XII. The distance scale. h"p://sgoodwin.staff.shef.ac.uk/phy111.html
|
|
- Annabella McCarthy
- 5 years ago
- Views:
Transcription
1 XII. The distance scale h"p://sgoodwin.staff.shef.ac.uk/phy111.html
2 0. How far away are galaxies? We discussed galaxies without thinking about how we know the distances to these galaxies. Only in the past 20 years have astronomers really started agreeing about the distances to other galaxies (when I did a similar course in about 1990 estimates varied by factors of two).
3 1. Standard candles Determining distances relies on what are known as standard candles if you know how bright a particular object is, then if you observe its apparent brightness in a distant galaxy you can calculate the distance to that galaxy. We use a variety of standard candles to work out from nearby parallax distances in the MW from local stars, to stars in clusters, to more distant stars and clusters. But all of our very local standard candles are faint and impossible to see in other galaxies.
4 1. The instability strip Some stars are unstable Particular zones in their interiors can have high opacities, this means energy cannot escape, and so they heat-up then they expand and cool, as they cool their opacities drop and so even more energy escapes, so they cool more which causes their opacities to rise This causes them to pulsate.
5 1. Cepheids The most important variables in the instability strip are Cepheid variables as they have luminosities of L sun, very distinctive lightcurves, and a (now) well-known periodluminosity relationship.
6 1. Cepheids One of the main reasons for building the HST (and why it is Hubble ) was to observe Cepheids out to about 20Mpc. This is the distance of the Virgo cluster of galaxies and knowing the distance to that allowed us to calibrate other distance indicators.
7 2. The Hubble Constant In the 1910s it was know that other galaxies were (almost) all receding from us: they all showed a redshift. Spectral lines will shift to the blue (shorter wavelength) if an object is approaching, or to the red (longer wavelength) if it is receding.
8 2. The Hubble Constant In 1929 Hubble showed what was anticipated by theory that recession velocity, v r, was proportional to distance, D: v r = H 0 D Where H 0 is the Hubble Constant. We now know H 0 ~70 km s -1 Mpc -1.
9 2. The Hubble Constant This tells us that the Universe is expanding and we can get an age estimate for the Universe, but for now we can just use it as a distance estimator. If a galaxy is receding at 7000 km/s, its redshift distance is ~100 Mpc. This works if the Hubble velocity is high enough to washout peculiar local motions due to the gravity of other galaxies (typically these are km/s). But recession velocity is a good proxy for distance.
10 2. Redshift, z Recession velocities are usually quoted as redshift (z) which is related to what fraction of the age of the Universe that distance corresponds to (as light takes time to reach us). The fraction of the age of the Universe is 1/(1+z) so we live at z=0 (fraction=1), z=1 is at half the current age (fraction=1/2).
11 2. Redshift, z In astronomy we are always looking at things as they were in the past. The light from a star 30pc away left it about 100 yrs ago (30pc~100 lyr). The light from the Andromeda galaxy left it about 1.5Myr ago, and the light from something in the Virgo Cluster about 65 Myr ago (about when the dinosaurs were killed). We ll see we think the Universe is ~14Gyr old, so light from an object >14Glyr (5000Mpc) away will not have had enough time to reach us yet. (It s rather more complex than this as the Universe is expanding and this adds all sorts of extra fiddly general relativity to the problem.)
12 3. SNIa Type Ia supernovae are used as a standard candle for extremely large distances (as they are very bright). They all have different peak brightnesses, but the speed at which they decay depends on that peak brightness, so they can each be scaled afterwards to determine their distance.
13 4. Secondary indicators There are various other distance indicators you might come-across (Tully-Fisher, surface brightness, globular cluster luminosity function, D n -Σ, etc.). These are calibrated from the Cepheid distances to the Virgo cluster and then can be used for more distant galaxies (and the vast majority of galaxies in which we haven t had a SNIa). But we really needn t bother with them here the astronomers will get to do them all later
14 5. Large scale structure Surveys of galaxies now get >10 5 galaxy redshifts and can map the distribution of galaxies in a huge fraction of the local Universe. They find many galaxies in clusters and super-clusters, with small groups (like our own local group) fairly common, and galaxies strung between clusters and super-clusters along filaments.
15 5. Large scale structure Surveys of galaxies now get >10 5 galaxy redshifts and can map the distribution of galaxies in a huge fraction of the local Universe. They find many galaxies in clusters and superclusters, with small groups (like our own local group) fairly common, and galaxies strung between clusters and superclusters along filaments.
16 5. Galaxy mergers Ellipticals are more common in clusters and superclusters, with spirals typically found in low-density regions. Ellipticals are more common in clusters because galaxies collide the denser the environment, the more often they collide. A collision causes a burst of star formation and exhausts the gas, destroys discs and leaves an elliptical galaxy.
17 Summary Distances are measured using standard candles the most important are Cepheid variables and SNIa. Combined with recession velocities this leads to Hubble s Law H 0 =v r D. The recession velocity is often quoted in terms of redshift how far back as a fraction of the age of the Universe we are observing. Galaxies are most often found in groups (like ours), clusters, and super-clusters, connected by filaments in a cosmic web.
18 Key points To understand what a standard candle is and why they are important. To understand how Hubble s Law can be used to get a distance from a recession velocity. And that redshift is a measure of both distance and lookback time.
19 Quickies At what redshift was the Sun born? At what Hubble recession velocity would a galaxy at 700 Mpc have? From observations of Cepheids we know a galaxy is at 10 Mpc. We measure its recession velocity as 30 km s -1. Why would this velocity surprise you, and what is the probable explanation?
20 Notes The relationship between redshift and distance is linear for low values of z, but becomes rather complex when we look at very distant objects (very far back in time). As the Universe expands the value of H 0 changes as the geometry of the Universe changes. Partly this is a standard result from applying general relativity, but recently it has become clear that something odd is happening. We ll talk about dark matter in the next lecture, and dark energy very briefly later. Really understanding this will have to wait until general relativity and cosmology courses in 3 rd year.
Hubble s Law. Tully-Fisher relation. The redshift. λ λ0. Are there other ways to estimate distances? Yes.
Distances to galaxies Cepheids used by Hubble, 1924 to show that spiral nebulae like M31 were further from the Sun than any part of the Milky Way, therefore galaxies in their own right. Review of Cepheids
More informationLecture 32: The Expanding Universe Readings: Sections 26-5 and 28-2
Lecture 32: The Expanding Universe Readings: Sections 26-5 and 28-2 Key Ideas Measuring the Distances to Galaxies and Determining the Scale of the Universe Distance Methods: Trigonometric Parallaxes Spectroscopic
More informationGalaxies and Cosmology
Galaxies and Cosmology Attendance Quiz Are you here today? (a) yes (b) no Here! (c) Cosmetology? Like hair and nails and makeup? Next Tuesday, 5/30: Dr. Jorge Moreno is unavailable, so class will be cancelled
More informationGalaxies. The majority of known galaxies fall into one of three major classes: spirals (78 %), ellipticals (18 %) and irregulars (4 %).
Galaxies Collection of stars, gas and dust bound together by their common gravitational pull. Galaxies range from 10,000 to 200,000 light-years in size. 1781 Charles Messier 1923 Edwin Hubble The distribution
More informationThe Cosmological Redshift. Cepheid Variables. Hubble s Diagram
SOME NEGATIVE EFFECTS OF THE EXPANSION OF THE UNIVERSE. Lecture 22 Hubble s Law and the Large Scale Structure of the Universe PRS: According to modern ideas and observations, what can be said about the
More informationGalaxies & Introduction to Cosmology
Galaxies & Introduction to Cosmology Other Galaxies: How many are there? Hubble Deep Field Project 100 hour exposures over 10 days Covered an area of the sky about 1/100 the size of the full moon Probably
More informationLecture 25: The Cosmic Distance Scale Sections 25-1, 26-4 and Box 26-1
Lecture 25: The Cosmic Distance Scale Sections 25-1, 26-4 and Box 26-1 Key Ideas The Distance Problem Geometric Distances Trigonometric Parallaxes Luminosity Distances Standard Candles Spectroscopic Parallaxes
More informationLearning Objectives. distances to objects in our Galaxy and to other galaxies? apparent magnitude key to measuring distances?
The Distance Ladder Learning Objectives! What is the distance ladder? How do we measure distances to objects in our Galaxy and to other galaxies?! How are the concepts of absolute magnitude and apparent
More informationAstronomy 102 Lab: Distances to Galaxies
Name: Astronomy 102 Lab: Distances to Galaxies You will access your textbook for this lab. Pre-Lab Assignment: As we began to talk about stars beyond the Sun, one of the most important pieces of information
More informationThe Extragalactic Distance Scale
One of the important relations in Astronomy. It lets us Measure the distance to distance objects. Each rung on the ladder is calibrated using lower-rung calibrations. Distance Objects Technique 1-100 AU
More informationThe Extragalactic Distance Scale
One of the important relations in Astronomy. It lets us Measure the distance to distance objects. Each rung on the ladder is calibrated using lower-rung calibrations. Distance Objects Technique 1-100 AU
More informationChapter 25 (and end of 24): Lecture Notes
Chapter 25 (and end of 24): Lecture Notes In order to understand the Hubble Law and its implications both for estimating distances and for interpreting the evolution of the universe, you have to be comfortable
More informationASTR 1120 General Astronomy: Stars & Galaxies
ASTR 1120 General Astronomy: Stars & Galaxies!NNOUNCEMENTS HOMEWORK #6 DUE TODAY, by 5pm HOMEWORK #7 DUE Nov. 10, by 5pm Dark matter halo for galaxies Dark matter extends beyond visible part of the galaxy
More informationASTR 1120 General Astronomy: Stars & Galaxies
ASTR 1120 General Astronomy: Stars & Galaxies!NNOUNCEMENTS HOMEWORK #6 DUE TODAY, by 5pm HOMEWORK #7 DUE Nov. 10, by 5pm Dark matter halo for galaxies REVIEW Dark matter extends beyond visible part of
More information24.1 Hubble s Galaxy Classification
Chapter 24 Galaxies Units of Chapter 24 24.1 Hubble s Galaxy Classification 24.2 The Distribution of Galaxies in Space 24.3 Hubble s Law 24.4 XXActive Galactic Nuclei XXRelativistic Redshifts and Look-Back
More informationBig Galaxies Are Rare! Cepheid Distance Measurement. Clusters of Galaxies. The Nature of Galaxies
Big Galaxies Are Rare! Potato Chip Rule: More small things than large things Big, bright spirals are easy to see, but least common Dwarf ellipticals & irregulars are most common Faint, hard to see Mostly
More informationGalaxies. With a touch of cosmology
Galaxies With a touch of cosmology Types of Galaxies Spiral Elliptical Irregular Spiral Galaxies Spiral Galaxies Disk component where the spiral arms are Interstellar medium Star formation Spheroidal
More informationAddition to the Lecture on Galactic Evolution
Addition to the Lecture on Galactic Evolution Rapid Encounters In case the encounter of two galaxies is quite fast, there will be not much dynamical friction due to lack of the density enhancement The
More informationName Midterm Exam October 20, 2017
Name Midterm Exam October 20, 2017 This test consists of three parts. For the first and second parts, you may write your answers directly on the exam, if you wish. For the other parts, use separate sheets
More informationNormal Galaxies (Ch. 24) + Galaxies and Dark Matter (Ch. 25) Symbolically: E0.E7.. S0..Sa..Sb..Sc..Sd..Irr
Normal Galaxies (Ch. 24) + Galaxies and Dark Matter (Ch. 25) Here we will cover topics in Ch. 24 up to 24.4, but then skip 24.4, 24.5 and proceed to 25.1, 25.2, 25.3. Then, if there is time remaining,
More informationThe Milky Way. Finding the Center. Milky Way Composite Photo. Finding the Center. Milky Way : A band of and a. Milky Way
The Milky Way Milky Way : A band of and a The band of light we see is really 100 billion stars Milky Way probably looks like Andromeda. Milky Way Composite Photo Milky Way Before the 1920 s, astronomers
More informationSurvey of Astrophysics A110
Goals: Galaxies To determine the types and distributions of galaxies? How do we measure the mass of galaxies and what comprises this mass? How do we measure distances to galaxies and what does this tell
More informationToday s Topics & Events
ASTR 1120: Stars & Galaxies Prof. Juri Toomre TA: Licia Ray Lecture 34 Wed 7 Apr 04 zeus.colorado.edu/astr1120-toomre toomre NGC 1232 Today s Topics & Events Today we look at the challenge of measuring
More informationTechniques for measuring astronomical distances generally come in two variates, absolute and relative.
Chapter 6 Distances 6.1 Preliminaries Techniques for measuring astronomical distances generally come in two variates, absolute and relative. Absolute distance measurements involve objects possibly unique
More informationThe Next 2-3 Weeks. Important to read through Chapter 17 (Relativity) before I start lecturing on it.
The Next 2-3 Weeks [27.1] The Extragalactic Distance Scale. [27.2] The Expansion of the Universe. [29.1] Newtonian Cosmology [29.2] The Cosmic Microwave Background [17] General Relativity & Black Holes
More informationAccording to the currents models of stellar life cycle, our sun will eventually become a. Chapter 34: Cosmology. Cosmology: How the Universe Works
Chapter 34: Cosmology According to the currents models of stellar life cycle, our sun will eventually become a a) Cloud of hydrogen gas b) Protostar c) Neutron star d) Black hole e) White dwarf id you
More informationTA Final Review. Class Announcements. Objectives Today. Compare True and Apparent brightness. Finding Distances with Cepheids
Class Announcements Vocab Quiz 4 deadline is Saturday Midterm 4 has started, ends Monday Lab was in the Planetarium. You still need to do the 2 questions Check PS100 webpage, make sure your clicker is
More informationThe Cosmic Distance Ladder. Hubble s Law and the Expansion of the Universe!
The Cosmic Distance Ladder Hubble s Law and the Expansion of the Universe! Last time: looked at Cepheid Variable stars as standard candles. Massive, off-main sequence stars: at a certain stage between
More informationStar systems like our Milky Way. Galaxies
Galaxies Star systems like our Milky Way Galaxies Contain a few thousand to tens of billions of stars,as well as varying amounts of gas and dust Large variety of shapes and sizes Gas and Dust in
More information11/9/2010. Stars, Galaxies & the Universe Announcements. Sky & Telescope s Week at a Glance. iphone App available now.
Stars, Galaxies & the Universe Announcements Reading Quiz #11 Wednesday Mix of questions from today s lecture & reading for Wed. on active galaxies HW#10 in ICON due Friday (11/12) by 5 pm - available
More informationLecture 27 Galaxy Types and the Distance Ladder December 3, 2018
Lecture 27 Galaxy Types and the Distance Ladder December 3, 2018 1 2 Early Observations Some galaxies had been observed before 1900 s. Distances were not known. Some looked like faint spirals. Originally
More informationChapter 20 Galaxies and the Foundation of Modern Cosmology Pearson Education, Inc.
Chapter 20 Galaxies and the Foundation of Modern Cosmology 20.1 Islands of Stars Our goals for learning: How are the lives of galaxies connected with the history of the universe? What are the three major
More informationClassification Distribution in Space Galaxy Clusters. Formation and Evolution Hubble s Law
The American astronomer Edwin Hubble in 1924, according to appearance of galaxies categorized them into four basic types. Classification Distribution in Space Galaxy Clusters Masses Formation and Evolution
More informationSet 5: Expansion of the Universe
Set 5: Expansion of the Universe Cosmology Study of the origin, contents and evolution of the universe as a whole Expansion rate and history Space-time geometry Energy density composition Origin of structure
More informationMeasuring the Hubble Constant through Cepheid Distances
Measuring the Hubble Constant through Cepheid Distances Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant Freedman, Madore, Gibson, et al., Astrophysical Journal
More information6. Star Colors and the Hertzsprung-Russell Diagram
What we can learn about stars from their light: II Color In addition to its brightness, light in general is characterized by its color (actually its wavelength) 6. Star Colors and the Hertzsprung-Russell
More informationThere are three basic types of galaxies:
Galaxies There are three basic types of galaxies: Spirals Ellipticals Irregulars To make a long story short, elliptical galaxies are galaxies that have used up all their gas forming stars, or they have
More informationA 103 Notes, Week 14, Kaufmann-Comins Chapter 15
NEARBY GALAXIES I. Brief History A 103 Notes, Week 14, Kaufmann-Comins Chapter 15 A. Kant B. Curtis-Shapley debate C. Distance to Andromeda II. Classification of nearby galaxies: Spirals, Ellipticals,
More informationA100 Exploring the Universe: Measuring the Universe. Martin D. Weinberg UMass Astronomy
A100 Exploring the : Measuring the Martin D. Weinberg UMass Astronomy weinberg@astro.umass.edu November 18, 2014 Read: Chaps 20, 21 11/18/14 slide 1 Age of the in an Exam #2 scores posted in Mastering.
More informationThe cosmic distance scale
The cosmic distance scale Distance information is often crucial to understand the physics of astrophysical objects. This requires knowing the basic properties of such an object, like its size, its environment,
More information- M31) Biggest is Andromeda (Sb. On Galaxy Evolution Lane. Large & Small Magellanic Clouds. ASTR 1040 Accel Astro: Stars & Galaxies
ASTR 1040 Accel Astro: Stars & Galaxies Prof. Juri Toomre TA: Nicholas Nelson Lecture 24 Thur 7 Apr 2011 zeus.colorado.edu/astr1040-toomre toomre Stefan s Quintet On Galaxy Evolution Lane Look at our local
More informationAstronomy 114. Lecture35:TheBigBang. Martin D. Weinberg. UMass/Astronomy Department
Astronomy 114 Lecture35:TheBigBang Martin D. Weinberg weinberg@astro.umass.edu UMass/Astronomy Department A114: Lecture 35 09 May 2005 Read: Ch. 28,29 Astronomy 114 1/18 Announcements PS#8 due Monday!
More informationToday. Lookback time. ASTR 1020: Stars & Galaxies. Astronomy Picture of the day. April 2, 2008
ASTR 1020: Stars & Galaxies April 2, 2008 Astronomy Picture of the day Reading: Chapter 21, sections 21.3. MasteringAstronomy Homework on Galaxies and Hubble s Law is due April 7 th. Weak Lensing Distorts
More informationThe Milky Way. Mass of the Galaxy, Part 2. Mass of the Galaxy, Part 1. Phys1403 Stars and Galaxies Instructor: Dr. Goderya
Foundations Chapter of Astronomy 15 13e Our Milky Way Seeds Phys1403 Stars and Galaxies Instructor: Dr. Goderya Selected Topics in Chapter 15 A view our Milky Way? The Size of our Milky Way The Mass of
More informationChapter 20 Galaxies And the Foundation of Modern Cosmology. Agenda. Lunar Eclipse. Saturn. Lunar Eclipse
Chapter 20 Galaxies And the Foundation of Modern Cosmology Agenda Lunar Eclipse Gallery Saturn Pic/Movie Jim Carrey on Quantum Physics Gravitational Lensing Picture Ch. 20 Galaxies Crab Lab Lunar Eclipse
More informationClusters: Observations
Clusters: Observations Last time we talked about some of the context of clusters, and why observations of them have importance to cosmological issues. Some of the reasons why clusters are useful probes
More informationGalaxies. Galaxy Diversity. Galaxies, AGN and Quasars. Physics 113 Goderya
Galaxies, AGN and Quasars Physics 113 Goderya Chapter(s): 16 and 17 Learning Outcomes: Galaxies Star systems like our Milky Way Contain a few thousand to tens of billions of stars. Large variety of shapes
More informationChapter 15 Galaxies and the Foundation of Modern Cosmology
15.1 Islands of stars Chapter 15 Galaxies and the Foundation of Modern Cosmology Cosmology: study of galaxies What are they 3 major types of galaxies? Spiral galaxies: like the milky way, look like flat,
More informationA100H Exploring the Universe: Evolution of Galaxies. Martin D. Weinberg UMass Astronomy
A100H Exploring the Universe: Evolution of Galaxies Martin D. Weinberg UMass Astronomy astron100h-mdw@courses.umass.edu April 12, 2016 Read: Chaps 20, 21 04/12/16 slide 1 Remainder of the semester: Chaps.
More informationAS1001:Extra-Galactic Astronomy. Lecture 3: Galaxy Fundamentals
AS1001:Extra-Galactic Astronomy Lecture 3: Galaxy Fundamentals Galaxy Fundamentals How many stars are in a galaxy? How did galaxies form? How many galaxies are there? How far apart are they? How are they
More informationGalaxies Guiding Questions
Galaxies Guiding Questions How did astronomers first discover other galaxies? How did astronomers first determine the distances to galaxies? Do all galaxies have spiral arms, like the Milky Way? How do
More information1. This question is about Hubble s law. The light received from many distant galaxies is red-shifted. (a) State the cause of this red-shift (1)
ROUND 2 - QUESTIONS 1. This question is about Hubble s law. The light received from many distant galaxies is red-shifted. (a) State the cause of this red-shift (1) expanding universe (b) State Hubble s
More informationM31 - Andromeda Galaxy M110 M32
UNIT 4 - Galaxies XIV. The Milky Way galaxy - a huge collection of millions or billions of stars, gas, and dust, isolated in space and held together by its own gravity M110 M31 - Andromeda Galaxy A. Structure
More informationExam 4 Review EXAM COVERS LECTURES 22-29
Exam 4 Review EXAM COVERS LECTURES 22-29 Theoretically is there a center of the universe? Is there an edge? Do we know where Earth is on this? There is no center to the Universe, What kind of light we
More informationOutline. Go over AGN problem, again, should be rotating BH Go over problem 6.6 Olber's paradox Distances Parallax Distance ladder Direct checks
Outline Go over AGN problem, again, should be rotating BH Go over problem 6.6 Olber's paradox Distances Parallax Distance ladder Direct checks Why is the night sky dark? (Olber s Paradox 1826) Or what
More informationChapter 20: Galaxies and the Foundation of Modern Cosmology
Chapter 20 Lecture Chapter 20: Galaxies and the Foundation of Modern Cosmology Galaxies and the Foundation of Modern Cosmology 20.1 Islands of Stars Our goals for learning: How are the lives of galaxies
More informationMIT Invitational, Jan Astronomy C. 2. You may separate the pages, but do not forget to put your team number at the top of all answer pages.
MIT Invitational, Jan 2019 Astronomy C Competitors: School name: Team number: INSTRUCTIONS 1. Please turn in all materials at the end of the event. 2. You may separate the pages, but do not forget to put
More informationLecture Outlines. Chapter 24. Astronomy Today 8th Edition Chaisson/McMillan Pearson Education, Inc.
Lecture Outlines Chapter 24 Astronomy Today 8th Edition Chaisson/McMillan Chapter 24 Galaxies Units of Chapter 24 24.1 Hubble s Galaxy Classification 24.2 The Distribution of Galaxies in Space 24.3 Hubble
More informationQuestion 1. Question 2. Correct. Chapter 16 Homework. Part A
Chapter 16 Homework Due: 11:59pm on Thursday, November 17, 2016 To understand how points are awarded, read the Grading Policy for this assignment. Question 1 Following are a number of distinguishing characteristics
More informationTuesday, Thursday 2:30-3:45 pm. Astronomy 100. Tom Burbine
Astronomy 100 Tuesday, Thursday 2:30-3:45 pm Tom Burbine tburbine@mtholyoke.edu www.xanga.com/astronomy100 OWL assignment (Due Today) There is be an OWL assignment due on Thursday April 14 at 11:59 pm.
More informationGalaxies and Hubble s Law
Galaxies and Hubble s Law Some Important History: Charles Messier In the early 19 th century, Charles Messier was hunting for comets, but in the telescopes of the time, identifying comets was difficult
More informationThe Virgo Cluster. Distance today: 20 Mpc (million parsecs) Distance in 100 years: 20 Mpc Mpc. (Oh well) Look-back time to Virgo Cluster:
The Virgo Cluster Map by Jan Wisniewski Distance today: 20 Mpc (million parsecs) Distance in 100 years: 20 Mpc + 1 10-9 Mpc. (Oh well) Look-back time to Virgo Cluster: 1 parsec = 3.26 light-years Light
More informationFigure 19.19: HST photo called Hubble Deep Field.
19.3 Galaxies and the Universe Early civilizations thought that Earth was the center of the universe. In the sixteenth century, we became aware that Earth is a small planet orbiting a medium-sized star.
More informationSet 1: Expansion of the Universe
Set 1: Expansion of the Universe Syllabus Course text book: Ryden, Introduction to Cosmology, 2nd edition Olber s paradox, expansion of the universe: Ch 2 Cosmic geometry, expansion rate, acceleration:
More informationThe Discovery of Other Galaxies. 24. Normal Galaxies
24. Normal Galaxies The discovery of other galaxies Edwin Hubble proved galaxies are very distant Edwin Hubble classified galaxies by shape Methods for determining distances to galaxies The Hubble Law
More informationBROCK UNIVERSITY. Test 2: July 2015 Number of pages: 9 Course: ASTR 1P02, Section 2 Number of students: 318
BROCK UNIVERSITY Page 1 of 9 Test 2: July 2015 Number of pages: 9 Course: ASTR 1P02, Section 2 Number of students: 318 Examination date: 4 July 2015 Time limit: 50 min Time of Examination: 13:00 13:50
More informationComplete Cosmos Chapter 23: Infinity Outline Sub-chapters
Complete Cosmos Chapter 23: Infinity The structure of the Universe - galaxies, clusters, strands. How we measure to a nearby galaxy and to the farthest quasar. Outline In the Australian night sky, the
More informationCampus Observatory. 7pm. you are here
Announcements Homework #9 is due today Course Evaluations available on line now Post-test Survey for At Play in the Cosmos now ready For extra credit: - must complete all 8 missions by Dec 10 - must complete
More informationThe Scale of the Universe
The Scale of the Universe The Measurement of distance in our Univers! Chapters 12.1.1 Allday; Chapter 3 Silk Measurement of Distance in the Universe Two IMPORTANT concepts that you should know well from
More informationCosmic Distance Determinations
Cosmic Distance Determinations Radar (works for inner solar system) Parallax D(pc) = 1 p(arcsec) GAIA satellite (2013) 20 micro-arcsec resolution! Thus D < 10 kpc Beyond Parallax: Standard Candles Use
More informationGalaxies and Cosmology
4/28/17 The Discovery of Galaxies Up to the 1920 s, astronomers were not sure exactly how far away galaxies were, and thus didn t know how big they are! Spiral Nebulae could be assumed to be inside our
More informationGalaxies and the expansion of the Universe
Review of Chapters 14, 15, 16 Galaxies and the expansion of the Universe 5/4/2009 Habbal Astro 110-01 Review Lecture 36 1 Recap: Learning from Light How does light tell us what things are made of? Every
More informationLecture 33: Announcements
Lecture 33: Announcements 1) Pick up graded hwk 5. Good job: Jessica, Jessica, and Elizabeth for a 100% score on hwk 5 and the other 25% of the class with an A. 2) Article and homework 7 were posted on
More informationExam # 3 Tue 12/06/2011 Astronomy 100/190Y Exploring the Universe Fall 11 Instructor: Daniela Calzetti
Exam # 3 Tue 12/06/2011 Astronomy 100/190Y Exploring the Universe Fall 11 Instructor: Daniela Calzetti INSTRUCTIONS: Please, use the `bubble sheet and a pencil # 2 to answer the exam questions, by marking
More informationCOSMOLOGY PHYS 30392 OBSERVING THE UNIVERSE Part I Giampaolo Pisano - Jodrell Bank Centre for Astrophysics The University of Manchester - January 2013 http://www.jb.man.ac.uk/~gp/ giampaolo.pisano@manchester.ac.uk
More informationBROCK UNIVERSITY. Test 2, March 2015 Number of pages: 9 Course: ASTR 1P02 Number of Students: 420 Date of Examination: March 5, 2015
BROCK UNIVERSITY Page 1 of 9 Test 2, March 2015 Number of pages: 9 Course: ASTR 1P02 Number of Students: 420 Date of Examination: March 5, 2015 Number of hours: 50 min Time of Examination: 18:00 18:50
More information6. Star Colors and the Hertzsprung-Russell Diagram
6. Star Colors and the Hertzsprung-Russell Diagram http://apod.nasa.gov/apod/ Supernovae Type Ia in M82 January 22, 2014 Still rising may go to m = 8 (or 10?) What we can learn about stars from their light:
More information6. Star Colors and the Hertzsprung-Russell Diagram.
6. Star Colors and the Hertzsprung-Russell Diagram http://apod.nasa.gov/apod/ Supernovae Type Ia in M82 January 22, 2014 Still rising may go to m = 8 (or 10?) What we can learn about stars from their light:
More informationLecture #21: Plan. Normal Galaxies. Classification Properties Distances
Lecture #21: Plan Normal Galaxies Classification Properties Distances Messier 31 = M31 Early 20 th Century The Great Debate (4/26/1920): Harlow Shapley (Mt Wilson) vs Heber Curtis (Lick Observatory) Smithsonian
More informationCosmology. Lecture Topics. Colliding Galaxy Simulations The expanding universe Cosmology. The Age of the Universe The Big Bang
Cosmology Lecture 27: Cosmology 27 1 APOD: GOODS project Lecture Topics Colliding Galaxy Simulations The expanding universe Cosmology The cosmological principle The Age of the Universe The Big Bang 2 27-1
More informationDefining Cosmological Parameters. Cosmological Parameters. Many Universes (Fig on pp.367)
Cosmological Parameters Composition of the universe What fraction is in the form of matter? m Always positive. What fraction is in the form of curvature? k Can be positive (hyperbolic) or negative (spherical).
More informationReview of Lecture 15 3/17/10. Lecture 15: Dark Matter and the Cosmic Web (plus Gamma Ray Bursts) Prof. Tom Megeath
Lecture 15: Dark Matter and the Cosmic Web (plus Gamma Ray Bursts) Prof. Tom Megeath A2020 Disk Component: stars of all ages, many gas clouds Review of Lecture 15 Spheroidal Component: bulge & halo, old
More informationAST 101 General Astronomy: Stars & Galaxies
Summary Distance Ladder to measure universe REVIEW AST 101 General Astronomy: Stars & Galaxies Different standard candles are useful for different distances Distance measurements allowed to make a MAJOR
More informationASTR 1040: Stars & Galaxies
ASTR 1040: Stars & Galaxies Our wide world (universe) of Galaxies Expanding universe: Hubble s discovery #2 Challenge of measuring s in universe review methods used Subtle concept of Lookback time Active
More informationGalaxies. Lecture Topics. Lecture 23. Discovering Galaxies. Galaxy properties. Local Group. History Cepheid variable stars. Classifying galaxies
Galaxies Lecture 23 APOD: NGC 3628 (The Hamburger Galaxy) 1 Lecture Topics Discovering Galaxies History Cepheid variable stars Galaxy properties Classifying galaxies Local Group 2 23-1 Discovering Galaxies
More informationClicker Question: Galaxy Classification. What type of galaxy do we live in? The Variety of Galaxy Morphologies Another barred galaxy
Galaxies Galaxies First spiral nebula found in 1845 by the Earl of Rosse. Speculated it was beyond our Galaxy. 1920 - "Great Debate" between Shapley and Curtis on whether spiral nebulae were galaxies beyond
More informationChapter 25: Galaxy Clusters and the Structure of the Universe
Chapter 25: Galaxy Clusters and the Structure of the Universe Distribution of galaxies Evolution of galaxies Study of distant galaxies Distance derived from redshift Hubble s constant age of the Universe:
More informationToday. life the university & everything. Reminders: Review Wed & Fri Eyes to the web Final Exam Tues May 3 Check in on accomodations
life the university & everything Phys 2130 Day 41: Questions? The Universe Reminders: Review Wed & Fri Eyes to the web Final Exam Tues May 3 Check in on accomodations Today Today: - how big is the universe?
More informationAS1001: Galaxies and Cosmology
AS1001: Galaxies and Cosmology Keith Horne kdh1@st-and.ac.uk http://www-star.st-and.ac.uk/~kdh1/eg/eg.html Text: Kutner Astronomy:A Physical Perspective Chapters 17-21 Cosmology Today Blah Title Current
More informationAST-1002 Section 0459 Review for Final Exam Please do not forget about doing the evaluation!
AST-1002 Section 0459 Review for Final Exam Please do not forget about doing the evaluation! Bring pencil #2 with eraser No use of calculator or any electronic device during the exam We provide the scantrons
More informationChapter 19 Galaxies. Hubble Ultra Deep Field: Each dot is a galaxy of stars. More distant, further into the past. halo
Chapter 19 Galaxies Hubble Ultra Deep Field: Each dot is a galaxy of stars. More distant, further into the past halo disk bulge Barred Spiral Galaxy: Has a bar of stars across the bulge Spiral Galaxy 1
More informationLecture 14: Other Galaxies A2020 Prof. Tom Megeath. The Milky Way in the Infrared 3/17/10. NGC 7331: the Milky Way s Twins. Spiral Galaxy bulge halo
Lecture 14: Other Galaxies A2020 Prof. Tom Megeath Our Galaxy: Side View We see our galaxy edge-on Primary features: Disk: young and old stars where we live. Bulge: older stars Halo: oldest stars, globular
More informationThe Cosmological Distance Ladder. It's not perfect, but it works!
The Cosmological Distance Ladder It's not perfect, but it works! First, we must know how big the Earth is. Next, we must determine the scale of the solar system. Copernicus (1543) correctly determined
More informationThe Milky Way Galaxy (ch. 23)
The Milky Way Galaxy (ch. 23) [Exceptions: We won t discuss sec. 23.7 (Galactic Center) much in class, but read it there will probably be a question or a few on it. In following lecture outline, numbers
More informationBASICS OF COSMOLOGY Astro 2299
BASICS OF COSMOLOGY Astro 2299 We live in a ΛCDM universe that began as a hot big bang (BB) and has flat geometry. It will expand forever. Its properties (laws of physics, fundamental constants) allow
More information4/10/18. Our wide world (universe) of Galaxies. Spirals ~80% of galaxies
ASTR 1040: Stars & Galaxies Prof. Juri Toomre TAs: Peri Johnson, Ryan Horton Lecture 23 Tues 10 Apr 2018 zeus.colorado.edu/astr1040-toomre Our wide world (universe) of Galaxies The rich range of galaxies:
More informationLarge Scale Structure
Large Scale Structure Measuring Distance in Universe-- a ladder of steps, building from nearby Redshift distance Redshift = z = (λ observed - λ rest )/ λ rest Every part of a distant spectrum has same
More informationDetermining distance. L 4π f. d = d = R θ. Standard candle. Standard ruler
Determining distance Standard candle d = L 4π f 1 2 d L Standard ruler d = R θ θ R Determining distance: Parallax RULER tanπ = R d π R d π R = 1AU = 1.5 10 13 cm Define new distance unit: parsec (parallax-second)
More informationPHY 475/375. Lecture 2. (March 28, 2012) The Scale of the Universe: The Shapley-Curtis Debate
PHY 475/375 Lecture 2 (March 28, 2012) The Scale of the Universe: The Shapley-Curtis Debate By the 1920 s a debate had developed over whether some of the spiral nebulae catalogued in the 18th century by
More informationAstronomy 210 Final. Astronomy: The Big Picture. Outline
Astronomy 210 Final This Class (Lecture 40): The Big Bang Next Class: The end HW #11 Due next Weds. Final is May 10 th. Review session: May 6 th or May 9 th? Designed to be 2 hours long 1 st half is just
More information