Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 1 Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture.

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 1 Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture 6 & 7

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 2 Prep For Today (is now due) – L6 Reading: –BBBHNM Unit 2 (Chapters 5-9) Pre-Lecture Reading Questions –Boot Camp Quizzes (already due) –Unit 2: Stage 1 (due before Class) –Unit 1 Revision (if needed): Will send email after regrades finished End-of-Chapter Quizzes –Chapter 4

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 3 Prep For Today (is now due) – L7 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions –Unit 2: Stage 2 (due before Class) –Unit 1 Revision (if needed): Will send email after regrades finished End-of-Chapter Quizzes –Chapter 4

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 4 Next Set of Topics: Physics We Need Finished our introduction Big and small things in the Universe Evidence and the Scientific Method Next we move on learn some of the physics we need in order to understand why scientists have confidence in the Big Bang Theory

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 5 Overview of Physics We Need Cosmology, the big bang and black holes are some of the most interesting things that can be understood However, to UNDERSTAND them better, and the EVIDENCE for them, we need to learn some physics

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 6 The Topics Some stuff we need learn a little about: 1.Light and Doppler Shifts 2.Gravity, General Relativity and Dark Matter 3.Atomic Physics and Quantum Mechanics 4.Nuclear Physics and Chemistry 5.Temperature and Thermal Equilibrium We won’t spend too long on each, just enough to get back to the big picture… Since there is no perfect way to present them (they all tie into each other) we’ll just start somewhere and get going…

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 7 Back to the Big Picture Questions we’re trying to answer: How did the Universe come into being? How did it evolve into what we know today? What is the evidence for all of this?

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 8 Light What we know about the universe comes from multiple places One of the most important is from looking at both outer space and inner space Need to know more about the “light we see”

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 9 Outline for Light 1.Light is a wave… 2.…and a particle 3.Light is REALLY fast, but does have a finite speed 4.Doppler effect

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 10 Part 1: Light is a Wave The light we see is a “wave”, like waves on an ocean Best described by it’s wavelength

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math Why do we believe light is a wave? Water and Sound are also both waves –Does light behave like water or sound? Can “see” water waves hitting a wall and what happens to them when they hit two small openings in a wall

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math Water waves moving towards a wall You are in the sky looking down at the waves as they go by 12

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 13 Why do we believe light is a wave? Shine light from a laser at two small holes in a wall and see what comes out on the wall behind it The waves make patterns on the wall the same way water waves do (Physics 202 & 208)

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 14 The Wavelength of Light Shine white light at a prism and it breaks up into its different colors Each color has a different wavelength which we can measure

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 15 Light is more than the colors we see You may have thought of Radio Waves and X-rays as different things, but they are just light with different wavelengths

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 16 Part 2: Light is a particle What if we look at smaller and smaller “amounts” of light? The light we see is actually LOTS of particles all moving together Call these Photons Lots of photons where its bright Very few photons where its dark

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 17 White Light = Lots of Different Color Photons

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math Another view… 18

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 19 The Energy of Particles We can think about Energy in many ways One way is the “energy of motion” –Kinetic Energy in the language of PHYS 201 and 218 For a particle (with mass) in motion: –The higher the speed the particle has, the more energy it has –The more mass the particle has (the heavier it is) the more energy it has

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 20 Clicker Question for Energy Which has more energy? (Which will do more damage to a tree?) 1. A) A Prius moving at 10mi/hr or B) An SUV at 10mi/hr? 2. A) An SUV moving at 10mi/hr or B) An SUV moving with 60mi/hr? 3. A) A Prius moving at 60mi/hr or B) An SUV moving at 10mi/hr? C) Depends on the masses of the Prius and the SUV

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 21 Photons What do we know about photons? Photons are a type of particle –Like an electron or proton Higher energy  smaller wavelength Has no mass, but does have energy –Aside for those of you who are interested: It has momentum

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 22 A Particle and a Wave Actually it’s really more complicated than that Light is both a wave and a particle… can describe it as either… it has properties of both

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 23 Part 3: The Speed of Light “Not just a good idea, it’s the law!”

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 24 Light has a Finite Speed Light has been measured to have a specific speed –3 x 10 8 meters per second –186,000 miles per second –1 foot per nanosecond –Really FAST –The fastest speed allowed

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 25 Maxwell’s Theory 1865: James Clerk Maxwell and others showed light was a wave and calculated its expected speed Gave the observed speed of light! –Confidence that his theories were correct –We can now measure the speed of light to incredible precision Physics 208 2.99792458 x 10 8 m/s

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 26 A Light-Year Some things are so far away that it’s easier to express their distance in light-years –Light travels at 3 x 10 8 meters/second and there are  x 10 7 seconds/year  ~10 16 m in a light-year

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 27 Time Machine The Sun is 8 light-minutes away, so we are seeing the Sun as it was 8 minutes AGO If a star is a light-year away and it must have taken a year for the light to get to us, we are observing the star the way it was a year ago If we look at light from something billions of light-years away, we are “observing” things that happened billions of years ago

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 28 Part 4: The Doppler Effect 1842: Christian Doppler What happens to waves when the “thing” creating the waves is moving towards us? –Or we’re moving towards it? Physics 221

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 29 Example with Sound From a Stationary Car The sound we hear is actually a wave –Sound waves

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 30 Now the Car is Moving Things coming at us have their waves “scrunched up” Things moving away have their waves “stretched”

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 31 The Doppler “Effect” for Cars Hears a Lower Pitched Sound Hears a Higher Pitched Sound A car blaring its horn and going past you will give the famous “Eeeeeeee-Yowwwwww” sound

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 32 What Does This Have to do with Light? Since both sound and light are waves, the Doppler “Effect” applies equally to both –Normally can’t see this effect for light since its wavelength is small and its speed is fast Can in special cases: –Things need to be moving really fast, like stars and galaxies –Need really good measuring devices like the ones Astronomers have

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 33 Doppler Effect and Light Blue Shift Sees light with a smaller wavelength Red Shift Sees light with a larger wavelength Galaxy moves to the right 

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 34 The light from galaxies moving away from us will appear to have longer wavelength light –The light is more Red, or shifted to the Red side of the light spectrum –“Red Shifted” The light from galaxies moving towards us will appear with shorter wavelength –The light is more Blue, or shifted to the Blue side of the light spectrum –“Blue Shifted” Look at Light from Galaxies

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 35 The Doppler Effect in Action Doppler Effect

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 36 Three Observers What does an object emitting light look like to different observers when it is 1)Not moving 2)Moving Doppler Shift

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 37 Look at some cases Next lets look at three cases where an “explosion” occurs and things expand from that point 1.I’m stationary and the exploding things are moving away from me (I’m the center of the explosion) 2.I’m moving along with the exploding things 3.Same as case 2, but how it would look to me in my reference frame

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 38 Two Objects Moving Away from Me What it looks like when I’m stationary (or in my reference frame)

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 39 Two Objects Moving Away From Me What it looks like when I’m moving relative to the objects

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 40 Same Thing: My Reference Frame Why were these three cases important? Sorry… you’ll have to wait until we look at galaxies sending us light

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 41 Doppler Effect and Light: Summary Compare the light coming from a car that’s parked and one that’s coming towards you If a car is coming toward you with its lights on 1.The color of the light changes 2.The speed of the light does not!

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 42 Putting It All Together Since stars can be billions of light- years away and are moving quickly we can use the Doppler effect on light to measure the speed and direction of all objects in the night sky (Can also use it to tell us what Stars are made of, but for that we need to learn about quantum mechanics…)

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 43 Outline for Unit 2: Physics We Need 1.Light and Doppler Shifts  Done 2.Gravity, General Relativity and Dark Matter  Next 3.Atomic Physics and Quantum Mechanics 4.Nuclear Physics and Chemistry 5.Temperature and Thermal Equilibrium

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 44 Prep For Next Time – L6 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions –Boot Camp Quizzes (already due) –Unit 2: Stage 2 (due before Class) –Unit 1 Revision (if needed): Will send email after regrades finished End-of-Chapter Quizzes –If we finished Chapter 5 then End- of-Chapter Quiz 5 (else just Chapter 4)

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 45 Prep For Next Time – L7 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions –Unit 2 Revision: Stage 1 (due before Class) –Unit 1 Revision (if needed): Will send email after regrades finished End-of-Chapter Quizzes –If we finished Chapter 5 then End-of- Chapter Quiz 5 (else just Chapter 4)

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 46

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 47 Clicker Quiz Q: What does it mean for an electron to be "stable?" a)It is balanced with exactly one proton b)Its orbit ring exists in one plane (no wobble) c)It has reached minimum size (10 -19 m) d)Undisturbed, it can go on living forever and ever e)They don't appear to be made of anything smaller

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 48 Clicker Quiz Which of the following travels the fastest? A.Radio waves B.Gamma rays C.Red light D.Blue light E.They all move at the same speed

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math Clicker Quiz We observe two objects in space. From other studies, we can tell that object X is emitting infrared light and the object Y is emitting Ultraviolet light. We observe the color of the light object X to be Red and the color of Object Y to be blue. Which statement is true? a)X and Y are moving towards us b)X and Y are moving away from us c)X is moving towards us and Y is moving away from us d)X is moving away from us and Y is moving towards us 49

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math Paper 0, Questions 1-5 1.Does the paper make it easy to understand what question is being answered, what the answer is, and how it will be answered? If anyone of those are missing, or if you can't follow the argument, then choose No. If the argument is clear, but not said very well (or is wordy), then you should still give a Yes. If the paper is clear to you, but would not be clear to someone who hasn’t taken the course choose No. Being easy to read isn't a good enough reason to give a Yes. Having a sentence or two that are hard to understand (or poorly written) within a basically clear paper is fine, and can still deserve a Yes if it is otherwise ok. 2.Are the pieces of evidence clearly and correctly enumerated in the opening paragraph? This includes the electrons going around atoms, the Moon orbiting the Earth, and planets orbiting the Sun. 3.Does the structure of the paper follow the instructions? Specifically: Is there an introduction paragraph, separate paragraphs discussing evidence, and a conclusion paragraph? If any are missing, choose No. Does the paper directly address the question and make the argument to answer it? If the paper addresses the question and makes an argument (right or wrong) to answer it, choose Yes (we will address the wrongness in a later question). Do not choose No due to a poorly written or confusing introduction. The paper does not need to have only three paragraphs, and the pieces of evidence can be intertwined within them. Do not choose No due to missing evidence or more than three paragraphs. Do not choose No just because evidence is not constrained to these paragraphs. If the paper does not end with a conclusion paragraph, choose No. Do not choose No due to a poorly written or confusing conclusion. 4.Is the paper generally free of extraneous evidence? If there is any significant evidence that is off topic or an argument that has nothing to do with the topic, choose “No.” If there is significant evidence from outside class, choose No. Do not choose “No” due to evidence that is unnecessary if the evidence is relevant to the topic. 5.Does the paper only use language and words that can be understood by the average lay-person? If the author uses an acronym, like GR, for general relativity that is ok but only if the acronym is clearly defined. If they use an acronym that isn't defined, then select No. Similarly, just because you saw these words in a high-school science class does not mean they are understood by the average person. The average person on the street would know what an atom is, but not know what a spectral line is. 50

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math Paper 0, Questions 6-10 6.Does the essay use language formal enough to give to a statesman? If the paper uses jokes, slang or other informal language, choose No. Do not choose No due to poor grammar, spelling mistakes, incomplete sentences, or poor sentence structure (we will take off points in a different question for this). Do not choose No due to the use of an acronym, like USA, since it is common usage and not slang. 7.Is the essay generally free of instances of bad grammar, incomplete sentences or spelling mistakes? If there are more than two minor mistakes, choose No. 8.Does the paper make clear how and why the evidence presented relates to the argument? If the facts are mentioned but show no clear connection to the argument, then choose No. If the facts are not addressed throughout the paper, then choose No. If it states the data without saying why it is evidence then choose No. 9.Do the middle (evidence) paragraphs clearly tie into the overall structure? 10.Does the paper use the scientific method and evidence based decision making? It’s OK if the words “scientific method” and “evidence-based decision making” are not mentioned specifically. 51

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math Paper 0, Questions 11-15 11.Does the essay make it clear what the Scientific Method is and why it is important in this paper? 12.Does the essay clearly tie together the pieces of evidence using the scientific method in the conclusion? 13.Does this paper say that the Moon orbits the Earth? 14.Does the paper mention explicitly that the Earth is much more massive than the Moon, and that it is important to why the Moon orbits the Earth instead of the other way around? If it mentions that the Earth is more massive, and that this is what is important, then this is good enough. If it just says that it is more massive without saying why that is important in some way, then answer No. If it says "bigger" or "larger" (or that the Moon is "smaller") that is good enough. 15.Does the paper mention that the Earth or the planets orbit the Sun? Either is fine. If neither is mentioned, then give a No. 52

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math Paper 0, Questions 16-20 16.Does the paper mention explicitly that the Sun is much more massive than the things orbiting it, and that it is important to say why they orbit the Sun instead of the other way around? If it mentions that the Sun is more massive, and that this is what is important, then this is good enough. If it just says that it is more massive without saying why that is important in some way, then answer No. If it says "bigger" or "larger" (or that the planets are "smaller") that is good enough. 17.Does the paper mention that electrons orbit protons or that electrons orbit a nucleus? Either one is fine. 18.Does the paper mention explicitly that the proton (or nucleus) is much more massive than the electron orbiting it, and that it is important to why they orbit the proton (or nucleus) instead of the other way around? If it mentions that the proton or nucleus is more massive, and that this is what is important, then this is good enough. If it just says that it is more massive without saying why that is important in some way, then answer No. If it says "bigger" or "larger" (or that the electron is "smaller") that is good enough. 19.Does the essay spend an appropriate amount of time on each topic? 20.Does the conclusion paragraph tie together all the big picture issues discussed in the other paragraphs? If the conclusion does not summarize the evidence, then chose No. If the conclusion simply re-states the pieces of evidence, then choose No. 53

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 54 Prep For Next Time – L7 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions –eCampus quizzes (all 6) –Unit 1 Revision (if needed): Stage 1 Let us know if you were misgraded –Unit 2: Stage 2 End-of-Chapter Quizzes –If we finished Chapter 5 then End- of-Chapter Quiz 5 (else just Chapter 4)

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 55 Prep For Today (is now due) – L7 Reading: –BBBHNM Unit 2 Pre-Lecture Reading Questions –eCampus quizzes (all 6) –Unit 1 Revision (if needed): Stage 1 due date postponed until Monday Let us know if you were misgraded –Unit 2: Stage 1 End-of-Chapter Quizzes –Chapter 4

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 56 Prep For Today (is now due) – L8 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions –eCampus quizzes (all 6) Many of you need to check these –Unit 1 Revision (if needed): Stage 1 Let us know if you were misgraded –Unit 2: Stage 2 End-of-Chapter Quizzes –(Chapter 4)

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 57 Prep For Next Time – L6 Reading: –Required: BBBHNM Unit 2 –Recommended Reading: See P3 of http://people.physics.tamu.edu/toback/109/Syllabus.pdf http://people.physics.tamu.edu/toback/109/Syllabus.pdf Pre-Lecture Reading Questions –Unit 1 Revision (if Needed): Stage 2 in CPR due Monday before class –Unit 2: Stage 2 due Monday before class End-of-Chapter Quizzes –If we finished Chapter 5 then End-of-Chapter Quiz 5 (else, just through Chapter 4)

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 58 Prep For Next Time – L7 Reading: –Required: BBBHNM Unit 2 –Recommended Reading: See P3 of http://people.physics.tamu.edu/toback/109/Syllabus.pdf http://people.physics.tamu.edu/toback/109/Syllabus.pdf Pre-Lecture Reading Questions –Unit 1 Revision: Let me know if you were misgraded –Unit 2: Let me know if you were misgraded –Unit 2 Revision (if desired): Stage 1 due Monday before class End-of-Chapter Quizzes –If we finished Chapter 5 then End-of-Chapter Quiz 5 (else, just through Chapter 4)

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 59 Was due today – L7 Reading: –BBBHNM: All reading through Chapter 6 Pre-Lecture Reading Questions: –All reading questions through Chapter 6 End-of-Chapter Quizzes: –All end-of-chapter quizzes through 4 Papers: –Should have been working on Paper 0 –Read the “Writing Prompt” and other stuff on CPR

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math Paper 1 Stuff I have extended the due date until Friday at 5:45PM Want feedback before turning it in? –Post it in eLearning in.doc (or.pdf) for comments by the TA by 5PM tomorrow –Make sure you polish it If you have lots of grammar and spelling mistakes we’ll just make you resubmit it –Will be due in CPR and turnitin.com in one week 60

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 61 Prep for Next Time – L6 Reading: –BBBHNM 6 Recommended: BHOT 4-6 Reading questions –Two questions from Chapter 6 or the recommended reading End-of-Chapter Quizzes –If we finished Chapter 5 then end-of- chapter quiz 5 (else just 4) Be working on Paper 1

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 62 Prep for Next Time – L7 Reading: –None Reading questions –None End-of-Chapter Quizzes –If we finished Chapter 5 then end-of- chapter quiz 5 (else just 4) Paper 1 –Phase II is due Friday at 5:45PM

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 63 Prep For Next Time – L6 Note: May change depending on how far we get in lecture Reading –BBBHNM: None Reading Questions: –None End-of-Chapter Quizzes –If we finished Chapter 5 then end-of-chapter quiz 5 (else just up to Chapter 4) Paper Stuff –Paper 0 in CPR and turnitin.com before class –Will talk more about Calibrations next time

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 64 Prep For Next Time – L7 Note: May change depending on how far we get in lecture Reading –BBBHNM: None Reading Questions: –None End-of-Chapter Quizzes –If we finished Chapter 5 then end-of-chapter quiz 5 (else just up to Chapter 4) Paper Stuff –Paper 0 in CPR and turnitin.com before class –Will talk more about Calibrations next time

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math Full set of Readings So Far Required: –BBBHNM: Chap 1-6 Recommended: –BHOT: Chap. 1-6 –SHU: Chap. 1-3 –TOE: Chap. 1 65

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 66 Prep for Today (is due now) – L6 Reading: –BBBHNM: Chap 5 Reading Questions: –Two questions from Chapter 5 or the recommended reading End-of-Chapter Quizzes –Chapter 4

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 67 Prep for Today (is due now) – L7 Reading: –BBBHNM: Chap 6 Reading Questions: –Two questions from Chapter 6 or the recommended reading End-of-Chapter Quizzes –Chapter 4 Paper 1 –Phase I (CPR and turnitin) was due Friday –Phase II (Calibrations) due Friday at 5:45

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 68 Why do we believe light is a wave? How do waves behave? Water waves and Sound waves Can “see” water waves hitting a wall and what happens to them when they hit two small openings in a wall Big Waves Here Small Waves Here Waves move this way

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math Phase I, Phase II and Phase III Phase I: (Paper due 1 week after we finish Chapter 4) Turn in a polished draft to eLearning TA’s will provide feedback, but not if there are multiple spelling/grammar mistakes Pass/Fail grade Phase II: (Due one week after Phase I) A revised version will be done 1 week later on CPR When you submit to CPR (after revision), you will need to also submit a copy of your to the turnitin.com line on eLearning Phase III: (Due one week after Phase II) Calibrations and Reviewing due one week after you submit 69

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 70 eLearning Quizzes – L8 You are expected to be working on the quizzes on eLearning You cannot pass this course without having gotten a perfect score on all of them You make take as many of each quiz as you like to get perfect scores without penalty Due before the class AFTER we finish a chapter

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 71 In-Class Quizzes Turn in your two questions on the reading During class you will write down two more –This is a separate quiz If you didn’t get a grade you wanted on one of the first few reading quizzes see me about trying again

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 72 What if we look more closely? What if we look at smaller and smaller “amounts” of light? The light we see is actually LOTS of particles all moving together Call these Photons LOTS of photons Lots of photons A few photons

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 73 In-Class Writing Assignment Write down, during the course of lecture, Two questions you want to know the answer to

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 74 Reading Full reading so far: BBBHNM: Chap 1-6 Prelude BHOT: Chap. 1-6, 9 and 11 (117-122) SHU: Chap. 1-3, 6, 7 (up-to- page 153) TOE: Chap. 1

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 75 Before we start the next topic Don’t forget to take your eLearning quizzes –Can’t pass the course without getting 100% on all of them Make sure your name and DATE are on EVERYTHING you turn in

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 76 How do we answer these questions? As previously discussed we have two avenues: Theory Experiment What do both have to say about Light?

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 77 Light as a Wave

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 78 Quiz What time is lecture on Wednesday? Where are we meeting? –Name –Today’s date

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 79 Before we begin As a special treat the class will attend a special Department of Physics colloquium on the LHC this Wednesday (Sept 17 th ) Class will start at 4PM in the teaching wing of the Engineering/Physics building, room 202 (big class room) Class will be over by 5PM You will be expected to sign in with me or Mike as your in class quiz

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 80 Light is more than the colors we see X-rays Radio Waves Infrared Visible color Ultraviolet Microwaves

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 81 In-Class Writing Assignment Write down, during the course of lecture Two questions you want to know the answer to

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 82 WebCT It has come to my attention that people are not finishing the quizzes in WebCT If they don’t get finished we will start requiring people to do them in Recitation to help enforce that they are done –You should be done with Quizzes 1-3 now –Done with Quizzes 4-6 by the end of next week

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 83 A Different Example It is as if a traveling salesman were to send a letter home once a week during his travels While he is traveling away from home, each successive letter will have a little farther to go than the one the week before  Letters will arrive a little more than a week apart On the way home each successive letter will have a shortest distance to travel  will arrive more frequently than once a week

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 84 Old beliefs Light is so fast that people used to believe that it was simply instantaneous You can measure the speed of sound pretty easily –Listen to the alumni side at a football game. When they sing, they’re always LATE! Couldn’t answer the question with an experiment until 1600’s

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 85 Why do we believe it has a finite speed? Danish Astronomer Ole Christian Roemer in 1676 Moons of Jupiter are helpful again! Look at the eclipses of the moons of Jupiter as it moves towards us and away from us We can measure this really accurately now, but that’s another story…

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 86 Eclipses of the Jupiter’s Moon Now you see it! Now you don’t!

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 87 Measure the Time Between Eclipses When Jupiter is moving towards us we get shorter times between eclipses When Jupiter is moving away from us we get longer times between eclipses

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 89 Announcements Recitation tomorrow in ENPH 210 No office hours today –Call/email if you need to meet WebCT Quizzez

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 90 Light: Wave and Particle

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 92 Stars can be billions of light years away! Binary system: SHU p68 Had a way of measuring both the direction and speed of travel of every source of light in the night sky

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 95 However, in reality they are separate particles (feynman diagram?) and each photon interacts with an atom individually. Again a diagram? Individual interacting with an atom (Figure here)

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 96 Question: How do we measure the distance to Jupiter?

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 98 Doppler Effect and Light Replace with P65 from SHU Galaxies moving towards us have shorter wavelength light The light is more Blue, or shifted to the Blue side of the light spectrum “Blue Shifted” Galaxies moving away from us have longer wavelength light The light is more Red, or shifted to the Red side of the light spectrum “Red Shifted”

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 101 We know the Doppler effect in sound… Both volume and pitch change. Picture SHU p65

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 102 Why do we believe light is a wave? Shine white light at a prism and it breaks up into its different colors These different colors are waves with different wavelengths

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 103 Light is a wave The light we see is a “wave” and it is best described by it’s wavelength

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 108 This is a test

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 1 Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture.

Similar presentations

Presentation on theme: "Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 1 Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture."— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 1 Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture.

Similar presentations

Presentation on theme: "Physics We Need Topic 1: Light and Doppler Shifts Big Bang, Black Holes, No Math 1 Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture."— Presentation transcript:

Similar presentations

About project

Feedback