DOCSLIB.ORG

Stars and Galaxies

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Stars and Galaxies Stars and Galaxies STUDENT PAGE Se e i n g i n to t h e Pa S t A galaxy is a gravitationally bound system of stars, gas, and dust. Gal- We can’t travel into the past, but we axies range in diameter from a few thousand to a few hundred thou- can get a glimpse of it. Every sand light-years. Each galaxy contains billions (10 9) or trillions (1012) time we look at the Moon, for of stars. In this activity, you will apply concepts of scale to grasp the example, we see it as it was a distances between stars and galaxies. You will use this understanding little more than a second ago. to elaborate on the question, Do galaxies collide? That’s because sunlight reflected from the Moon’s surface takes a little more EX P LORE than a second to reach Earth. We see On a clear, dark night, you can see hundreds of bright stars. The next table the Sun as it looked about eight minutes shows some of the brightest stars with their diameters and distances from ago, and the other stars as they were a the Sun. Use a calculator to determine the scaled distance to each star few years to a few centuries ago. (how many times you could fit the star between itself and the Sun). Hint: And then there’s M31, the Androm- you first need to convert light-years and solar diameters into meters. One eda galaxy — the most distant object light-year equals 9.46 x 1015 meters, and the Sun’s diameter is 1.4 x 109 that’s readily visible to human eyes. meters. This great amalgamation of stars stands almost directly overhead late this eve- Star Diameter Distance Scaled Distance ning. When viewed from a dark sky- (Constellation) (Sun=1) (light-years) (distance÷diameter) watching location, far from city lights, Spica (Virgo) 8 261 it looks like a faint, fuzzy blob. But that blob is the combined glow of hundreds Betelgeuse (Orion) 600 489 of billions of stars — seen as it looked Deneb (Cygnus) 200 1,402 more than two million years ago. Altair (Aquila) 2 17 Andromeda is like a larger version of Vega (Lyra) 2.7 26 our own Milky Way galaxy. It’s a flat disk that spans more than a quarter-mil- Sirius (Canis Major) 1.6 8.6 lion light-years. Its brightest stars form spiral arms that make the galaxy look There are three galaxies beyond the Milky Way that you can see without like a pinwheel. Yet the galaxy is so optical aid: the Andromeda galaxy, the Small Magellanic Cloud, and the far away that its structure is visible only Large Magellanic Cloud. Figure the scaled distance to these galaxies (how through telescopes. many times you could fit the galaxy between itself and the Milky Way). The light from M31 has to travel about two and a half million light-years Diameter Distance Scaled Distance Galaxy (distance÷diameter) to reach us — about 15 quintillion (light-years) (light-years) miles — the number 15 followed by (no conversion needed) 18 zeroes. Yet even across such an Milky Way 100,000 0 enormous gulf, the galaxy is so bright Andromeda Galaxy 125,000 2,500,000 that we can see it — faintly — with our own eyes, crossing high overhead late Large Magellanic Cloud 31,000 165,000 tonight. Small Magellanic Cloud 16,000 200,000 EX P LAIN How does the scaled distance of galaxies compare to stars? This is the transcript of a StarDate radio episode that aired October 14, 2006. Script by Damond Benningfield, ©2006. ELABORATE Do you think galaxies collide? Why or why not? 28 S TAR D ATE /UNIVER S O TEACHER GU I D E Texas Essential Knowledge and Skills Science: §112.20. grade 8 - 8(D) model and describe how light years are used to measure distances and sizes in the universe. Astronomy, grade 9-12: §112.33.(c) - 6(C) examine the scale, size, and distance of the stars, Milky Way, and other galaxies through the use of data and modeling. §112.33.(c) - 6(E) demonstrate the use of units of measurement in astronomy, including Astronomical Units and light years. .
Load more

Recommended publications
  • Metallicity Relation in the Magellanic Clouds Clusters,,
    A&A 554, A16 (2013) Astronomy DOI: 10.1051/0004-6361/201220926 & c ESO 2013 Astrophysics Age – metallicity relation in the Magellanic Clouds clusters,, E. Livanou1, A. Dapergolas2,M.Kontizas1,B.Nordström3, E. Kontizas2,J.Andersen3,5, B. Dirsch4, and A. Karampelas1 1 Section of Astrophysics Astronomy & Mechanics, Department of Physics, University of Athens, 15783 Athens, Greece e-mail: [email protected] 2 Institute of Astronomy and Astrophysics, National Observatory of Athens, PO Box 20048, 11810 Athens, Greece 3 Niels Bohr Institute Copenhagen University, Astronomical Observatory, Juliane Maries Vej 30, 2100 Copenhagen, Denmark 4 Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, B1900 FWA La Plata Buenos Aires, Argentina 5 Nordic Optical Telescope, Apartado 474, 38700 Santa Cruz de La Palma, Spain Received 14 December 2012 / Accepted 2 March 2013 ABSTRACT Aims. We study small open star clusters, using Strömgren photometry to investigate a possible dependence between age and metallicity in the Magellanic Clouds (MCs). Our goals are to trace evidence of an age metallicity relation (AMR) and correlate it with the mutual interactions of the two MCs and to correlate the AMR with the spatial distribution of the clusters. In the Large Magellanic Cloud (LMC), the majority of the selected clusters are young (up to 1 Gyr), and we search for an AMR at this epoch, which has not been much studied. Methods. We report results for 15 LMC and 8 Small Magellanic Cloud (SMC) clusters, scattered all over the area of these galaxies, to cover a wide spatial distribution and metallicity range. The selected LMC clusters were observed with the 1.54 m Danish Telescope in Chile, using the Danish Faint Object Spectrograph and Camera (DFOSC) with a single 2k × 2k CCD.
    [Show full text]
  • Unusual Orbits in the Andromeda Galaxy Post-16
    Unusual orbits in the Andromeda galaxy Post-16 Topics covered: spectra, Doppler effect, Newton’s law of gravitation, galaxy rotation curves, arc lengths, cosmological units, dark matter Teacher’s Notes In this activity students will use real scientific data to plot the rotation curve of M31 (Andromeda), our neighbouring spiral galaxy. They will use Kepler’s third law to predict the motion of stars around the centre of M31. They will then measure the wavelengths of hydrogen emission spectra taken at a range of radii. The Doppler equation will be used to determine whether these spectra come from the approaching or receding limb of the galaxy and the velocity of rotation at that point. They will plot a velocity vs radius graph and compare it with their predicted result. A flat rotation curve indicates the presence of dark matter within Andromeda. Equipment: calculator, ruler, graph paper (if needed) Questions to ask the class before the activity: What is the Universe composed of? Answer: energy, luminous matter, dark matter, dark energy. What is a spectrum and how so we get spectral lines? Answer: a ‘fingerprint’ of an object made of light. The spectrum of visible light is composed of the colours of the rainbow. Absorption lines arise from electrons absorbing photons of light and jumping an energy level or levels; emission lines occur when electrons fall down to a lower energy level and emit a photon in the process. What can a spectrum tell us? Answer: the composition of an object such as a star, its temperature, its pressure, the abundance of elements in the star, its motion (velocity).
    [Show full text]
  • Atomic Gas Far Away from the Virgo Cluster Core Galaxy NGC 4388
    Astronomy & Astrophysics manuscript no. H4396 November 5, 2018 (DOI: will be inserted by hand later) Atomic gas far away from the Virgo cluster core galaxy NGC 4388 A possible link to isolated star formation in the Virgo cluster? B. Vollmer, W. Huchtmeier Max-Planck-Institut f¨ur Radioastronomie, Auf dem H¨ugel 69, D-53121 Bonn, Germany Received / Accepted 7 ′ Abstract. We have discovered 6 10 M⊙ of atomic gas at a projected distance greater than 4 (20 kpc) from the highly inclined Virgo spiral galaxy NGC 4388. This gas is most probably connected to the very extended Hα plume detected by Yoshida et al. (2002). Its mass makes a nuclear outflow and its radial velocity a minor merger as the origin of the atomic and ionized gas very unlikely. A numerical ram pressure simulation can account for the observed Hi spectrum and the morphology of the Hα plume. An additional outflow mechanism is still needed to reproduce the velocity field of the inner Hα plume. The extraplanar compact Hii region recently found by Gerhard et al. (2002) can be explained as a stripped gas cloud that collapsed and decoupled from the ram pressure wind due to its increased surface density. The star-forming cloud is now falling back onto the galaxy. Key words. Galaxies: individual: NGC 4388 – Galaxies: interactions – Galaxies: ISM – Galaxies: kinematics and dynamics 1. Introduction stripping. Based on their data they favoured a combina- tion of (iii) and (iv). Yoshida et al. (2002) on the other The Virgo cluster spiral galaxy NGC 4388 is located at hand favoured scenario (i) and (iv).
    [Show full text]
  • Messier Objects
    Messier Objects From the Stocker Astroscience Center at Florida International University Miami Florida The Messier Project Main contributors: • Daniel Puentes • Steven Revesz • Bobby Martinez Charles Messier • Gabriel Salazar • Riya Gandhi • Dr. James Webb – Director, Stocker Astroscience center • All images reduced and combined using MIRA image processing software. (Mirametrics) What are Messier Objects? • Messier objects are a list of astronomical sources compiled by Charles Messier, an 18th and early 19th century astronomer. He created a list of distracting objects to avoid while comet hunting. This list now contains over 110 objects, many of which are the most famous astronomical bodies known. The list contains planetary nebula, star clusters, and other galaxies. - Bobby Martinez The Telescope The telescope used to take these images is an Astronomical Consultants and Equipment (ACE) 24- inch (0.61-meter) Ritchey-Chretien reflecting telescope. It has a focal ratio of F6.2 and is supported on a structure independent of the building that houses it. It is equipped with a Finger Lakes 1kx1k CCD camera cooled to -30o C at the Cassegrain focus. It is equipped with dual filter wheels, the first containing UBVRI scientific filters and the second RGBL color filters. Messier 1 Found 6,500 light years away in the constellation of Taurus, the Crab Nebula (known as M1) is a supernova remnant. The original supernova that formed the crab nebula was observed by Chinese, Japanese and Arab astronomers in 1054 AD as an incredibly bright “Guest star” which was visible for over twenty-two months. The supernova that produced the Crab Nebula is thought to have been an evolved star roughly ten times more massive than the Sun.
    [Show full text]
  • Downloading Rectification Matrices the first Step Will Be Downloading the Correct Rectification Matrix for Your Data Off of the OSIRIS Website
    UNDERGRADUATE HONORS THESIS ADAPTIVE-OPTICS INTEGRAL-FIELD SPECTROSCOPY OF NGC 4388 Defended October 28, 2016 Skylar Shaver Thesis Advisor: Dr. Julie Comerford, Astronomy Honor Council Representative: Dr. Erica Ellingson, Astronomy Committee Members: Dr. Francisco Müller-Sánchez, Astrophysics Petger Schaberg, Writing Abstract Nature’s most powerful objects are well-fed supermassive black holes at the centers of galaxies known as active galactic nuclei (AGN). Weighing up to billions of times the mass of our sun, they are the most luminous sources in the Universe. The discovery of a number of black hole-galaxy relations has shown that the growth of supermassive black holes is closely related to the evolution of galaxies. This evidence has opened a new debate in which the fundamental questions concern the interactions between the central black hole and the interstellar medium within the host galaxy and can be addressed by studying two crucial processes: feeding and feedback. Due to the nature of AGN, high spatial resolution observations are needed to study their properties in detail. We have acquired near infrared Keck/OSIRIS adaptive optics-assisted integral field spectroscopy data on 40 nearby AGN as part of a large program aimed at studying the relevant physical processes associated with AGN phenomenon. This program is called the Keck/OSIRIS nearby AGN survey (KONA). We present here the analysis of the spatial distribution and two-dimensional kinematics of the molecular and ionized gas in NGC 4388. This nearly edge-on galaxy harbors an active nucleus and exhibits signs of the feeding and feedback processes. NGC 4388 is located in the heart of the Virgo cluster and thus is subject to possible interactions with the intra-cluster medium and other galaxies.
    [Show full text]
  • Spring Constellations Leo
    Night Sky 101: Spring Constellations Leo Leo, the lion, is very recognizable by the head of the lion, which looks like a backwards question mark, and is commonly known as “the sickle.” Regulus, Leo’s brightest star, is also easy to pick out in most lights. The constellation is best seen in April and May, but rises after the Spring Equinox in March. Within the constellation, there are several spiral galaxies: M65, M66, M95, and M96. It is possible to fit M65 and M66 into the same view on a low powered telescope. In Greek mythology, Leo was the Nemean lion, who was completely impervious to bronze, steel and any kind of metal. As part of his 12 labors, Hercules was charged to fight the lion and killed him Photo Credit: Starry Night by strangling him. Hercules took the lion’s pelt as a prize and Leo, the lion, was placed in the stars to commemorate their fight. Virgo Virgo is best seen in the late spring and early summer, usually May to June. The bright star Arcturus, in the constellation Boötes, lines up with the Virgo’s brightest star Spica, which makes it easy to find. Within the constellation is the Virgo Galaxy Cluster, which is a conglomerate of thousands of unnamed galaxies. These galaxies are about 65 million light years away, and usually only appear as smudges in a telescope. Virgo, the maiden, is also known as Persephone, or the daughter of the Demeter. Hades, god of the Un- derworld, fell in love with Virgo and took her to the Underworld.
    [Show full text]
  • Inverse and Joint Variation 9.1.1
    Inverse and joint variation 9.1.1 One of the first things that scientists do with data is to graph it in various ways to see if a pattern emerges. If two variables are selected that lead to a smooth curve, the variables can be shown to lead to ‘correlated’ behavior that can either represent a direct, or inverse, variation. The specific shape of the curve indicates the exponent. The example to the left shows that for Cepheid variable stars, the Log of the star’s luminosity, L, is proportional to its period because the slope of the curve is ‘fit’ by a linear equation. Problem 1 – The radius of a black hole, R, is proportional to its mass, M, and inversely proportional to the square of the speed of light, c. If the constant of proportionality is twice Newton’s constant of gravity, G, what is the mathematical equation for the black hole radius? Problem 2 – The luminosity, L, of a star is proportional to the square of its radius, R, and proportional to its surface temperature, T, to the fourth power. What is the equation for L if the proportionality constant is C? Problem 3 – The thickness of a planetary atmosphere, H, is proportional to temperature, T, and inversely proportional to the product of its molecular mass, m, and the local acceleration of gravity, g. What is the equation for H if the constant of proportionality is k? Problem 4 – The temperature of a planet, T, to the fourth power is proportional to the luminosity, L, of the star that it orbits, and inversely proportional to the square of its distance from its star, D.
    [Show full text]
  • 18. Mapping the Universe the Local Group: Over 30 Galaxies
    Astronomy 242: Foundations of Astrophysics II 18. Mapping the Universe The Local Group: Over 30 Galaxies two large spirals with satellites one smaller spiral many dwarf elliptical and irregular galaxies Local Group The M81 Group M81 and M82 deep field The M81 Group in HI Tidal dwarfs in the M81 group The M81 Group M81 and M82 deep field The Virgo Cluster:: Over 1000 Galaxies! Distance: ~16 Mpc three massive elliptical galaxies many MW-sized galaxies The Virgo Cluster Abell 1689 Distance: ~754 Mpc Abell 1689: A Galaxy Cluster Makes Its Mark Abell 1689 in X-rays 7 keV Fe line (redshifted) X-ray Spectrum Abell 1689: A Galaxy Cluster Makes Its Mark Abell 1689 Central Galaxy Abell 1689: A Galaxy Cluster Makes Its Mark Abell 1689 Lensed galaxy in background Abell 1689: A Galaxy Cluster Makes Its Mark The Super-Galactic Plane Cosmography of the Local Universe Local Cosmography Pavo-Indus Super-Galactic Plane Perseus-Pisces Virgo Cluster 0 4000 8000 vr (km/s) Fornax Cluster Cosmography of the Local Universe The 2MASS Redshift Survey RESEARCH LETTER Extended Data Figure 3 | One of three orthogonal views that illustrate SGY 5 0 showing the region obscured by the plane of the Milky Way. As in the limits of the Laniakea supercluster. This SGX–SGY view at SGZ 5 0 Fig 2 in the main text, the orange contour encloses the inflowing streams, extends the scene shown in Fig. 2 with the addition of dark blue flow lines away hence, defines the limits of the LaniakeaThe Laniakea Supercluster supercluster of Galaxies containing the mass of from the Laniakea local basin of attraction, and also includes a dark swath at 1017 Suns and 100,000 large galaxies.
    [Show full text]
  • Messier 58, 59, 60, 89, and 90, Galaxies in Virgo
    Messier 58, 59, 60, 89, and 90, Galaxies in Virgo These are five of the many galaxies of the Coma-Virgo galaxy cluster, a prime hunting ground for galaxy observers every spring. Dozens of galaxies in this cluster are visible in medium to large amateur telescopes. This star hop includes elliptical galaxies M59, M60, and M89, and spiral galaxies M58 and M90. These galaxies are roughly 50 to 60 million light years away. All of them are around magnitude 10, and should be visible in even a small telescope. Start by finding the Spring Triangle, which consists of three widely- separated first magnitude stars-- Arcturus, Spica, and Regulus. The Spring Triangle is high in the southeast sky in early spring, and in the southwest sky by mid-Summer. (To get oriented, you can use the handle of the Big Dipper and "follow the arc to Arcturus"). For this star hop, look in the middle of the Spring Triangle for Denebola, the star representing the back end of Leo, the lion, and Vindemiatrix, a magnitude 2.8 star in Virgo. The galaxies of the Virgo cluster are found in the area between these two stars. From Vindemiatrix, look 5 degrees west and slightly south to find ρ (rho) Virginis, a magnitude 4.8 star that is easy to identify because it is paired with a slightly dimmer star just to its north. Center ρ in the telescope with a low-power eyepiece, and then just move 1.4 degrees north to arrive at the oval shape of M59. Continuing with a low-power eyepiece and using the chart below, you can take hops of less than 1 degree to find M60 to the east of M59, and M58, M89, and M90 to the west and north.
    [Show full text]
  • Facilitator Information – Galaxies
    Facilitator Information (All you need to know about galaxies to survive the day) What is a galaxy? Galaxies are large collections of stars and gas and dust. They have millions to billions of stars, all held into a cluster by gravitational attraction. Most galaxies are flat, but there are different shapes — some are spirals, some are elliptical, and some are irregular. Our Galaxy The Milky Way is a galaxy, a slowly rotating cluster of more than 200,000,000,000 stars! Our Milky Way Galaxy looks a little like a pinwheel. It is a spiral galaxy, about 100,000 light years across. Spiral galaxies have: a bulge in the center (called the nuclear bulge) that contains the nucleus; a wide, flat disk with distinct spiral arms containing stars; and a surrounding halo of stars. There are several “spiral arms” in our Milky Way: Sagittarius, Cygnus, Perseus, and Orion. Where are we in the Milky Way Galaxy? We are in one of the spiral arms, about 30,000 light years from the center of the Milky Way Galaxy — or about two-thirds of the way from the center. Can you see the Milky Way? Yes! On a very dark night, away from bright lights, you can see a faint, hazy — or milky — band in the sky. This is the Milky Way. The hazy appearance is because there so many stars that are very distant; your eye cannot distinguish the stars as separate points of light. By using binoculars or a telescope, you can see the individual stars. The Milky Way is like a big, flat disk in space.
    [Show full text]
  • The Andromeda Galaxy's Most Important Merger
    The Andromeda Galaxy’s most important merger ~ 2 Gyrs ago as M32’s likely progenitor Richard D’Souza* & Eric F. Bell Although the Andromeda Galaxy’s (M31) proximity offers a singular opportunity to understand how mergers affect galaxies1, uncertainty remains about M31’s most important mergers. Previous studies focused individually on the giant stellar stream2 or the impact of M32 on M31’s disk3,4, thereby suggesting many significant satellite interactions5. Yet, models of M31’s disk heating6 and the similarity between the stellar populations of different tidal substructures in M31’s outskirts7 both suggested a single large merger. M31’s outer low- surface brightness regions (its stellar halo) is built up from the tidal debris of satellites5 and provides decisive guidance about its important mergers8. Here we use cosmological models of galaxy formation9,10 to show that M31’s massive11 and metal-rich12 stellar halo, containing intermediate-age stars7, dramatically narrows the range of allowed interactions, requiring a 10 single dominant merger with a large galaxy (M*~2.5x10 M¤, the third largest member of the Local Group) ~2 Gyr ago. This single event explains many observations that were previously considered separately: its compact and metal-rich satellite M3213 is likely to be the stripped core of the disrupted galaxy, M31’s rotating inner stellar halo14 contains most of the merger debris, and the giant stellar stream15 is likely to have been thrown out during the merger. This interaction may explain M31’s global burst of star formation ~2 Gyr ago16 in which ~1/5 of its stars were formed.
    [Show full text]
  • Extragalactic Astronomy: the U Nivcre Bey Nd Our Galaxy
    U1IJT RESUPE EU 1J3 199 021 775 dacon Eenneth Char TITLE Extragalactic Astronomy: The U nivcre Bey nd Our Galaxy. American Astronomical Society, Princeton, N.J. SFONS AGENCY National Aeronautics and Space Administra ashingtonl D.C.; National Science Foundation, Washington, D.C. REPOBT NO NASA-i:T-129 PUB DATE Sep 76 NOTE 44p.; FOF ltEd aocunents, _e SE 021 773-776 AVAII,AULE Superintendent of Documents, U.S. G-vernment Prin ing Office, Washington, D.C. 20402(5 ock Number 033-000-00657-8, $1.30) E.-RS PE10E 1F-$0.03 HC-$2.06 Plus Postige. DESCilIPTORS *Astronomy; Curriculum; *Instructional Materials; Science Education; *Scientific iesearch; Secondary Education; *Secondary School Science; *Space Sciences TIF NASA; National Aeronautics and Space Administration BSTRACT This booklet is part of an American Astronomical Society curriculum project designed to provide teaching materials to teachers or secondary school chemistry, physics, and earth science. The material is presented in three parts: one section provides the fundamental content of extragalactic astronomy, another section discusses modern discoveries in detail, and the last section summarizes the earlier discussions within the structure of the Big Bang Theory of Evolution. Each of the three sections is followed by student exercises and activities, laboratory projects, and questions and answers. The glossary contains unfamiliar terms used in the text and a collection of teacher aids such as literature references and audiovisual materials. (111) ***** *** * ** ** ***************** ********** Document., acquired by IC include many informal unpublished aterials not available from other sources. ERIC makes every effort * * to obtain the best copy available. Nevertheless, items of marginal * * reproducibility are often encountered and tbis affects the quality * * of the microfiche and hardcopy reproductions ERIC makes available * * via the ERIC Document Reproduction Service (EDRS).
    [Show full text]