Wilhelm Roentgen: In 1895 he discovered that something still emerged after cathode rays (electrons) passed through a thin film of aluminum with a cardboard backing. He noticed that this unknown phenomenon produced fluorescence in material some distance away, and correctly surmised that it represented a new type of ray or radiation.
a process that wrapped up: The project that became known as the Wide Angle ROSAT Pointed Survey (WARPS for short) started in 1995 and resulted in seven major scientific papers, the most recent in 2009. Along the way we had help from Matt Malkan at UCLA and others. The first paper was Scharf et al., “The Wide-Angle ROSAT Pointed X-ray Survey of Galaxies, Groups, and Clusters. I. Method and First Results,” Astrophysical Journal 477 (1997): 79.
produced a camera: The submillimeter camera used in Hawaii was called the Submillimeter Common User Bolometer Array, or SCUBA for short, built by a team at what was then the Royal Observatory in Edinburgh, Scotland.
uninspiring name of 4C41.17: As with many astronomical objects, this dull name indicates the source of its first detection and its location, 4C being the fourth Cambridge radio survey and 41.17 indicating the angular declination of the object in the Earth’s northern sky. The first inklings that this object might represent a baby galaxy cluster were given by Rob Ivison and colleagues: “An Excess of Submillimeter Sources near 4C 41.17: A Candidate Protocluster at Z = 3.8?,” Astrophysical Journal 452 (2000): 27.
Dan Schwartz: Schwartz’s paper was “X-ray Jets as Cosmic Beacons,” Astrophysical Journal Letters 569 (2002): 23.
Jim Felten and Philip Morrison: Felten and Morrison’s paper was “Omnidirectional Inverse Compton and Synchrotron Radiation from Cosmic Distributions of Fast Electrons and Thermal Photons,” Astrophysical Journal 146 (1966): 686.
Arthur Compton: Winner of the Nobel Prize in Physics in 1927. Biography available from the Nobel Foundation: www.nobelprize.org/nobel_prizes/physics/laureates/1927/compton-bio.html.
Wil van Breugel: The results that Wil showed us came out of his team’s more extensive program of observing distant objects. See for example Michiel Reuland et al., “Giant Lyα Nebulae Associated with High-Redshift Radio Galaxies,” Astrophysical Journal 592 (2003): 755.
report our findings: We did, and the paper is by Caleb Scharf, Ian Smail, Rob Ivison, Richard Bower, Wil van Breugel, and Michiel Reuland: “Extended X-ray Emission Around 4C41.17 at z = 3.8,” Astrophysical Journal 596 (2003): 105. The “z = 3.8” in the title refers to the cosmological redshift (a surrogate for distance) of the light from this object, which in turn indicates an apparent velocity away from us that is 3.8 times the speed of light. Of course, it is the universe itself that is expanding and stretching the wavelength of the photons to give this impression.
Only some 4 percent of galaxies: This statistic has been derived from survey data of the local universe. See for example Xin et al., “Active Galactic Nucleus Pairs from the Sloan Digital Sky Survey. I. The Frequency on ~ 5–100 kpc Scales” (in preprint form at http://arxiv.org/abs/1104.0950, 2011). Also, a related work discusses how the gravitational interactions between other galaxies may encourage the feeding of supermassive black holes: Xin et al., “Active Galactic Nucleus Pairs from the Sloan Digital Sky Survey. II. Evidence for Tidally Enhanced Star Formation and Black Hole Accretion” (also as a preprint, http://arxiv.org/abs/1104.0951, 2011).
7. ORIGINS: PART I HELPS CONTROL THE PRODUCTION OF STARS: NUMEROUS REVIEWS HAVE NOW BEEN WRITTEN IN THE SCIENTIFIC LITERATURE ABOUT THE RELATIONSHIP OF BLACK HOLES TO STAR AND GALAXY PROPERTIES. ONE USEFUL ARTICLE IS BY ANDREA CATTANEO ET AL: “THE ROLE OF BLACK HOLES IN GALAXY FORMATION AND EVOLUTION,” NATURE 460 (2009): 213.
some galaxies lack: The nature of the central stellar bulges of galaxies and their black holes is very much at the forefront of current research—and controversy. In particular, why some galaxies, such as our own, have so little central bulge is a bit of a mystery. A good starting point for this discussion is a short summary by Jim Peebles, “How Galaxies Got Their Black Holes,” Nature 469 (2011): 305.
can change a planet: This is not an idle comment. It is now clear that the evolution of life (particularly single-celled microbial life, the bacteria and the archaea) is completely intertwined with the surface evolution of the Earth—from chemistry to climate—over the past 4 billion years. An excellent and provocative discussion is by Paul Falkowski, Tom Fenchel, and Edward DeLong, “The Microbial Engines That Drive Earth’s Biogeochemical Cycles,” Science 320 (2008): 1034.
under the thrall: Although this research on chemistry around stars of different masses is still very new, it is quite compelling, because the physical explanation makes a lot of sense. For more on this, see Pascucci et al., “The Different Evolution of Gas and Dust in Disks Around Sun-like and Cool Stars,” Astrophysical Journal 696 (2009): 143.
but not unreasonable: Indeed it’s not. The jury is still very much out on how the surface chemistry developed on the young planet Earth. We do know, however, that the planet was being pelted by a lot of meteoritic material containing a rich mixture of organic and inorganic molecules. Some fraction of the early chemistry must have been due to this extraterrestrial material—the tail end of planet formation itself.
stellar giants: For the idea that the first stars in the universe were huge, and would give rise to large black hole remains, see, for example, Piero Madau and Martin Rees, “Massive Black Holes as Population III Remnants,” Astrophysical Journal 551 (2001): L27.
sufficiently huge blob: Skipping over any true stellar object and going directly to a large black hole: see, for example, Begelman et al., “Formation of Supermassive Black Holes by Direct Collapse in Pregalactic Halos,” Monthly Notices of the Royal Astronomical Society 370 (2006): 289.
enormous whirlpools: These simulations and their implications are reported by L. Mayer et al., “Direct Formation of Supermassive Black Holes via Multi-scale Gas Inflows in Galaxy Mergers,” Nature 466 (2010): 1082. These results and their broader implications are also discussed by Marta Volonteri: “Astrophysics: Making Black Holes from Scratch,” Nature 466 (2010): 1049.
“dark ages” of the cosmos: This is a large area of research. One expert is the astronomer Zoltán Haiman of Columbia University, who also gives an excellent overview and discussion of the possible role of smaller black holes in “Cosmology: A Smoother End to the Dark Ages,” Nature 472 (2011): 47.
Felix Mirabel: Led the study that is reported by Mirabel et al., “Stellar Black Holes at the Dawn of the Universe,” Astronomy & Astrophysics 528 (2011).
molecular hydrogen cools much faster: This is likely critically important in the very young universe. An excellent reference is Zoltán Haiman, Martin Rees, and Abraham Loeb, “H2 Cooling of Primordial Gas Triggered by UV Irradiation,” Astrophysical Journal 467 (1996): 522.
8. ORIGINS: PART II THE ANDROMEDA GALAXY: ALSO OFTEN KNOWN BY ITS MORE “OFFICIAL” ASTRONOMICAL NAME OF MESSIER 31, OR M31 FOR SHORT.
something resembling an elliptical: Gravitational simulations of the Andromeda/Milky Way collision suggest that this is a possibility. The largest source of uncertainty in what will happen is actually due to our lack of very high-precision measurements of the relative motion of the two galaxies—we can measure Andromeda’s velocity toward us very well, but measuring transverse motion is difficult, so we cannot be certain that it is approaching us precisely head-on.
Sloan Digital Sky Survey: The SDSS finally began in 2000; its genesis was quite prolonged. A primary leader and advocate for the project (which at the time was a very new concept) was the Princeton astronomer Jim Gunn. The SDSS uses a technique known as drift scanning: the telescope remains fixed, and as the Earth rotates, a strip of the sky the width of the instrument’s cameras passes by. Data are continually acquired.
project called Galaxy Zoo: The project has an excellent website (http://zoo1.galaxyzoo.org/), and a great discussion of the history of the project has been written by Forston et al., “Galaxy Zoo: Morphological Classification and Citi
zen Science” (available as a preprint, http://arxiv.org/abs/1104.5513, 2011).
duty cycle is related: The specific results are presented by Schawinski et al., “Galaxy Zoo: The Fundamentally Different Co-evolution of Supermassive Black Holes and Their Early-and Late-type Host Galaxies,” Astrophysical Journal 711 (2010): 284.
astronomers have recently realized: Several groups of researchers have stated that the Milky Way seems to be a green valley galaxy. It is possible that Andromeda is one as well, albeit a bit more red than green. A nice discussion is by Mutch et al., “The Mid-life Crisis of the Milky Way and M31” (available as a preprint, http://arxiv.org/abs/1105.2564, 2011).
zones of X-ray light: The center of our galaxy produces all sorts of X-ray emissions, coming from both small and large structures, making it very hard to peel apart the layers. For example, see Snowden et al., “ROSAT Survey Diffuse X-ray Background Maps. Part II.,” Astrophysical Journal 485 (1997): 125.
In 2010: The results that revealed the gamma-ray structure in our galaxy are reported by Meng Su, Tracey Slatyer, and Doug Finkbeiner, “Giant Gamma-ray Bubbles from FERMI-LAT: Active Galactic Nucleus Activity or Bipolar Galactic Wind?,” Astrophysical Journal 724 (2010): 1044.
the X-rays we see are echoes: There are several lines of evidence for activity from our central black hole, and I have used the X-ray evidence for discussion. One example of this type of reflection observation is given by Ponti et al., “Discovery of a Superluminal Fe K Echo at the Galactic Center: The Glorious Past of Sgr A* Preserved by Molecular Clouds,” Astrophysical Journal 714 (2010): 732.
9. THERE IS GRANDEUR
maximum size for black holes: There may indeed be a maximum (excluding the possibility of the merger of two or more already supermassive holes). In our cosmic neighborhood it’s around 10 billion times the mass of our Sun, 2,500 times the size of the Milky Way’s central black hole. See, for example, Priya Natarajan and Ezequiel Treister, “Is There an Upper Limit to Black Hole Masses?,” Monthly Notices of the Royal Astronomical Society 393 (2009): 838.
stars to be born: There is evidence of rings of young blue stars orbiting within three light-years of the central black hole of the Milky Way galaxy, as well as in Andromeda. For example, see Paumard et al., “The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics, and Formation,” Astrophysical Journal 643 (2006): 1011. Theoretical models seem to concur with the possibility of stars forming out of disks around the black holes; see, for example, Bonnell and Rice, “Star Formation Around Supermassive Black Holes,” Science 321 (2008): 1060.
flung out: It’s really still speculative, but the Chandra X-ray Observatory may have caught just such a thing. See Jonker et al., “A Bright Off-nuclear X-ray Source: A Type IIn Supernova, a Bright ULX or a Recoiling Supermassive Black Hole in CXOJ122518.6+144545,” Monthly Notices of the Royal Astronomical Society 407 (2010): 645.
known as gravity waves: These gravitational ripples produce strain on spacetime. Waves expected from astrophysical sources (such as merging black holes) will have polarizations, and will produce a very particular strain pattern that moves free masses back and forth. The frequency of the waves can be quite high, causing perhaps thousands of oscillations a second. The strength of the wave (its amplitude) also drops off with distance from the source.
Black Hole Imager: At this stage BHI is still a concept, albeit with a number of laboratory test-bed experiments being carried out to investigate the necessary techniques. Two thorough descriptions written by Keith Gendreau and colleagues were submitted to the United States Astronomy Decadal Review in 2010: “The Science Enabled by Ultrahigh Angular Resolution X-ray and Gamma-ray Imaging of Black Holes” (http://maxim.gsfc.nasa.gov/documents/Astro2010/Gendreau_BlackHoleImager_CFP_GAN_GCT.pdf), and “Black Hole Imager: What Happens at the Edge of a Black Hole?” (http://maxim.gsfc.nasa.gov/documents/Astro2010/Gendreau_BHI.pdf).
INDEX
The index that appeared in the print version of this title does not match the pages in your eBook. Please use the search function on your eReading device to search for terms of interest. For your reference, the terms that appear in the print index are listed below.
acceleration
Active Galactic Nuclei (AGN) Advanced Satellite for Cosmology and Astrophysics (ASCA) Alpha Centauri A
American Journal of Science Andromeda galaxy
anthropic principles
antielectrons
antineutrinos
Arms and Insecurity (Richardson) astronomy
astrophysics
atoms; see also subatomic particles Auriga (Charioteer)
baby galaxies
baby stars
Bayeux Tapestry
“beaming”
Bell, Jocelyn
Bell Labs
beta decay
Big Bang theory
binary black holes
binary stars
Black Hole Imager (BHI) black holes: accretion disks of; in Andromeda galaxy; author’s research on; baby systems of; bubbles formed by; collapse of; composite map of; compression and condensation in; coronas of; dark matter in; density of; detection and investigation of; development and growth of; duty cycles of; electromagnetic radiation from; energy produced by; ergosphere of; event horizon of; frictional forces (rotational energy) produced by; in galaxies; gas fields around; gravitational field of; as “gravity’s engines”; jets of particles from; life cycle of; life forms as dependent on; light emitted by; mass of; matter absorbed by; Michell-Laplace theory of; in Milky Way galaxy; models and theories of; orbiting pair of (binary); origins; photographic images of; quantum properties of; quasars and; radio waves emitted from; relativity effects of; Schwarzchild radius for; singularities of; size of (light-years); sound waves in; spacetime distorted by; spinning of; star formation and; subatomic particles in; supermassive; “switched on”; temperatures of; as term; in universe formation; velocity of; X-rays from Blandford, Roger
blue galaxies
blueshift
blue stars
Boehringer, Hans
Bohr, Niels
bremsstrahlung (“braking radiation”) brown dwarfs
Burbidge, Geoffrey
carbon
carbon monoxide
Carina
Cavendish, Henry
Cepheids
Chandrasekhar, Subramanyan Chandra X-ray Observatory clusters, galactic
Cobalt-60 isotope
Columbia space shuttle complexity
Compton, Arthur
computer simulations
constellations
Copernicus, Nicolaus
cosmic background radiation Cygnus A
Cygnus X-1
Darwin, Charles
Darwin, Erasmus
Darwin, George
degeneracy pressure
Delta Cephei
density
Doppler effect
“dumbbell” structures
dwarf galaxies
dwarf stars
E=mc2
Earth
Ebeling, Harald
Eddington, Arthur
Einstein, Albert
Einstein tensor
electricity
electromagnetic radiation electrons
elements
elliptical galaxies
embedding diagrams
Epicureans
Eukarya
European Space Agency
evolution
exoplanetary systems
Exposition du système du monde (Laplace) Fabian, Andrew
Felten, Jim
Fermi, Enrico
field equation (formula) Finkbeiner, Doug
4C41.17 object
Fowler, Ralph
frames of reference
Franklin, Benjamin
galaxies; see also specific galaxies Galaxy Zoo
Galileo Galilei
gamma rays (black)
Gendreau, Keith
General Electric
&n
bsp; general theory of relativity Giacconi, Riccardo
globular clusters
Gondwana
gravity: acceleration and; collapse of; as constant (G); fields of; force of; laws of; in relativity theory; tides of; waves of; wells of “green valley” galaxies Gunn, Jim
Halley’s comet
“headlight effect”
Heisenberg, Werner
heliopause
helium
Herschel, William
Hewish, Antony
Hilbert, David
Hoover Dam
Horner, Donald
Hoyle, Fred
Hubble, Edwin
Hubble Space Telescope
hydroelectric power
hydrogen
infrared light
interference patterns
interstellar clouds (nebulae) interstellar dust
“inverse Compton scattering”
ions
iron
isotopes
Israel, Werner
James Clerk Maxwell Telescope Jansky, Karl
Jeans, James
Jeans Mass
Jones, Laurence
Jupiter
Kaufmann, Gordon B.
Keck Observatory
Kerr, Roy
kinetic energy
Laplace, Pierre-Simon
Large Hadron Collider
Lascaux caves
Laser Interferometer Gravitational-Wave Observatory (LIGO) Laser Interferometer Space Antenna (LISA) lasers
laws, physical
Lense-Thirring effect
life forms
light: aether as medium for; corpuscular theory of; interference patterns of; particles of; spectrum of; speed of; in vacuum; waves of light-years
Local Group
“luminiferous aether”
Lynden-Bell, Donald
M87 galaxy
magnetism; see also electromagnetic radiation mass
Gravity's Engines: How Bubble-Blowing Black Holes Rule Galaxies, Stars, and Life in the Cosmos Page 24