The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 1 Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture 19

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 2 Was due Today – L19 Reading: –(Unit 4) Pre-Lecture Reading Questions: –Unit 4: Stage 2 End-of-Chapter Quizzes: –Chapter 12 Papers: –Paper 2 Revision (if desired): Stage 1 was due today –Paper 3: Stage 1 due Monday before class Honors Papers: –(Stage 2) –Final paper due on the last day of class

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 3 Unit 4: Evolution of the Universe Big Picture of the Evolution of the Universe: Temperature and Time Collisions and how they explain what we see The First Three Minutes After the First Three Minutes

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 4 Getting Started We now have a basic understanding of the evidence for the Big Bang Lets look at the Origin and Evolution of the Universe

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 5 The Big Bang Ideally we’d start telling the story at the Big Bang itself and then move forward Maybe even talk about what came BEFORE the Big Bang Unfortunately, we don’t REALLY understand the Bang part or if there even was a bang

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 6 Best We Can Do The best we can do with confidence is start describing the Universe a short time AFTER its beginning Start there, then work our way forward and backward in time What happened RIGHT AFTER the Big Bang? Then what happened after that? Then what? Etc.

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 7 The Big Bang Theory A Big Bang occurs and the early Universe comes into thermal equilibrium with lots of high energy particles Then the Universe gets –Bigger –Older and –Colder As time goes by it changes over time –Often we use the word evolves

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 8 The History of the Universe Universe expands as time passes Universe cools down as time passes 1 second 10 billion years 10 billion degrees 1 degree Bigger wavelengths  Smaller energies  Smaller Temperature

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 9 What happens at Different Times? Particles, nuclei and atoms interact in different ways at early times and later times –Early Times  High Temperature  High energy collisions –Later Times  Low Temperature  Low energy collisions

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 10 Various Times Explain what happens during each of a number of different periods in time –The VERY early universe –The first three Minutes –The next 300,000 years –The next billion years –~13 billion years later (now) –The ultimate fate of the universe? The first four will take a couple of lectures } Chap 14 } Chaps } Unit 6 } Chap 13

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 11 What Happening? What happens to the particles at each of these times? Collisions!

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 12 Collisions In each collision a number of things can happen Can create new particles »Only in high energy collisions –Particles can combine to form composite objects »Protons, neutrons, atoms etc. –Composite particles can get broken up –Collisions can transfer energy Thus, the energy of the particles and what particles CAN exist in nature has a HUGE impact on the evolution of the early universe Should also say that particles can decay

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 13 A Brief History of Time Zero Well before a trillionth of a second One millionth of one second A few minutes A few hundred thousand years 100 million to 1 billion years 9 billion years ~13.5 billion years The Big Bang (?) Universe comes into Thermal Equilibrium Quarks and gluons combine to form protons and neutrons Protons and Neutrons combine to form deuterium and helium nuclei Protons and electrons combine to form hydrogen atoms Stars and galaxies begin to form Our solar system forms You take ASTR/PHYS 109

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 14 More detail

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Confidence in this Story? How do we know this is what happened back then? What is the evidence for it? Will walk through the reasons next… It’s all about the energy of the collisions… 15

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 16 The Evolution of the Universe Overview 1.The Early Universe 2.The First Three Minutes 3.The next 300,000 years 4.The next billion years 5.The next ~13 billion years, until today The particles have the same temperature everywhere –Once the Universe comes into Thermal Equilibrium, it doesn’t really depend too much on what came before it

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 17 Not exactly sure how it all starts… Call it a Big Bang Artists conception…

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 18 Before a Millionth of a Second Lots of free particles at VERY high energies Quarks Photons Electrons Others  Back when the Universe was very small it quickly came into Thermal Equilibrium

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 19 Before a millionth of a Second Lots of free particles, all with the same temperature…

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 20 Quarks can combine in the Early Universe to make a proton, but are quickly broken apart by high energy photons in the Universe Quark  Proton Nuclear Reaction Quark qqq  Proton High Energy Photon Photon + Proton  qqq

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 21 Before a millionth of a second  very high energy collisions Lots of free quarks to make protons Not many protons in the Universe because they are quickly busted apart Protons-in-The-Early- Universe Bathtub Particles in the Universe: The Bathtub analogy

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 22 Time passes The Universe Expands and Cools Our story starts at a millionth of a second after the Big Bang Cool enough that when quarks combine to form a proton or neutron they stay together –Said differently, other particles aren’t energetic enough to bust them apart

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 23 A Millionth of a Second after the Big Bang The quarks have combined to form Protons and Neutrons

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math The Evolving Universe The Universe changes from this to this 24 Early UniverseLater Times

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 25 Protons after a Millionth of a Sceond After a millionth of a second No more free quarks to make more protons Number of protons doesn’t decrease because they aren’t getting busted apart by high energy photons –Don’t exist

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 26 Very Early Universe is Still Very Complicated The other fundamental and composite particles also have a big impact One example is a Muon which is (for our purposes) just a heavier version of an electron –Discuss them more in Chapter 19

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 27 Photons and Muons At very high energies photons can also turn into Muon pairs Muon pairs can turn into Photons

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 28 Electron Anti-Electron Photon Muon pairs can always produce photon pairs If the photons are energetic enough they can interact and create muon pairs (or vice versa)  muons, electrons and photons all have the same temperature Muons are an Important Part of the Early Universe Muon Anti-Muon

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 29 Why Aren’t They Around anymore? Most particles, except protons, electrons and photons decay REALLY quickly –Some at sec, some sec –Muons can live for sec Can study lots of different types of particles here in experiments on Earth Need an accelerator to produce most new ones if you want to study them The photons in Today’s Universe aren’t energetic enough to produce new ones

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 30 Muons can also decay - - Muon Electron Neutrino

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 31 Muons in the Universe Early UniverseLater Times

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 32 Very Early Universe is Very Complicated What particles CAN exist determine what’s going on in the Very Early Universe Problem: We don’t know if we have discovered all the fundamental particles yet! Good reasons to believe there are new ones out that we just haven’t found yet –Need bigger accelerators and/or Other tools –More on this later also

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 33 Nuclei in the Early Universe Proton  Deuterium Nuclear Reaction High Energy Photon A high energy photon can break apart the Nucleus before it can find an electron to create an Atom or find another nucleon to form a bigger nucleus Proton + Proton  Deuterium Deuterium + Photon  Proton + Neutron

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 34 What’s happening at about a millionth of a second after the Bang? Lots of protons –photons can’t break them apart any more Not many heavy nuclei: every time one forms a photon busts it apart Not many atoms: every time one forms a photon busts it apart Few “fancy” particles since most would have decayed already, new ones not being produced

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 35 Moving towards later times… Universe gets bigger, older and colder By one hundredth of a second after the Big Bang there are basically no fancy particles left and the story is simpler to tell Protons, Neutrons, Electrons, Photons etc.

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 36 Where are we? Fancy particles gone by this time

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 37 Electron Positron Low Energy photon Electron pairs and interact and annihilate but photon pairs no longer turn into particle pairs No easy way to produce more positrons Photons and Electrons at Later Times

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 38 Approaching the Three Minute Mark By three minutes after the bang the Universe is cool enough for Helium nuclei to form ( 4 He) even though it doesn’t happen too much… Complicated to produce 4 He, lots of intermediate steps that are easier to break apart

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 39 Nuclei at Lower Temperatures Proton  Deuterium Nuclear Reaction Photon At these lower energies the photon can’t often break apart the Nucleus  Amount of Deuterium in the Universe rises

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 40 For Next Time– L19 Reading: –(Unit 4) Pre-Lecture Reading Questions: –Unit 4 Revision (if Desired): Will open after Regrades End-of-Chapter Quizzes: –Chapter 13 (if we finished Chapter 13, else just 12) Papers: –Paper 2 Revision (if desired): Stage 2 due next Wednesday –Paper 3: Stage 1 due Monday Honors Papers: –(Stage 2) –Final paper due on the last day of class

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 41

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 1 Paragraph Essay Question Why are there so many more hydrogen and helium atoms in the universe than any other type of atom? 42

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Clicker Question Why is hydrogen the most abundant element in the universe today? a)It is the lightest element b)Any heavy elements that might have been present would have been broken apart by high energy photons in the early universe c)Both of these contribute 43

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Clicker Question Why do the photons in the universe appear to be in thermal equilibrium? a)Because they all have exactly the same energy b)They are in thermal equilibrium c)The universe has the same temperature in all directions, and the photons are just one of the particles in the Universe 44

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Clicker Question Let's say I have two galaxies in space and they are exactly stationary relative to each other. What will happen next? a)Since they are so massive that they will attract each other by gravity and start moving towards each other. b)Since space-time is expanding, the distance between them will grow as space-time expands so they will start moving away from each other. c)It depends on the overall distance between them. 45

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Clicker Question What was the last thing a typical photon in the universe (part of the Cosmic Background Radiation) did before we detected it? a)Broke apart a hydrogen atom b)Broke apart a helium nuclei c)Broke apart a Proton 46

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Clicker Question If the universe were contracting, which of the following would be evidence for it? a)Distant galaxies would be less red- shifted b)The Cosmic Background Radiation would have a lower temperature c)Distant galaxies would be blue shifted d)The Earth would be getting closer to the Sun e)Atoms would start shrinking 47

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Clicker Question Q: Which of the following statements is MOST correct? a)The photons in the cosmic background radiation are there because the Universe has been expanding for ~13 billion years b)The photons in the cosmic background radiation are there because the universe was in thermal equilibrium c)The photons in the cosmic background radiation are there because photons can exist forever 48

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Clicker Question If space-time is expanding, is our galaxy expanding? a)Yes. Everything in the universe is moving away from everything else. b)No. It isn't expanding because the gravitational attraction of masses pulls the galaxy back together again 49

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Clicker Question If space-time is expanding, are atoms expanding? a)Yes. Everything in the universe is moving away from everything else. b)No, they aren't expanding because the electric charge attraction and quantum mechanics keep the atoms the same size in space 50

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Clicker Question If the universe stated contracting, which of the following would be evidence for it? a)Distant galaxies would be less red-shifted b)The CMB would have a lower temperature c)We would start seeing distant galaxies have blue shifts d)The Earth would start getting closer to the Sun e)Atoms would start shrinking 51

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Clicker Question Why do we think that the Universe is an expansion of space-time and not an explosion? Fix me. a)Because distant galaxies are moving away from us. b)Because the farther away a galaxy is, the faster it is moving away c)Because hydrogen and helium are most of the atoms in the universe d)Because of the Cosmic Background Radiation e)Not great... 52

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 53 For Next Time– L15 Reading: –Unit 4 Pre-Lecture Reading Questions: –Unit 3 Revision in CPR (if desired): Stage 1 –Unit 4: Stage 1 End-of-Chapter Quizzes: –If we finished Chapter 12, then Chapter 12 (if not, Chapter 11) Papers: –Paper 1 Revision (if desired): Stage 2 due Monday March 17 by 11:55PM –Paper 2: Stage 2 due Monday March 17 by 11:55PM –Paper 3: If we finished Chapter 12, Stage 1 due Monday before class

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 54 Prep For Next Time – L19 Note: May change depending on how far we get in lecture Reading: –BBBHNM: All reading through Chapter 15 Reading Questions: –All reading questions through 15 End-of-Chapter Quizzes: –If we finished Chapter 13 then end-of-chapter quiz 13 (else just through Chapter 12)

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 55 Prep For Next Time – L20 Note: May change depending on how far we get in lecture Reading: –BBBHNM: All reading through Chapter 16 Reading Questions: –All reading questions through 16 End-of-Chapter Quizzes: –If we finished Chapter 13 then end-of-chapter quiz 13 (else just through Chapter 12)

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Papers 56 Papers: –Paper 0 Revision: Still working on re-grades. –Paper 1: All regrades now done. Let us know if you see any further mistakes. –Paper 1 Revision: Assignment closed before class. Let us know if you were misgraded –Paper 2: Working on re-grades –Paper 2 Revision: Posted. New due date is Monday Nov 4 th before class –Paper 3: Posted, text due Wed Nov 6 th before class

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 57 Was due for Today – L20 Reading: –BBBHNM: 15 Pre-Lecture Reading Questions: –Chapter 15 End of Chapter Quizzes: –Chapter 12 Papers: –Paper 0 Revision: Still working on re-grades. –Paper 1: All regrades now done. Let us know if you see any further mistakes. –Paper 1 Revision: Assignment closed before class. Let us know if you were misgraded –Paper 2: Working on re-grades –Paper 2 Revision: Posted. New due date is Monday Nov 4 th before class –Paper 3: Posted, text due Wed Nov 6 th before class

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 58 Was Due Today – L9 Reading –BBBHNM: All reading through Chapter 14 Reading Questions: –All reading questions through 14 eLearning Quizzes: –All quizzes through Chapter 12 Papers: –Paper 2 calibrations, reviews and self- assessment due before class –Paper 3 text due in CPR and turnitin.com due Wednesday!

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Tentative Due Dates – L9 Wednesday March 27 th –Paper 3 text due in CPR and turnitin (2-day extension) Monday April 1 st –Paper 3 Calibrations, Reviews and self-assessment due in CPR –Paper 2 Revisions (if desired) due in CPR and turnitin 59

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 60 Prep For Next Time – L8 Note: May change depending on how far we get in lecture Reading: –BBBHNM: All reading through Chapter 17 Reading Questions: –All reading questions through 17 eLearning Quizzes: –If we finished Chapter 13 then end-of-chapter quiz 13 (else just through Chapter 12) Papers: –Paper 3 text due in CPR and turnitin.com before class on Tuesday

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Prep for Next Time – P17 61 Reading –BBBHNM 14 Reading questions –Chapter 14 End-of-Chapter Quizzes –If we finished Chapter 13 then end-of- chapter quiz 13 (else just 12) Papers –Paper 2 Revision: Text due Monday before class –Paper 3: Text due Monday before class

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Prep for Next Time – P18 62 Reading –BBBHNM 14 Reading questions –Chapter 14 End-of-Chapter Quizzes –If we finished Chapter 13 then end-of-chapter quiz 13 (else just 12) Papers –Paper 1: Misgraded? Let us know –Paper 2: Misgraded? Let us know. Revisions due Monday –Paper 3: Due Wednesday

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Full set of Readings So Far Required: –BBBHNM: Chaps Recommended: –TFTM: Chaps. 1-5 –BHOT: Chaps. 1-7, 8 (68-76), 9 and 11 ( ) –SHU: Chaps. 1-3, 4(77-86), 5(95-114), 6, 7 (up-to-page 159) –TOE: Chaps. 1 & 2 63

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Paper 3 What is the evidence for the Big Bang? Make sure to read all the instructions in CPR Due 1 week from today (Wednesday) –If you want TA feedback, must be submitted by Friday –After that it’s best-effort by TA’s and first-come-first-served Same format at Paper 2 64

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Paper 2 Revision Will allow Paper 2 revisions Not happy about some of the quality of the papers and calibrations –If you are not going to submit a good paper, then we aren’t going to give you a chance to revise –If you aren’t doing well with calibrations, we expect you to ask for help If this doesn’t change, we won’t do revisions for the third paper 65

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 66 Prep for Today (Is now due) – L17 Reading: –BBBHNM 13 Reading questions: –Chapter 13 End-of-Chapter Quizzes: –Chapter 12 Paper Stuff –Paper 1: Misgraded? Let us know –Paper 2: Misgraded? Let us know –Paper 3: Due next Wednesday

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 67 Prep for Today (Is now due) – L18 Reading: –BBBHNM 14 Reading questions: –Chapter 14 End-of-Chapter Quizzes: –Chapter 12 Paper Stuff –Paper 1: Misgraded? Let us know –Paper 2: Misgraded? Let us know –Paper 3: Due Wednesday

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 68 Why not? General Relativity can’t be the entire story –Can’t make predictions at infinitely small sizes Quantum Mechanics doesn’t work in curved space time No good theory of Quantum-Gravity yet Universe went through thermal equilibrium, can’t tell what happened before then Some other understanding?

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 69 The Reading So Far and For Unit 4 Full reading so far for Unit 4: BBBHNM: Chaps TFTM: Chaps. 1-5 BHOT: Chaps. 1-7, 8 (68-76), 9 and 11 ( ) SHU: Chaps. 1-3, 4(77-86), 5( ), 6, 7 (up-to-page 159) TOE: Chaps. 1 & 2 Lecture prep: Turn in on eLearning Two questions from Chapter 14 you want to know the answer to

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Papers 1 and 2 Done with grades for both –Graded unfairly? Let us know! –Want to do better? We can help! Want to revise Paper 2? –CPR now open, due Friday at noon –You are required to do the calibrations for the new papers –You are required to do the reviews for your peers –Overall grade will reflect both original paper and the revision 70

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Papers 3 and 4 Paper 3: –Due Wed. March 24 th before class –1 week after we finished Chapter 12 –Now open Paper 4: –Will be assigned after we start Chapter 17 71

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Other Stuff Elearning: –Unit 3 now due, Unit 4 in progress Make sure you pick up the latest version of the online textbook!!! –Been updating it all semester 72

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 73 The Reading So Far Full reading so far: BBBHNM: Chaps TFTM: Chaps. 1-5 BHOT: Chaps. 1-7, 8 (68-76), 9 and 11 ( ) SHU: Chaps. 1-3, 4(77-86), 5( ), 6, 7 (up-to-page 159) TOE: Chaps. 1 & 2 Seeds (from the web)

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 74 Writing Assignments 1.Short Assignment 1 Revised submissions were due last on Friday. Want to revise again? Talk to me. Still not getting the structure right? Need to get you to the writing center! 2.Short Assignment 2 is posted Currently due Thursday Oct 29 th, one week after we finish Chapter 12 eLearning: Unit 3 now due Need to be working on Unit 4

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 75 Papers AFTER Paper 2 Two options 1.Research Paper If you want to do the research paper option you must turn in Stage 0 by Thurs Oct 29 th Stage 1 due Thurs Nov 5 th Final paper due the last day of class, Tuesday Dec 8 th 2.Two short papers like the first one One on Black Holes (due mid Nov) One on Dark Matter (due last day of class)

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 76 Part II In class Quiz for Next Time: What is happening in each region? {

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math Second after the bang At about 14 seconds after the bang the temperature has dropped to ~3 Billion degrees Now low enough temperatures that photons are not energetic enough to produce electron pairs Since electrons and positrons can still annihilate, the number of electrons and positrons is dropping rapidly!

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 78 One Second after the bang Still 10 billion degrees  too hot for protons and neutrons to bind into a nucleus and stay that way

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 79 Electron Positron High energy photon Still high enough energy for electrons, positrons, and photons to be in equilibrium between pair production and annihilation The Early History of the Universe

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math th of a Second after the Bang 100 Billion degrees A Universe of matter (protons, neutrons, electrons, neutrinos) and photons (also known as radiation) All colliding with each other and interacting the way they usually do

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 81 Very Early Universe is Very Complicated Above 1.5 Trillion degrees (0.1 seconds after the Big Bang) the presence of all the other “fancy” fundamental particles makes things very complicated Why aren’t they around any more?

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 82 Electron Positron Low Energy Photon Electron pairs and interact and annihilate but photon pairs no longer turn into particle pairs  Fewer positrons and electrons Later Times and Lower Energies

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 83 Electron Positron Photon Electron pairs can always produce photon pairs If the photons are energetic enough they can interact and create electron pairs  electrons and photons in thermal equilibrium Photons and Electrons above 6 Billion Degrees

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 84 Note… There are lots of numbers in The First Three Minutes While they’re really important to the physicists (and why we believe the story), they aren’t important for telling the story… I’ll try to stay away from them in general, but some of them are important… Also, TFTM was written in 1988 so the particle physics is fairly out of date…

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 85 Quarks Combine to Form Nucleons Quark  Proton Nuclear Reaction Quark qqq  Proton

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 86 Photon Energies at Various Times Universe expands as time passes Universe cools down as time passes 10.8 Trillion Degrees  1 GeV photons (proton mass) 6 Billion Degrees  0.5 MeV photons (electron mass and nuclear binding energy) 1.2 Trillion Degrees  105 MeV photons (muon mass) 3000 Degrees  10 eV photons (atom binding energy) Second Frame Third Frame

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 87 Photons As we’ve seen photons turn out to be one of the most important particles in the universe… focus on them for now Remember E=MC 2 Some numbers: –1 Giga-electron Volt = 1 GeV –1 GeV ≈ Mass of the proton

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 88 Photon Energies at Various Times Universe expands as time passes Universe cools down as time passes 10.8 Trillion Degrees  1 GeV photons (proton mass) 6 Billion Degrees  0.5 MeV photons (electron mass and nuclear binding energy) 1.2 Trillion Degrees  105 MeV photons (muon mass) 3000 Degrees  10 eV photons (atom binding energy) Will point out why each of these energies/ masses are important as we move on

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 89 Lecture 1 is 1-36 Lecture 2 is 1-6, and then from Lecture 3 is 1-6, 13-16, 51-71

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 90 Switching The Order of the Syllabus New Section 5: The VERY Early Universe and the Fate of the Universe New Section 6: Big Objects: The formation of Galaxies, Stars and Black Holes New version of the reading order on the Web

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 91 In class Quiz What is happening in this region? {

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 92 3 Lectures Today: Big Picture of the Evolution of the Universe: Temperature and Time Collisions and how they explain what we see Next Time: The First Three Minutes After the First Three Minutes After that: Stellar and Galaxy Formation

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 93 Why not lots of Heavier Nuclei? Protons and neutrons Combine to Form a few helium nuclei  Almost no elements heavier than helium are produced Nuclear Physics  No stable nuclei with 5 – 8 protons These decay so quickly its hard to produce heavier nuclei ~90% are hydrogen (~75% by mass) ~10% in helium

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 94 Another Crappy Word: Reionization After less than ~ 1 billion years, the first stars form Formation of the first stars and Heavy elements Ultraviolet radiation from the first stars re-ionizes gas in the early universe Reionization  universe becomes opaque again

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 95 TFTM Chapter 4 Recipe for a Hot Universe The CMB appears to be ~3 degrees now and leftover from a time when the universe was opaque, 1000 times smaller and hotter than now. At really early times, the energy of the photons was SO HIGH that collisions between photons could produce particles!

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 96 Question: Why do we believe the Universe went through a period of thermal equilibrium? Is this the only way it could have happened? Actually, this is an assumption and it makes predictions that are consistent with observations –Uniform everywhere… Other models, but none work (yet?)

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 97 TFTM 3 cont… Since the universe was in equilibrium at some point it retains little of the conditions about what happened BEFORE it went into equilibrium

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 98 Cool pictures TCP Page 635: Evolution of the universe TCP 22.1 (634). Temperature vs. time Feynman diagrams 22.3

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 99 SHU 6 When matter and anti-matter meet they annihilate and disappear in a burst of energy Evidence for anti-electrons (positrons) in 1932

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 100 How could all the matter in the universe exist and be easily detectible if theoretically there should be just as much antimatter around? Either the matter and antimatter should have annihilated each other, or we ought to be able to detect as much antimatter in the universe, which we clearly do not

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 101 Neutron Fraction vs. Time

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 102 This

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 103 PHOTON SCATTERING ELECTRON FROM ATOM e-e- p+p+ n PHOTON

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 104 PHOTON SCATTERING ELECTRON FROM ATOM e-e- p+p+ n PHOTON

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 105 PHOTON SCATTERING ELECTRON FROM ATOM e-e- p+p+ n PHOTON

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 106 PHOTON SCATTERING ELECTRON FROM ATOM e-e- p+p+ n ELECTRON ABSORBS ENERGY OF PHOTON TO ESCAPE

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 107 PHOTON BREAKING A NUCLEUS PHOTON (γ) HELIUM (He)

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 108 PHOTON BREAKING A NUCLEUS PHOTON (γ) HELIUM (He)

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 109 PHOTON BREAKING A NUCLEUS PHOTON (γ) HELIUM (He)

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 110 PHOTON BREAKING A NUCLEUS PHOTON (γ) HYDROGEN (H)

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 111 TFTM 3: Cont… Quantized energies: photons are particles! Don’t want to spend too long on this, but smaller wavelength is the same as high energy! Hard to make high energy (i.e., hard to make small wavelength) photons. Random number: It takes 13.6 electron volts to knock an electron out of a hydrogen atom. Nuclear interactions are a million times more powerful. Picture?

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 112 TFTM 3 cont… However, since the photons are in thermal equilibrium as the universe expands they stay one wavelength apart, so the wavelength goes up (i.e., they are red-shifted) and the energy goes down to what we see today.

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 113 Penzias and Wilson found a radiation temperature of 3 degrees Kelvin, which is what would be expected if the universe had expanded by a factor of a 1000 since the time when the temperature was high enough (3000 degrees K) to keep matter and radiation in thermal equilibrium

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 114 Blackbody Radiation Blackbody radiation: "Any body at a temperature above absolute zero will always emit radio noise produced by thermal motion of electrons within the body. Inside a box with opaque walls, the intensity of the radio waves at any given wavelength depends only on the temperature of the walls - the higher the temperature, the more intense the static“ Need this?

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 115 Define nucleosynthesis?

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 116 Distribution

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 117 Text

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 118 TFTM 3 cont… "This radiation would have survived the subsequent expansion of the universe, only that its equivalent temperature would continue to fall (to cool) as the universe expanded. " In other words, the "present universe should also be filled with radiation (photons), but with an equivalent temperature vastly less than it was in the first few minutes"

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 119 We still see the glow of the early universe because the light from very distant parts of it would only now be reaching us However, the expansion of the universe meant that this light would appear so greatly red-shifted that it would appear as low-energy light

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 120 TFTM 3 cont… At a time in the past, the universe was so dense (lets call it 700,000 years after the big bang) that light couldn't travel very far before it interacted with SOMETHING In fact, when it interacted with something like an atom it would typically break it apart Thus, atoms couldn’t form and stay formed for very long. Thus, stars (and galaxies and such) could not be created

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 121 TFTM 3: Continued “There must have been a time when the universe was so hot and dense that atoms were dissociated into their nuclei and electrons, and the scattering of photons by free electrons maintained a thermal equilibrium between matter and radiation As time passed the universe expanded and cooled, eventually reaching a temperature (about 3000 degrees Kelvin) cool enough to allow the combination of nuclei and electrons into atoms

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 122 TFTM 3 cont… The sudden disappearance of free electrons broke the thermal contact between radiation and matter, and the radiation continued thereafter to expand freely.” What happened to the photons since then? Individual photons would not be created or destroyed, so the average distance between photons would simply increase in proportion to the size of the universe

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 123 TFTM 3 Cont… Big picture: the differentiation of matter into galaxies and stars could not have begun until the time when the cosmic temperature became low enough for electrons to be captured into atoms. Picture of this? Video clip?

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 124 TFTM 3 cont… When electrons are free they “feel” the photons and there is lots of “pressure” on them But when they are in atoms they stop feeling the pressure (Quantum Mechanics) and its now easier for atoms to stop getting blown apart and start clumping into stars and galaxies All this “shifts” at 3000 degrees K

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 125 Above 4000 K, most of the energy in the universe was in the photons “radiation dominated” and now it’s matter dominated (i.e., the mass of the proton using E=Mc 2 ) gives us most of the energy in the universe

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 126 TFTM Chapter 4 Recipe for a Hot Universe The CMB appears to be ~3 degrees now and leftover from a time when the universe was opaque, 1000 times smaller and hotter than now. At really early times, the energy of the photons was SO HIGH that collisions between photons could produce particles!

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 127 Stuff Stuff about anti-particle and the matter excess…

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 128 TFTM 4 cont… “If the universe in the first few minutes was really composed of precisely equal numbers of particles and anti-particles, they would have all annihilated as the temperature dropped below a billion degrees and nothing would be left but radiation However, there is good evidence against this possibility – we are here!” There must have been some excess of electrons over anti-electrons, protons over anti- protons etc…

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 129 TFTM 4 Cont… Conservation laws? Energy Electric charge (Maxwell’s equations) Baryon number (Why is this conserved? Is it conserved?) Lepton number (why is this conserved? Is it conserved)? Neutron decay (page 93?)

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 130 So what? Since in the early universe there were LOTS of protons and anti-protons as the universe How many more protons than anti- protons? Only 1 part in a billion more. However, as the universe cooled and the protons annihilated with the anti-protons all that was left was this small fractional excess… however this small fractional excess is all the stuff in the the universe as we know it now!!!

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 131 The same is true for electrons and neutrons. Random note: 87% of nuclear particles are protons (not exactly sure why…)

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 132 Comments about Neutrinos?

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 133 TFTM 4: Cont… Random fact about neutrinos: They interact so “weakly” that in order to have an interaction with ordinary matter we would need it to pass through several light years of lead!!

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 134 Put Figure 8 in here somewhere… Page 87

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 135 Recipe for a Hot Universe

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 136 TFTM 4 final Recipe for a hot universe: “Take a charge per photon equal to zero, a baryon number per photon number equal to one part in a billion, and a lepton number per photon uncertain but small. Take the temperature at any given time to be greater than 3000 degrees of the present radiation background by the ratio of the present size of the universe to the size at that time

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 137 Stir well so that the detailed distributions are determined by the requirement of thermal equilibrium. Place in an expanding universe, with a rate of expansion governed by the gravitational field produced by this medium. After a long enough wait, this concoction should turn into our present universe”

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 138 How do we deal with this aside?

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 139 TFTM 4 cont… Why don’t we believe there are anti- matter galaxies out there? Two reasons: –No signs of anti-matter in the universe –Most cosmic rays hitting the earth are matter (rarely antimatter) –Where are the photons from matter- antimatter collision out in space? They should have a specific energy from the annihilation mass!

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 140

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 141 Nuclei in the Early Universe Proton  Deuterium Nuclear Reaction Photon Breaks up Nucleus before it can find an electron to create an Atom or find another nucleon to form a bigger nucleus  Free soup of protons and neutrons High Energy Photon

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 142 Atoms in the Early Universe Proton Electron  Hydrogen Atom ElectroMagnetic Reaction High Energy Photon Breaks up Atoms quickly  Free soup of electrons and protons High Energy Photon

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 143 Photons and Electrons Photons turn into Electron pairs Electron pairs turn into Photons

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 144 Electron Positron Gamma-ray photon Electron pairs and photon pairs interact and annihilate  electron and photon Soup Electron Photon Soup

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 145 Electron and Photon Soup If we have lots of electrons they will interact and create more photons If there are lots of high energy photons they will interact and create more electrons Eventually the two come into equilibrium. I.e., the market clears

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 146

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 147 Fundamental Building Blocks What does the Universe look like a second after the big bang? What are the things that happen at different temperatures as the Universe expands and cools? Many things COULD happen Quarks could combine to form protons and neutrons Protons/neutrons could combine to form nuclei Nuclei and electrons could combine to form atoms –We’ll talk about earlier times and later times in a future lecture…

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 148

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 149 With these types of interactions dominating what happens how do we explain what we see?

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 150 For the first million years radiation and matter were in thermal equilibrium and the universe must have been filled with photons with a temperature equal to that of the material contents of the universe

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 151 Cosmic Background Radiation Its this photon “gas” that is what we see as the Cosmic Background Radiation

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 152 Give average energies of the two following photons –10 eV to break apart an atom –1MeV to break apart a nucleus? –0.5 MeV per photon to create an electron-positron pair What temperatures would those correspond to? –What times do these correspond to?

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 153 Preview of Particle Physics As we said before when two photons collide they can produce a pair of electrons

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 154 Feynman diagram! Question: Why don’t they produce neutrinos? Too small a production cross section at those energies? However, this is a HUGE energy, ~0.5 Million eV or translating this to energy, that’s 6 billion degrees!! (center of the sun is only 15 million degrees) Muons here?

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 155 More examples: muons  Mass of 105 MeV  Can be created at temperatures of 1.2 trillion degrees. Protons  1 GeV  10.8 trillion degrees More high mass particles later!

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 156 TFTM 4 Cont… Again, thermal equilibrium –Rate of production of electrons is the same as the rate of electrons annihilating with positrons. I know the math starts getting bad here… Don’t sweat it… Lets just get the ideas… Bottom line: It took about 700,000 years for the universe to cool from 100 million degrees (below electron-pair production) to 3000 degrees (opacity)

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 157 Reminder: at 3000 K the average photon energy is just enough to keep atoms from forming (eV energies)

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 158 Too Complicated For Now… In this chapter we’re going to move from RIGHT AFTER the big bang through… awhile later… Right after the Big Bang we had (we think) HUGE energy (temperature) and density Note: TFTM was written in 1988 so it’s a bit out of date, I’ll point out places where we know more here and we’ll get back to it later. They don’t really affect the story for now

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 159 Why start at 0.1 Sec? I’m going to start at 0.1 sec because that’s the time where I don’t have to worry about the creation of the heavy elementary particles –More on them later… At really early times, the energy of the photons was SO HIGH that collisions between photons could produce particles E=MC 2 holds here! If the energy is high enough to create the rest mass of the particle, then we can create them

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 160 First Frame Stuff on Neutrinos The density is so thick that the neutrinos are constantly interacting –remember they typically need to travel through light years of lead to have, on average, a single interaction

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 161 Need Size for Anything Yet?

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 162 A long Aside As we go back in time and the universe gets hotter and hotter, pairs of photons can start producing the heavy fundamental particles Thus, what particles CAN exist in nature has a HUGE impact on the evolution of the early universe Say a little about this…

The Evolution of the Universe Topic 1: The Early Universe Big Bang, Black Holes, No Math 163 Third Frame and Neutrinos… Neutrinos are long longer important to the story…