AAS207Excite

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Published on March 19, 2008

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Things that Excite Me at the 207th AAS Meeting, January 8-12 :  Things that Excite Me at the 207th AAS Meeting, January 8-12 By Dr. Harold Williams of Montgomery College Planetarium http://montgomerycollege.edu/Departments/planet/ http://capitalastronomer.org Honorable Anthony Williams, mayor of Washington, DC:  Honorable Anthony Williams, mayor of Washington, DC Amateur Astronomer Observed Solar Eclipse in the Dakota’s while he was in Harvard Law School Welcome Thanks for the Taxes Russell Lecture, J.E. Gunn, Princeton University :  Russell Lecture, J.E. Gunn, Princeton University No abstract http://www.aas.org/publications/baas/v37n4/aas207/S30.htm Sloan Digital Sky Survey http://www.sdss.org/ He is the project Scientist http://www.sdss.org/directorate/index.html Half Century of Cosmology:  Half Century of Cosmology 50 years ago Hubble constant only known to within a factor of two Universe Expanding Big Bang or Steady State? Now Big Bang most probable Ho= 71 ±4 km/(sec Mpc) ≈1/14 Giga years Most probable Compositions of the Universe:  Most probable Compositions of the Universe 5% Baryonic, stars and gas, normal matter 25% “Dark Matter,” composition unknown, flat rotation curve of galaxies, galaxies in clusters 70% “Dark Energy,” Super Nova Ia, SNIa, standard candle, universe expanding was decelerating for several Giga years after creation, now accelerating for several Giga years Apache Point, New Mexico:  Apache Point, New Mexico Sloan Digital Sky Survey Telescope:  Sloan Digital Sky Survey Telescope Lots of new instruments soon:  Lots of new instruments soon Planck will follow WMAP, (Wilkinson Microwave Anisotropy Probe) (will do a better job of CMB, (Cosmic Microwave Background) polarization) and COBE, (Cosmic Background Explorer) http://www.rssd.esa.int/index.php?project=PLANCK ESA, European Space Agency Some NASA Missions:  Some NASA Missions Constellation X http://constellation.gsfc.nasa.gov/ LISA Laser Interferometer Space Antenna http://lisa.jpl.nasa.gov/ Gravitational Waves NSF missions:  NSF missions LIGO, Laser Interferometer Gravitational-Wave Observatory http://www.ligo.caltech.edu/ Hanford, Washington http://www.ligo-wa.caltech.edu/ Livingston, Louisiana http://www.ligo-la.caltech.edu/ Taking data still no gravitational wave detection. Detecting Gravitational-Waves with Interferometers by Nergis Mavalvala, MIT:  Detecting Gravitational-Waves with Interferometers by Nergis Mavalvala, MIT hµν =2G/(c4r) Ϊµν h =4π2GM/(c4r) R2 forb2 h≈10-21, if M~1030 kg, R~20km, r~1023m Vigo Cluster of galaxies, f~400hz DWD Systems as Sources of Gravitational Radiation:  DWD Systems as Sources of Gravitational Radiation Taken from … http://lisa.jpl.nasa.gov/gallery/ligo-lisa.html DWD Systems as Sources of Gravitational Radiation:  DWD Systems as Sources of Gravitational Radiation Taken from … http://lisa.jpl.nasa.gov/gallery/ligo-lisa.html Slacker Astronomy:  Slacker Astronomy Because if you are not going to care about something, you may as not care about astronomy http://slackerastronomy.org/ Pamela Gay, Really good Pod Casting, MP3 AAVSO, MIT, Harvard, Boston, Massachusetts Slide15:  Did not go to. Friends told me about radio astronomy observatory on the back side of the moon in the future. NASA GSFC friends seem to be a little less nervous with this administrator. 94.01 The Vision for Space Exploration M. Griffin (NASA Headquarters) Measuring Cosmological Parameters by Wendy Freedman, director of CO-CIW:  Measuring Cosmological Parameters by Wendy Freedman, director of CO-CIW Now 10 parameter not 2 parameters H0=72±7km/(sec Mpc) Hubble constant now q0 , Acceleration parameter now ω=p/ρ, pressure over mass density t0 =13.7±0.2Giga years, age of the universe now T0=2.71K , temperature of the universe now Critical Densities:  Critical Densities Ω0=1.01±0.02, How close we are to critical density now Ω0= Ωb+ ΩCDM+ Ων+ Ωx Ωb, “Mass density in Baryons (normal matter)” ΩCDM, “Mass density in Cold Dark Matter” Ων, “Mass density in neutrinos” Ωx, “Dark Energy” Learn what the Sunyaev-Zel’dovich Effect is!:  Learn what the Sunyaev-Zel’dovich Effect is! Sunyaev-Zel'dovich effect (occasionally abbreviated as the SZ effect) is due to high energy electrons distorting the cosmic microwave background radiation (CMB) through the inverse Compton scattering, in which some of the energy of the electrons is transferred to the low energy photons. Observed distortions of the cosmic microwave background spectrum are used to detect the density perturbations of the universe. Using the Sunyaev-Zeldovich effect, dense clusters of galaxies have been observed. The Sunyaev-Zeldovich theory can be divided into: thermal effects kinetic effects polarization http://en.wikipedia.org/wiki/Sunyaev-Zel%27dovich_effect Titan: A Fiercely Frozen Echo of the Early Earth by Tobias Owen:  Titan: A Fiercely Frozen Echo of the Early Earth by Tobias Owen Thick Nitrogen atmosphere http://en.wikipedia.org/wiki/Titan_%28moon%29 [107.01] Titan: A Fiercely Frozen Echo of the Early Earth T. Owen (University of Hawaii), S. Atreya (University of Michigan), H. Niemann (Goddard Space Flight Center), M. Zolotov (Arizona State University) :  [107.01] Titan: A Fiercely Frozen Echo of the Early Earth T. Owen (University of Hawaii), S. Atreya (University of Michigan), H. Niemann (Goddard Space Flight Center), M. Zolotov (Arizona State University) As the only other world we know with a thick nitrogen atmosphere, Titan clearly invites comparisons with Earth. The key to the origin of Titan's nitrogen lies with the very low abundances of primordial noble gases in the atmosphere. For nitrogen to arrive as N2, one expects a solar ratio of N/36Ar, instead of the orders of magnitude larger value found by the Huygens GCMS. Possible carriers then include NH3 and other N-compounds, including organic compounds, all trapped in the icy planetesimals that accreted to form the satellite. The ratio of 15N/14N on Earth implies a similar origin for our nitrogen, but the much lower relative abundances of primordial noble gases on Titan suggest a decisive difference in the volatile carriers: those contributing to Titan would have been warmer. In this case, methane and CO would not have been trapped, and the methane we see on Titan today must be stored or produced in the satellite's interior and released episodically to the atmosphere. Methane can be produced through high-pressure hydrothermal transformations of organic compounds under hydrogen-rich conditions created by water-rock interactions. Alternatively, both methane and noble gases may have been brought in as clathrates and may now reside as clathrates hidden in the depths of a liquid water mantle. The need for replenishment of methane is established by the short photochemical lifetime (10--20 Myr) of the atmospheric complement, and confirmed by the much lower depletion of 12C compared with 14N. The nitrogen isotope ratio on Titan reveals massive loss of the early atmosphere, assuming a starting value similar to ours. These findings may be relevant for models of an early reducing atmosphere on Earth. Slide23:  Image of Titan's surface taken by the Huygens lander on January 14, 2005; the simulated color is based on spectral measurements taken by the probe. Initially thought to be rocks or ice blocks, they are more pebble-sized. The two rock-like objects just below the middle of the image are about 15 centimeters (left) and 4 centimeters (center) across respectively, at a distance of about 85 centimeters from Huygens. The surface is darker than originally expected, consisting of a mixture of water and hydrocarbon ice. There is also evidence of erosion at the base of these objects, indicating possible fluvial activity. 61.01 The Pierre Auger Observatory for the highest energy cosmic rays: Is it really astronomy? J. W. Cronin (U. Chicago) :  61.01 The Pierre Auger Observatory for the highest energy cosmic rays: Is it really astronomy? J. W. Cronin (U. Chicago) The nature and origin of the highest energy cosmic rays is a mystery. While there are many theories, only with measurements can the mystery be solved. The Pierre Auger Observatory has been built in Argentina to observe the highest energy cosmic rays, those with energy > 1019 eV. The flux of these cosmic rays is about 1/km2/year so a large area (3000 km2) is required. Primary cosmic rays are detected by the shower of particles produced in the atmosphere. Interaction with the Cosmic Microwave Background limits the sources to be < 100 Mpc. With such short distances the charged cosmic rays may not be significantly deflected by magnetic fields and hence have the observed direction point to the source. The cosmic ray shower particles are detected both by water tanks on the ground and by telescopes that detect the fluorescence of the shower particles in the nitrogen of the atmosphere. The observatory is 2/3 complete and has been taking useful data for the past two years as it has grown. The talk will describe the observatory and present some initial results. http://www.auger.org/ :  http://www.auger.org/ Two different Detectors:  Two different Detectors 1,400 meters on the Argentinean, Pampa Water filled Cerenkov counters, work all of the time, Monday, January 9, 930 working out of 1080 eventual, very rugged. 300-400nm florescence in the ultraviolet only useable during the dark of the Moon, air conditioned only 4 on perimeter, very persnickety. Slide29:  108.01 Bold Dreams and Big Questions: The Future of Astronomy in the 21st and NSF's Role M. S. Turner (NSF) Did not go to, mailed job application instead got in right after it. Session 160. Astronomy Visualization: The State of the Art :  Session 160. Astronomy Visualization: The State of the Art Scientific visualization is a fast developing field. The rapid developments in computer graphics, though done primarily for movies and video games, has enabled scientific graphics to achieve a level of polish never before seen. Astronomy, being the most visual of the sciences, has benefited more than any other from computer graphics. In addition, the current transition from traditional optical star ball based planetariums to full-dome digital theaters has increased the demand, supply, and quality of astronomical visualizations. This special session will bring together the best astronomy visualizations done for research, outreach, and public presentation. Speakers were invited based on a juried selection of visualizations during the fall of 2005. Join us for a look at the coolest animations, details of how they are made, and the scientific stories that they tell. The goal is to foster communication and collaboration between astronomers and artists to increase the breadth and depth of stunning astronomical visuals available. Run Astronomy Visualization DVD:  Run Astronomy Visualization DVD Future visualizations need two versions, one like current for art, more labels for the scientific understanding. Michael Norman during Visualization session:  Michael Norman during Visualization session Population III star start at z=100, 3Mega years to AGB, Asymptotic Giant Branch, dispersal of heavy elements, very large variance. 3D Adaptive Mesh hydrodynamics. What all does this mean for cosmic chemical evolution! Meeting Complaints:  Meeting Complaints More coffee and cookies at breaks. Volunteers need larger value lunch chits. Volunteers should be solicited in early November not December 23. [188.13] High resolution HI, imaging of VIRGOHI 21 - a dark galaxy in the Virgo Cluster :  [188.13] High resolution HI, imaging of VIRGOHI 21 - a dark galaxy in the Virgo Cluster R. F. Minchin (Arecibo Observatory), J. I. Davies, M. J. Disney (Cardiff University), A. R. Marble, C. D. Impey (Steward Observatory), P. J. Boyce, D. A. Garcia, M. Grossi (Cardiff University), C. A. Jordan (Jodrell Bank Observatory), R. H. Lang, S. Roberts (Cardiff University), S. Sabatini (Osservatorio Astronomico di Roma), W. van Driel (Observatoire de Paris) VIRGOHI21 discovered at Jodrell Bank VIRGOHI21 first heard about at Blackwater Falls star party this summer in West Virginia.:  VIRGOHI21 first heard about at Blackwater Falls star party this summer in West Virginia. Dark Matter supposedly dominates the extragalactic Universe, yet no totally dark structure of galactic proportions has ever been convincingly identified. Minchin et al. (2005) suggested that VIRGOHI 21, a 21-cm source found in the Virgo Cluster by Davies et al. (2004), was probably such a dark galaxy because of its broad line-width (~200 km/s) unaccompanied by any visible massive object to account for it. We have now imaged VIRGOHI 21 in the neutral hydrogen line, and indeed we find what appears to be a dark, edge-on, spinning disk with the mass and diameter of a typical spiral galaxy. We also find that there is an indubitable interaction with NGC 4254, a luminous spiral with an odd one-armed morphology but lacking the massive interactor normally linked with such a feature. Published numerical models of NGC 4254 call for a close interaction ~108 years ago with a perturber of ~1011 Msun. This we take as further, independent evidence for the massive nature of VIRGOHI 21. VIRGOHI21:  VIRGOHI21 I thought VIRGOHI21 as a dark galaxy of gas without any stars would have a low Dark Matter to Gas Mass instead of a high one of 750 if “Dark Matter” encouraged star formation. Maybe CDM, Cold Dark Matter, is in trouble. MOND, MOdified Newtonian Dynamics, needs no “Dark Matter.”

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