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Cosmic Dawn

Page 28

by George Rhee


  Blackbody curve or spectrumThe distribution over wavelengths or frequencies of the energy radiated by a blackbody

  Blackbody radiationThe energy radiated by a blackbody

  Cepheid variableA particular type of pulsating star, whose period of pulsation is related to its luminosity

  BosonOne of the two fundamental classes of subatomic particles, the other being fermions. In contrast to fermions, bosons with the same energy can occupy the same place in space. Photons are examples of bosons

  COBEThe Cosmic Background Explorer (COBE), was a satellite dedicated to cosmology. Its goals were to investigate the cosmic microwave background radiation (CMB) of the universe

  Cosmic microwave background radiation (CMB)The relic, blackbody radiation from the early Universe, currently at a temperature of 2.725 K

  Cosmic WebStars are organized into galaxies, which in turn form clusters and superclusters that are separated by immense voids, creating a vast foam-like structure known as the cosmic web

  Cosmological constantA constant that enters the equations of general relativity

  Dark matterUnidentified, nonluminous matter

  Dark Matter HaloA hypothetical component of a galaxy, which extends beyond the edge of the visible galaxy and dominates the total mass

  Dark energyGeneric name for the unknown energy postulated to give rise to the acceleration of the Universe and possibly to the cosmological constant

  DeuteriumA one-electron atom whose nucleus contains one neutron and one proton

  Doppler shiftThe change in frequency or wavelength of sound or radiation when either the emitter or the observer (or both) is in motion

  Electromagnetic radiationThe energy emitted (radiated) either by microscopic systems when they decay from a higher to a lower energy level or when a charged particle changes its velocity

  Electromagnetic spectrumThe entire range of wavelengths or frequencies over which radiant energy occurs

  ElectronA negatively charged point particle, about 2,000 times lighter than a proton

  ESAThe European Space Agency established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states

  FermionGeneric name for certain types of particles, of which electrons, protons, neutrons, and quarks are examples

  FrequencyThe repetition rate (number of recurrence times per second) of a periodic system

  GalaxyA very large collection of stars and gas held together by gravity

  Gravitational forceThe force between bodies due exclusively to their possessing mass

  Gravitational lensingThe bending of light due to the warping or distortion of space by a massive object such as a quasar or galaxy

  HadronA baryon or a meson

  HeliumThe second lightest element in nature and the only one to have been discovered in the sun before it was discovered on earth

  Herschel Space ObservatoryAn ESA satellite launched in 2009 that covers the entire range from far-infrared to submillimeter wavelengths. It studies otherwise invisible dusty and cold regions of the cosmos, both near and far

  Hertzprung-Russell diagramA diagram on which stars are placed according to the values of their luminosities and temperatures

  Homogeneous (homogeneity)The property wherein no location can be distinguished from any other

  HSTThe Hubble Space Telescope; a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. The 2.4-m aperture telescope observes in the near ultraviolet, visible, and near infrared

  Hubble LawAlmost all galaxies appear to be moving away from us. This is observed as a redshift of a galaxy’s spectrum. The redshift is larger more distant galaxies. The recession velocity is observed to increase porportionaly to the distance, a correlation known as Hubble’s Law

  Hydrogen atoman atom containing a single electron and one proton in its nucleus

  IonAn atom or molecule in which electrons have been added or subtracted

  InflationA theory postulating that the Universe increased enormously in size in a very short time very early in its history

  IsotopeA nucleus differing from another only by the number of neutrons it contains

  IsotropyThe property wherein no direction can be distinguished from any other

  JWSTThe James Webb Space Telescope is a large, infrared optimized space telescope. The project is working to a 2018 launch date. Webb will find the first galaxies that formed in the early Universe, connecting the Big Bang to our own Milky Way Galaxy

  KelvinThe unit in which absolute temperatures are measured

  LSSTThe Large Synoptic Survey Telescope. It can detect faint objects with short exposures. Taking more than 800 panoramic images each night, it can cover the sky twice each week

  LeptonThe generic name for any member of the family of electrons and neutrinos, plus their antiparticles

  Light year Approximately 10 13:  km, the distance light travels in 1 year

  Lyman-alpha LineA specific ultra violet spectral line created by hydrogen which occurs when a hydrogen electron falls from its second to lowest energy level

  Lyman Break GalaxiesStar-forming galaxies at high redshift that are selected using the differing appearance of the galaxies in several imaging filters

  LuminosityThe energy per second radiated by a hot object, typically a star or galaxy

  Main SequenceThe broad band of stars running from upper left to lower right on the Hertzprung-Russell diagram

  MassThe quantity of matter in a body

  MegaparsecOne million parsecs

  NeutrinoAn almost massless, neutral particle that is emitted when a neutron decays into it, a proton and an electron

  NeutronA neutral particle found in most nuclei; it is slightly heavier than a proton

  Neutron starA stellar end stage that can occur after a supernova explosion; the stellar remnant consists entirely of neutrons

  NovaA short-lived explosive event that occurs on the surface of a white dwarf star when it accretes matter from a red giant companion star

  Nucleus (nuclei)The tiny, central core of an atom; it is composed of protons and (other than in the case of hydrogen) neutrons

  ParallaxA method for determining distance by observing an object from two vantage points separated by a known distance and then measuring the angle between the lines of sight to the object. One half of this angle is the angle of parallax

  Parsec3.26 light years, which is the distance from the earth to an object whose angle of parallax is 1 s of arc

  PeriodThe time it takes for an orbiting or other type of repeating/oscillating system to return to any point in its path

  PhotonThe massless, particle-like, discrete bundle or quantum of energy that constitutes electromagnetic radiation

  PlanckA space observatory of the European Space Agency (ESA) designed to observe the anisotropies of the cosmic microwave background (CMB) over the entire sky, at a high sensitivity and angular resolution

  PlasmaA state of matter consisting of electrically charged particles and photons

  PositronThe antiparticle to an electron

  Primordial nucleosynthesisFormation of very light nuclei in the early Universe

  ProtonA positively charged particle found in all nuclei, slightly less massive than a neutron

  QuarkOne of a class of fundamental objects that are currently believed to be the only constituent of neutrons and protons

  QuasarThe supermassive black hole at the center of a highly luminous galaxy

  RecombinationThe formation of neutral atoms from protons and electrons(mainly hydrogen) in the early Universe, thereby allowing photons to flow freely

  Red giantA large volume, low (surface) temperature stage into which a star of roughly the suns mass evolves from the Main Sequence phase of its life

  RedshiftThe increase in wavelength of radiation emitted when the source, the observer, or both are receding from each other

  Redshift parameterA quantity that measures t
he fractional change in wavelength of the radiation emitted by an object receding from the earth; it is denoted by the symbol z

  ReionizationAn event, initiated by the first galaxies and quasars, in which ultraviolet photons are absorbed by hydrogen atoms, breaking them up into their constituent protons and electrons

  Scale factorThe single length that characterizes a homogeneous, isotropic universe

  SKAThe Square Kilometer Array will be the worlds largest and most sensitive radio telescope. Construction is scheduled to start in 2016

  SupernovaA violent stellar event in which an enormous amount of energy is radiated

  SDSSThe Sloan Digital Sky Survey. This survey carried out with a 2.5 m telescope, obtained deep, multi-color images covering more than a quarter of the sky and created 3-dimensional maps containing more than 930,000 galaxies and more than 120,000 quasars

  SWIFTA NASA satellite dedicated to the study of gamma-ray burst science. Its three instruments work together to observe the bursts and afterglows in the gamma ray, X-ray, ultraviolet, and optical wavebands

  VLAThe Very Large Array is a radio telescope consisting of 27 radio antennas in a Y-shaped configuration on the Plains of San Agustin 50 miles west of Socorro, New Mexico

  WavelengthThe smallest spatial distance between similar points on the oscillations of a periodic system

  WMAPThe Wilkinson Microwave Anisotropy Probe was a NASA mission that launched June 2001 and made measurements of numbers fundamental to cosmology

  Bibliography

  Appenzeller, I. (2009): High-Redshift Galaxies (Springer, Heidelberg)

  Balbi, A. (2010): The Music of the Big Bang: The cosmic Microwave Background and the New Cosmology (Springer-Verlag, Berlin)

  Berendzen, R. Hart R. and Seeley D. (1976): Man Discovers the Galaxies (Science History Publications, New York)

  Blandford, R. et al. (2010): New Worlds, New Horizons in Astronomy and Astrophysics, Committee for a Decadal Survey of Astronomy and Astrophysics; National Research Council (The National Academies Press)

  Bloom, J. (2011): What Are Gamma-Ray Bursts? (Princeton University Press, Princeton)

  Boorstin, D. (1983): The Discoverers (Random House, New York)

  Chown, M. (2001): The Magic Furnace: The Search for the Origins of Atoms (Oxford university Press, Oxford)

  Dyson, G. (2012): Turing’s Cathedral: The Origins of the Digital Universe (Pantheon Books, New York)

  Gingerich, O. (2004): The Book Nobody Read: Chasing the Revolutions of Nicolaus Copernicus (Walker and Company, New York)

  Finkbeiner, A. K., (2010): An Extraordinary New Map of the Universe Ushering In A New Era of Discovery (Simon & Schuster, New York)

  Freeman, K. and McNamara, G. (2006): In Search of Dark Matter (Springer-Praxis, Berlin)

  Gardner, J. et al. (2006): The James Webb Space Telescope, Space Science Reviews volume 123, pp 485–606 (Springer, Berlin)

  Goodstein, D. (2012): Adventures in Cosmology (World Scientific, Singapore)

  Harrison, E. R. (2000): Cosmology , 2nd ed. (Cambridge University Press, Cambridge, UK)

  Harwit, M. (1981): Cosmic Discovery; The Search, Scope, and Heritage of Astronomy (Basic Books, New York)

  Kirshner, R. (2002): The Extravagant Universe: Exploding Stars, Dark Energy, and the Accelerating Cosmos (Princeton University Press, Princeton)

  Loeb, A. (2010): How Did the First Stars and Galaxies Form? (Princeton University Press, Princeton)

  Loeb, A., Ferrara A., and Ellis, R. S. (2009): First Light in the Universe (Springer, New York)

  Mudrin, P. (2011): Mapping the Universe: The Interactive History of Astronomy (Carlton Books, London)

  Nussbaumer H. and Bieri L. (2009): Discovering the Expanding Universe (Cambridge University Press, Cambridge)

  Panek, R. (2011): The 4% Universe (Houghton Mifflin Harcourt, New York)

  Peebles, P., Page, L. and Partridge R. (2009): Finding the Big Bang (Cambridge University Press, Cambridge)

  Rees, M. J. (2000): Just Six Numbers (Basic Books, New York)

  Ryden, B. (2003): Introduction to Cosmology (Addison Wesley, San Francisco)

  Serjeant, S. (2010): Observational Cosmology (Cambridge University Press, Cambridge)

  Schulte-Ladbeck R., Hopp, U., Brinks, E. and Kravtsov A. (2010): Dwarf-Galaxy Cosmology in Advances in Astronomy, (Hindawi Publishing Corporation)

  Sofue Y. and Rubin V. (2001): Rotation Curves of Spiral Galaxies (Annual Review of Astronomy and Astrophysics, Volume 39, pp 137–174)

  Stiavelli, M. (2009): From First Light to Reionization (Wiley-VCH, Weinheim)

  Struck, C. (2011): Galaxy Collisions (New York, Springer-Praxis)

  Tayler, R. J. and Everett A. S. (1972): The Origin of the Chemical Elements (Taylor and Francis, London)

  Waller W. H. and Hodge P. W. (2003): Galaxies and the Cosmic Frontier (Harvard University Press)

  Weinberg, S. (1993): The First Three Minutes (Basic books, New York)

  Index

  A

  Adams, John

  Alpher, Ralph

  Andromeda galaxy

  halo

  Andromeda nebula

  astronomical surveys

  B

  Baade, Walter

  baryon abundance

  basic research

  value of

  Bessel, Friedrich

  big bang

  idea of

  black body radiation

  black holes

  at the centers of galaxies

  brown dwarfs

  Bruno, Giordano

  bullet cluster

  C

  Casimir, Hendrik

  Cepheid

  clusters of galaxies

  and the virial theorem

  Coma cluster

  mass from gravitational lensing

  COBE satellite

  computer simulations

  including gas

  initial conditions

  N-body models

  of galaxy formation

  state of the art

  Virgo consortium

  Copernicus, Nicolaus

  cosmic background radiation

  brightness variations

  discovery

  prediction

  spectrum

  WMAP

  cosmic web

  Curtis, Heber

  D

  dark ages, the

  dark energy

  dark matter

  nature of

  neutrinos

  de Sitter, Willem

  Decadal Survey, funding priorities

  Descartes, Rene

  deuterium

  abundance of

  formation of

  Digges, Thomas

  Dirac, Paul

  Doppler shift

  dwarf galaxies

  detection of

  star formation

  ultra faint dwarfs

  E

  Einstein, Albert

  element abundances

  ESO Extremely Large Telescope

  expansion of the universe

  discovery of

 

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