PHY 102 1st EditionOutline of Last LectureI. Reviewa. Hubble Constantb. Big Bangc. Radiationd. Matter condensesII. Specific Lawsa. Weir’s Lawb. Stefan Boitzmann LawIII. Expansion and Olber’s ParadoxIV. Echo of the Big BangOutline of Current LectureI. Big Bang ReviewII. The First Epocha. Temperature, not timeb. PredictionsIII. Standard Model’s Cosmic Zooa. Quarksb. RadiationIV. The Second EpochThese 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.V. The Third EpochVI. The Fourth EpochVII. The Fifth EpochVIII. Proton-Proton ReactionIX. The Sixth EpochX. The Seventh EpochXI. SummaryCurrent Lecture I. Big Bang Reviewa. Evidence for the Big Bangi. Hubble’s law, v = HR, shows that galaxies at greater distances move fasterii. 2.7k scosmic background radiationiii. Look-back time shows ‘evolution’iv. Theoretical models of the universe are consistent with observationsb. The expansion age of the universe is 1/H which gives 13.8 billion yearsc. Farther out you go, the further back in time you go.II. The First Epoch, 1014K < T < infinitya. Considerationsi. Time is not as important as temperature because temperature determines makeup of the universe1. Astronomers do not understand the beginning of the universe2. Temperatures at the beginning were near infinityii. Predictions do appear to match observationsb. Ignoring details for a moment, radiation quickly condenses into quarks, leptons, and bosonsc. Quarks become hadrons with the number of matter particles slightly outnumbering the anti-particles due to CP (charge conjugation, parity) violationi. Quarks are the smallest particle of matter (if one can even say that)d. The universe is expanding and the material in the universe is simply being carriedalong by the expansionIII. Standard Model’s Cosmic Zooa. Quarks are the building blocks of hadrons (baryons/mesons)i. We have never looked inside of a proton to see the quarks but from indirect observation we know they existb. Quarks have various intrinsic properties, including electric and color charge, mass, and spinc. They are never directly observed or found in isolation today due to their high threshold temperaturesd. Each quark and lepton has its own antiparticlee. Gauge bosons are force carriersf. Geiger Counteri. We are being showered with radiant particles as they approach the speedof lightii. We might have very highly energized objects hitting the atmosphere and showering the earth with highly charged particlesIV. The Second Epoch, 1012K < T < 1014Ka. As space expands and temperature drops ( a few nanoseconds after BB), quarks and anti-quarks begin to separate and experience the “strong” nuclear force mediated by the gluons – force carriers – due to symmetry breakingi. Einstein went to President and said to have discovered the atomic bomb based on e = mc2ii. By 1947, a nuclear bomb was usedb. Radiant Energy flows from the antiquarks to the quarksi. The forces that attract quarks is so strong that the only way to separate them is to be put under extremely high radiation pressure and extremely high temperature (can’t be done on earth)c. Quarks combine to form hadronsV. Epoch 3: 1010K < T < 1012Ka. The universe is now 1/10,000 seconds oldb. A small “contamination” of protons and neutrons due to their earlier formation from quarksc. Radiant energy produces quarks, quarks produce protons and neuronsVI. Epoch 4: 109K < T < 1010 Ka. One second has passed since the Big Bangb. The universe is composed mostly of electrons, positrons, 3 types of neutrinos, photons, and a small amount of protons and neutronsi. There are roughly the same number of protons as there are electronsii. Electrons pull into the nuclei and allow a burst of radiation to scatter through the universe - decouplingc. Electrons actually form a fog which scatters lightd. Overall density of the universe has dropped and neutrinos “decouple” from mattere. At the end of this period, anti-matter has pretty much disappeared due to CP violation – matter now dominatesVII. Epoch 5: 108K < T < 109Ka. 3 minutes after Big Bangb. Photons and neutrinos still dominatec. Protons and neutrons start to interact with each otherd. Nuclear particles: 87% protons, 13% neutronse. Universe “cooks” protons and neutrons producing alpha particles – the nuclei of He – in the proton-proton reactionf. At the end, the main mass of the universe is 74% H nuclei and 26% He nuclei by mass (90% H and 10% He by number)VIII. Proton-Proton Reactionsa. What powers the hydrogen bombs – basically bring small suns to the surface of the earthb. Processi. Hydrogens “floating around”ii. When they get close enough they exchange gluonsiii. Create positrons and neutrinosiv. Mass is conserved by converting hydrogen to helium and the rest of the mass is antimatter, neutrinos, and positronsc. During WWII, Germans were using water and pulled out the deuteron from the water in order to attempt a nuclear bombIX. Epoch 6: 15,000 K <T < 108Ka. About 5 hours after the big bangb. H and He nuclei and electrons are immersed in a sea of photonsc. 1.6 billion photons for every nucleon, a ratio that remains fixed even todayd. Universe still dominated by neutrinos and radiatione. Electromagnetic radiation “trapped” due to scattering processes with charged particlesX. Epoch 7: 3,000 K < T < 15,000 Ka. 25,000 years after big bangb. Matter begins to dominatec. Temperature dropsXI. Summary – Ia. The cause of the Big Bang is unknown to scientistsb. It began with pure radiant energyc. One could not have “stood outside” and watched the Big Bang, as space was partof the Big Bang as well.d. As the universe expanded and cooled, matter formed according to Einstein’s equation E = mc2e. Among the first particles to form were electrons and quarks; quarks later formed the nucleons (e.g., protons, neutrons) in equal amounts, both matter and antimatterf. It is not well understood why matter dominates today; one possible answer is theCP violationg. As the universe continued to expand and cool, radiation became decouple d frommatter and that is the origin from cosmic background radiationh. The cosmic radiation is seen as highly red shifted today due to the expansion of the universe, and has a black body temperature of 2.725 K observedi. The early protons and neutrons fused to form He nucleus via the proton-proton reaction and limited amountsj. The