Where results make sense

About us   |   Why use us?   |   Reviews   |   PR   |   Contact us

Topic: Deceleration parameter

    Note: these results are not from the primary (high quality) database.

astronomical constant concept from the Astronomy knowledge base Since the deceleration parameter is equivalent to omega (assuming a cosmological constant of zero, as often done), it determines the ultimate fate and spatial geometry of the universe. The deceleration parameter equals omega (another cosmological parameter) when the universe is dominated by radiation, approximately the first 100000 years after the big bang, and 1/2 omega when the universe is dominated by matter. It can be interpreted physically as an energy density associated with space itself., A parameter that determines the strength of the cosmological term in the equations of general relativity. www.csi.uottawa.ca:4321 /astronomy/astronomicalconstant.html

HST findings shed new light on the fate of the Cosmos ("q-naught"), a positive value of the deceleration parameter means the universe is slowing down (foot on the brake), a value of 0 means the universe is expanding at a constant speed (coasting), and a negative value means that the universe is accelerating (foot on the gas). The larger the density parameter, the more stuff there is. Issues related to "missing mass" are often tied up in measurements of the density parameter that turn out to be smaller than one needs to theoretically halt the expansion, for example through the self-gravitation of all objects in the Universe. Hubble had the insight to realize that not only were these objects apparently speeding away, but the farther away they were, the faster they appeared to be moving. science.nasa.gov /newhome/headlines/ast25may99_2.htm

IHS ESDU: Data Item 76011 A parameter is added to the correlation including the ratio decision speed/take-off safety speed; a correlation for that parameter is also included depending on the average deceleration available during the stopping phase and a table is given of typical values depending on runway condition and braking methods available. However, for balanced field length a second correlation is given taking into account different levels of deceleration in the stopping phase. Both distances are correlated using second segment climb gradient as one parameter and a second parameter involving aircraft weight, lift coefficient at take-off safety speed, and thrust. www.esdu.com /graphics/dataitem/76011a.htm   (189 words)

HST findings shed new light on the fate of the Cosmos Two other numbers that are often discussed in cosmology, the "cosmological constant," which Einstein referred to as one of his greatest blunders, and the "curvature of the Universe," are determined by the density parameter and the deceleration parameter. If the Hubble Constant is large enough, for example, for a given age of the Universe, the deceleration parameter must be negative, meaning that the Universe is not slowing down, but instead is accelerating its expansion. The Hubble Constant is usually expressed in units of "kilometers per second, per Megaparsec." One parsec is a unit of distance equal to about 3.2 light years, and a Megaparsec is a million times this, or about 3.2 million light years. science.nasa.gov /newhome/headlines/ast25may99_2.htm   (2311 words)

ScienceDaily -- Browse Topics: Science/Astronomy/Cosmology Planck Satellite - ESA mission designed to find the three cosmological parameters: the Hubble parameter, the density and the deceleration parameter from variations in the cosmic background radiation. Includes chapters on CMBR, the large scale structure of universe, and the physics of the early universe. Cosmology: A Research Briefing - An online book from the National Academy of Sciences. www.sciencedaily.com /directory/Science/Astronomy/Cosmology   (2311 words)

Omega Valve: Servo Valve and Actuator Control System Generally, a non-symmetrical spool configuration is ideal for matching the differential area of the actuator to yield better performance in the deceleration phase of the cycle. If you want to increase total production rates, OSVACS is available pre-configurable, user-defined and developed, with the aid of user-friendly software and subroutines that provide rapid switchover for parameter optimization. Programming is done through a Windows interface with a general setup routine that queries the user for each parameter to match the valve to the actuator and load. www.omegavalve.com   (1418 words)

Searchalot Directory for Top/Science/Astronomy/Cosmology ESA mission designed to find the three cosmological parameters: the Hubble parameter, the density and the deceleration parameter from variations in the cosmic background radiation. WMAP is a NASA Explorer mission measuring the temperature of the cosmic background radiation over the full sky. MAP measures temperature differences ("anisotropy") in the cosmic microwave background radiation. www.searchalot.com /Top/Science/Astronomy/Cosmology   (1418 words)

Graduate Cosmology Syllabus Comparing the Friedman models with observations (5) - determining Hubble's constant, tests for the density of the universe and the deceleration parameter, diameters, magnitudes and evolutionary effects Simple Relativistic Cosmologies (4) - Robertson-Walker metric, the Friedman models, vacuum energy and other wrinkles in the equation of state. www.sdss.jhu.edu /~ethan/cosmsyl.html   (1418 words)

Professor Mathews -- Publications Janches, D., J. Mathews, D. Meisel, and Q.-H. Zhou, “Micrometeor observations using the Arecibo 430 MHz radar: I. Determination of the ballistic parameter from observed Doppler velocity and deceleration results,” Icarus, 145, 53-63 (2000). Mathews, J. Janches, D. Meisel, and Q.-H. Zhou, “Arecibo radar studies of micrometeors: Zodiacal and interstellar dust in the solar system and the atmospheric fate of this dust,” paper contributed, Eighth Workshop on the Physics of Dusty Plasmas, Santa Fe (26-28 April, 2000). Janches, D., J. Mathews, and D. Meisel, “A study of the Arecibo micrometeor entry kinetics in the upper atmosphere,” paper Poster, CEDAR 2000, Boulder, CO (25-30 June 2000). www.ee.psu.edu /faculty/mathews/mathews2.html   (1418 words)

Publications Zhou, 2000, Micrometeor Observation using the Arecibo 430 MHz Radar: I. Determination of the Ballistic Parameter from measured Doppler Velocity and Deceleration Results,Icarus, 145, 2, 53-63. Janches Diego, David D. Meisel, and John D. Mathews, 2001, Orbital Properties of the Arecibo Micrometeors at Earth Intersection,Icarus,150, 2, 206-218. Janches Diego, David D. Meisel, and John D. Mathews, 2001, Micrometeor Observation using the Arecibo 430 MHz Radar: II. www.personal.psu.edu /users/d/x/dxj111/Publications   (1418 words)

An Introduction to Mathematical Cosmology It then goes on to discuss Friedmann models, the Hubble constant and deceleration parameter, singularities, the early universe, inflation, quantum cosmology and the distant future of the universe. This new edition contains a rigorous derivation of the Robertson-Walker metric. books.cambridge.org /0521496500.htm   (1418 words)

Electrons and Mythologies The cosmological constant, conventionally denoted by the Greek letter, is a parameter describing the energy density of the vacuum (empty space), and a potentially important contributor to the dynamical history of the universe. In a universe with both matter and vacuum energy, there is a competition between the tendency of to cause acceleration and the tendency of matter to cause deceleration, with the ultimate fate of the universe depending on the precise amounts of each component. The value of the cosmological constant is an empirical issue which will ultimately be settled by observation; meanwhile, physicists would like to develop an understanding of why the energy density of the vacuum has this value, whether it is zero or not. www.rgrace.org /99/99GGGGelectrons.html   (1418 words)

JLABTN03039.doc In this example, an achromat with a gross diameter of 2.5 m was constrained to provide first- and second-order compactions appropriate to energy recovery with energy compression during deceleration at 20o before trough from ~100 MeV to ~7 MeV using a 750 MHz RF system. Further investigation has led to the recognition — for certain parameter sets — that it is desirable to operate the various dipoles of the achromat at different excitations. The orbit behavior, by construction, was as expected; of greater interest is the fact that the betatron behavior is quite good over a reasonably large (10%) momentum interval. www.jlab.org /~douglas/ULTRAFEL/JLABTN03039.doc   (672 words)

"The Quest for the General Theory of Aging and Longevity" - Synopsis Gompertz also found that at advanced ages mortality rates increase less rapidly than an exponential function, thus forestalling two centuries ago the recent fuss over 'late-life mortality deceleration', 'mortality leveling off', and 'late-life mortality plateaus'. Moreover, the 'apparent aging rate' (the relative rate of age-related mortality acceleration corresponding to parameter a in the Gompertz law) increases, according to reliability theory, with higher redundancy levels. The Gompertz law of exponential increase in mortality rates with age is observed in many biological species (Strehler, 1978; Finch, 1990), including humans, rats, mice, fruit flies, flour beetles, and human lice (Gavrilov and Gavrilova, 1991), and, therefore, some general theoretical explanation for this phenomenon is required. longevity-science.org /Synopsis.html   (2330 words)

Active Galaxies and Quasars - Evolution of Quasars The transformation from redshift to cosmic time uses the approximation of a low-density Universe; for simplicity; changing the amount of matter in the Universe alters the deceleration parameter, and thus the exact correspondence between linear time and redshift z. The number of quasars per unit volume must be examined in what are known as comoving coordinates - that is, with the expansion of the Universe factored out. Otherwise, whatever kind of objects we observe would show a cubic dependence on (1+z) simply because they were more squeezed together at earlier times. www.astr.ua.edu /keel/agn/qsoevol.html   (2330 words)

Physics Today Online - American Vacuum Society Sandage, staff astronomer emeritus with the Carnegie Institution of Washington, is being recognized for "his relentless pursuit of the true values of the Hubble constant, the deceleration parameter, and the age of the universe." Peebles, Albert Einstein Professor of Science at Princeton University, is being honored for advancing "our understanding of phenomena, which range from the creation of the lightest elements to the formation of galaxies and the cosmic distribution of matter and radiation," the foundation reports. In April, Physics Today (page 58) reported on the establishment of the prize, which will be given in a formal presentation at the Pontifical Academy of Sciences at the Vatican in November. www.aip.org /pt/vol-53/iss-10/p95a.html   (265 words)

Physics Today Online - American Vacuum Society Sandage, staff astronomer emeritus with the Carnegie Institution of Washington, is being recognized for "his relentless pursuit of the true values of the Hubble constant, the deceleration parameter, and the age of the universe." Peebles, Albert Einstein Professor of Science at Princeton University, is being honored for advancing "our understanding of phenomena, which range from the creation of the lightest elements to the formation of galaxies and the cosmic distribution of matter and radiation," the foundation reports. The Cosmology Prize of the Peter Gruber Foundation will be awarded to P. www.aip.org /pt/vol-53/iss-10/p95a.html   (265 words)

Arecibo Observatory Publications *Janches, D., Mathews, J.D., Meisel, D.D., and Zhou, Q.-H., Micrometeor Observations Using the Arecibo 430 MHz Radar I. Determination of the Ballistic Parameter from Measured Doppler Velocity and Deceleration Results, Icarus, 145, 53, May 2000. *Freudling, W., Zehavi, I., da Costa, L.N., Dekel, A., Elda, A., Giovanelli, R., Haynes, M.P., Salzer, J.J., Wegner, G. and Zaroubi, S., Large-Scale Power Spectrum and Cosmological Parameters from SFI Peculiar Velocities, Astrophys. Tully-Fisher Peculiar Velocities for 52 Abell Custers, Astron. www.naic.edu /vscience/publtion/pub99-00.sht   (1757 words)

Plasma Laser Stars 1976 Paper The indication was that the angular size falls off with redshift faster than one might expect for values of the deceleration parameter, q0, as determined from the apparent magnitude-redshift diagram for galaxies. Curves obtained for the angular size from two world models, namely those of Einstein-de Sitter, and de Sitter, for a source of a fixed linear size of 290 kpc were found to provide reasonable upper envelopes to the plotted points. The envelope function in the largest angular size-redshift diagram for quasars is shown to be a consequence of the distribution of their redshifts and to have no intrinsic physical significance. laserstars.org /V1976a   (1376 words)

Try your search on: Qwika (all wikis)

About us   |   Why use us?   |   Reviews   |   Press   |   Contact us   Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.