Charles Hakes Fort Lewis College1

Charles Hakes Fort Lewis College2

Charles Hakes Fort Lewis College3 Large Scale Structure

Charles Hakes Fort Lewis College4 Outline Homework (don’t forget them) Final Monday, 9:45. bring a scantron; good eraser, or extra scantron; sharp pencils calculator Review Hubble’s Law Large Scale Structure

Charles Hakes Fort Lewis College5 Probable Job Opportunity The Academic Success Program regularly funds Astronomy Tutors/ Study Group leaders. If you might be interested in this for next fall, please let me know via .

Charles Hakes Fort Lewis College6 The Tully-Fisher Relation exists between the galaxy's luminosity and its: A) color. B) size. C) age. D) rotation.

Charles Hakes Fort Lewis College7 The Tully-Fisher Relation exists between the galaxy's luminosity and its: A) color. B) size. C) age. D) rotation.

Charles Hakes Fort Lewis College8 What method would be most appropriate to determine the distance to a nearby galaxy? A) Spectroscopic parallax B) Cepheid variables C) Hubble’s law D) Radar ranging

Charles Hakes Fort Lewis College9 What method would be most appropriate to determine the distance to a nearby galaxy? A) Spectroscopic parallax B) Cepheid variables C) Hubble’s law D) Radar ranging

Charles Hakes Fort Lewis College10 Large-Scale Structure

Charles Hakes Fort Lewis College11 Figure 16.3 Cosmic Distance Ladder

Charles Hakes Fort Lewis College12 Large-Scale Structure Use the scale of 1m = 1 A.U.

Charles Hakes Fort Lewis College13 Large-Scale Structure Use the scale of 1m = 1 A.U. The Earth is 1 m from the Sun

Charles Hakes Fort Lewis College14 Large-Scale Structure Use the scale of 1m = 1 A.U. The Earth is 1 m from the Sun The Nearest star is near Albuquerque

Charles Hakes Fort Lewis College15 Large-Scale Structure Use the scale of 1m = 1 A.U. The Earth is 1 m from the Sun The Nearest star is near Albuquerque The center of the Milky Way galaxy would be 4 times as far as the moon.

Charles Hakes Fort Lewis College16 Large-Scale Structure Use the scale of 1m = 1 A.U. The Earth is 1 m from the Sun The Nearest star is near Albuquerque The center of the Milky Way galaxy would be 4 times as far as the moon. The Andromeda galaxy would be near Mars

Charles Hakes Fort Lewis College17 Figure 16.3 Cosmic Distance Ladder

Charles Hakes Fort Lewis College18 Large-Scale Structure Redshift surveys of galaxies are used to determine the large-scale structure of the universe.

Charles Hakes Fort Lewis College19 Figure 16.9 First Galaxy Survey from the mid-1980 ’ s

Charles Hakes Fort Lewis College20 Figure The Local Universe

Charles Hakes Fort Lewis College21 Large-Scale Structure Redshift surveys of galaxies are used to determine the large-scale structure of the universe. Observed structure includes: Strings Filaments Voids The most likely explanation is a slice through “Bubbles.” Only a few of these “slices” have been completed.

Charles Hakes Fort Lewis College22 Figure 17.1 Galaxy Survey

Charles Hakes Fort Lewis College23 Galaxy Survey The universe is homogeneous - it looks the same everywhere The universe is isotropic - it looks the same in all directions Cosmological principle - the universe is isotropic and homogeneous.

Charles Hakes Fort Lewis College24 Tools to study structure..

Charles Hakes Fort Lewis College25 Central Black Hole /gc/pictures/orbitsMovie.shtml /gc/pictures/orbitsMovie.shtml ~4x10 6 Solar Masses

Charles Hakes Fort Lewis College26 Quasars

Charles Hakes Fort Lewis College27 Quasars Quasars are the active nuclei of very distant galaxies. (Cannot observe the “rest” of the quasar’s galaxy.) Energy output ~1000x Milky Way. Powered by material accreting onto a supermassive black hole. Very large redshifts = Very distant. Can use spectra to study closer material.

Charles Hakes Fort Lewis College28 Figure Twin Quasar

Charles Hakes Fort Lewis College29 Figure Gravitational Lens

Charles Hakes Fort Lewis College30 Figure Einstein Cross

Charles Hakes Fort Lewis College31 Figure Galaxy Cluster Lensing

Charles Hakes Fort Lewis College32 Figure Dark Matter Map

Charles Hakes Fort Lewis College33 Figure Absorption Line “ Forest ”

Charles Hakes Fort Lewis College34 Review Questions

Charles Hakes Fort Lewis College35 RR Lyrae stars helped astronomers to: A) Find the distance to nearby galaxies B) Determine the center of the Milky Way C) Verify spectroscopic parallax D) Complete the H-R diagram

Charles Hakes Fort Lewis College36 RR Lyrae stars helped astronomers to: A) Find the distance to nearby galaxies B) Determine the center of the Milky Way C) Verify spectroscopic parallax D) Complete the H-R diagram

Charles Hakes Fort Lewis College37 What does the Hubble constant measure? A) The density of galaxies in the universe B) The luminosity of distant galaxies C) The rate of expansion of the universe D) the speed of a galaxy of known redshift E) the reddening of light by intergalactic dust clouds

Charles Hakes Fort Lewis College38 What does the Hubble constant measure? A) The density of galaxies in the universe B) The luminosity of distant galaxies C) The rate of expansion of the universe D) the speed of a galaxy of known redshift E) the reddening of light by intergalactic dust clouds

Charles Hakes Fort Lewis College39 What method would not be appropriate to determine the distance to a nearby galaxy? A) Tully-Fisher relationship B) Cepheid variables C) Hubble’s law D) Type I Supernovae

Charles Hakes Fort Lewis College40 What method would not be appropriate to determine the distance to a nearby galaxy? A) Tully-Fisher relationship B) Cepheid variables C) Hubble’s law D) Type I Supernovae

Charles Hakes Fort Lewis College41 Olber’s Paradox

Charles Hakes Fort Lewis College42 Olber’s Paradox Why isn’t the sky bright? If the universe is infinite, no matter which way you look, you should see a star.

Charles Hakes Fort Lewis College43 Figure 17.2 Olbers ’ s Paradox

Charles Hakes Fort Lewis College44 Olber’s Paradox Why isn’t the sky bright? If the universe is infinite, no matter which way you look, you should see a star. Since the sky is not bright, either… Universe is finite. Universe evolves with time.

Charles Hakes Fort Lewis College45 The Big Bang At some time in the past, everything was at a single point.

Charles Hakes Fort Lewis College46 The Big Bang At some time in the past, everything was at a single point. When - Approximately 14 billion years ago. The Big Bang provides the resolution of Olber’s Paradox

Charles Hakes Fort Lewis College47 Figure 17.3 Receding Galaxies - where was the Big Bang? The Big Bang happened everywhere at once.

Charles Hakes Fort Lewis College48 Chapter 17 Ultra Deep Field - more than 1000 galaxies are in this picture. Total estimate for the universe - ~40,000,000,000.

Charles Hakes Fort Lewis College49 Chapter 17 Cosmology

Charles Hakes Fort Lewis College50 Cosmology How big is the universe? How long has it been here? How did it start? How long will it last?

Charles Hakes Fort Lewis College51 The Fate of the Universe Will it keep expanding forever? Will gravity cause it to collapse?

Charles Hakes Fort Lewis College52 From closest to farthest, which methods are used to find the distance to something? A) radar, spectroscopic parallax, Cepheid variables B) radar, RR Lyrae variables, spectroscopic parallax C) parallax, Cepheid variables, RR Lyrae variables D) Tully Fisher relation, Cepheid variables, parallax

Charles Hakes Fort Lewis College53 From closest to farthest, which methods are used to find the distance to something? A) radar, spectroscopic parallax, Cepheid variables B) radar, RR Lyrae variables, spectroscopic parallax C) parallax, Cepheid variables, RR Lyrae variables D) Tully Fisher relation, Cepheid variables, parallax

Charles Hakes Fort Lewis College54 Interstellar gas is composed mainly of: A) only hydrogen. B) some hydrogen, but mainly carbon dioxide. C) 10% hydrogen, 90% helium by numbers of atoms. D) 75% hydrogen, 25% helium by weight. E) ammonia, methane, and water vapor.

Charles Hakes Fort Lewis College55 Interstellar gas is composed mainly of: A) only hydrogen. B) some hydrogen, but mainly carbon dioxide. C) 10% hydrogen, 90% helium by numbers of atoms. D) 75% hydrogen, 25% helium by weight. E) ammonia, methane, and water vapor.

Charles Hakes Fort Lewis College56 What is the single most important determinant of the temperature, density, radius, luminosity, and pace of evolution of a protostar? A) its mass B) its composition C) its molecules D) its magnetic field E) its spin

Charles Hakes Fort Lewis College57 What is the single most important determinant of the temperature, density, radius, luminosity, and pace of evolution of a protostar? A) its mass B) its composition C) its molecules D) its magnetic field E) its spin

Charles Hakes Fort Lewis College58 Which of these lies ahead for our Sun? A) supernova of type II B) brown dwarf C) nova D) planetary nebula E) pulsar

Charles Hakes Fort Lewis College59 Which of these lies ahead for our Sun? A) supernova of type II B) brown dwarf C) nova D) planetary nebula E) pulsar

Charles Hakes Fort Lewis College60 A massive object, heavier than the Sun, which could fit inside a city, is a: A) asteroid B) white dwarf C) neutron star D) brown dwarf

Charles Hakes Fort Lewis College61 A massive object, heavier than the Sun, which could fit inside a city, is a: A) asteroid B) white dwarf C) neutron star D) brown dwarf

Charles Hakes Fort Lewis College62 It is easiest to spot a newly formed protostar with which types of telescopes? A) ultraviolet scopes at the South Pole, through the ozone hole B) radio telescopes with the VLA in New Mexico C) x-ray telescopes like Chandra, up in orbit D) visible light scopes on Mount Palomar E) infrared scopes on Mauna Kea

Charles Hakes Fort Lewis College63 It is easiest to spot a newly formed protostar with which types of telescopes? A) ultraviolet scopes at the South Pole, through the ozone hole B) radio telescopes with the VLA in New Mexico C) x-ray telescopes like Chandra, up in orbit D) visible light scopes on Mount Palomar E) infrared scopes on Mauna Kea

Charles Hakes Fort Lewis College64 Three Minute Paper Write 1-3 sentences. What was the most important thing you learned today? What questions do you still have about today’s topics?