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? . ...