Structure of the Milky Way. Structure of the Milky Way. The Milky Way

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Structure of the Milky Way. Structure of the Milky Way. The Milky Way"

Transcription

1 Key Concepts: Lecture 29: Our first steps into the Galaxy Exploration of the Galaxy: first attempts to measure its structure (Herschel, Shapley). Structure of the Milky Way Initially, star counting was used Assume all stars are about the same luminosity See how many stars are in each direction to map the Galaxy First done by the (German-born) British astronomer William Herschel ( ) and his son. The Structure of the Galaxy Our first encounter with Dark Matter The Milky Way Faint band of light circling sky First resolved into stars by Galileo using his telescope Herschel also discovered infrared light Structure of the Milky Way What Herschel found We are in a flattened disk of stars It extends about 6000 light years We appeared to be at or near the center!! SUN

2 Shapley Maps the Galaxy with Globular Clusters Harlow Shapley ( ) RR Lyrae Stars Horizontal branch stars Brightness varies because they pulsate All have the same average luminosity Found in globular clusters Shapley Maps the Galaxy Distribution of globular clusters is not symmetric about our position in the Galaxy 30% of G.C.s are found in only 2% of the sky toward Sagittarius Shapley Maps the Galaxy Shapley s Results Shapley mapped the distribution of globular star clusters Used RR Lyrae Stars to estimate distances RR Lyrae stars all have the same Luminosity Measure Flux (i.e. apparent brightness) Used Inverse Square Law to get Distance, d flux = luminosity /(4π d 2 ) 47 Tucana M5 Sun is not in center of Galaxy! Center of G.C.s is 26,000 LY = 8000 parsecs from Earth Center in direction of Sagittarius (see Links section of class webpage for more on Shapley s debate with Curtis about the size of the Galaxy, our location in it, and the nature of the nebulae.)

3 What Herschel Got Wrong The star counts do indeed end at 6000 light years ~=2000parsecs They are cutoff by thick clouds of dust Dust tends to: Absorb and scatter blue light Has little effect on light with wavelengths longer than the size of the dust grains The actual extent of the Milky Way is much larger than can be seen in visible light The Structure of the Milky Way A thin highly flattened disk 100,000 LY in diameter 1000 LY thick - About the relative thickness of a CD The Sun is in this disk Contains younger stars & gas (called Population I stars: Pop I) Nuclear Bulge - Central region 10,000 LY across Contains old stars (Pop II) A spherical Halo component Contains globular clusters Contains old stars (Pop II) Different Views of the Milky Way The Structure of the Milky Way Hydrogen Gas in the Radio Star Formation Regions traced by hot dust at 12 microns Old Stars in the Near-IR From COBE

4 Weighing the Milky Way Most stars & gas in the MW disk are on roughly circular orbits This allows us to measure the mass of the Galaxy using Newton s version of Kepler s Third Law e.g. for Sun s orbit: M Galaxy + M sun = a 3 /P 2 a = 26,000 LY = 1.6 x 10 9 A.U. P = 2.25 x 10 8 years M Galaxy + M sun M Galaxy = 2x10 11 M sun This estimate tells us how much mass is inside the Sun s orbit. Can we write this in terms of the speed? Newton s version of Kepler s 3rd law M Galaxy + M sun = a 3 /P 2 P = distance / speed P = 2π a / v a / v M Galaxy + M sun a v 2 We see that v is approximately constant in galaxies (does not depend on a). Therefore the Mass inside radius a increases linearly with a. Question? If we were to measure the velocities of more distant parts of the Milky Way and we find that they are moving faster than the Sun, so that their orbital periods are all about the same as the Sun, what does this tell us about the total mass of the Galaxy? Hint in the solar system the more distant planets orbit much more slowly. M Galaxy + M sun = a 3 /P 2 Mass of the Milky Way Most of the luminous matter in the Galaxy drops off at distances > 30,000 LY Mass of Galaxy should be ~ M Sun However there are a few globular clusters and some gas clouds that lie beyond this boundary These objects move faster than the Sun! Must be more gravity than supplied by luminous matter Total Mass of Galaxy ~ M Sun DARK MATTER - Only about 10% of mass is visible

5 The Search for MACHOs Gravitational Lensing See textbook What is the Dark Matter? Some kind of faint star? White dwarfs Brown dwarfs Examples of MAssive Compact Halo Objects MACHOs Exotic subatomic particles? Have mass Don t interact with matter Formed in early universe Weakly Interacting Massive Particles WIMPs

Chapter 14 The Milky Way Galaxy

Chapter 14 The Milky Way Galaxy Chapter 14 The Milky Way Galaxy Spiral Galaxy M81 - similar to our Milky Way Galaxy Our Parent Galaxy A galaxy is a giant collection of stellar and interstellar matter held together by gravity Billions

More information

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Distances & the Milky Way. The Curtis View. Our Galaxy. The Shapley View 3/27/18

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Distances & the Milky Way. The Curtis View. Our Galaxy. The Shapley View 3/27/18 Astronomy 113 Dr. Joseph E. Pesce, Ph.D. Distances & the Milky Way 14-2 Historical Overview: the Curtis-Shapley Debate ³What is the size of our galaxy? ³What is the nature of spiral nebula? The Curtis

More information

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Dr. Joseph E. Pesce, Ph.D.

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Dr. Joseph E. Pesce, Ph.D. Astronomy 113 Dr. Joseph E. Pesce, Ph.D. Distances & the Milky Way Historical Overview: the Curtis-Shapley Debate ³What is the size of our galaxy? ³What is the nature of spiral nebula? 14-2 ³Occurred in

More information

Our Galaxy. We are located in the disk of our galaxy and this is why the disk appears as a band of stars across the sky.

Our Galaxy. We are located in the disk of our galaxy and this is why the disk appears as a band of stars across the sky. Our Galaxy Our Galaxy We are located in the disk of our galaxy and this is why the disk appears as a band of stars across the sky. Early attempts to locate our solar system produced erroneous results.

More information

The Milky Way, Hubble Law, the expansion of the Universe and Dark Matter Chapter 14 and 15 The Milky Way Galaxy and the two Magellanic Clouds.

The Milky Way, Hubble Law, the expansion of the Universe and Dark Matter Chapter 14 and 15 The Milky Way Galaxy and the two Magellanic Clouds. The Milky Way, Hubble Law, the expansion of the Universe and Dark Matter Chapter 14 and 15 The Milky Way Galaxy and the two Magellanic Clouds. Image taken from the European Southern Observatory in Chile

More information

The Milky Way Galaxy (ch. 23)

The 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 information

ASTR 200 : Lecture 22 Structure of our Galaxy

ASTR 200 : Lecture 22 Structure of our Galaxy ASTR 200 : Lecture 22 Structure of our Galaxy 1 The 'Milky Way' is known to all cultures on Earth (perhaps, unfortunately, except for recent city-bound dwellers) 2 Fish Eye Lens of visible hemisphere (but

More information

The Milky Way - Chapter 23

The Milky Way - Chapter 23 The Milky Way - Chapter 23 The Milky Way Galaxy A galaxy: huge collection of stars (10 7-10 13 ) and interstellar matter (gas & dust). Held together by gravity. Much bigger than any star cluster we have

More information

Number of Stars: 100 billion (10 11 ) Mass : 5 x Solar masses. Size of Disk: 100,000 Light Years (30 kpc)

Number of Stars: 100 billion (10 11 ) Mass : 5 x Solar masses. Size of Disk: 100,000 Light Years (30 kpc) THE MILKY WAY GALAXY Type: Spiral galaxy composed of a highly flattened disk and a central elliptical bulge. The disk is about 100,000 light years (30kpc) in diameter. The term spiral arises from the external

More information

The Milky Way & Galaxies

The Milky Way & Galaxies The Milky Way & Galaxies The Milky Way Appears as a milky band of light across the sky A small telescope reveals that it is composed of many stars (Galileo again!) Our knowledge of the Milky Way comes

More information

Astronomy A BEGINNER S GUIDE TO THE UNIVERSE EIGHTH EDITION

Astronomy A BEGINNER S GUIDE TO THE UNIVERSE EIGHTH EDITION Astronomy A BEGINNER S GUIDE TO THE UNIVERSE EIGHTH EDITION CHAPTER 14 The Milky Way Galaxy Lecture Presentation 14.0 the Milky Way galaxy How do we know the Milky Way exists? We can see it even though

More information

The Milky Way Galaxy Guiding Questions

The Milky Way Galaxy Guiding Questions The Milky Way Galaxy Guiding Questions 1. What is our Galaxy? How do astronomers know where we are located within it? 2. What is the shape and size of our Galaxy? 3. How do we know that our Galaxy has

More information

The Milky Way Galaxy

The Milky Way Galaxy The Milky Way Galaxy Guiding Questions 1. What is our Galaxy? How do astronomers know where we are located within it? 2. What is the shape and size of our Galaxy? 3. How do we know that our Galaxy has

More information

Our View of the Milky Way. 23. The Milky Way Galaxy

Our View of the Milky Way. 23. The Milky Way Galaxy 23. The Milky Way Galaxy The Sun s location in the Milky Way galaxy Nonvisible Milky Way galaxy observations The Milky Way has spiral arms Dark matter in the Milky Way galaxy Density waves produce spiral

More information

Chapter 23 The Milky Way Galaxy Pearson Education, Inc.

Chapter 23 The Milky Way Galaxy Pearson Education, Inc. Chapter 23 The Milky Way Galaxy The Milky Way is our own galaxy viewed from the inside. It is a vast collection of more than 200 billion stars, planets, nebulae, clusters, dust and gas. Our own sun and

More information

Our Galaxy. Chapter Twenty-Five. Guiding Questions

Our Galaxy. Chapter Twenty-Five. Guiding Questions Our Galaxy Chapter Twenty-Five Guiding Questions 1. What is our Galaxy? How do astronomers know where we are located within it? 2. What is the shape and size of our Galaxy? 3. How do we know that our Galaxy

More information

Lecture 29. Our Galaxy: "Milky Way"

Lecture 29. Our Galaxy: Milky Way Lecture 29 The Milky Way Galaxy Disk, Bulge, Halo Rotation Curve Galactic Center Apr 3, 2006 Astro 100 Lecture 29 1 Our Galaxy: "Milky Way" Milky, diffuse band of light around sky known to ancients. Galileo

More information

Lecture Outlines. Chapter 23. Astronomy Today 8th Edition Chaisson/McMillan Pearson Education, Inc.

Lecture Outlines. Chapter 23. Astronomy Today 8th Edition Chaisson/McMillan Pearson Education, Inc. Lecture Outlines Chapter 23 Astronomy Today 8th Edition Chaisson/McMillan Chapter 23 The Milky Way Galaxy Units of Chapter 23 23.1 Our Parent Galaxy 23.2 Measuring the Milky Way Discovery 23-1 Early Computers

More information

Our Galaxy. Milky Way Galaxy = Sun + ~100 billion other stars + gas and dust. Held together by gravity! The Milky Way with the Naked Eye

Our Galaxy. Milky Way Galaxy = Sun + ~100 billion other stars + gas and dust. Held together by gravity! The Milky Way with the Naked Eye Our Galaxy Milky Way Galaxy = Sun + ~100 billion other stars + gas and dust Held together by gravity! The Milky Way with the Naked Eye We get a special view of our own galaxy because we are part of it!

More information

Chapter 15 The Milky Way Galaxy

Chapter 15 The Milky Way Galaxy Chapter 15 The Milky Way Galaxy Guidepost This chapter plays three parts in our cosmic drama. First, it introduces the concept of a galaxy. Second, it discusses our home, the Milky Way Galaxy, a natural

More information

Galaxies: The Nature of Galaxies

Galaxies: The Nature of Galaxies Galaxies: The Nature of Galaxies The Milky Way The Milky Way is visible to the unaided eye at most place on Earth Galileo in 1610 used his telescope to resolve the faint band into numerous stars In the

More information

The Milky Way Galaxy and Interstellar Medium

The Milky Way Galaxy and Interstellar Medium The Milky Way Galaxy and Interstellar Medium Shape of the Milky Way Uniform distribution of stars in a band across the sky lead Thomas Wright, Immanuel Kant, and William Herschel in the 18th century to

More information

M31 - Andromeda Galaxy M110 M32

M31 - 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 information

Ay162, Spring 2006 Week 8 p. 1 of 15

Ay162, Spring 2006 Week 8 p. 1 of 15 Astronomy 162, Week 8 Milky Way Galaxy, continued Patrick S. Osmer Spring, 2006 Rotation of Galaxy How do we know the galaxy is rotating, and how do we measure its rotation? Measure radial velocities of

More information

The Galaxy. (The Milky Way Galaxy)

The Galaxy. (The Milky Way Galaxy) The Galaxy (The Milky Way Galaxy) Which is a picture of the Milky Way? A A is what we see from Earth inside the Milky Way while B is what the Milky Way might look like if we were far away looking back

More information

The Milky Way Galaxy. Some thoughts. How big is it? What does it look like? How did it end up this way? What is it made up of?

The Milky Way Galaxy. Some thoughts. How big is it? What does it look like? How did it end up this way? What is it made up of? Some thoughts The Milky Way Galaxy How big is it? What does it look like? How did it end up this way? What is it made up of? Does it change 2 3 4 5 This is not a constant zoom The Milky Way Almost everything

More information

Stars, Galaxies & the Universe Lecture Outline

Stars, Galaxies & the Universe Lecture Outline Stars, Galaxies & the Universe Lecture Outline A galaxy is a collection of 100 billion stars! Our Milky Way Galaxy (1)Components - HII regions, Dust Nebulae, Atomic Gas (2) Shape & Size (3) Rotation of

More information

ASTR 101 Introduction to Astronomy: Stars & Galaxies

ASTR 101 Introduction to Astronomy: Stars & Galaxies ASTR 101 Introduction to Astronomy: Stars & Galaxies If your clicker grade on BlackBoard is 0 and you have been in class, please send your clicker # to TA Cameron Clarke for checking The Milky Way Size

More information

telescopes resolve it into many faint (i.e. distant) stars What does it tell us?

telescopes resolve it into many faint (i.e. distant) stars What does it tell us? The Milky Way From a dark site the Milky Way can be seen as a broad band across the sky What is it? telescopes resolve it into many faint (i.e. distant) stars What does it tell us? that we live in a spiral

More information

Chapter 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 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 information

Distance Measuring Techniques and The Milky Way Galaxy

Distance Measuring Techniques and The Milky Way Galaxy Distance Measuring Techniques and The Milky Way Galaxy Measuring distances to stars is one of the biggest challenges in Astronomy. If we had some standard candle, some star with a known luminosity, then

More information

The Great Debate: The Size of the Universe (1920)

The Great Debate: The Size of the Universe (1920) The Great Debate: The Size of the Universe (1920) Heber Curtis Our Galaxy is rather small, with Sun near the center. 30,000 LY diameter. Universe composed of many separate galaxies Spiral nebulae = island

More information

Chapter 23: Dark Matter, Dark Energy & Future of the Universe. Galactic rotation curves

Chapter 23: Dark Matter, Dark Energy & Future of the Universe. Galactic rotation curves Chapter 23: Dark Matter, Dark Energy & Future of the Universe Galactic rotation curves Orbital speed as a function of distance from the center: rotation_of_spiral_galaxy.htm Use Kepler s Third Law to get

More information

Lecture 25 The Milky Way Galaxy November 29, 2017

Lecture 25 The Milky Way Galaxy November 29, 2017 Lecture 25 The Milky Way Galaxy November 29, 2017 1 2 Size of the Universe The Milky Way galaxy is very much larger than the solar system Powers of Ten interactive applet 3 Galaxies Large collections of

More information

The Milky Way Galaxy

The Milky Way Galaxy 1/5/011 The Milky Way Galaxy Distribution of Globular Clusters around a Point in Sagittarius About 00 globular clusters are distributed in random directions around the center of our galaxy. 1 1/5/011 Structure

More information

The Milky Way. 20 March The Shape of the Galaxy Stellar Populations and Motions Stars as a Gas. University of Rochester

The Milky Way. 20 March The Shape of the Galaxy Stellar Populations and Motions Stars as a Gas. University of Rochester The Milky Way The Shape of the Galaxy Stellar Populations and Motions Stars as a Gas 20 March 2018 University of Rochester The Milky Way Today s lecture: The shape of the Galaxy Stellar populations and

More information

11/6/18. Today in Our Galaxy (Chap 19)

11/6/18. Today in Our Galaxy (Chap 19) ASTR 1040: Stars & Galaxies Prof. Juri Toomre TAs: Ryan Horton, Loren Matilsky Lecture 21 Tues 6 Nov 2018 zeus.colorado.edu/astr1040-toomre Edge-on spiral galaxy NGG 4013 Today in Our Galaxy (Chap 19)

More information

Survey of Astrophysics A110

Survey 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 information

Today in Astronomy 142: the Milky Way

Today in Astronomy 142: the Milky Way Today in Astronomy 142: the Milky Way The shape of the Galaxy Stellar populations and motions Stars as a gas: Scale height, velocities and the mass per area of the disk Missing mass in the Solar neighborhood

More information

Black Holes and Curved Space-time. Paths of Light and Matter. The Principle of Equivalence. Implications of Gravity Bending Light

Black Holes and Curved Space-time. Paths of Light and Matter. The Principle of Equivalence. Implications of Gravity Bending Light Black Holes and Curved Space-time When a massive star collapses at the end of its life, it can become a black hole A black is an object that is so massive that light cannot escape from it The theory that

More information

Ch. 25 In-Class Notes: Beyond Our Solar System

Ch. 25 In-Class Notes: Beyond Our Solar System Ch. 25 In-Class Notes: Beyond Our Solar System ES2a. The solar system is located in an outer edge of the disc-shaped Milky Way galaxy, which spans 100,000 light years. ES2b. Galaxies are made of billions

More information

BROCK UNIVERSITY. Test 2, March 2018 Number of pages: 9 Course: ASTR 1P02, Section 1 Number of Students: 465 Date of Examination: March 12, 2018

BROCK UNIVERSITY. Test 2, March 2018 Number of pages: 9 Course: ASTR 1P02, Section 1 Number of Students: 465 Date of Examination: March 12, 2018 BROCK UNIVERSITY Page 1 of 9 Test 2, March 2018 Number of pages: 9 Course: ASTR 1P02, Section 1 Number of Students: 465 Date of Examination: March 12, 2018 Number of hours: 50 min Time of Examination:

More information

3 The lives of galaxies

3 The lives of galaxies Discovering Astronomy : Galaxies and Cosmology 24 3 The lives of galaxies In this section, we look at how galaxies formed and evolved, and likewise how the large scale pattern of galaxies formed. But before

More information

AST 301 Introduction to Astronomy

AST 301 Introduction to Astronomy AST 301 Introduction to Astronomy John Lacy RLM 16.332 471-1469 lacy@astro.as.utexas.edu Myoungwon Jeon RLM 16.216 471-0445 myjeon@astro.as.utexas.edu Bohua Li RLM 16.212 471-8443 bohuali@astro.as.utexas.edu

More information

How does the galaxy rotate and keep the spiral arms together? And what really lies at the center of the galaxy?

How does the galaxy rotate and keep the spiral arms together? And what really lies at the center of the galaxy? Ch 14: Mysteries of the Milky Way How does the galaxy rotate and keep the spiral arms together? And what really lies at the center of the galaxy? The Structure of the Galaxy We know that our galaxy has

More information

The Milky Way Galaxy. Sun you are here. This is what our Galaxy would look like if we were looking at it from another galaxy.

The Milky Way Galaxy. Sun you are here. This is what our Galaxy would look like if we were looking at it from another galaxy. The Milky Way Galaxy Sun you are here. This is what our Galaxy would look like if we were looking at it from another galaxy. Examples of three Milky-Way like Galaxies 1. Roughly 100,000 light years across

More information

Astro 242. The Physics of Galaxies and the Universe: Lecture Notes Wayne Hu

Astro 242. The Physics of Galaxies and the Universe: Lecture Notes Wayne Hu Astro 242 The Physics of Galaxies and the Universe: Lecture Notes Wayne Hu Syllabus Text: An Introduction to Modern Astrophysics 2nd Ed., Carroll and Ostlie First class Wed Jan 3. Reading period Mar 8-9

More information

Physics HW Set 3 Spring 2015

Physics HW Set 3 Spring 2015 1) If the Sun were replaced by a one solar mass black hole 1) A) life here would be unchanged. B) we would still orbit it in a period of one year. C) all terrestrial planets would fall in immediately.

More information

BROCK UNIVERSITY. Test 2, March 2015 Number of pages: 9 Course: ASTR 1P02 Number of Students: 420 Date of Examination: March 5, 2015

BROCK 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 information

Galaxies and the Universe. Our Galaxy - The Milky Way The Interstellar Medium

Galaxies and the Universe. Our Galaxy - The Milky Way The Interstellar Medium Galaxies and the Universe Our Galaxy - The Milky Way The Interstellar Medium Our view of the Milky Way The Radio Sky COBE Image of our Galaxy The Milky Way Galaxy - The Galaxy By Visual Observation

More information

Exam # 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 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 information

The Milky Way, Our galaxy

The Milky Way, Our galaxy The Milky Way, Our galaxy Diffuse Band of light that crosses the Sky in the North Galileo: it s faint stars Early speculation and fleshing out where we are 1 Milky Way from Zuerich Milky Way from Australia

More information

Basic Facts about the Milky Way

Basic Facts about the Milky Way THE MILKY WAY Basic Facts about the Milky Way The Sun is one of about 200 billion stars in the Milky Way Galaxy The Milky Way is a spiral galaxy, with a flat disk, central bulge and bar, and spherical

More information

The Milky Way Galaxy. sun. Examples of three Milky-Way like Galaxies

The Milky Way Galaxy. sun. Examples of three Milky-Way like Galaxies The Milky Way Galaxy sun This is what our Galaxy would look like if we were looking at it from another galaxy. Examples of three Milky-Way like Galaxies 1. Roughly 100,000 light years across 2. Roughly

More information

Lecture 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. 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 information

A100 Exploring the Universe: The Milky Way as a Galaxy. Martin D. Weinberg UMass Astronomy

A100 Exploring the Universe: The Milky Way as a Galaxy. Martin D. Weinberg UMass Astronomy A100 Exploring the Universe: The Milky Way as a Galaxy Martin D. Weinberg UMass Astronomy astron100-mdw@courses.umass.edu November 12, 2014 Read: Chap 19 11/12/14 slide 1 Exam #2 Returned and posted tomorrow

More information

Star systems like our Milky Way. Galaxies

Star 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 information

Galaxies and the expansion of the Universe

Galaxies 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 information

View of the Galaxy from within. Lecture 12: Galaxies. Comparison to an external disk galaxy. Where do we lie in our Galaxy?

View of the Galaxy from within. Lecture 12: Galaxies. Comparison to an external disk galaxy. Where do we lie in our Galaxy? Lecture 12: Galaxies View of the Galaxy from within The Milky Way galaxy Rotation curves and dark matter External galaxies and the Hubble classification scheme Plotting the sky brightness in galactic coordinates,

More information

Chapter 19: Our Galaxy

Chapter 19: Our Galaxy Chapter 19 Lecture Chapter 19: Our Galaxy Our Galaxy 19.1 The Milky Way Revealed Our goals for learning: What does our galaxy look like? How do stars orbit in our galaxy? What does our galaxy look like?

More information

Astro 1050 Fri. Apr. 14, 2017

Astro 1050 Fri. Apr. 14, 2017 Astro 1050 Fri. Apr. 14, 2017 Today: Ch. 19: Our Galaxy, the Milky Way Reading in Bennett: Ch 12 this week, Ch. 13 for next week 1 2 Chapter 12 The Milky Way Galaxy Band of light running around sky in

More information

AST1100 Lecture Notes

AST1100 Lecture Notes AST1100 Lecture Notes 4 Stellar orbits and dark matter 1 Using Kepler s laws for stars orbiting the center of a galaxy We will now use Kepler s laws of gravitation on much larger scales. We will study

More information

Clicker Question: Clicker Question: Clicker Question: Clicker Question: What is the remnant left over from a Type Ia (carbon detonation) supernova:

Clicker Question: Clicker Question: Clicker Question: Clicker Question: What is the remnant left over from a Type Ia (carbon detonation) supernova: Test 3 results D C Grades posted in cabinet and Grades posted on-line B A F If you are not properly registered then come see me for your grade What is the ultimate origin of the elements heavier than helium

More information

Side View. disk mostly young stars and lots of dust! Note position of the Sun, just over half way out. This Class (Lecture 28): More Milky Way

Side View. disk mostly young stars and lots of dust! Note position of the Sun, just over half way out. This Class (Lecture 28): More Milky Way This Class (Lecture 28): More Milky Way Next Class: Nearby Galaxies Music: Under the Milky Way The Church HW 10 due on 2 nd Sunday! Nov. 17, 2009! The 2009 Leonids could produce more than 500 shooting

More information

Einführung in die Astronomie II

Einführung in die Astronomie II Einführung in die Astronomie II Teil 12 Peter Hauschildt yeti@hs.uni-hamburg.de Hamburger Sternwarte Gojenbergsweg 112 21029 Hamburg 13. September 2017 1 / 77 Overview part 12 The Galaxy Historical Overview

More information

Dark Matter: What is it?

Dark Matter: What is it? Dark Matter: What is it? Dark Matter: What is it? Key Concepts 1) Some dark matter consists of MACHOs (MAssive Compact Halo Objects). 2) Some dark matter may consist of WIMPs (Weakly Interacting Massive

More information

The hazy band of the Milky Way is our wheel-shaped galaxy seen from within, but its size

The hazy band of the Milky Way is our wheel-shaped galaxy seen from within, but its size C H A P T E R 15 THE MILKY WAY GALAXY 15-1 THE NATURE OF THE MILKY WAY GALAXY How do astronomers know we live in a galaxy? The hazy band of the Milky Way is our wheel-shaped galaxy seen from within, but

More information

Our goals for learning: 2014 Pearson Education, Inc. We see our galaxy edge-on. Primary features: disk, bulge, halo, globular clusters All-Sky View

Our goals for learning: 2014 Pearson Education, Inc. We see our galaxy edge-on. Primary features: disk, bulge, halo, globular clusters All-Sky View Our Galaxy Chapter 19 Lecture The Cosmic Perspective 19.1 The Milky Way Revealed What does our galaxy look like? What does our galaxy look like? How do stars orbit in our galaxy? Seventh Edition Our Galaxy

More information

Arvind Borde / AST 10, Week 2: Our Home: The Milky Way

Arvind Borde / AST 10, Week 2: Our Home: The Milky Way Arvind Borde / AST 10, Week 2: Our Home: The Milky Way The Milky Way is our home galaxy. It s a collection of stars, gas and dust. (1) What holds it together? Its self-gravity. (2) What did the last slide

More information

Chapter 16 Dark Matter, Dark Energy, & The Fate of the Universe

Chapter 16 Dark Matter, Dark Energy, & The Fate of the Universe 16.1 Unseen Influences Chapter 16 Dark Matter, Dark Energy, & The Fate of the Universe Dark Matter: An undetected form of mass that emits little or no light but whose existence we infer from its gravitational

More information

Chapter 15 The Milky Way Galaxy. The Milky Way

Chapter 15 The Milky Way Galaxy. The Milky Way Chapter 15 The Milky Way Galaxy The Milky Way Almost everything we see in the night sky belongs to the Milky Way We see most of the Milky Way as a faint band of light across the sky From the outside, our

More information

Figure 69.01a. Formation of Stars

Figure 69.01a. Formation of Stars 1. One cloud many clumps 2. Up to 1000 cores can form within 1 clump 3. Core: begins to build a star by attracting material from the cloud 4. Protostar, MS star 5. Up to 1000 stars 6. Stars usually form

More information

Exam 3 Astronomy 114

Exam 3 Astronomy 114 Exam 3 Astronomy 114 Select the answer that is the most appropriate among the choices given. 1. What is the Hubble law? (A) a relation between a galaxy s mass and radius. (B) a rule that describes the

More information

Chapter 19 Lecture. The Cosmic Perspective. Seventh Edition. Our Galaxy Pearson Education, Inc.

Chapter 19 Lecture. The Cosmic Perspective. Seventh Edition. Our Galaxy Pearson Education, Inc. Chapter 19 Lecture The Cosmic Perspective Seventh Edition Our Galaxy 19.1 The Milky Way Revealed Our goals for learning: Where are we located within our galaxy? What does our galaxy look like? How do stars

More information

Lecture #21: Plan. Normal Galaxies. Classification Properties Distances

Lecture #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 information

Milky Way Kinematics, or how we discovered the geometry and dynamics of our own galactic environment. Compiled by Paul R. Woodward and B.

Milky Way Kinematics, or how we discovered the geometry and dynamics of our own galactic environment. Compiled by Paul R. Woodward and B. Milky Way Kinematics, or how we discovered the geometry and dynamics of our own galactic environment. Compiled by Paul R. Woodward and B. Kevin Edgar The name galaxy comes from the Greek word for milk.

More information

Exam #3. Median: 83.8% High: 100% If you d like to see/discuss your exam, come to my office hours, or make an appointment.

Exam #3. Median: 83.8% High: 100% If you d like to see/discuss your exam, come to my office hours, or make an appointment. Exam #3 Average: 80.1% Median: 83.8% High: 100% Scores available on Blackboard If you d like to see/discuss your exam, come to my office hours, or make an appointment. Exam #3 The Sun is made of A) all

More information

Neutron Stars. Neutron Stars and Black Holes. The Crab Pulsar. Discovery of Pulsars. The Crab Pulsar. Light curves of the Crab Pulsar.

Neutron Stars. Neutron Stars and Black Holes. The Crab Pulsar. Discovery of Pulsars. The Crab Pulsar. Light curves of the Crab Pulsar. Chapter 11: Neutron Stars and Black Holes A supernova explosion of an M > 8 M sun star blows away its outer layers. Neutron Stars The central core will collapse into a compact object of ~ a few M sun.

More information

The Milky Way Galaxy

The Milky Way Galaxy The Milky Way Galaxy A. Expert - I have done a lot of reading in this area already. B. Above Average - I have learned some information about this topic. C. Moderate - I know a little about this topic.

More information

7/5. Consequences of the principle of equivalence (#3) 1. Gravity is a manifestation of the curvature of space.

7/5. Consequences of the principle of equivalence (#3) 1. Gravity is a manifestation of the curvature of space. 7/5 Consequences of the principle of equivalence (#3) 1. Gravity is a manifestation of the curvature of space. Follow the path of a light pulse in an elevator accelerating in gravityfree space. The dashed

More information

Astronomy 102: Stars and Galaxies Examination 3 Review Problems

Astronomy 102: Stars and Galaxies Examination 3 Review Problems Astronomy 102: Stars and Galaxies Examination 3 Review Problems Multiple Choice Questions: The first eight questions are multiple choice. Except where explicitly noted, only one answer is correct for each

More information

Notes for Wednesday, July 16; Sample questions start on page 2 7/16/2008

Notes for Wednesday, July 16; Sample questions start on page 2 7/16/2008 Notes for Wednesday, July 16; Sample questions start on page 2 7/16/2008 Wed, July 16 MW galaxy, then review. Start with ECP3Ch14 2 through 8 Then Ch23 # 8 & Ch 19 # 27 & 28 Allowed Harlow Shapely to locate

More information

Reminders! Observing Projects: Both due Monday. They will NOT be accepted late!!!

Reminders! Observing Projects: Both due Monday. They will NOT be accepted late!!! Reminders! Website: http://starsarestellar.blogspot.com/ Lectures 1-15 are available for download as study aids. Reading: You should have Chapters 1-14 read. Read Chapters 15-17 by the end of the week.

More information

Chapter 19 Lecture. The Cosmic Perspective Seventh Edition. Our Galaxy Pearson Education, Inc.

Chapter 19 Lecture. The Cosmic Perspective Seventh Edition. Our Galaxy Pearson Education, Inc. Chapter 19 Lecture The Cosmic Perspective Seventh Edition Our Galaxy Our Galaxy 19.1 The Milky Way Revealed Our goals for learning: Where are we located within our galaxy? What does our galaxy look like?

More information

Name Date Period. 10. convection zone 11. radiation zone 12. core

Name Date Period. 10. convection zone 11. radiation zone 12. core 240 points CHAPTER 29 STARS SECTION 29.1 The Sun (40 points this page) In your textbook, read about the properties of the Sun and the Sun s atmosphere. Use each of the terms below just once to complete

More information

Thom et al. (2008), ApJ

Thom et al. (2008), ApJ Star S674 along the same LOS as Complex C Star S441 along the same LOS as Complex C Thom et al. (2008), ApJ Distances to HVCs From spectroscopy of high Galactic latitude stars at small angular separations

More information

Summary: Nuclear burning in stars

Summary: Nuclear burning in stars Summary: Nuclear burning in stars Reaction 4 1 H 4 He 3 4 He 12 C 12 C + 4 He 16 O, Ne, Na, Mg Ne O, Mg O Mg, S Si Fe peak Min. Temp. 10 7 o K 2x10 8 8x10 8 1.5x10 9 2x10 9 3x10 9 Evolution through nuclear

More information

Chapter 12 Stellar Evolution

Chapter 12 Stellar Evolution Chapter 12 Stellar Evolution Guidepost This chapter is the heart of any discussion of astronomy. Previous chapters showed how astronomers make observations with telescopes and how they analyze their observations

More information

LESSON 1. Solar System

LESSON 1. Solar System Astronomy Notes LESSON 1 Solar System 11.1 Structure of the Solar System axis of rotation period of rotation period of revolution ellipse astronomical unit What is the solar system? 11.1 Structure of the

More information

Chapter 30. Galaxies and the Universe. Chapter 30:

Chapter 30. Galaxies and the Universe. Chapter 30: Chapter 30 Galaxies and the Universe Chapter 30: Galaxies and the Universe Chapter 30.1: Stars with varying light output allowed astronomers to map the Milky Way, which has a halo, spiral arm, and a massive

More information

Neutron Stars. Chapter 14: Neutron Stars and Black Holes. Neutron Stars. What s holding it up? The Lighthouse Model of Pulsars

Neutron Stars. Chapter 14: Neutron Stars and Black Holes. Neutron Stars. What s holding it up? The Lighthouse Model of Pulsars Neutron Stars Form from a 8-20 M Sun star Chapter 14: Neutron Stars and Black Holes Leftover 1.4-3 M Sun core after supernova Neutron Stars consist entirely of neutrons (no protons) Neutron Star (tennis

More information

Astronomy 114. Lecture 27: The Galaxy. Martin D. Weinberg. UMass/Astronomy Department

Astronomy 114. Lecture 27: The Galaxy. Martin D. Weinberg. UMass/Astronomy Department Astronomy 114 Lecture 27: The Galaxy Martin D. Weinberg weinberg@astro.umass.edu UMass/Astronomy Department A114: Lecture 27 18 Apr 2007 Read: Ch. 25,26 Astronomy 114 1/23 Announcements Quiz #2: we re

More information

The interpretation is that gravity bends spacetime and that light follows the curvature of space.

The interpretation is that gravity bends spacetime and that light follows the curvature of space. 7/8 General Theory of Relativity GR Two Postulates of the General Theory of Relativity: 1. The laws of physics are the same in all frames of reference. 2. The principle of equivalence. Three statements

More information

The Milky Way. The Milky Way

The Milky Way. The Milky Way The Milky Way The Milky Way The Milky Way is a continuous band of diffuse light. The band is thicker and brighter in one part of the sky and 180 o away it is thinner and fainter. The band is tilted about

More information

What is the solar system?

What is the solar system? Notes Astronomy What is the solar system? 11.1 Structure of the Solar System Our solar system includes planets and dwarf planets, their moons, a star called the Sun, asteroids and comets. Planets, dwarf

More information

Cosmology, Galaxies, and Stars OUR VISIBLE UNIVERSE

Cosmology, Galaxies, and Stars OUR VISIBLE UNIVERSE Cosmology, Galaxies, and Stars OUR VISIBLE UNIVERSE Cosmology Cosmology is the study of the universe; its nature, origin and evolution. General Relativity is the mathematical basis of cosmology from which

More information

Clicker Question: Clicker Question: What is the expected lifetime for a G2 star (one just like our Sun)?

Clicker Question: Clicker Question: What is the expected lifetime for a G2 star (one just like our Sun)? How Long do Stars Live (as Main Sequence Stars)? A star on Main Sequence has fusion of H to He in its core. How fast depends on mass of H available and rate of fusion. Mass of H in core depends on mass

More information

Beyond Our Solar System Chapter 24

Beyond Our Solar System Chapter 24 Beyond Our Solar System Chapter 24 PROPERTIES OF STARS Distance Measuring a star's distance can be very difficult Stellar parallax Used for measuring distance to a star Apparent shift in a star's position

More information

Results better than Quiz 5, back to normal Distribution not ready yet, sorry Correct up to 4 questions, due Monday, Apr. 26

Results better than Quiz 5, back to normal Distribution not ready yet, sorry Correct up to 4 questions, due Monday, Apr. 26 Brooks observing April 19-22: 9:00 PM to at least 10:15 PM Tonight is a go! April 26-29: 9:30 PM to at least 10:45 PM Regular Friday evening public observing after planetarium shows also an option Begins

More information