaxies have 74% H and 26% He by massi. Oldest stars we see are in globular clusters and tend to have mostly hydrogen and helium and hardly anything elseii. E = mc2 is the energy poured out from the reactions that produce visible lightd. 2nd generation stars are enriched – our sun is at least a second generation stare. Triple Alpha Processi. Helium in a core, then all the helium in the core is converted to carbon ina matter of minutesII. Star Formationa. As H and He accrete, gas pressure increases limiting further growth unless there is suffiecient matter; maximum star mass is about 60Msun.b. The Jeans mass (=105Msun) constitutes the minimum amount of mass required for star formation (corresponds to globular star cluster)c. Collapses of smaller clouds are helped along by:i. Stochastic processes (wakes of exploding stars or two or more gas clouds merging)ii. Compression by magnetic field of galaxy1. Pushes a gas cloud over its limit and forces stars to be formediii. Spiral galaxies show star formation1. There are not more stars in the arms of a spiral galaxy, but the stars in the brighter regions are younger stars that are massive and bright2. Large bright stars die out quickly and the magnetic waves in the galaxyIII. Wrinkles in Spacetimea. COBE observed the cosmic microwave background, but there was an ever-so-slight variation in temperature (and thus density) from point to point across the skyi. There is variation in the background radiation, we are not quite sure whyii. Some areas are hotter, some are coolerIV. Problems with the Standard Model of Cosmologya. The model of the expanding universe works quite well to explain:i. Olber’s paradox1. The night sky is dark because the universe is expanding proportionally to the light reaching the earth2. Objects close to the edge of the universe are so red shifted that we no longer see them3. Cosmological Constant added by Einsteinii. X, Y, and Z abundances (74%, 26%, 0%, and later)iii. Hubble’s relationship, v = HRiv. 2.725K cosmic background radiationb. 3 major problems remaini. The flatness problem1. If shortly after the Big Bang the universe was even remotely non-flat, we would not have the relatively flat universe we observe today2. Why did the universe’s original flatness balance on a knife’s edge when so many other possibilities existed?a. 11 dimensions currently known ofii. The horizon problem1. The cosmic microwave background is amazingly uniform but for every minute variations equal to about .00001 K2. How is this possible when opposite “ends” of the universe cannot “communicate”?a. It appears that multiple universes existiii. The structure problem1. Friedmann’s assumption of homogeneity and isotropy is not entirely correct as seen in the pockets of higher density in the universe as shown in the cosmic background radiation.V. Inflationary Cosmologya. In an attempt to solve these three problems, the suggestion was made of an inflationary period in the early universe.b. Between 10-34 and 10-32 seconds after the Big Bang, the universe grew exponentially – from the size of a nucleonVI. Galaxy Formation Uncertaina. Did galaxy or star formation come first?i. Could be at the same timeii. Could be that the gas clouds formed firstb. Unclear, and problem is confounded by the presence of dark matter the nature of which is completely unknowni. If it really is law that the period is related to the average distance, then the farther out in the galaxy you go, the rate of particle’s motion should drop ofii. This is not the case, the velocity of stars remains relatively constant c. Its presence is deduced from rotation curvesVII. Death of a Stara. Stars with diferent masses will evolve at diferent ratesb. H – He – C – N – Oi. All stars begin this way – 90% H and 10% He by particle #ii. As higher pressure and temperatures occur, they can collapse into more dense particlesc. Near the end of their life spans, stars become red giantsd. 3 possible end states determined by the mass of the star:i. White dwarf (low mass)1. Produced in planetary nebula phase where atmosphere begins a runaway process2. An earth-sized core is revealed at 100,000 K +a. Core becomes larger and hotter as it compressesb. The outer envelope of the star expandsc. Surface layer are charged particles expanding quicklyd. The larger the star, the lower the escape velocity of the outer particlese. Outer envelope goes out into space3. Hotter inner layers take of into spaceii. Neutron star (medium)1. Produced during a supernova explosion resulting in a pulsar2. Protons and electrons are crushed to produce neutronsa. Energy that has been supporting the star is now sucked into the coreb. Core begins collapsing and a violent explosion occursc. Gas layers surrounding the coreiii. Black hole (high mass)1. Produced in supernova explosions but neutron degeneracy cannot stop collapse (neutrons crash into neutrons)2. No known forces can stop the matter from simply vanishing3. Gravity is so strong that even light cannot escapea. Photons become infinitely red shifted and light cannot get outb. Physical velocity is greater than the speed of light4. We know about electromagnetism, gravitation, strong, and weak force5. Accretion disk (such as Cygnus X-1) often found in binary star systems6. Detectiona. X-ray sourcesb. Gravitational efects on binary