1Birthof theUniverseevidence, on-going experimentsMonday, December 5, 112Learning Goals for this Lecture• Describe the empirical data (the observations) that led to the assumption that there was a “Big Bang.”• Outline the events that led to the discovery of the cosmic microwave background radiation.• Explain why it is that we will never be able to use “look-back time” to witness the Big Bang.• Summarize the main points in the current theory of the birth of the Universe and the supporting observational evidence:– Inflationary period– Particle era• Explain what experiments the Large Hadron Collider is conducting that will simulate the conditions at the Big Bang.Monday, December 5, 113The Universe is Expanding - € v = HodMonday, December 5, 114Discovery of cosmic microwave background radiationhttp://www.youtube.com/watch?v=SB_Qfngi0mo26:15 - 31:15Monday, December 5, 115Consensus for this model brought about by the presence of empirical data• Recession of distant galaxies• Evolution of galaxies - look back time• Weak radio static that fills the Universe: Heat of the birth• A dark night skyObservational FoundationsMonday, December 5, 116Olber’s Paradox: Why isn't the night sky uniformly bright?Why do we expect the night sky to appear uniformly bright in a Steady State Universe? This theory is based on three assumptions: Universe is 1. Uniform (will observe no differences among galaxies) 2. not expanding (will observe no redshifts) 3. of infinite proportions (in both time and space)In ALL directions, our eyes would fall upon a star. If not a star, then a galaxy.Solution: Universe had a beginning. Light from distant galaxies hasn’t reached us yet. Stars die.WikipediaMonday, December 5, 117The CMBR is a curtain that prevents our seeing farther(Explain why it is that we will never be able to use “look-back time” to witness the Big Bang.)Monday, December 5, 118Learning Goals for this Lecture• Describe the empirical data (the observations) that led to the assumption that there was a “Big Bang.”• Outline the events that led to the discovery of the cosmic microwave background radiation.• Explain why it is that we will never be able to use “look-back time” to witness the Big Bang.• Summarize the main points in the current theory of the birth of the Universe and the supporting observational evidence:– Inflationary period– Particle era• Explain what experiments the Large Hadron Collider is conducting that will simulate the conditions at the Big Bang.Monday, December 5, 119Universe started as asingularity about the sizeof a grapefruit....Monday, December 5, 1110All of space AND time was created in that instantMonday, December 5, 1110Big Bang was not centered in any one place – it occurred everywhere because there was nowhere else!All of space AND time was created in that instantMonday, December 5, 1111Inflationary theory explains 3 main sticky points:1) Where does structure come from?2) Why is the overall distribution of matter so uniform?3) Why is the density of the universe so close to the critical density?Monday, December 5, 1111Our visible UniverseInflationary theory explains 3 main sticky points:1) Where does structure come from?2) Why is the overall distribution of matter so uniform?3) Why is the density of the universe so close to the critical density?Monday, December 5, 1112You are hereMonday, December 5, 1113Inflationary Period Explains1) Where does structure come from?2) Why is the overall distribution of matter so uniform?3) Why is the density of the universe so close to the critical density?Monday, December 5, 1114Review of the first 3 minutesMonday, December 5, 1115Chapter S4 of textpp. 449 - 465FermilabMonday, December 5, 1116Large Hadron ColliderHadrons are made of quarks held together by the strong force (gluons)--baryons (made of three quarks; e.g. protons, neutrons) --mesons (made of one quark and one antiquark; charged mesons decay to electrons and neutrinos. Uncharged mesons may decay to photons.)Monday, December 5, 1117Fundamental building blocks of atoms: up quark, down quark, and electronmatter and antimatter are real€ m =Ec2⇔ E = mc2Monday, December 5, 1118•Decoupling of light and matter•Atomic Era•Ratio H : He set•Nucleosynthesis•Quarks combined•Particle EraMonday, December 5,
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