The efficiency of interaction of radiation with a particle and hence its optical properties depend on the particle chemical composition, size, shape, structure, etc. ... Particle size expressed in units of the wavelength of incident radiation, together with chemical composition, most strongly affects the optical properties of a scatterer. ... There are many methods to solve the light-scattering problem for a homogeneous spheroid (our survey of the light-scattering methods see here ). ...

The rates of build-up in the atmosphere of human-made compounds that deplete the ozone layer (e.g., chlorofluorocarbons (CFCs) and halons) have slowed in recent years as a direct result of reductions in global emissions of these compounds. ... The peak global ozone depletions are expected to occur during the next several years. ... Methyl bromide continues to be viewed as a significant ozone- depleting chemical. ...

... Bojan Nikolic web pages (r. 329) . ... We present a Bayesian approach to calculating the coefficients that convert the outputs of ALMA 183 GHz water-vapour radiometers into estimates of path fluctuations that can be used to correct the observed interferometric visibilities. ... Inference of Coefficients for Use in Phase Correction . ... Simulating Atmospheric Phase Errors, Phase Correction and the Impact on ALMA Science . ... Copyright 2005 -- 2016, Bojan Nikolic feedback welcome ...

Next: M.D. Smith, Research Astronomer Up: W.M. Napier, Emeritus Honorary Previous: W.M. Napier, Emeritus Honorary . Recent years have seen a downgrading of the threat assessment due to impacts from comets and asteroids. ... Bill Napier, however, has been using new approaches to the problem and finds that the celestial hazard due to impacts may be a factor 5 higher these estimates. ... These bodies may constitute the dominant impact hazard in the 100,000 megaton range. ...

... ATNF Colloquium . 3D precessing jet simulations for radio galaxy Hydra A . ... We study the structure of an iconic radio source Hydra A focussing on detailed models of the inner 30 kpc of its northern jet. ... Image caption: A comparison between the jet-lobe morphology of the Hydra A northern jet and the best matching simulated jet. ... Panel (b): The synthetic total intensity image of the simulated jets with directional parameters, line of sight angle = 42 degr and viewing angle = 45 degr. ...

... 2) Correlate H velocity distribution distortions from Maxwellian as a function of H+ composition. ... 4) Determine exobase winds using measurements of the Doppler shifted, infrared, He emission. ... Instrument Setup 430 CH receiver 430 CH radar Atmospheric Optical Instruments: Tilt-Photometer Fabry-Perot Ionosonde Description of Observer Equipment: Infrared Fabry-Perot interferometer Special Equipment or setup: Experiment requires two Observatory Fabry-Perot interferometers, and two photometers. ...

... Tonight's Sky . ... News . ... solar system . ... New findings from New Horizons shape understanding of Pluto and its moons . ... New Horizons has also found new and more stringent limits for an atmosphere on Pluto s largest moon, Charon. ... New Horizons scientists are also presenting findings about how Pluto and its moons interact with the solar wind, a constant stream of particles and plasma that flows from the Sun and is still traveling at 900,000 miles per hour (1.4 million kilometers) at Pluto...

... Although many of the images are used for teacher-driven activities, students do have the opportunity to work with scientists on original research projects. ... The primary goal is to have teachers experience astronomy research and then to bring the research data into their classrooms via the internet. ... They also learn how to process their data, build a solar telescope to take home to their classrooms, and learn background information from astronomers in each of the three research areas. ...

Russian SHAREABLE DATA CENTER Institute of Solar-Terrestial Physics SB RAS . ... A most promising problem is to investigate the interaction of two VHF powerful radiowave beams in the ionosphere, whose difference frequency is equal to the plasma frequency in some ionospheric area (that is, the difference frequency is taken in the range 1-8 MHz). ... Two-frequency interaction effects are based on radiowave non-linear mixing, which is rather complicated when describing and modelling the experiment. ...

... It was developed co-operatively by scientific institutions in the USA, Great Britain and Russia to carry out studies on the thermal infrared radiation of the Martian atmosphere. ... The Martian atmosphere consists of 95% carbon dioxide. ... Despite the "hidden" water on Mars, its current role in the planet's life is quite significant: it can even be a regulator, which keeps the content of the carbon dioxide in the atmosphere at a constant level. ... a) how large are the water resources on Mars? . ...

... 2007 June 5 . Jet Approaching a Crescent Moon . ... On the left, an airplane cruises through the atmosphere leaving a contrail in its wake. ... Far in the distance, to the right of the plane, is the young Moon . ... The above image is framed by an eerie gray sky, too far from day to be blue, too far from night to be black. ... The plane crossed the Moon. The contrail dispersed. ... The Moon set. ... About APOD | ... NASA Official: Phillip Newman Specific rights apply . ...

Astronomy Picture of the Day . Jet Approaching a Crescent Moon . ... On the left, an airplane cruises through the atmosphere leaving a contrail in its wake. ... The above image is framed by an eerie gray sky, too close to day to be blue, too close to night to be black. Within minutes the impromptu sky show ended. ... NASA Web Site Statements, Warnings, and Disclaimers . ... U. Based on Astronomy Picture Of the Day . Publications with keywords: Moon . Publications with words: Moon . ...

The very metal-poor local dwarf galaxies - the analogs of primordial galaxies in young Universe . ... The goal of this project is the study of the properties of the local eXtremely Metal-Deficient (XMD) dwarf galaxies. ... S.A. Pustilnik, J.-M. Martin . ... Pustilnik S.A. "Dark galaxies" and local very metal-poor gas-rich galaxies: possible interrelations, in: Dark Galaxies and Lost Baryons, Edited by J.Davies and M.Disney, Proceedings of IAU Symposium No. 244, held 25-30 June, 2007 in Cardiff, UK. ...

... Shematovich, V.I . ... Shematovich, V. I. ; Bisikalo, D. V.; Marov , M. Ya . ... Shematovich, V.I., Bisikalo, D.V., and Gerard J.-C. Superthermal particles in the planetary atmosphere. ... Shematovich, V.I., Bisikalo, D.V., and Gerard, J.-C. The thermospheric odd nitrogen photochemistry : role of non-thermal N(4S) atoms (abstract) . ... Geophys ., ... Gerard, J.C., Shematovich, V.I., and Bisikalo, D.V. Effect of hot N( 4S) atoms on the NO solar cycle variation in the lower thermosphere (abstract) . ...

Композиты и наноструктуры COMPOSITES and NANOSTRUCTURES ?2 2009 СОДЕРЖАНИЕ Ю.Р.Колобов, А.Г.Липницкий, М.Б.Иванов, Е.В.Голосов Роль диффузионно-контролируемых проце ссов в формировании структуры и свойств металлических наноматериалов .. ... 2009 3 ?2 2009 Композиты и наноструктуры COMPOSITES and NANOSTRUCTURES CONTENS Yu.R.Kolobov, A.G. ipnitsky, M.B.Ivanov, E.V.Golosov The role of diffusion-controlled processes in structure and properties formation of metallic nanomaterials .. ... 2009 ...

... We cannot use for this purpose equivalent widths and profiles of HI lines (well known criteria of atmospheric conditions for normal supergiants), since these lines are strongly distorted in the spectrum of IRAS04296 as seen in Fig. ... Figure: Upper: iron abundance FeI (circles) and FeII (crosses) calculated for IRAS04296+3429 with model parameters , and using lines with different excitation potentials EP of a low level; bottom: the same as a function of the equivalent width W . ...

By encouraging student participation and interaction during the lecture, Peer Instruction encourages students to critically think through the arguments being developed, and to discuss their ideas and insights with their neighbors. ... After one minute, the students record an answer and are then asked to turn to their neighbors to try and convince them of their answers. ... After another minute or so, the students are asked to reconsider their answer and record it again. ...

... NASA Lunar Orbiter . ... The Lunar Prospector is designed for a low-polar orbit investigation of the Moon, including mapping of surface composition and possible polar ice deposits, measurements of magnetic and gravity fields, and study of lunar outgassing events. Data from the 1- to 3-year mission will allow construction of a detailed map of the surface composition of the Moon, and will improve our understanding of the origin, evolution, current state, and resources of the Moon. ...

... We want to know time-scales, and sequences of events, and the ages of stars. ... We would, ideally, like to create a solar comparison sample by finding stars of essentially the same mass, composition, and age and then observing the range of behavior they exhibit. ... At best we can estimate a star 's age. ... Having to construct models that work consistently across a broad range of masses constrains the problem, and yet even for the nearest open clusters we do not know the age to even 10%. ...

... One of this year's largest mass ejections from the Sun's atmosphere was recorded last Sunday by TESIS telescopes aboard the CORONAS-PHOTON satellite ( video - wmv 4.3 MB ). ... Over the course of a week, two gigantic solar prominences were simultaneously ejected from the surface of the Sun. ... Earth will not feel the Sun's influence either. ... The TESIS observatory ї TESIS: www.tesis.lebedev.ru . ... One of this year's largest mass ejections from the Sun's atmosphere (movie WMV, 4.3 MB) . ...