The Cosmic Distance Ladder
|
|
- Edwina Fletcher
- 5 years ago
- Views:
Transcription
1 The Cosmic Distance Ladder (Mário Santos)
2 What is it? A way to calculate distances to objects very far away based on the measured distances to nearby objects: 1. Start with the distance to the Sun (1 AU) 2. Measure the distance to nearby stars in terms of the distance to the Sun 3. Calculate the distance to other galaxies using the measurements to nearby stars 4. Measure the size of the Universe!
3 Example: using parallax Change in apparent position of an object relative to background Knowing the angle of this change and the distance between the 2 viewpoints we can calculate the distance to the object It allows humans to see depth and perspective!
4 Measuring distances to nearby stars Measure apparent movement (angle) of nearby stars against the background of more distant stars But nearby stars are far away! Need large distances to observe the angle Cannot use 2 points on Earth - make observations as the Earth moves around the Sun (say July and January) parallax angle Small angle: So, for 1 : sin(p) = 1AU d d 1AU p [radians] distance to star AU p [arcsec] d AU 1 parsec [pc]
5 Measuring distances to nearby stars But need to know distance to the Sun (AU) Determine relative distance of planets to the Sun (e.g. Kepler) Measure distance of Earth to planets (e.g. parallax during transit of Venus) Modern values use direct radar measurements 1 AU = 149,597,870,700 metres
6 Distance to nearby stars: examples Ground based parallaxes up to ~ 0.01 out to 100 pc ~ 1000 stars First measurement: 61 Cygni ~ 3.5 pc (Friedrich Bessel ) Nearest star: Proxima Centauri ~ 1.31 pc Hipparcos satellite ~ up to 1000 pc ~ 100,000 stars GAIA (2013) ~ up to 50 Kpc ~ 1 billion stars
7 Note: Luminosity distances Indirect distance estimate: Measure the object s Flux (apparent brightness), F Assume the object s Luminosity (absolute brightness), L Apply inverse square law of brightness to determine distance, d L F = L 4 d 2 L =) d L = r L 4 F Assume Measure Need to know L beforehand! Use Standard Candles
8 Next step: spectroscopic parallax Measure the apparent brightness of a nearby star Determine distance using the parallax method Determine the Luminosity Analyse the spectrum of the star Construct the Hertzprung- Russell diagram: Luminosity (absolute brightness) versus spectral type (color)
9 Next step: spectroscopic parallax Use diagram to measure distances to stars farther away: From the spectra, determine the position of the star on the H-R diagram Read off the Luminosity (absolute brightness) From the measured apparent brightness determine the distance to the star Good up to ~ 100 Kpc
10 Going one step further in the ladder: Distance to other galaxies A certain class of stars (Cepheids) were observed to oscillate in brightness periodically Knowing the distance to these stars (using spectroscopic parallax) we can calculate its absolute brightness Found precise relationship between Luminosity and period! Get L and calculate d L! Measure period Henrietta Swan Leavitt, 1912
11 Cepheids Up to 100,000 times more luminous than the Sun Distance Limit: Megaparsecs (Hubble Space Telescope) Crucial for measuring distances to galaxies
12 Distance to galaxies farther away: Supernovae Type Ia supernovae are great standard candles Basically the same (constant Luminosity) Very bright ~ 100,000 times brighter than Cepheids -> can see to large distances! Most distant: SN 1997ff - distance ~ 5 Gpc!
13 Final step: the Universe Measure a galaxy doppler shift - z (fractional change in the wavelength of light) Radial speed of the galaxy: v=c z (c - speed of light) Measure distance to galaxies - d (using Cepheids) Hubble law: v=h d (Edwin Hubble) Galaxies are receding from us - the Universe is expanding! Current value: H 71 Km/s/Mpc (using the Hubble satellite with Cepheids) NASA
14 Final step: the Universe We can use Hubble s law to calculate distances to galaxies very far away: Measure redshift z - velocity d=cz/h (for large z need to include General Relativity effects) Radius of the visible Universe ~ 14 Gpc Comparison of the expected distance to a Galaxy from the redshift to the measured distance using supernovae Ia told us that the Universe is accelerating - dark energy! Hubble deep field, NASA
Learning Objectives. distances to objects in our Galaxy and to other galaxies? apparent magnitude key to measuring distances?
The Distance Ladder Learning Objectives! What is the distance ladder? How do we measure distances to objects in our Galaxy and to other galaxies?! How are the concepts of absolute magnitude and apparent
More informationThe Cosmological Distance Ladder. It's not perfect, but it works!
The Cosmological Distance Ladder It's not perfect, but it works! First, we must know how big the Earth is. Next, we must determine the scale of the solar system. Copernicus (1543) correctly determined
More informationHubble s Law. Tully-Fisher relation. The redshift. λ λ0. Are there other ways to estimate distances? Yes.
Distances to galaxies Cepheids used by Hubble, 1924 to show that spiral nebulae like M31 were further from the Sun than any part of the Milky Way, therefore galaxies in their own right. Review of Cepheids
More informationLecture 25: The Cosmic Distance Scale Sections 25-1, 26-4 and Box 26-1
Lecture 25: The Cosmic Distance Scale Sections 25-1, 26-4 and Box 26-1 Key Ideas The Distance Problem Geometric Distances Trigonometric Parallaxes Luminosity Distances Standard Candles Spectroscopic Parallaxes
More informationChapter 11 Surveying the Stars
Chapter 11 Surveying the Stars Luminosity Luminosity: Rate of energy emitted by star every second. Apparent brightness (flux): Amount of energy passing through every second per unit area. Luninosity =
More informationStars: basic observations
Stars: basic observations Basic properties of stars we would like to know in order to compare theory against observations: Stellar mass M Stellar radius R Surface temperature - effective temperature T
More informationThe Scale of the Universe
The Scale of the Universe The Measurement of distance in our Univers! Chapters 12.1.1 Allday; Chapter 3 Silk Measurement of Distance in the Universe Two IMPORTANT concepts that you should know well from
More informationCosmic Distance Determinations
Cosmic Distance Determinations Radar (works for inner solar system) Parallax D(pc) = 1 p(arcsec) GAIA satellite (2013) 20 micro-arcsec resolution! Thus D < 10 kpc Beyond Parallax: Standard Candles Use
More informationLecture 32: The Expanding Universe Readings: Sections 26-5 and 28-2
Lecture 32: The Expanding Universe Readings: Sections 26-5 and 28-2 Key Ideas Measuring the Distances to Galaxies and Determining the Scale of the Universe Distance Methods: Trigonometric Parallaxes Spectroscopic
More information5. A particular star has an angle of parallax of 0.2 arcsecond. What is the distance to this star? A) 50 pc B) 2 pc C) 5 pc D) 0.
Name: Date: 1. How far away is the nearest star beyond the Sun, in parsecs? A) between 1 and 2 pc B) about 12 pc C) about 4 pc D) between 1/2 and 1 pc 2. Parallax of a nearby star is used to estimate its
More informationLecture 12: Distances to stars. Astronomy 111
Lecture 12: Distances to stars Astronomy 111 Why are distances important? Distances are necessary for estimating: Total energy released by an object (Luminosity) Masses of objects from orbital motions
More informationThe Extragalactic Distance Scale
One of the important relations in Astronomy. It lets us Measure the distance to distance objects. Each rung on the ladder is calibrated using lower-rung calibrations. Distance Objects Technique 1-100 AU
More informationThe Extragalactic Distance Scale
One of the important relations in Astronomy. It lets us Measure the distance to distance objects. Each rung on the ladder is calibrated using lower-rung calibrations. Distance Objects Technique 1-100 AU
More informationMeasuring Distances. Taking the Measure of the Universe
Measuring Distances Taking the Measure of the Universe The Importance of Distance We talked about how the brightness of a star can be due to 2 effects: distance or luminosity. Without a direct measurement
More informationChapter 10 Measuring the Stars
Chapter 10 Measuring the Stars Some of the topics included in this chapter Stellar parallax Distance to the stars Stellar motion Luminosity and apparent brightness of stars The magnitude scale Stellar
More informationAddition to the Lecture on Galactic Evolution
Addition to the Lecture on Galactic Evolution Rapid Encounters In case the encounter of two galaxies is quite fast, there will be not much dynamical friction due to lack of the density enhancement The
More informationSet 5: Expansion of the Universe
Set 5: Expansion of the Universe Cosmology Study of the origin, contents and evolution of the universe as a whole Expansion rate and history Space-time geometry Energy density composition Origin of structure
More informationThe Cosmic Distance Ladder. Hubble s Law and the Expansion of the Universe!
The Cosmic Distance Ladder Hubble s Law and the Expansion of the Universe! Last time: looked at Cepheid Variable stars as standard candles. Massive, off-main sequence stars: at a certain stage between
More informationSet 1: Expansion of the Universe
Set 1: Expansion of the Universe Syllabus Course text book: Ryden, Introduction to Cosmology, 2nd edition Olber s paradox, expansion of the universe: Ch 2 Cosmic geometry, expansion rate, acceleration:
More informationParallax: Measuring the distance to Stars
Measuring the Stars Parallax: Measuring the distance to Stars Use Earth s orbit as baseline Parallactic angle = 1/2 angular shift Distance from the Sun required for a star to have a parallactic angle of
More informationStellar distances and velocities. ASTR320 Wednesday January 24, 2018
Stellar distances and velocities ASTR320 Wednesday January 24, 2018 Special public talk this week: Mike Brown, Pluto Killer Wednesday at 7:30pm in MPHY204 Why are stellar distances important? Distances
More informationChapter 8: The Family of Stars
Chapter 8: The Family of Stars Motivation We already know how to determine a star s surface temperature chemical composition surface density In this chapter, we will learn how we can determine its distance
More informationGalaxies. Galaxy Diversity. Galaxies, AGN and Quasars. Physics 113 Goderya
Galaxies, AGN and Quasars Physics 113 Goderya Chapter(s): 16 and 17 Learning Outcomes: Galaxies Star systems like our Milky Way Contain a few thousand to tens of billions of stars. Large variety of shapes
More informationTechniques for measuring astronomical distances generally come in two variates, absolute and relative.
Chapter 6 Distances 6.1 Preliminaries Techniques for measuring astronomical distances generally come in two variates, absolute and relative. Absolute distance measurements involve objects possibly unique
More informationGalaxies and the expansion of the Universe
Review of Chapters 14, 15, 16 Galaxies and the expansion of the Universe 5/4/2009 Habbal Astro 110-01 Review Lecture 36 1 Recap: Learning from Light How does light tell us what things are made of? Every
More informationV. M. Slipher ( ) was an astronomer who worked at Lowell Observatory in Flagstaff, Arizona. In 1909 he began studying the spectrum of the
Hubble s Law V. M. Slipher (1875-1969) was an astronomer who worked at Lowell Observatory in Flagstaff, Arizona. In 1909 he began studying the spectrum of the Andromeda Nebula. He found that that object
More informationOutline. Go over AGN problem, again, should be rotating BH Go over problem 6.6 Olber's paradox Distances Parallax Distance ladder Direct checks
Outline Go over AGN problem, again, should be rotating BH Go over problem 6.6 Olber's paradox Distances Parallax Distance ladder Direct checks Why is the night sky dark? (Olber s Paradox 1826) Or what
More information6. Star Colors and the Hertzsprung-Russell Diagram
In addition to its brightness, light in general is characterized by its color. 6. Star Colors and the Hertzsprung-Russell Diagram http://apod.nasa.gov/apod/ Depending on the temperature of the matter at
More information6. Star Colors and the Hertzsprung-Russell Diagram
6. Star Colors and the Hertzsprung-Russell Diagram http://apod.nasa.gov/apod/ Supernovae Type Ia in M82 January 22, 2014 Still rising may go to m = 8 (or 10?) What we can learn about stars from their light:
More information6. Star Colors and the Hertzsprung-Russell Diagram.
6. Star Colors and the Hertzsprung-Russell Diagram http://apod.nasa.gov/apod/ Supernovae Type Ia in M82 January 22, 2014 Still rising may go to m = 8 (or 10?) What we can learn about stars from their light:
More information15.1 Properties of Stars
Surveying the Stars 15.1 Properties of Stars Our goals for learning: How do we measure stellar luminosities? How do we measure stellar temperatures? How do we measure stellar masses? How do we measure
More informationAST1100 Lecture Notes
AST1100 Lecture Notes 11-12 The cosmic distance ladder How do we measure the distance to distant objects in the universe? There are several methods available, most of which suffer from large uncertainties.
More information24.1 Hubble s Galaxy Classification
Chapter 24 Galaxies Units of Chapter 24 24.1 Hubble s Galaxy Classification 24.2 The Distribution of Galaxies in Space 24.3 Hubble s Law 24.4 XXActive Galactic Nuclei XXRelativistic Redshifts and Look-Back
More informationGalaxies. With a touch of cosmology
Galaxies With a touch of cosmology Types of Galaxies Spiral Elliptical Irregular Spiral Galaxies Spiral Galaxies Disk component where the spiral arms are Interstellar medium Star formation Spheroidal
More information6. Star Colors and the Hertzsprung-Russell Diagram
What we can learn about stars from their light: II Color In addition to its brightness, light in general is characterized by its color (actually its wavelength) 6. Star Colors and the Hertzsprung-Russell
More informationGALAXIES. Prof Steve Phillipps Physics Room 4.12 Level H Spring 2007
GALAXIES Prof Steve Phillipps Physics Room 4.12 Level H Spring 2007 Galaxies in the Universe Galaxies are basically large systems of stars (though we will see as we go along that there is more to them
More informationThe Milky Way. Finding the Center. Milky Way Composite Photo. Finding the Center. Milky Way : A band of and a. Milky Way
The Milky Way Milky Way : A band of and a The band of light we see is really 100 billion stars Milky Way probably looks like Andromeda. Milky Way Composite Photo Milky Way Before the 1920 s, astronomers
More informationThere are three basic types of galaxies:
Galaxies There are three basic types of galaxies: Spirals Ellipticals Irregulars To make a long story short, elliptical galaxies are galaxies that have used up all their gas forming stars, or they have
More informationASTRONOMY. Chapter 19 CELESTIAL DISTANCES PowerPoint Image Slideshow
ASTRONOMY Chapter 19 CELESTIAL DISTANCES PowerPoint Image Slideshow FIGURE 19.1 Globular Cluster M80. This beautiful image shows a giant cluster of stars called Messier 80, located about 28,000 light-years
More informationAST1100 Lecture Notes
AST1100 Lecture Notes 11 12 The cosmic distance ladder How do we measure the distance to distant objects in the universe? There are several methods available, most of which suffer from large uncertainties.
More informationAST2000 Lecture Notes
AST2000 Lecture Notes Part 3A The cosmic distance ladder Questions to ponder before the lecture 1. How do we know that the distance to our closest star is 4 light years? 2. How do we know that our galaxy
More informationObserved Properties of Stars ASTR 2120 Sarazin
Observed Properties of Stars ASTR 2120 Sarazin Extrinsic Properties Location Motion kinematics Extrinsic Properties Location Use spherical coordinate system centered on Solar System Two angles (θ,φ) Right
More informationLecture 14: Other Galaxies A2020 Prof. Tom Megeath. The Milky Way in the Infrared 3/17/10. NGC 7331: the Milky Way s Twins. Spiral Galaxy bulge halo
Lecture 14: Other Galaxies A2020 Prof. Tom Megeath Our Galaxy: Side View We see our galaxy edge-on Primary features: Disk: young and old stars where we live. Bulge: older stars Halo: oldest stars, globular
More informationRelativity and Astrophysics Lecture 15 Terry Herter. RR Lyrae Variables Cepheids Variables Period-Luminosity Relation. A Stellar Properties 2
Stellar Properties Relativity and Astrophysics Lecture 15 Terry Herter Outline Spectroscopic Parallax Masses of Stars Periodic Variable Stars RR Lyrae Variables Cepheids Variables Period-Luminosity Relation
More informationThe 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 informationThe Cosmic Perspective. Surveying the Properties of Stars. Surveying the Stars. How do we measure stellar luminosities?
Surveying the Stars Chapter 15 Lecture The Cosmic Perspective 15.1 Properties of Stars Our goals for learning: How do we measure stellar luminosities? How do we measure stellar temperatures? How do we
More informationASTR-1020: Astronomy II Course Lecture Notes Section III
ASTR-1020: Astronomy II Course Lecture Notes Section III Dr. Donald G. Luttermoser East Tennessee State University Edition 4.0 Abstract These class notes are designed for use of the instructor and students
More informationToday s Topics & Events
ASTR 1120: Stars & Galaxies Prof. Juri Toomre TA: Licia Ray Lecture 34 Wed 7 Apr 04 zeus.colorado.edu/astr1120-toomre toomre NGC 1232 Today s Topics & Events Today we look at the challenge of measuring
More informationAstronomy 102 Lab: Distances to Galaxies
Name: Astronomy 102 Lab: Distances to Galaxies You will access your textbook for this lab. Pre-Lab Assignment: As we began to talk about stars beyond the Sun, one of the most important pieces of information
More informationAstronomical Distance Determination.
Astronomical Distance Determination http://apod.nasa.gov/apod/ Distance ladder (beyond the AU): Determine distances, d 1, for some nearby set of objects using technique 1, but then Find new brighter objects
More informationGalaxies. The majority of known galaxies fall into one of three major classes: spirals (78 %), ellipticals (18 %) and irregulars (4 %).
Galaxies Collection of stars, gas and dust bound together by their common gravitational pull. Galaxies range from 10,000 to 200,000 light-years in size. 1781 Charles Messier 1923 Edwin Hubble The distribution
More informationAS1001: Galaxies and Cosmology
AS1001: Galaxies and Cosmology Keith Horne kdh1@st-and.ac.uk http://www-star.st-and.ac.uk/~kdh1/eg/eg.html Text: Kutner Astronomy:A Physical Perspective Chapters 17-21 Cosmology Today Blah Title Current
More information2. 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 informationASTRONOMY 2 Overview of the Universe Second Practice Problem Set Solutions
ASTRONOMY 2 Overview of the Universe Second Practice Problem Set Solutions 1. Consider a 2 M neutron star. The mass of a neutron is 1.67 10 24 g, and 1 M = 2 10 33 g. (i) How many neutrons are in this
More informationDefining Cosmological Parameters. Cosmological Parameters. Many Universes (Fig on pp.367)
Cosmological Parameters Composition of the universe What fraction is in the form of matter? m Always positive. What fraction is in the form of curvature? k Can be positive (hyperbolic) or negative (spherical).
More informationBig Galaxies Are Rare! Cepheid Distance Measurement. Clusters of Galaxies. The Nature of Galaxies
Big Galaxies Are Rare! Potato Chip Rule: More small things than large things Big, bright spirals are easy to see, but least common Dwarf ellipticals & irregulars are most common Faint, hard to see Mostly
More informationPage # Astronomical Distances. Lecture 2. Astronomical Distances. Cosmic Distance Ladder. Distance Methods. Size of Earth
Size of Astronomical istances ecture 2 Astronomical istances istance to the Moon (1 sec) istance to the Sun (8 min) istance to other stars (years) istance to centre of our Galaxy ( 30,000 yr to centre)
More informationHubble s Law and the Cosmic Distance Scale
Lab 7 Hubble s Law and the Cosmic Distance Scale 7.1 Overview Exercise seven is our first extragalactic exercise, highlighting the immense scale of the Universe. It addresses the challenge of determining
More informationStar systems like our Milky Way. Galaxies
Galaxies Star systems like our Milky Way Galaxies Contain a few thousand to tens of billions of stars,as well as varying amounts of gas and dust Large variety of shapes and sizes Gas and Dust in
More informationGalaxies & Introduction to Cosmology
Galaxies & Introduction to Cosmology Other Galaxies: How many are there? Hubble Deep Field Project 100 hour exposures over 10 days Covered an area of the sky about 1/100 the size of the full moon Probably
More informationASTRONOMY QUIZ NUMBER 11
ASTRONOMY QUIZ NUMBER. Suppose you measure the parallax of a star and find 0. arsecond. The distance to this star is A) 0 light-years B) 0 parsecs C) 0. light-year D) 0. parsec 2. A star is moving toward
More informationThe Observable Universe: Redshift, Distances and the Hubble-Law. Max Camenzind Sept 2010
The Observable Universe: Redshift, Distances and the Hubble-Law Max Camenzind Bremen @ Sept 2010 Key Facts Universe 1. The Universe is expanding and presently even accelerating. Hubble Expansion: Space
More informationThe Stars. Background & History The Celestial Sphere: Fixed Stars and the Luminaries
The Stars Background & History The Celestial Sphere: Fixed Stars and the Luminaries The Appearance of Stars on the Sky Brightness and Brightness Variations Atmospheric Effects: Twinkling Variable Stars
More informationTelescopes and estimating the distances to astronomical objects
Telescopes and estimating the distances to astronomical objects Why do we use telescopes? 1. Light-collecting area: A telescope is a light bucket Q: How much more light can a telescope with a diameter
More informationWeek 1 Introduction: GR, Distances, Surveys
Astronomy 233 Spring 2011 Physical Cosmology Week 1 Introduction: GR, Distances, Surveys Joel Primack University of California, Santa Cruz Modern Cosmology A series of major discoveries has laid a lasting
More informationGuiding Questions. Measuring Stars
Measuring Stars Guiding Questions 1. How far away are the stars? 2. What is meant by a first-magnitude or second magnitude star? 3. Why are some stars red and others blue? 4. What are the stars made of?
More informationCOSMIC DISTANCE LADDER
ASTC02 - PROF. HANNO REIN COSMIC DISTANCE LADDER ADAPTED FROM SLIDES BY TERENCE TAO (UCLA) HOW FAR AWAY IS COSMIC DISTANCE LADDER Work out the answer in steps (rungs) Starting with short distances ( human
More informationHUBBLE SPACE TELESCOPE
ASTRO 202 Age of the Universe Tuesday February 19, 2008 STARS: How and where do they form? From clouds of dust and gas primarily hydrogen -in our galaxy and other galaxies Part of the Orion nebula (Hubble
More informationBasic Properties of the Stars
Basic Properties of the Stars The Sun-centered model of the solar system laid out by Copernicus in De Revolutionibus (1543) made a very specific prediction: that the nearby stars should exhibit parallax
More informationAstronomy. The Nature of Stars
Astronomy A. Dayle Hancock adhancock@wm.edu Small 239 Office hours: MTWR 10-11am The Nature of Stars Distances to stars A Star's brightness and Luminosity A Magnitude scale Color indicates a Star's temperature
More informationLecture Outlines. Chapter 17. Astronomy Today 8th Edition Chaisson/McMillan Pearson Education, Inc.
Lecture Outlines Chapter 17 Astronomy Today 8th Edition Chaisson/McMillan Chapter 17 Measuring the Stars Units of Chapter 17 17.1 The Solar Neighborhood 17.2 Luminosity and Apparent Brightness 17.3 Stellar
More informationIntro to Astrophysics
Intro to Astrophysics Dr. Bill Pezzaglia 1 III. Introduction To Astrophysics A. Distances to Stars B. Binary Stars C. HR Diagrams 2 Updated: Nov 2007 A. Stellar Distances 1. Method of Parallax 2. Absolute
More informationV. Astronomy Section
EAS 100 Planet Earth Lecture Topics Brief Outlines V. Astronomy Section 1. Introduction, Astronomical Distances, Solar System Learning objectives: Develop an understanding of Earth s position in the solar
More informationDetermining distance. L 4π f. d = d = R θ. Standard candle. Standard ruler
Determining distance Standard candle d = L 4π f 1 2 d L Standard ruler d = R θ θ R Determining distance: Parallax RULER tanπ = R d π R d π R = 1AU = 1.5 10 13 cm Define new distance unit: parsec (parallax-second)
More informationLecture 16 The Measuring the Stars 3/26/2018
Lecture 16 The Measuring the Stars 3/26/2018 Test 2 Results D C B A Questions that I thought were unfair: 13, 18, 25, 76, 77, 80 Curved from 85 to 79 Measuring stars How far away are they? How bright are
More informationGalaxies and Cosmology
4/28/17 The Discovery of Galaxies Up to the 1920 s, astronomers were not sure exactly how far away galaxies were, and thus didn t know how big they are! Spiral Nebulae could be assumed to be inside our
More informationGalaxies. Hubbleʼs Law. Author: Sarah Roberts
Galaxies Hubbleʼs Law Author: Sarah Roberts Hubbleʼs Law Introduction The first galaxies were identified in the 17th Century by the French astronomer Charles Messier, although at the time he did not know
More informationStars I. Distance and Magnitude. How Does One Measure Distance? Distances. Stellar Parallax. Distance Equation some examples!
Stars I Distance and Magnitude Chapter 17 Why doesn t comparison work? Distances The nearest star (Alpha Centauri) is 40 trillion kilometers away(4 ly) Distance is one of the most important quantities
More informationChapter 15: Surveying the Stars
Chapter 15 Lecture Chapter 15: Surveying the Stars Surveying the Stars 15.1 Properties of Stars Our goals for learning: How do we measure stellar luminosities? How do we measure stellar temperatures? How
More informationStructure & Evolution of Stars 1
Structure and Evolution of Stars Lecture 2: Observational Properties Distance measurement Space velocities Apparent magnitudes and colours Absolute magnitudes and luminosities Blackbodies and temperatures
More informationHow to Understand Stars Chapter 17 How do stars differ? Is the Sun typical? Location in space. Gaia. How parallax relates to distance
How to Understand Stars Chapter 7 How do stars differ? Is the Sun typical? Image of Orion illustrates: The huge number of stars Colors Interstellar gas Location in space Two dimensions are easy measure
More informationChapter 15 Surveying the Stars Pearson Education, Inc.
Chapter 15 Surveying the Stars 15.1 Properties of Stars Our goals for learning: How do we measure stellar luminosities? How do we measure stellar temperatures? How do we measure stellar masses? 1. How
More informationMeasuring the Properties of Stars (ch. 17) [Material in smaller font on this page will not be present on the exam]
Measuring the Properties of Stars (ch. 17) [Material in smaller font on this page will not be present on the exam] Although we can be certain that other stars are as complex as the Sun, we will try to
More information11/9/2010. Stars, Galaxies & the Universe Announcements. Sky & Telescope s Week at a Glance. iphone App available now.
Stars, Galaxies & the Universe Announcements Reading Quiz #11 Wednesday Mix of questions from today s lecture & reading for Wed. on active galaxies HW#10 in ICON due Friday (11/12) by 5 pm - available
More informationOPTION E, ASTROPHYSICS TEST REVIEW
IB PHYSICS Name: DEVIL PHYSICS Period: Date: BADDEST CLASS ON CAMPUS OPTION E, ASTROPHYSICS TEST REVIEW S1. This question is about the nature of certain stars on the Hertzsprung-Russell diagram and determining
More informationMEASURING DISTANCES IN ASTRONOMY
Basic Principles: MEASURING DISTANCES IN ASTRONOMY Geometric methods Standard candles Standard rulers [the last two methods relate quantities that are independent of distance to quantities that depend
More informationDistances to Stars. Important as determines actual brightness but hard to measure as stars are so far away
SECTION II: Nature of Stars Astronomers measure properties of Stars Distance Mass Apparent Brightness Surface Temperature Radius Find that some are related Large Mass Large Absolute Brightness We will
More informationAstronomical Distance Determination
Distance ladder (beyond the AU): Determine distances, d 1, for some nearby set of objects using technique 1, but then Astronomical Distance Determination http://apod.nasa.gov/apod/ Find new brighter objects
More information1 (a) Explain what is meant by a white dwarf when describing the evolution of a star [1]
1 (a) Explain what is meant by a white dwarf when describing the evolution of a star.... [1] (b) Antares is a red giant and one of the brightest stars in the night sky. The parallax angle for this star
More informationTHE EXPANSION RATE AND AGE OF THE UNIVERSE
THE EXPANSION RATE AND AGE OF THE UNIVERSE I. Introduction: The visible Universe contains about 100 billion galaxies of several different types. The oldest galaxies are the elliptical galaxies, which show
More informationA 103 Notes, Week 14, Kaufmann-Comins Chapter 15
NEARBY GALAXIES I. Brief History A 103 Notes, Week 14, Kaufmann-Comins Chapter 15 A. Kant B. Curtis-Shapley debate C. Distance to Andromeda II. Classification of nearby galaxies: Spirals, Ellipticals,
More informationAST 248, Lecture 2. James Lattimer. Department of Physics & Astronomy 449 ESS Bldg. Stony Brook University. January 28, 2015
AST 248, Lecture 2 James Lattimer Department of Physics & Astronomy 449 ESS Bldg. Stony Brook University January 28, 2015 The Search for Life in the Universe james.lattimer@stonybrook.edu Distances in
More informationAstronomical Distance Determination
Astronomical Distance Determination http://apod.nasa.gov/apod/ For relatively nearby sources, one can measure distances by surveying - by measuring the very small angles that a star s position is displaced
More informationAstro 13 Galaxies & Cosmology LECTURE 4 Tues 18 Jan 2011 P. Madau. I Cosmological Principles 25m II Why is the Sky Dark? (Olber s
Astro 13 Galaxies & Cosmology LECTURE 4 Tues 18 Jan 2011 P. Madau 20m I Cosmological Principles 25m II Why is the Sky Dark? (Olber s Paradox) 10m III Break 15m IV Expanding Univ. - Hubble Constant 20m
More informationOPTION E, ASTROPHYSICS TEST REVIEW
IB PHYSICS Name: DEVIL PHYSICS Period: Date: # Marks: XX Raw Score: IB Curve: BADDEST CLASS ON CAMPUS OPTION E, ASTROPHYSICS TEST REVIEW S1. This question is about the nature of certain stars on the Hertzsprung-Russell
More information27.1: Characteristics of Stars
27.1: Characteristics of Stars STAR NOTES: Part 1 What is a Star? A body of gases that gives off energy in the form of light and heat. 27.1: Characteristics of Stars Are all stars the same? No 1. Stars
More informationEarth-based parallax measurements have led to the conclusion that the Pleiades star cluster is about 435 light-years from Earth.
1 The Pleiades star cluster is a prominent sight in the night sky. All the stars in the cluster were formed from the same gas cloud. Hence the stars have nearly identical ages and compositions, but vary
More informationClicker Questions (chapters 6-18)
Clicker Questions (chapters 6-18) 1. Officially, how many planets are there in our solar system? a. 8 b. 9 c. dozens 2. The Doppler formula is v = ( λ/λ) 300,000 km/sec for light waves. A particular feature
More informationLecture 14: Studying the stars. Astronomy 111 Monday October 16, 2017
Lecture 14: Studying the stars Astronomy 111 Monday October 16, 2017 Reminders Homework #7 due Monday I will give a lecture on DES and LIGO tomorrow at 4pm in the Mitchell Institute Studying the stars
More information