Big Bang Black Holes No Math ASTRPHYS 109
Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture 42 Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 3: Inflation 1
Was due Today – L 42 • • • General: – Mis-graded on any Assignment? Let us know End-of-Chapter Quizzes: – Chapter 19 – Will need to do AMS 2 before you can get to Chapter 20 Papers – Paper 4: • Text: Was due Yesterday • Reviews: Due Tomorrow, Wed May 1 st • Back-Evaluations: Due Monday May 6 th Honors Paper: – All Stages must be approved explicitly – Final paper due on the last day of class at 11: 55 PM on e. Campus. Let us know if you need an extension Other Notes: – Today is the last day of class – Make sure you have turned in Paper 4 to Turn. It. In – All EOC quizzes will be due Friday May 3 rd at 11: 55 PM. You cannot pass the course without doing all of them – Won’t start calculating grades until after May 7 th – Please do the Course Evaluations Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 3: Inflation 2
Unit 6 Going back in time and going forward in time Before the first millionth of a second and the Fate of the Universe Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 3
Today’s Outline 1. Possible Fates of the Universe, Dark Matter and Dark Energy 2. Particle Physics, Dark Matter and the Very Early Universe 3. Inflation Last Topic Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 4
Today’s Outline • There are many pieces of evidence that point to something “odd” happening in the very early universe, but we’ll focus on the one piece that is easiest to understand • A Universe where the particles have an energy that looks like temperature, and is the same in all directions • Why this is “unexpected” • Inflation in the VERY early Universe Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 5
Problem Same Temperature Everywhere or said differently Why does the Universe look like it’s in Thermal Equilibrium or was in Thermal Equilibrium? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 6
Thermal Equilibrium? Up until now we’ve said the Universe essentially looks the same everywhere because it evolved from particles in thermal equilibrium Assumption: All the stuff in the Universe had enough time to come into thermal equilibrium Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 7
How Uniform is It? Temperature Map of the Universe Uniform to 1 part in 10, 000 Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 8
Problem According to General Relativity if the Universe expanded to have the speeds we see now then the “stuff” in the Universe would have expanded so quickly that it would never have had time to come into thermal equilibrium A cooler with ice and water will eventually come into thermal equilibrium, but it takes a while Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 9
Why? The Speed of Light Particles can’t move faster than the speed of light to bang into each other and bring everything into equilibrium – Space would have separated the particles in the early Universe so quickly that they would never have been able to interact with each other enough to come into thermal equilibrium Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 10
The Problem If the Universe didn’t have time to come into thermal equilibrium, how is it that it looks like it was in thermal equilibrium? • In English: How did every part of the entire universe get to be so nearly the same temperature everywhere if big chunks of the Universe didn’t have time to interact? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 11
Is/Was the Universe in Thermal Equilibrium? Not from thermal equilibrium? The explosion we call the Big Bang would need to have to occurred in such a way that the Universe is almost EXACTLY the same in every direction – Ever seen a bomb/fireworks explode in exactly the same way in all directions? Seems unlikely Would also need to produce energy’s that looks like a temperature distribution – Even harder to imagine… Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 12
The Million Dollar Question The Universe we live in today appears to have been in Thermal Equilibrium at some point Question: How could this have happened? How did a Universe that didn’t have time to come into Thermal Equilibrium come to look like was in Thermal Equilibrium? Big Bang, Black Early Times & Fate of The Universe 13 Holes, No Math Topic 4: Inflation
Thermal Equilibrium Three main options: 1. Eithere is a creator (or something else) that made the explosion look like it created a nearly perfect temperature distribution 2. There is something else going on and the Universe was in thermal equilibrium at some point 3. The universe was the same everywhere back when it was small. Over time things came into thermal equilibrium locally, but evolved to have the same temperature Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 14
Our best Hypothesis: Inflation Noto Bene: we don’t really understand what caused inflation yet Anyone want a Nobel Prize? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 15
What is “Inflation”? • Can explain this “problem” (and many others) if there was a sudden “inflation” when the Universe was very young • This would be an expansion of space-time that is much more extreme than that predicted by the simple Big Bang theory Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 16
Overview Example Brief History of Our Universe Now Time Our Universe right 1. Universe grows after the bang slowly for awhile 2. Then grows really quickly for awhile 3. Then grows at the Black rate. Early we Times & Fate of The Universe Big Bang, 17 Holes, No Math Topic 4: Inflation see now
An “Inflationary” Version of History 1. The Big Bang occurs, the universe expands and cools much more slowly than it does today – For the first 10 -35 seconds the expansion is SO SLOW that the Universe comes into thermal equilibrium 2. The Universe starts expanding VERY RAPIDLY for a really short time – Call this time period “Inflation” – Grows by between 1020 and 1030 times 3. After inflation is done, the Universe grows with the rate consistent with what we observe today Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 18
Put this in Perspective • Before Inflation: The visible Universe was about the size of an atom • During Inflation: It grew to about the size of a cherry pit • After Inflation: Continued with a “slower” expansion to its current size Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 19
Aside on Relativity • Remember: No THING can travel THROUGH SPACE faster than the speed of light • However: General Relativity doesn’t place a limit on the speed at which Space-Time can stretch Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 20
How does this make the Universe look like it’s in Thermal Equilibrium? • Before inflation the Universe was really small The stuff in it had plenty of time to come into Thermal Equilibrium • After inflation all that occurs is the expansion of a Universe that at one point was in thermal equilibrium • Thus, you live in an observable universe with the same temperature Bigin Bang, Early Times & Fate of The Universe all. Black directions 21 Holes, No Math Topic 4: Inflation
Quantum Fluctuations and Inflation • The quantum fluctuations in the early universe are what provided the seeds for galaxy formation • Fluctuations occurred in the universe BEFORE inflation (when universe was small enough for quantum mechanics to be important) • Just “stayed in place” during the rapid expansion – Same temperature everywhere, even though not in thermal equilibrium today Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 22
Now we are able to explain all the major stages of the Evolution of The Universe Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 23
Inflation The problem with the model Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 24
What Caused Inflation? Don’t really know • SHU Chapters 12 and 13 present some ideas, but its not clear they’re right • The reading “Cosmology in the 21 st Century” is closer to our current guess • Scientists are still working on this… Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 25
Lecture on Chapter 20 now complete Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 3: Inflation 26
Rest of Semester – L 39 (Last Class) Date Lecture number Due Before class/11: 55 PM What we do in Class Assigned after class Fri Apr 16 th* 34 EOC 13 (A-F), EOC 14 (A-D) Chapters 16 EOC 14 (E-G) Mon Apr 19 th 35 EOC 14 (E-G) Finish Chapter 16 + Start Chapter 17 EOC 15, Unit 6 Reading Wed Apr 21 st 36 EOC 15, Unit 6 Reading Chapter 17 EOC 16 + 17, Paper 4 Assigned, Unit 6 PLRQ Quiz Fri Apr 23 rd 37 Unit 6 Quiz, EOC 16 + 17 Start Chapter 18 (Work on Paper 4) Mon Apr 26 th 38 (Work on Paper 4) Finish Chapter 18 + Start 19 EOC 18 Wed Apr 28 th 39 (Redefined day, Last day of Class) Paper 4 Text Due, EOC 18 Please do Course Evaluations Finish Chapters 19 and 20 EOC 19, AMS II and EOC 20 Fri Apr 30 th No class EOC 19, AMS II and EOC 20, Reviews, Feedback and any Revisions must be submitted by today - - Tues May 4 th No Final All Reviews and Feedbacks due - - Notes: • Mis-graded on any Assignment? Let us know • Will start calculating grades on Tuesday May 4 th Honors Section: • Stage 4, Final Draft due Mon Apr 26 th • Stage 5, First Draft due Mon May 3 rd • Stage 5, Final Draft due Tuesday May 4 th Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 3: Inflation 27
End of Semester Notes • – • • • End of Chapter quizzes • While the EOC quizzes are due before then, I’m planning to do my final download on Tuesday May 4 th at 11: 55 PM • This includes AMS 2 – End of semester measure of some of the things you learned – Not part of your grade, but you will need to do it before you can attempt the rest of the end of chapter quizzes If you don’t pass the EOC quizzes for all 20 Chapters the EOC quizzes (50%), you cannot get a passing grade for the course • If you need an extension, let me know ahead of time We will accept Revisions for all papers, but you need to do them with enough time for you to get a grade before the 4 th There is no statue of limitation on mis-graded items. If you think you were mis-graded on ANYTHING, we will work to make sure you get the grade you deserve Please do your course evaluations Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 3: Inflation 28
• Interested in learning more next semester? • Take Astronomy 111 Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 3: Inflation 29
That’s it! • Best of luck finishing all the papers and quizzes • Best of luck on finals! Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 30
Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 31
Fixes for this year • Water cooler and remove flatness. • • Grid for expansion. • • Burnt orange cmb Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 3: Inflation 32
Today’s Outline • Two pieces of evidence: 1. A Universe with the Critical Density and a Flat space-time 2. A Universe where the Temperature is the same in all directions • Why these are “unexpected” • Inflation in the VERY early Universe Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 33
End of the Semester • • • Pre-Lecture Reading Questions (PLRQ) – Unit 6, Stage 2: Due before usual class time Wednesday, May 3 rd – Unit 6 Revision (if desired), only by request (send me an email if you are interested) End-of-Chapter Quizzes: – All chapters due by Monday May 8 th at 11: 55 PM (Final download of EOC quizzes) – Will need to do AMS 2 before you can get to Chapter 20 Papers: – Paper 4, Stage 1: Due before the usual class time on Wednesday, May 3 rd – Paper 4, Stage 2: Due Tuesday May 9 th by 11: 55 PM – Paper 4 Revision (if desired), only by request (send me an email if you are interested) Honors Paper: – Due tonight at 11: 55 PM in turnitin. Let me know if you need an extension Other notes: – Won’t start calculating grades until after Wednesday May 10 th – Please do the Course Evaluations – CPR: Mis-graded on any Assignment? Let us know – All paper and PLRQ grades are in CPR and won’t get ported to e. Campus – Make sure you have turned in all papers (including Revisions) into turnitin. You will lose points if you don’t. – Extra credit for students who do PLRQ Unit 6 and/or Paper 4 stuff in Peerceptiv Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 3: Inflation 34
First Problem Universe appears to have exactly the critical density Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 35
Density of the Universe and General Relativity teaches us that the Density of the Universe determines the Curvature of Space-Time Remember, we’re not talking about local curvature, but the curvature of the entire universe Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 36
Look at the Spots We know what the size of the spots should be back during recombination, but we can ask how much the light was lensed as it moved through space Big Crunch Early Times & Fate Critical Density 37 Expands Forever
Critical Universe Flat Space Time Crunch The Data Big Bang, Black Holes, No Math Critical Forever? Data points to a Universe with the critical density and flat space. Early Times & Fate of The Universe time 38 Topic 4: Inflation
Flatness and General Relativity • General Relativity tells what the Bang must have been like to evolve into something that gives a flat space-time AND has the speed we observe • This isn’t a problem… BUT it also tells us that if the Universe were “slightly different” from that at the beginning it would become VERY un-flat now, or would have collapsed already Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 39
Critical Density Slightly too dense? Would expand then quickly collapse back onto itself It’s as if we threw up a ball on the Earth 13. 5 billion years ago with exactly the right speed such that now it’s in outer space now with EXACTLY zero speed Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 40
Another Analogy: Kicking a Football • Kick the ball from the 50 yard line to within the region from the end zone to the 25 yard line – 1 part in 2 • Kick the ball from the 50 yard line to within 10 yards of the goal – 1 part in 5 • From the 50 yard line to within 1 yard of the goal – 1 part in 50 • Hit the goal line itself About 1 in 100 • Land on a dime on the goal line 1 in a thousand • Land on a hair on the goal line 1 in 105 Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 41
How close to perfect? • We observe the Universe to be within 1 part in 10, 000 (105) of being flat now – Could be exactly flat – Actually, making the Universe flat isn’t as easy as kicking a ball. Closer to trying to putt a golf ball down a mountain into a hole at the bottom • Unless something special happened RIGHT AFTER the Big Bang the Universe would have had to be in exactly the right configuration to 1 part in ~1050 to have evolved to be as flat as we observe now Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 42
Flatness and Temperature Problems How did we get from a Universe of Infinite Curvature at the Big Bang to one with almost EXACTLY no curvature now? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 43
Flatness Think about two options: 1. Eithere is a creator (or something else) that “tuned” the explosion perfectly 2. There is something else going on to make the Universe flat Lucky for us the Universe is flat; life as we know it couldn’t exist otherwise Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 44
How does this Help Flatness? • The sudden inflation would have forced whatever curvature there was in the universe towards zero – Like inflating a balloon makes a small spot on its surface flatter – Smoothes out any wrinkles • Thus, you live in a Universe that is almost perfectly flat because of that sudden inflation long ago Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 45
End of Semester Part 2 • Papers: – Paper 4 Revision (if desired): • Stage 1 due Wednesday night at 11: 55 PM • Stage 2 due Friday night at 11: 55 PM • Grades: – All paper and PLRQ grades are in CPR and won’t get ported to e. Campus – Will start calculating grades after all the revisions are done (may take awhile) • Please do the Course Evaluations Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 46
Was Due Today– L 2 • Reading & Pre-Lecture Reading Questions: – None • End-of-Chapter Quizzes: – If we finished Chapter 19, then Chapter 19 (if not, then just Chapter 18) • Papers: – Paper 4: Stage 2 • Notes: – Monday is the last day of class – All EOC quizzes will be due before Finals Week. You cannot pass the course without doing all of them – Make sure you have turned in all papers into turnitin. You will lose points if you don’t. 47
Was Due Today– L 2 • Reading & Pre-Lecture Reading Questions: – None • End-of-Chapter Quizzes: – If we finished Chapter 19, then Chapter 19 (if not, then just Chapter 18) • Papers: – Paper 4: Stage 2 • Notes: – Monday is the last day of class – All EOC quizzes will be due before Finals Week. You cannot pass the course without doing all of them – Make sure you have turned in all papers into turnitin. You will lose points if you don’t. 48
Prep For Next Time – L 12 • Note: May change depending on how far we get in lecture • Reading: – BBBHNM: All reading through Chapter 20 • Reading Questions: – All reading questions through 20 • e. Learning Quizzes: – If we finished Chapter 18 then end-of-chapter quiz 18 (else just through Chapter 17) • Papers: – Text of Paper 4 assignment due Wednesday at 11: 55 PM – Calibrations, Reviews and Self-assessment due before class on Monday 49
Prep for Next Time – P 26 • Reading – BBBHNM 22 • Reading questions – Chapter 22 • End-of-Chapter Quizzes – If we finished Chapter 20 then end-of-chapter quiz 20 (else just 19) • Papers – Paper 1, 2 or 3: Misgraded? Let us know – Paper 3 revision: Due tonight at Midnight – Paper 4: Due tonight at Midnight 50
The Reading for Unit 6 Full reading for Unit 6: • BBBHNM: Chaps. 18 -22 • SHU: 8 (159 -164) • BHOT: 11 (122 -137), 12 • Seeds (Cosmology in the 21 st Century, Web Handout) Full reading through Unit 6: • BBBHNM: Chaps. 1 -22 • TFTM: Chaps. 1 -5 • BHOT: Chaps. 1 -7, 8 (68 -76), 9 and 11 (117 -137), 12 • SHU: Chaps. 1 -3, 4(77 -86), 5(95 -114), 6 -8 (up-topage 164) • TOE: Chaps. 1 -3 • Seeds (Cosmology in the 21 st Century) Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 51
Papers & End of Semester • Last day of class • Cancelled the last paper • Paper 4: – CPR due on Monday (no class, attend Friday class) – Will finish grades shortly after that • Let us know if you see problems – Only doing text revisions: Email ASAP to be considered • Honors papers: – Due tonight at midnight if you want to do a revision – You can turn it in on Monday, but with no chance for revision • End of Chapter quizzes for all chapters due Monday – Can’t pass the course without them 52
Prep for Today (Is now due) – L 26 • Reading: – BBBHNM 22 • Reading questions: – Chapter 22 • End-of-Chapter Quizzes: – Chapter 20 • Paper Stuff – Paper 1, 2 or 3: Misgraded? Let us know – Paper 3 revision: CPR due Monday – Paper 4: CPR due Monday 53
Course Evaluations Course evaluations will be done online via the Department of Physics On-Line Course Evaluation System • You should have gotten an email about this already The Fall 2011 evaluation period will: • Began on November 18 • Ends on Friday, December 23 at 8 AM Please do these ASAP… won’t take long 54
Schedule from Here on Out • Thursday: Dec 3 rd Chapter 21 – The rest of the reading is now due – Be working on e. Learning Unit 6 stuff • Tuesday: Dec 8 th Chapter 22 – Paper due at midnight • Thursday Dec 10 th, No classes, Reading period • Tuesday 15 th: Finals week, no final – Paper revisions due 55
Last Paper Due last day of class • Dark Matter Paper Or • Research Paper Turn in at e. Learning like usual 56 56
Writing Assignments Short Assignments 1, 2 & 3 Re-do’s are still possible. Want to revise again? Talk to me e. Learning: Unit 5 past due Need to be working on Unit 6 57 57
Schedule from Here on Out • Mon April 27 th: 25 th lecture – The rest of the reading is now due – Stage 1 Research Topic Proposal must be approved – Web. CT Unit 6 stuff • Wed April 29 th: 26 th lecture • Mon May 4 th: Class cancelled – Research paper due at noon on Tuesday May 5 th • Wed May 6 th: No classes, Reading period • Mon May 8 th: Finals week, no final Big Bang, Black Early Times & Fate of The Universe 58 – Paper revisions due Holes, No Math Topic 4: Inflation
Why? The Speed of Light Objects can’t move faster than the speed of light to bang into each other and come to equilibrium – Objects separated by even a small one angular degree in the sky would have separated so quickly that they would never have been able to interact with each other and come into thermal equilibrium Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 59
Schedule from Here on Out Next time: Finish the story of the Evolution of the Universe Dark Energy • Wed Nov 19 th: 25 th lecture: – Recitation for Paper 2 • Will be checked off at the end of class as your in-class quiz – Inflation • Mon Nov 24 th: 26 th lecture: Dark Energy • Wed Nov 26 th: No class – Research paper and 2 nd short paper due at midnight – Day before Thanksgiving. Class cancelled • Dec 1 st: No classes redefined day • Dec 3 rd: Reading period, no classes • Dec 8 th: Finals week, no final Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 60
The $64, 000 Question: Why is the Universe SO flat and Isotropic? – The Flatness problem – The Isotropy problem Start by explaining why these issues should concern us Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 61
Today’s Lecture: Inflation • The story described so far doesn’t really explain the observed flatness and Isotropy of the Universe • How “Inflation” helps (and what the word “Inflation” means here) • A few words on what might have caused inflation – We don’t know what caused inflation – Any one want a Nobel Prize? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 62
The Universe we live in today appears to have a remarkably Flat spacetime and is incredibly Isotropic (the same everywhere) Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 63
What type of Universe? Not perfect? In a Closed Universe it expands and then collapses back onto itself It’s as if we threw up a ball on the Earth 15 billion years ago with exactly the right speed such that now it’s in outer space with EXACTLY zero speed Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 64
Small Aside • What if it didn’t have this “perfect” initial condition? • Example problem: If the rate of expansion (or amount of “stuff” in the universe) was too small then the whole thing could collapse again • Wouldn’t need to be too far off for the Universe to collapse REALLY quickly Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 65
Paper 2 Notes • Big Picture: This is a paper about particle physics and COSMOLOGY • Answer the question: “Why would the experimental discovery of Supersymmetric particles help us understand the Universe? ” Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 66
Common Paper 2 Problems • Forgot to mention about WHY we are asking for money – Can't just say "build experiments to study Dark Matter“ – How would experiments study it? – What would we need money to DO? • Can’t just answer the question “Why do we believe in Dark Matter? ” • Can’t just say that the goal is to solve the Dark Matter “problem” (that’s an astronomy problem). Need to explain how understanding the Dark Matter tell us about the origin and evolution of the universe • Didn’t explain how supersymmetry could provide a Dark Matter candidate Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 67
Schedule from Here on Out • Wed Nov 28 th (today): 27 th lecture – Finish up Inflation and Dark Energy – Research paper due at midnight • Dec 3 rd: No classes redefined day • Dec 5 th: Reading period, no classes. Meet at the Chicken • Dec 10 th: Finals week, no final All paper revisions due by Dec 12 th Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 68
Aside… • Sometimes small happenings can have big effects • Sometimes a butterfly flapping its wings in China can affect the weather in Chicago Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 69
What Caused Inflation? Perhaps Inflation was caused by the sudden energy release from the decoupling of the strong and Big Bang, Black Early Times & Fate of The Universe electroweak Holes, No Math Topic 4: Inflation 70
The Isotropy Problem • While it’s nice to think that the Universe exploded in such a way that the Universe is almost EXACTLY the same in every direction (isotropic) this also seem unlikely – Ever seen a bomb explode in exactly the same way in all directions? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 71
More on the Isotropy Problem Said differently: Since the particles can only travel through the Universe at the speed of light then different parts of the Universe wouldn’t have been able to come into Thermal Equilibrium EVERYWHERE and show the same temperature of the Cosmic Background Radiation Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 72
Summarizing the Data so Far 1. Hubble Constant gives us the speed of expansion fairly accurately 2. The Universe appears really isotropic 3. The measured density of the “stars and stuff” is about 4% of the critical density 4. The measured Curvature of the Universe is consistent with being exactly flat Density is 100% of the critical density Something is inconsistent… Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 73
Next Two Topics We can use the evidence that we live in a Flat, Homogenous and Isotropic Universe as evidence for two main things 1. Inflation (Today) 2. Other Mass/Energy in the Universe (Next Time) There is other evidence that this story is correct Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 74
• Not sure what to do with these pictures yet! Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 75
t t = 14 billion years 500 M yrs Galaxy Formation Relic Radiation Decouples: WMAP 1 s 10 -7 s SUSY Relic 10 -11 s Big Bang, Black Early Times & Fate of The Universe 10 -43 s Holes, No Math Topic 4: Inflation Quantum Gravity 76
Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 77
• This is some text… What happened here? { Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 78
• when it became so cool atht the EWK and Strong force began to disconnect from each other and behave in very different ways • This released tremendous energy, which suddently inflated the universe by a factor between 1020 and 1030 Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 79
SHU 12 cont… • Tiny vacuum “popped” into existence. Has a small amount of energy… • How does it become all the matter in the universe? • What would happen if the tiny vacuum of energy somehow popped into existence, expanded rapidly, and failed to pop OUT of existence again? • Would the expansion of the energy continue and be sustained enough long enough to allow for the emergence of a universe full of matter anything like the one we observe today? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 80
SHU 12 cont… • Suppose all the energy in the vacuum was released, rather like the gas in a carbonated drink when the bottle is opened. In the drink, many bubbles of gas, not just one big bubble, rush to the top of the bottle when the cap is unscrewed and the pressure is released • Why not imagine that the energy in the vacuum breaks up into billions of tiny bubble in a similar way; and that only one of these bubbles expands to become our universe? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 81
• Question: What about the other bubbles? • If each bubble becomes a universe, then we’d never see them… oh well… Other observable consequences? Somewhere there has to be an infinite number of universes… • So rather than saying ours is special, it says ours is just one of many… • However this is un-predictive… Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 82
SHU 13 • Not really inflation but… • Smolin’s idea: What if lots of universes were created, but only one of them were “fit” enough (like Darwin’s ideas) to develop into what we see today. Or perhaps lots exist (parallel to ours) but ours is special in that it allows life. Not predictive, but interesting to think about… Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 83
• BHOT 8, SHU 12 Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 84
http: //www. damtp. cam. ac. uk/user/gr/public/bb_history. html t t = 14 billion years 500 M yrs Galaxy Formation Relic Radiation Decouples: WMAP 1 s 10 -7 s SUSY Relic 10 -11 s Big Bang, Black Early Times & Fate of The Universe 10 -43 s Holes, No Math Topic 4: Inflation Quantum Gravity 85
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Outline • We really should say SOMETHING about inflation… not really sure what… • TOE 5. Does this go as part of Evolution of the universe or as part of speculations? • SHU 12, starting on page 241 Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 88
BHOT 8 • There is some stuff in BHOT 8 about this stuff (page 74) • Inflation is important in the evolution of the universe Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 89
SHU 12 • What might have caused the rapid expansion of the early universe? • Why do we think there was a rapid expansion (faster than the speed of light) of the early universe? • There is no way the universe could end up at its present size, with the rate of expansion we observe today… Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 90
SHU 14 • Hawkings ‘No boundary’ solution. People still think about this? ? • There are no boundaries marking the end of space or time, even though the universe as a whole has a finite size. • Example: Think about walking on the earth. You will never meet a boundary… You can’t tell if you are on the inside or outside of a balloon. Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 91
TOE 5 • P 97 -107 is really just a quick summary of the evolution of the universe stuff we’ve already done • Inflation: More on why we need it… TOE is pretty unclear. SHU better? • Inflation says that the early universe had a period of very rapid (exponential) expansion • The size of the universe expanded much faster than the speed of light in a tiny fraction of a second • Relativity only talks about the speed of objects, SPACE is allowed to expand as quickly as it wants Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 92
TOE 5 cont… • Not really a good chapter… Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 93
BHOT 8 • The universe (according to Friedmann models) has a beginning at about 13. 7 Billion years ago • I. e. , the distance between neighboring galaxies must have been zero • First set of problems: Theories of space time is smooth and flat • That means our theories break down at the big bang: a space-time with infinite density means infinite curvature so it isn’t flat! • This means we cannot predict what Big Bang, Black Early Times & Fate of The Universe 94 happened BEFORE the big bang Holes, No Math Topic 4: Inflation
Isotropy problem • The CMB is isotropic to at least one part in 1000. Yet when you look at the background radiation coming from two points in the sky separated by more than a degree, you look at two parts of the big bang that were not “causally connected” when the radiation was emitted. • Said differently, when recombination occurred and the gas of the big bang became transparent to the radiation, the universe was not old enough for any signal to have traveled from one of these regions to the other. Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 95
• Thus, the two spots you look at did not have time to exchange heat and even out their temperatures Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 96
BHOT 8 cont… • “In the hot big bang model there was not enough time in the early universe for heat to have flowed from one region to another • This means that the initial state of the universe would have had exactly the same temperature everywhere in order to account for the fact that the microwave background has the same temperature everywhere we look Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 97
Why does this help explain things? • all the irregularities would have been smoothed out by the expansion (kind of like wrinkles in a balloon smooth out when you blow it up) Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 4: Inflation 98
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