1 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
2 This Week in Astronomy Credit: NASA/JPL-Caltech A Very Fast Supernova! M. Pursiainen / University of Southampton and DES collaboration Animation of KSN 2015K exploding as a supernova event. Very fast rise time of light curve thought to be due to a cocoon of material that surrounded the star prior to explosion.
3 What lies in the center of our galaxy?
4 Stars appear to be orbiting something massive but invisible a black hole? Orbits of stars indicate a mass of about 4 million M sun.
5 Milky Way s central black hole has a mass of M BH = 4 million M Sun (a bit low-weight as central black holes go; most massive are 10 billion M Sun ) These supermassive black holes are believed to occur only at the centers of galaxies. Black hole is only a tiny fraction of the mass of the entire Galaxy (weight of your hair vs. weight of your body) and only affects stars very near it.
6 X-ray flares from the galactic center suggest that tidal forces of the suspected black hole occasionally tear apart chunks of matter about to fall in.
7 What would happen to the Earth/Sun if the Milky Way s central black hole suddenly disappeared? A) The Earth/Sun system would move toward the center of the Galaxy. B) The Earth/Sun system would fly away, since the mass of the black hole was gone. C) The Earth/Sun system would be basically unaffected. D) The Earth/Sun system would move into the halo of the Galaxy.
8 What would happen to the Earth/Sun if the Milky Way s central black hole suddenly disappeared? A) The Earth/Sun system would move toward the center of the Galaxy. B) The Earth/Sun system would fly away, since the mass of the black hole was gone. C) The Earth/Sun system would be basically unaffected. D) The Earth/Sun system would move into the halo of the Galaxy. The mass of the black hole is tiny compared to the Galaxy s mass only stars very near the black hole would be affected.
9 Chapter 15 Study Guide 1) The Milky Way is both a band of light across the sky and the name of the galaxy in which we reside. 2) Much of the light from our galaxy is obscured by dust/gas led early astronomers to assume we were in the center of it (wrong). 3) Our galaxy is composed of (know geometry) : Sun disk: thin/flat, old+new heavy element-rich stars, gas/dust bulge: central/spherical, old stars, no gas/dust halo: spherical/large, old heavy element-poor stars, no gas/ dust globular clusters: compact star cluster, very old, orbit our galaxy in halo, about 150 of them.
10 Chapter 15 Study Guide 4) Sun is on 230 million year merry-go-round orbit around center of galaxy at a distance of 27,000 light years. 5) Can use velocity, distance of Sun to measure mass of Galaxy using Newton s gravity law at least 100 billion M Sun. 6) Star gas star cycle recycles gas: stars blow winds and/or blow up hot gas cools neutral gas molecular gas star formation repeat (see Summary of Galactic Recycling slide) 7) Star formation sites can be identified by presence of ionization nebulae (gas lit up by UV light from young, hot stars) found in spiral arms of the disk, but not in halo or bulge. 8) Disk is where all the action is: gas/dust/star formation.
11 Chapter 15 Study Guide 10) Spiral galaxies probably formed like individual stars form, but on a much larger scale huge cloud collapses, forms a disk 11) Orbits of stars in the center of Milky Way bulge indicates the presence of a 4 million M Sun black hole in the center. Mass of black hole is very small compared to mass of entire Milky Way galaxy. 12) All galaxies probably harbor supermassive black holes in their centers.
12 Chapter 16 A Universe of Galaxies
13 How large is the Observable Universe? Sun Pluto Neptune Uranus Earth Venus Mercury 590m 450m 287m 15m 11m 6m If the Milky Way is the size of a football stadium how big is the observable Universe? 1:10 19 scale Larger than the Pacific Ocean!
14 Galaxies and Cosmology A galaxy s age, its distance, and the age of the universe are all closely related. The study of galaxies is thus intimately connected with cosmology the study of the structure and evolution of the universe.
15 What are the three major types of galaxies?
16 Hubble Ultra Deep Field 1 million second exposure Nearly every point of light is a galaxy with billions of stars each.
17 Hubble Ultra Deep Field
23 Disk Component: stars of all ages, merry-go-round orbits many gas clouds, active star formation Spiral Galaxy Spheroidal Component: Bulge/halo/globular clusters, old stars, few gas clouds, 3-D orbits In general we call the bulge +halo+globular clusters of a spiral galaxy the spheroidal component.
24 Disk Component: stars of all ages, many gas clouds Blue-white color indicates ongoing star formation Spheroidal Component: bulge/halo/ globular clusters, old stars, few gas clouds Red-yellow color indicates older star population
25 Elliptical Galaxy: All spheroidal component, with no disk component No blue stars, no cold gas, no dust, no recent star formation Red-yellow color indicates older star population.
26 Elliptical Galaxy: All spheroidal component, virtually no disk component Random, 3-D (beehive) stellar orbits, like a giant spiral bulge No recent star formation red and dead galaxies
27 For decades it was believed that ellipticals did not contain a gaseous interstellar medium (ISM). Very little if any cold molecular or cool neutral gas. Where did all the gas from stellar mass loss (planetary nebula + white dwarf supernova) go?
28 Elliptical Galaxies X-ray binaries Hot gas Optical X-ray Elliptical galaxies lack a cold interstellar medium (no star formation), but can have large amounts of HOT (10 million K), X-ray emitting ISM. The gas is too hot to form stars.
29 Irregular Galaxy: Neither spiral nor elliptical. Blue-white color indicates ongoing star formation.
30 You observe a galaxy with significant recent star formation. What type of galaxy can it not be? A) spiral galaxy B) irregular galaxy C) elliptical galaxy
31 You observe a galaxy with significant recent star formation. What type of galaxy can it not be? A) spiral galaxy B) irregular galaxy C) elliptical galaxy Remember, elliptical galaxies do not have much cold gas/dust little of any ongoing star formation (this is why they do not appear blue in photographs). They are red and dead.
32 How are galaxies grouped together?
33 Spiral galaxies are often found in groups of galaxies (up to a several dozen galaxies per group). They are gravitationally bound together. Our Milky Way belongs to the Local Group.
34 The Local Group of Galaxies
35 Elliptical galaxies are much more common in huge clusters of galaxies (hundreds to thousands of galaxies). Most galaxies in clusters are ellipticals.
36 How do we measure the distances to galaxies?
37 Brightness alone does not provide enough information to measure distance (for both stars and galaxies). Can t distinguish near/low luminosity from distant/high luminosity based on brightness alone. This makes distance determinations crucial.
38 We measure galaxy distances using a chain of interdependent techniques: the cosmic distance ladder Cepheids Main sequence fitting Parallax Radar
39 Step 1 (Radar) Determine size of Solar System using radar. Determining the distance to the Sun (1 astronomical unit or AU = 150 million km) is particularly important (as we will see in Step 2).
40 Step 2 (Parallax) Determine distances of nearest stars out to ~1600 lightyears using parallax Parallax technique Crucial to know the value of 1 AU (from Step 1) in order to utilize parallax method
41 Clusters of stars are useful distance indicators if we know the spectral type of their constituent stars.
42 Hyades Cluster Hyades cluster: close enough that the distance to the stars in the cluster (and therefore the cluster itself) can be found by stellar parallax (from Step 2).
43 Step 3 (Main sequence fitting technique) Apparent brightness of star cluster s main sequence tells us its distance H-R diagram Main sequence fitting technique Example: the G (Sun-type) stars in Hyades are brighter than the G stars in Pleiades The Hyades must be closer
44 Cepheid stars are a special type of pulsating variable, very luminous star (not a main sequence star). The period of the pulsation is directly proportional to how luminous it is longer period = more luminous
45 Cepheid Variable Stars The light curve of this Cepheid variable star shows that its brightness alternately rises and falls over a 50-day period (for example).
46 Cepheid variable stars with longer periods have greater luminosities. Note that we need to know the distances of nearby Cepheid stars (in star clusters) to pin down this relation.
47 Step 4 (Cepheid variable stars) Because the period of a Cepheid variable star tells us its luminosity, we can use these stars as standard candles. Need to calibrate method by finding Cepheid variables in clusters of known distance (Step 3)
48 Step 4 (Cepheid variable stars) Cepheids are luminous enough that we can see them in other nearby galaxies! Allows us to determine distances to nearby galaxies first step in distance ladder that allows us to step outside our galaxy.
49 White dwarf supernovae can also be used as standard candles. Recall: White dwarf supernovae occur when a white dwarf steals too much matter from a companion star and explodes. All white dwarf supernovae reach the same peak luminosity.
50 Peak luminosity at 10 billion Suns!! Can be brighter than entire host galaxy! White dwarf supernovae always peak at the same luminosity can be used as a standard candle
51 Step 5 (White Dwarf Supernovae) Apparent brightness of white-dwarf supernova tells us the distance to its host galaxy. Can use to determine distances up to 10 billion light-years White dwarf supernovae examples Need to calibrate using galaxies that also contain Cepheids (Step 4)
52 Which of the following is the crucial rung of the cosmological distance ladder that allows us to bridge the gap between objects in the Milky Way and objects in other galaxies? A) White dwarf supernovae method B) Cepheid variable stars method C) Parallax distance measurements D) Using radar to find the Earth-Sun distance
53 Which of the following is the crucial rung of the cosmological distance ladder that allows us to bridge the gap between objects in the Milky Way and objects in other galaxies? A) White dwarf supernovae method B) Cepheid variable stars method C) Parallax distance measurements D) Using radar to find the Earth-Sun distance Cepheids are bright enough to be seen in nearby galaxies.
54 What is Hubble s law?
55 The Puzzle of Spiral Nebulae Before Edwin Hubble (circa 1920), some scientists argued that spiral nebulae like the Andromeda Galaxy were entire galaxies like our Milky Way, whereas other scientists maintained they were smaller collections of stars within the Milky Way. The debate remained unsettled until someone finally measured the distances of spiral nebulae.
56 Edwin Hubble settled the debate by measuring the distance to the Andromeda Galaxy using Cepheid variables as standard candles.
57 Distance to the Andromeda Galaxy turned out to be over 2 million light years spiral nebulae were galaxies!
58 Hubble also knew that the spectral features of virtually all galaxies are redshifted they re all moving away from us.
59 Discovering Hubble's Law By measuring distances to galaxies (Cepheid variable method Step 4), Hubble found that redshift (velocity) and distance are related in a special way.
60 The farther away a galaxy (larger distance) is, the faster it is moving away from us (larger velocity). Hubble s law: velocity = H 0 distance Hubble s constant (a constant of nature)
61 Redshift of a galaxy tells us its distance through Hubble s law: distance = velocity H 0 Redshift is minor for nearby galaxies, but significant for distant galaxies. If you can measure the velocity of a a galaxy, you can learn its distance!
Chapter 20 Galaxies and the Foundation of Modern Cosmology 20.1 Islands of Stars Our goals for learning: How are the lives of galaxies connected with the history of the universe? What are the three major
Chapter 20 Lecture Chapter 20: Galaxies and the Foundation of Modern Cosmology Galaxies and the Foundation of Modern Cosmology 20.1 Islands of Stars Our goals for learning: How are the lives of galaxies
Chapter 20 Galaxies And the Foundation of Modern Cosmology Agenda Lunar Eclipse Gallery Saturn Pic/Movie Jim Carrey on Quantum Physics Gravitational Lensing Picture Ch. 20 Galaxies Crab Lab Lunar Eclipse
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
Chapter 20 Lecture The Cosmic Perspective Seventh Edition Galaxies and the Foundation of Modern Cosmology Galaxies and the Foundation of Modern Cosmology 20.1 Islands of Stars Our goals for learning: How
19.3 The History of the Milky Way Our goals for learning: What clues to our galaxy's history do halo stars hold? How did our galaxy form? What clues to our galaxy's history do halo stars hold? Halo Stars:
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
ASTR 1120 General Astronomy: Stars & Galaxies!NNOUNCEMENTS HOMEWORK #6 DUE TODAY, by 5pm HOMEWORK #7 DUE Nov. 10, by 5pm Dark matter halo for galaxies Dark matter extends beyond visible part of the galaxy
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?
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,
Chapter 16 Homework Due: 11:59pm on Thursday, November 17, 2016 To understand how points are awarded, read the Grading Policy for this assignment. Question 1 Following are a number of distinguishing characteristics
A100H Exploring the Universe: Discovering Galaxies Martin D. Weinberg UMass Astronomy email@example.com April 05, 2016 Read: Chap 19 04/05/16 slide 1 Exam #2 Returned by next class meeting
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
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
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
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
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
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
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
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
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.
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
Reading Quiz Clickers The Cosmic Perspective Seventh Edition Our Galaxy 19.1 The Milky Way Revealed What does our galaxy look like? How do stars orbit in our galaxy? Where are globular clusters located
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
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
Galaxies and Cosmology Attendance Quiz Are you here today? (a) yes (b) no Here! (c) Cosmetology? Like hair and nails and makeup? Next Tuesday, 5/30: Dr. Jorge Moreno is unavailable, so class will be cancelled
Galaxies Collection of stars, gas and dust bound together by their common gravitational pull. Galaxies range from 10,000 to 200,000 light-years in size. 1781 Charles Messier 1923 Edwin Hubble The distribution
Lecture Outlines Chapter 24 Astronomy Today 8th Edition Chaisson/McMillan Chapter 24 Galaxies Units of Chapter 24 24.1 Hubble s Galaxy Classification 24.2 The Distribution of Galaxies in Space 24.3 Hubble
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
A100 Exploring the : Measuring the Martin D. Weinberg UMass Astronomy firstname.lastname@example.org November 18, 2014 Read: Chaps 20, 21 11/18/14 slide 1 Age of the in an Exam #2 scores posted in Mastering.
Lecture 15: Dark Matter and the Cosmic Web (plus Gamma Ray Bursts) Prof. Tom Megeath A2020 Disk Component: stars of all ages, many gas clouds Review of Lecture 15 Spheroidal Component: bulge & halo, old
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
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
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
SOME NEGATIVE EFFECTS OF THE EXPANSION OF THE UNIVERSE. Lecture 22 Hubble s Law and the Large Scale Structure of the Universe PRS: According to modern ideas and observations, what can be said about the
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
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
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?
Skills Worksheet Directed Reading A Section: The Life Cycle of Stars TYPES OF STARS (pp. 444 449) 1. Besides by mass, size, brightness, color, temperature, and composition, how are stars classified? a.
The Milky Way Three Major Components Bulge young and old stars Disk young stars located in spiral arms Halo oldest stars and globular clusters Components are chemically, kinematically, and spatially distinct
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
Prentice Hall EARTH SCIENCE Tarbuck Lutgens Chapter 25 Beyond Our Solar System 25.1 Properties of Stars Characteristics of Stars A constellation is an apparent group of stars originally named for mythical
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
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
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
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
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
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
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
Lecture 12: Black Holes & the Milky Way A2020 Prof. Tom Megeath Review: Creating Stellar Remnants Binaries may be destroyed in white dwarf supernova Binaries be converted into black holes Review: Stellar
Stars & Galaxies Chapter 27 Modern Earth Science Chapter 27, Section 1 27.1 Characteristics of Stars Composition & Temperature Scientists use the following tools to study stars Telescope Observation Spectral
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
Galaxies Galaxies First spiral nebula found in 1845 by the Earl of Rosse. Speculated it was beyond our Galaxy. 1920 - "Great Debate" between Shapley and Curtis on whether spiral nebulae were galaxies beyond
By tracing their orbits and using our understanding of gravity, we can conclude that the object these stars are orbiting (shown here as a 5- pointed star) must have a mass over 2.5 million times greater
29:50 Stars, Galaxies, and the Universe Final Exam December 13, 2010 Form A There are 40 questions. Read each question and all of the choices before choosing. Budget your time. No whining. Walk with Ursus!
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,
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
I. Stars have color, brightness, mass, temperature and size. II. Distances to stars are measured using stellar parallax a. The further away, the less offset b. Parallax angles are extremely small c. Measured
Stars & Galaxies Chapter 27 Modern Earth Science Chapter 27, Section 1 27.1 Characteristics of Stars How do astronomers determine the composition and surface temperature of a star? Composition & Temperature
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
Classifying Stars In the early 1900s, Ejnar Hertzsprung and Henry Russell made some important observations. They noticed that, in general, stars with higher temperatures also have brighter absolute magnitudes.
Section: Stars Pages 32-38 Study Guide Chapter 2 Circle the letter of the best answer for each question. 1. What do scientists study to learn about stars? a. gravity c. space b. starlight d. colors COLOR
Department of Physics and Geology Laboratory: Milky Way Astronomy 1402 Equipment Needed Quantity Equipment Needed Quantity Milky Way galaxy Model 1 Ruler 1 1.1 Our Milky Way Part 1: Background Milky Way
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
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
A100 Exploring the Universe: The Milky Way as a Galaxy Martin D. Weinberg UMass Astronomy email@example.com November 12, 2014 Read: Chap 19 11/12/14 slide 1 Exam #2 Returned and posted tomorrow
Universe Now 9. Interstellar matter and star clusters About interstellar matter Interstellar space is not completely empty: gas (atoms + molecules) and small dust particles. Over 10% of the mass of the
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!
Big Galaxies Are Rare! Potato Chip Rule: More small things than large things Big, bright spirals are easy to see, but least common Dwarf ellipticals & irregulars are most common Faint, hard to see Mostly
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
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.
Chapter 28 Stars and Their Characteristics Origin of the Universe Big Bang Theory about 10-20 bya all matter in the universe existed in a hot dense state about the size of an atom (tiny). That matter sort
Stars and Galaxies 1 Characteristics of Stars 2 Star - body of gases that gives off great amounts of radiant energy as light and heat 3 Most stars look white but are actually different colors Antares -
Galaxies Galaxies are collections of billons of stars; our home galaxy, the Milky Way, is a typical example. Stars, gas, and interstellar dust orbit the center of the galaxy due to the gravitational attraction
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
Milky Way Galaxy Milky Way spiral galaxy - flattened disk 150,000 LY in diameter with about 400 billion stars we sit in a gas/dust arm - active star formation - absorbs visible light study using IR/radio/gamma
The Electromagnetic Spectrum Three Kinds of Spectra Sun: The Nearest Star Radius 696,000 km 109 Re Mass 2 x 10^30 kg 300,000 Me Density 1400 kg/m^3 Luminosity 3.8x10^26 Watts (board calc.) Comp. 70% H,
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