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

Size: px
Start display at page:

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

Transcription

1 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. The Galaxy appears to us like a river of milk, and hence its name, the Milky Way. Kinematics describes the motion without consideration of the causes leading to the motion. Dynamics describes the relationship between motion of objects and its causes

2

3 Just What is a Galaxy? Was everyting seen in telescopes part of the Milky Way? Stars Clusters SNR Planetary Nebulae Dark Nebulae Reflection Nebulae Spiral Nebulae Was the Milky Way the entire Universe? Debate raged well into the 20 th Century

4 Mapping from the Inside What is the Earth's place in the Universe (As Usual, we first thought we were at the center) What is the Sun's place in the Galaxy (For a long time we thought the Sun was at the center of the Milky Way)

5 Starting With Star Counts 1. William Herschel Star Gauging 683 regions around the sky Assumed Galaxy uniformly filled with stars to edge His data were almost completly uniform e.g. Sun at Center

6 William Herschel s Universe, 1785

7 Starting With Star Counts continued 2. Jacobus Kapetyn 1906 First Modern attempt using photography Assumed all stars have same intrinsic brightness Determine distance based on apparent and intrinsic magnitudes Bright stars uniformly distributed Fainter stars concentrated in a band Galactic Equator Conceived a lens shaped galaxy 25,000 light years thick Solar System near the center

8 Map local stellar environment by means of star counts. First plot positions on sky of stars brighter than some level 1. Then plot positions of stars between brightness levels 1 and 2. And so on. If distribution of stars in space is uniform, each plot will be also. Number of stars per square degree in each successive plot will increase in a fashion that we could predict. Find stars concentrated in band of sky, the galactic equator. Find that numbers of fainter stars do not increase away from the galactic equator so rapidly (as uniform distribution would imply). This true also toward galactic equator, although shortfall is smaller. Led to Kapteyn Universe with us in center.

9

10 Typical Cepheid Light Curve Henrietta Levitt and Cepheid variables

11 Cepheid Period-Luminosity Relation To determine the Absolute Magnitude (M V ), essentially the luminosity, of a Cepheid: first find the Period of the Cepheid along the horizontal axis (x-axis), go up to the diagonal line which corresponds to the Period-Luminosity relation, then read across to the vertical axis (y-axis) to see what value of M V it corresponds to. Write the corresponding value of M V in the correct column on your Cepheid Data Sheet.

12 Cepheid period luminosity relation.

13 In 1917, after Henrietta Levitt s discovery of the period-luminosity relation for the Cepheid variable stars in the Small Magellanic Cloud, Harlow Shapley proposed that these stars were pulsating. The explanation that we can determine the intrinsic luminosity of one of these special, pulsating stars from measuring its pulsational period goes like this. The pulsational period depends upon the size of the object. This is because the pulsation is a pressure-driven phenomenon. One period is the time it takes sound (a pressure wave) to propagate from the surface to the deep interior and back. The longer this distance is, the longer the period of the pulsation. This should be familiar to you from the different sounds of large and small bells or of long and short vibrating strings (in a piano, violin, or guitar). Big bells sound low notes. Big stars have low frequency pulsations.

14 So we see the relationship between the pulsational period and the size of the pulsating star. The size of the star is in turn related to its intrinsic luminosity, because the Cepheid variable stars are all giant stars that are located in a nearly vertical strip in the H-R diagram. This means that they all have about the same surface temperature. The properties of the black body spectrum then imply that their luminosities are given by a nearly constant factor determined by their nearly identical surface temperatures multiplied by the areas of their surfaces. This is summed up by the period-luminosity relation for Cepheid variable stars that is shown on the previous slide.

15 Shapley applied Levitt s relation to RR-Lyrae variable stars in globular clusters, to get their distances. He did not realize that the period-luminosity relationship for this different class of variable stars is not the same as for the Cepheid variables studied by Henrietta Levitt. His globular cluster stars were very old, and contained relatively few heavy elements, so they had a different periodluminosity relation. Because of this mistake, Shapley got systematic overestimates for the distances to these star clusters, but he got the right geometrical distribution. Globular clusters have spherical distribution centered on a position about 30,000 light years from us (the modern, corrected distance) in the direction of the galactic equator. Thus we live in a disk, far from its center. Globular clusters orbit center in all directions, disk stars all go around in one direction and in a single plane.

16 1918

17 Shapley Curtis Debate (1920) the Scale of the Universe Main Questions: * What is the nature of the ` nebulae'? * What is the size of our Galaxy? * Is the Sun in the center of the Galaxy?

18 Shapley believed: * diameter of our Galaxy was 300,000 light-years * Sun was not at Galaxy's center, but 60,000 light-years away * Milky Way was so large, it was the entire universe * spiral nebulae were gaseous clouds repelled by Milky Way's light pressure Curtis believed: * diameter of our Galaxy was 30,000 light-years (10x smaller!) * Sun was very close or at center of Galaxy * spiral nebulae were galaxies -- island universes in their own right * Did NOT Believe that Cepheids had a strong period-luminosity relation

19

20 The Andromeda Galaxy

21 * located Cepheids in nearest major spiral nebula *derived distances larger than even Shapley's estimate of Milky Way's size * Shapley admits he was wrong about spiral nebulae (an issue that he did not consider at the heart of the 1920 debate) Edwin Hubble 1924 at the 100in on Mount Wilson

22 Trumpler's Discovery 1930 Robert Trumpler was studying star clusters Noticed some appear fainter than expected based on their assumed size Concluded (correctly) that space is filled with dust and gas which scatters light This scattering is called Interstellar Extinction Therefore Herschel and Kapteyn were only seeing the local stars

23 1930 Trumpler s Discovery

24 Walter Baade Mt Wilson 100 inch Hooker Telescope He took advantage of wartime blackout conditions during World War II, which reduced light pollution at Mount Wilson Observatory, to resolve stars in the center of the Andromeda galaxy for the first time, which led him to define distinct populations for stars (Population I and Population II).

25

26 Milky Way in Sagittarius

27 Milky Way in Sagittarius; Spitzer Infrared image

28 How by looking at stars in the sun s vicinity, we are able to deduce the structure and dynamics of the Galactic disk: See small number of high velocity stars near us moving rapidly relative to rest of material in disk. All appear to be going in about same direction. Bertil Lindblad said they are a population with little rotation about the Galaxy, and hence with large radial velocities. We are rotating past this small population of stars.

29

30

31

32

33

34

35

36 We can measure this rate of shear in disk star motions (how much faster or slower stars orbit with distance toward or away from galactic center). Also need to measure orbital velocity at radius of sun. Bertil Lindblad figured out how to do this last thing, later confirmed by Jan Oort. Measure dispersion of stellar velocities in two directions, along orbit and in direction of galactic center. 2 dispersions would be equal if galaxy rotated like a solid body. Measure amount that they are unequal, and then can calculate orbital period of stars near us. This turns out to be related to the Oort constants mentioned earlier. Answer is about 230 million years. Use sun s orbital velocity to weigh the galaxy inside sun s orbit. Result is 130 billion solar masses.

37

38 The Visible Sky

39 This galaxy looks pretty symmetrical, and pretty thin. NGC 891, a spiral galaxy in the constellation Andromeda that is seen edge on, probably looks pretty much the way our galaxy would look when viewed from outside and edge on.

40 Mapping our Galaxy by observing neutral hydrogen emission: Henk van de Hulst realized that neutral hydrogen gas emits radio waves of 21 cm wavelength. This radiation goes clear across the Galaxy without absorption. Small radio telescope left in Holland by German army was then used to map the entire galactic disk. This gave full rotation curve and revealed spiral arms as well. At 21 cm, you can see forever, but result is confusion. Consider single line of sight on diagram. Only aid in handling confusion is different Doppler shifts of radiation from different regions along line of sight. Gives a line profile, and is an art to interpret one.

41 The 21-centimeter Sky

42

43 To interpret line profile, use model of gas motions in galactic disk. Simplest is circular orbits everywhere. Then is single point along line of sight, the so-called tangent point, where gas has maximum velocity relative to us. This maximum velocity measures speed of galactic rotation at one radius, radius of tangent point. Whole series of such measurements gives the rotation curve.

44

45 Rest of the line profile: 2 locations on line of sight can produce each other velocity. Radiation from near location would extend farther above and below galactic plane than radiation from far location. Radiation from tangent point gives thickness of disk at that radius. From all tangent points, get idea of disk thickness trend in radius. This helps untangle near and far point problem. This done in 1968 by Frank Kerr. Some guess work, but result fairly clear. We live in a spiral galaxy. No doubt about it.

46

47 This sometimes allows us to choose one of the locations unambiguously. Sometimes not.

48

49 Can do same thing with CO emission from much denser, colder gas. Get much flatter distribution. Also see a molecular ring in inner disk, where spiral arms strongest.

50 Ring of Molecules around the core of the Milky Way

51 Molecular Clouds

52 Molecular Clouds

53 On CO diagram, see rotation curve traced by maximum velocities. As near center, max velocity does not go up, but goes down. Not like rotation curve for solar system. So all mass in central region not concentrated at center. In CO diagram, see ridges of bright emission along diagonal lines. These are the spiral arms. It takes a complex model to understand the shapes of these ridges. This is a big, big deal. The spiral arms are the crests of a WAVE. Kind of like white caps on a lake. Explained by Lin and Shu in Believed by everyone 10 years later.

54

55 Based upon a large number of modern observations, this is the present consensus idea of how our galaxy would look if we could go outside of it and view it face on. The sun is located on the Orion Spur, between the 2 principal spiral arms.

56 NGC628. Except for the inner bar, our galaxy s inner region probably would look pretty much like this galaxy if we could see it face on.

57 Size and Parts of the Milky Way Disk between 100,000 and 160,000 light years in diameter up to 2000 light years thick Central Bulge around the nucleus 6500 light years in diameter Halo The globular clusters trace out the halo population

58

59 Typical orbit of disk star. Vertical velocity is small compared to orbital velocity. Oscillates up and down about center plane of disk. Stars in the central bulge swarm around the center in all directions.

60

61 Weighing the Galaxy Hard to see rotation of galaxy, because we are revolving with it. But stars closer to center revolve faster; stars farther out go slower. Like planets going around sun (remember Kepler s laws?) So our galactic disk is rotating differentially. Rotation curve: plot orbital velocity trend with radius. For solid body, like merry-go-round, get straight line. For solar system, with Kepler s laws and nearly all mass at center, get rapidly falling curve. For galactic disk, encompass ever more mass as go out, so curve does not drop off. If look toward and away from galactic center, we see that stars generally orbit faster and slower, respectively.

62 Jan Oort observed bright red giant stars near sun. Got positions and line-of-sight velocities (Doppler shifts). Concluded these stars are in disk. Positions gave disk thickness and velocities gave mass in disk. This mass was twice what you get from adding up visible matter. Thus mass-to-light ratio of disk stars near us 5 times solar value. Mostly have faint dwarfs, so no surprise. Visible matter in galactic halo has only few % of disk mass. Dynamical arguments say halo 10 times disk mass. So mass-to-light ratio in halo is likely to be huge. Nearby disk stars go around galactic center in almost circular orbits. Typical orbit does not close on itself.

63

64

65

66 Determining the mass of an object Use small orbiting object. Kepler s third law: P 2 = a 3 Newton s law of gravitation: P 2 = a 3 [4π 2 / G (m 1 + m 2 )] If one mass dominates, plot P 2 against a 3 and slope gives M: P 2 = (4 π 2 / GM) a 3 Solve for M in terms of the other quantities: M = (4 π 2 / G) (a 3 /P 2 ) Measure G in the laboratory, then put in a and P for a planet to get M for the sun. If measure a as an angle on the sky, then need to use the distance to the object M to convert a into distance units.

67

68

69 Use stars in disk to measure mass of Galaxy inside their orbits. Galaxy is very flat (with small bulge in center). Assume circular orbits and axisymmetric distribution of mass. (Axisymmetric means that the mass density is constant along every circle centered on the Galaxy s rotation axis. Thus, if you were to spin the Galaxy a bit, an observer would see no difference, since an axisymmetric Galaxy looks the same as you go out along any radial line.) Also assume orbits of all stars lie in same plane (flat Galaxy).

70 The Milky Way, photographed in diffuse infrared radiation by the COBE satellite. In infrared light that penetrates dust clouds, our galaxy looks really flat. To get a rough measure of the mass from velocities of orbiting stars, we need only assume circular orbits and an axisymmetric distribution of mass. We will also assume all orbits lie within a single plane.

71 The Milky Way, photographed in infrared radiation by the UMass 2 micron all-sky survey. In infrared light that penetrates dust clouds, our galaxy looks really flat. To get a rough measure of the mass from velocities of orbiting stars, we need only assume circular orbits and an axisymmetric distribution of mass. We will also assume all orbits lie within a single plane.

72 We assume that the mass of the galaxy is distributed evenly around each ring near a given radius (we assume that the galaxy is axisymmetric). Then chunks A and B of the typical ring shown A B have equal masses. They pull on the star equally in the directions indicated by the arrows. If we add up these two forces, the components pulling up and down on the page cancel, leaving only the component directed toward the galactic center.

73 Each chunk, A, of a given ring has an equal-mass mirror chunk, B, so that the total force exerted on the star from each whole ring of matter is directed toward the galactic center. We get this total force by adding up the contributions from all the chunks, A. A B Therefore the total force on the star from all the matter closer than the star to the galactic center is directed toward the galactic center. With a computer, or using the calculus, we could add up all these force contributions, from all the chunks in all the rings, to get the total.

74 Similarly, we can show that the total force on our star from each ring located outside its radius is directed away from the galactic center. However, it takes only a much smaller mass located at the center of the disk to cancel this outward pull. A B To find the mass contained in each annulus of our galaxy, given a series of measured stellar revolution velocities at increasing radii from the center, we must solve what is called an inverse problem.

75 Given a set of choices for the masses of the various annuli (rings), Newton s laws and some calculus (or some computer-enabled algebra) allow us to calculate the accelerations, and hence the rotation velocities of all the stars whose orbits define the annuli. The rotation velocity of this star determines the mass in the shaded ring. But what we really want to do is to compute things the other way around. We know the stellar velocities but not the masses of the annuli. Again, we can use a computer to make thousands or even millions of trials in a matter of minutes, giving us the answer.

76 Are our assumptions true for other galaxies? Nearby spiral galaxy M83 seen nearly face-on. Prominent spiral arms. Not very axisymmetric. But we see light distribution, not mass distribution. Spiral arms traced out by bright, massive stars. They are incredibly bright for their mass. If look in infrared, get better idea of mass distribution. Then see it is nearly axisymmetric. See that edge-on galaxies are extremely flat. Can also use companion galaxies to weigh whole galaxies. Could use two small companions of Andromeda Galaxy. Could use Magellanic Clouds to weigh our Galaxy. Weighing an irregular galaxy like the Large Magellanic Cloud would require that we generalize our methods, since it is neither axisymmetric nor flat.

77 Clearly, if our galaxy is like M83, shown here, our assumption of mass spread out evenly around concentric rings is in trouble. Happily, what we see in this picture is the distribution of light in M83, not the distribution of mass. We have built our model of our own galaxy partly by looking at other ones in order to get a better perspective. This one is M83, 14 million light years away from us.

78 This galaxy has two companions, that we could use to help determine its mass The Andromeda Galaxy, which is probably quite like our own. Its nuclear bulge is about 12,000 light years across.

79 These two companions of our own galaxy should have motions that we could relate to our galaxy s mass. The Magellanic Clouds as viewed from Australia

80 The Large Magellanic Cloud, a satellite of our own Milky Way We could use the velocities of stars in this irregular galaxy to help to determine its mass, but we would have to generalize our method.

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

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

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

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 - 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

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

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

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

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

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 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

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

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 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, 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

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

Lecture 30. The Galactic Center

Lecture 30. The Galactic Center Lecture 30 History of the Galaxy Populations and Enrichment Galactic Evolution Spiral Arms Galactic Types Apr 5, 2006 Astro 100 Lecture 30 1 The Galactic Center The nature of the center of the Galaxy is

More information

A100H Exploring the Universe: Discovering Galaxies. Martin D. Weinberg UMass Astronomy

A100H Exploring the Universe: Discovering Galaxies. Martin D. Weinberg UMass Astronomy A100H Exploring the Universe: Discovering Galaxies Martin D. Weinberg UMass Astronomy astron100h-mdw@courses.umass.edu April 05, 2016 Read: Chap 19 04/05/16 slide 1 Exam #2 Returned by next class meeting

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

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

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

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

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

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

A 103 Notes, Week 14, Kaufmann-Comins Chapter 15

A 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 information

Figure 19.19: HST photo called Hubble Deep Field.

Figure 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 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

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

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

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

2. Can observe radio waves from the nucleus see a strong radio source there Sagittarius A* or Sgr A*.

2. Can observe radio waves from the nucleus see a strong radio source there Sagittarius A* or Sgr A*. 7/7 The Nucleus of the MW its center 1. Can t see the nucleus in visible light too much stuff in the way. 2. Can observe radio waves from the nucleus see a strong radio source there Sagittarius A* or Sgr

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

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

Galaxies and Cosmology

Galaxies 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 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

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

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

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

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

Galaxies. What is a Galaxy? A bit of History. A bit of History. Three major components: 1. A thin disk consisting of young and intermediate age stars

Galaxies. What is a Galaxy? A bit of History. A bit of History. Three major components: 1. A thin disk consisting of young and intermediate age stars What is a Galaxy? Galaxies A galaxy is a collection of billions of stars, dust, and gas all held together by gravity. Galaxies are scattered throughout the universe. They vary greatly in size and shape.

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

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

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

4/6/17. SEMI-WARM stuff: dust. Tour of Galaxies. Our Schedule

4/6/17. SEMI-WARM stuff: dust. Tour of Galaxies. Our Schedule ASTR 1040: Stars & Galaxies Super-bubble blowout in NGC 3709 Prof. Juri Toomre TAs: Piyush Agrawal, Connor Bice Lecture 22 Thur 6 Apr 2017 zeus.colorado.edu/astr1040-toomre Tour of Galaxies Look at complex

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

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

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 Milky Way. Finding the Center. Milky Way Composite Photo. Finding the Center. Milky Way : A band of and a. Milky Way

The 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 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

Tour of Galaxies. stuff: dust SEMI-WARM. ASTR 1040 Accel Astro: Stars & Galaxies. Dust+dark molecular clouds. in close-up VLT.

Tour of Galaxies. stuff: dust SEMI-WARM. ASTR 1040 Accel Astro: Stars & Galaxies. Dust+dark molecular clouds. in close-up VLT. ASTR 1040 Accel Astro: Stars & Galaxies Prof. Juri Toomre TA: Nicholas Nelson, Zeeshan Parkar Lecture 23 Tues 6 Apr 2010 zeus.colorado.edu/astr1040-toomre toomre Tour of Galaxies Role of dust in absorbing/scattering

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

It is about 100,000 ly across, 2,000 ly thick, and our solar system is located 26,000 ly away from the center of the galaxy.

It is about 100,000 ly across, 2,000 ly thick, and our solar system is located 26,000 ly away from the center of the galaxy. The Galaxies The Milky Way Galaxy Is a spiral galaxy in which our solar system is located. The center of the galaxy lies in the Sagittarius Constellation. It is about 100,000 ly across, 2,000 ly thick,

More information

Chapter 15 Galaxies and the Foundation of Modern Cosmology

Chapter 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 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

Tour of Galaxies. Sgr A* VLT in IR + adaptive optics. orbits. ASTR 1040 Accel Astro: Stars & Galaxies VLT IR+AO

Tour of Galaxies. Sgr A* VLT in IR + adaptive optics. orbits. ASTR 1040 Accel Astro: Stars & Galaxies VLT IR+AO ASTR 1040 Accel Astro: Stars & Galaxies Prof. Juri Toomre TA: Kyle Augustson Lecture 23 Tues 8 Apr 08 zeus.colorado.edu/astr1040-toomre toomre Tour of Galaxies Briefly revisit Monster in the Milky Way

More information

11/8/18. Tour of Galaxies. Our Schedule

11/8/18. Tour of Galaxies. Our Schedule ASTR 1040: Stars & Galaxies Super-bubble blowout in NGC 3709 Prof. Juri Toomre TAs: Ryan Horton, Loren Matilsky Lecture 22 Thur 8 Nov 2018 zeus.colorado.edu/astr1040-toomre Tour of Galaxies Look at complex

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

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

Exam 4 Review EXAM COVERS LECTURES 22-29

Exam 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 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

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

This Week in Astronomy

This Week in Astronomy Homework #8 Due Wednesday, April 18, 11:59PM Covers Chapters 15 and 16 Estimated time to complete: 40 minutes Read chapters, review notes before starting This Week in Astronomy Credit: NASA/JPL-Caltech

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

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

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

Galaxies. CESAR s Booklet

Galaxies. CESAR s Booklet What is a galaxy? Figure 1: A typical galaxy: our Milky Way (artist s impression). (Credit: NASA) A galaxy is a huge collection of stars and interstellar matter isolated in space and bound together by

More information

Our Solar System: A Speck in the Milky Way

Our Solar System: A Speck in the Milky Way GALAXIES Lesson 2 Our Solar System: A Speck in the Milky Way The Milky Way appears to be curved when we view it but in reality it is a straight line. It is curved due to the combination of pictures taken

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

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

Galaxies & Introduction to Cosmology

Galaxies & 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 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

Galaxies Guiding Questions

Galaxies 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 information

The King's University College Astronomy 201 Mid-Term Exam Solutions

The King's University College Astronomy 201 Mid-Term Exam Solutions The King's University College Astronomy 201 Mid-Term Exam Solutions Instructions: The exam consists of two sections. Part A is 20 multiple choice questions - please record answers on the sheet provided.

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

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

Astronomy Stars, Galaxies and Cosmology Exam 3. Please PRINT full name

Astronomy Stars, Galaxies and Cosmology Exam 3. Please PRINT full name Astronomy 132 - Stars, Galaxies and Cosmology Exam 3 Please PRINT full name Also, please sign the honor code: I have neither given nor have I received help on this exam The following exam is intended to

More information

According to the currents models of stellar life cycle, our sun will eventually become a. Chapter 34: Cosmology. Cosmology: How the Universe Works

According 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 information

PHY 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 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 information

The Milky Way. Mass of the Galaxy, Part 2. Mass of the Galaxy, Part 1. Phys1403 Stars and Galaxies Instructor: Dr. Goderya

The 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 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

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

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

Gravitation and Dark Matter

Gravitation and Dark Matter PHYS 1105 SMU Physics Dept. Gravitation and Dark Matter Goal: To calculate the amount of Dark Matter in galaxy NGC 134 The (Very) Big Picture The force of gravity acts upon any object with mass and is

More information

The cosmic distance scale

The 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

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

Earth Science, 13e Tarbuck & Lutgens

Earth Science, 13e Tarbuck & Lutgens Earth Science, 13e Tarbuck & Lutgens Beyond Our Solar System Earth Science, 13e Chapter 24 Stanley C. Hatfield Southwestern Illinois College Properties of stars Distance Distances to the stars are very

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

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

There are three basic types of galaxies:

There 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 information

Galaxies and The Milky Way

Galaxies and The Milky Way Galaxies and The Milky Way Attendance Quiz Are you here today? Here! (a) yes (b) no (c) To infinity and beyond! Next Tuesday, 5/30, I will be away at a meeting. There will be a guest lecture by Dr. Jorge

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

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

24.1 Hubble s Galaxy Classification

24.1 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 information

9.6. Other Components of the Universe. Star Clusters. Types of Galaxies

9.6. Other Components of the Universe. Star Clusters. Types of Galaxies Other Components of the Universe 9.6 The most common type of celestial object astronomers see in space is a star. Most stars appear to be gravitationally bound together into groups, and some groups are

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

BHS Astronomy: Galaxy Classification and Evolution

BHS Astronomy: Galaxy Classification and Evolution Name Pd Date BHS Astronomy: Galaxy Classification and Evolution This lab comes from http://cosmos.phy.tufts.edu/~zirbel/ast21/homework/hw-8.pdf (Tufts University) The word galaxy, having been used in English

More information

IX. Stuff that's Bigger than the Solar System

IX. Stuff that's Bigger than the Solar System IX. Stuff that's Bigger than the Solar System Physics II 3/26/09 Leeson IX. A. Galaxies M104 Sombrero Galaxy (in Virgo) M31 A. 1. What is a Galaxy? A system of stars, planets, dust, and gas held together

More information

Stellar Populations in the Galaxy

Stellar Populations in the Galaxy Stellar Populations in the Galaxy Stars are fish in the sea of the galaxy, and like fish they often travel in schools. Star clusters are relatively small groupings, the true schools are stellar populations.

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