MATHEMATICAL MODELING: . ... This model is developed on the base of the probabilistic description of the collisional aeronomical processes and is realized on a computer as the numerical system (stochastic model). ... Shematovich, V.I., Bisikalo , D.V.             Nonequilibrium processes in the planetary and cometary atmospheres. ... In Russian) . ... Piarnpuu , A. A.; and Shematovich, V. I.       Construction of structural stochastic models of collision processes in rarefied gas media (abstract) . ...

The ion rocket is another means of providing thrust, more gradually but also more efficiently than a conventional rocket. ... As in the nuclear rocket, the energy which propels the xenon jet comes from a different source; here it is electrical energy from solar cells. The reason an ion rocket is much more efficient than ordinary rockets is the way its jet is produced. ... As with solar sails, solar ion engines are mainly practical in the inner solar system, where ample sunlight is available. ...

Astronomy Picture of the Day . ... 27.09.1998 . ... Einstein 's many visionary scientific contributions include the equivalence of mass and energy (E=mc^2), how the maximum speed limit of light affects measurements of time and space ( special relativity ), and a more accurate theory of gravity based on simple geometric concepts ( general relativity ). ... NASA Web Site Statements, Warnings, and Disclaimers . ... Publications with keywords: time - space . Publications with words: time - space . ...

... Aurora from Space . ... Magnetic Storms . ... The "ring of fire" seen by satellite cameras around the polar caps (picture below) is probably created by electrons leaking from the tail's plasma sheet, whose magnetic field lines form a somewhat imperfect trap. ... One possible explanation involves the close association between auroral arcs and electric currents which flow along field lines between the ionosphere and distant space ( Birkeland currents ). ... Why no aurora at the magnetic poles? ...

Next: Mission Element Points-of-Contact . Previous: Mission Operations Data Transfer . ... Each mission element should ensure that their contact information remains current and notify the RSOG of any changes. ... Non-RSOG mission elements will also use the "dit" list to notify the RSOG (and all other mission elements) of unexpected events that may impact operations elsewhere, e.g., if a tracking station discovers that the spacecraft is in an unexpected configuration. ...

... Equations are obtained for the plane relative motion of the system on the taut thread (on the assumption that the centre of mass of the system moves along the Keplerian elliptic orbit). ... The torques of gravitational forces, aerodynamic pressure, aerodynamic friction and the aerogradient effect are taken into account. ... First, the problem is investigated in case of taut thread and Keplerian elliptic motion of the centre of mass. ... In a general case the free motion is bound to become connected....

... Research objects and scientific purposes . Space scientific program includes development and launch of two supersmall spacecrafts "Universitetskiy" and "Kompas-2" intended for monitoring of radiation conditions near the Earth. ... All the studies conducted in the near-Earth space are characterised by strong radiation fields. ... The circular polar orbits, which cover all the near-Earth space, are the most favorable for comprehensive studies of the radiation conditions near the Earth. ...

... The code delay gives the correct delay for the satellite signal. ... TELESCOPE A IF Output GLONASS Phase Tracking Oscillator TELESCOPE B IF Output GLONASS Phase Tracking Oscillator DELAY TRACK OUTPUT A CORRELATE DELAY TRACK OUTPUT B + - RAW Signal modelling GaCA Random Noise ma CORRELATE CORRECTED + + + Signal modelling GbCA Random Noise mb + Figure 1: Diagram showing principles used in cancelling GLONASS interference from the cross correlation of two antennas. ...

Next: Polarization efficiency: size/shape/orientation effects Up: Optical properties of cosmic Previous: The 2175? feature . To model the interstellar polarization one needs to calculate the forward-transmitted radiation for an ensemble of non-spherical aligned dust grains. ... Let non-polarized stellar radiation passes through a dusty cloud with a homogeneous magnetic field. ... The angle between the line of sight and the magnetic field is ( ). ... where the angle is connected with and ( ). ...

The Arcetri Spectral Code (Landi and Landini 1998) allows to evaluate the spectrum of continuum and line radiation emitted by hot and optically thin plasmas in the spectral range 1-2000 Angstrom. The Code is composed by a large database of atomic data and transition probabilities for calculating spectral line emissivities and a suite of fortran programs able to evaluate free-free, free-bound and two-photon continuum radiation. ... To get he Arcetri Spectral Code related publications . ...

... Planets . ... An artistтАЩs impression of Ceres located in the asteroid belt, with plumes of water vapour rising from its surface. Could Ceres have more water than on Earth? (image credit: ESA/ATG medialab) . ... Ceres, captured by the Dawn Space craft in December 2014, Dawn was 740,000 miles (1.2 million km) from Ceres at the time. (image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA) . ... Now itтАЩs a dwarf planet. (image credit: NASA/ESA/SWRI/Cornell University/University of Maryland/STSci) . ...

... Russian KOI8 . ... Radio galaxies and cosmology [in Russian]) . ... The book is devoted to investigations of powerful radio galaxies in the different wavelength ranges. ... The history of study for radio galaxies is given and the outlook on radio galaxy exploring is considered. ... The cosmological tests to check the Universe evolution parameters constructed on the observational data of radio galaxies are considered in details. ... List of detected misprints (in Russian). ...

... Bad Astronomy . ... Bitesize Astronomy . ... Bad Astro Store . ... Site Info . ... It is from from Voyager 1 and shows a whopping big impact crater dominating the profile of the moon. Note that Mimas is about 400 kilometers across (about 250 miles). ... The wall around the crater is 5 kilometers high, and that central peak rises 6 kilometers above the surface (many impact craters have a large central peak which is caused by a pressure rebound from the impact). ... 2008 Phil Plait. ...

... The procedure of radiometer signal integration can be considered as a sort of reducing dimension of the initial sampling space, where the samples are the result of analog-to-digital conversion. ... The probability distribution of the signal and spikes is completely known. ... The quality of the considered algorithm could be also illustrated by Figure 2 . ... One could see the considered adaptive algorithm is preferable even by low degree of compression, because all spikes have been depressed. ...

Natural Satellites Service. ... Apparent Encounters . of the Tycho-2 Catalogue stars and the main natural planetary satellites . ... with the Tycho-2 Catalogue stars. ... Instead of three numbers (ntch1 ntch2 ntch3) describing a position of a star in the Tycho-2 catalogue, one conditional number is given. ... Apparent Encounters of the Tycho-2 Catalogue stars and the Galilean satellites of Jupiter . Apparent Encounters of the Tycho-2 Catalogue stars and the major satellites of Saturn . ...

Astronomical Data Center . ... You can access the files described here in three ways: . ... Use CDS' VizieR Service at ADC to explore the data files. ... Get the data files via anonymous FTP. ... 1981) -------------------------------------------------------------------------------- Byte-per-byte Description of file : table1a Byte-per-byte Description of file : table1b -------------------------------------------------------------------------------- Bytes Format Units Label Explanations ...

... These electrons may be free or bound to an atom or ion. ... The modelling of a stellar atmospheres (or any astrophysical object) and its emergent radiation requires a detailed model of how photons interact with electrons. ... These "atomic data" are fundamental to accurate astrophysical modelling. ... For calculating model spectra of early-type helium stars in LTE, I maintain a database of atomic data for, mostly, blue-visual absorption lines of light elements. ... Simon's home page . ...

Blackholes2 Forum Message . Forums: . Atm ћ Astrophotography ћ Blackholes ћ Blackholes2 ћ CCD ћ Celestron ћ Domes ћ Education . ... Post . ... Could This Be Considered The .. ... Post Message | ... www.astronomy.net . About Astronomy Net | ... Unless otherwise specified, web site content Copyright 1994-2016 John Huggins All Rights Reserved . Forum posts are Copyright their authors as specified in the heading above the post. "dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" . ...

Next: Identification and Analysis of Binary Star Systems using Probability Theory . ... We present a computing code for modelling energy flux distributions, photometric indices and spectral line profiles of (non-)radially pulsating Main-Sequence stars. ... In the case of slowly rotating stars one can use the zero-rotation approximation to describe stellar pulsations. Such a model was used already by Cugier, Dziembowski & Pamyatnykh (1994) to study nonadiabatic observables of Cephei stars. ...

... The analysis shows, that asteroid ­ rubble pile loses its fast fragments in no time but the retaining fragments forms a compact structure immersed in dust ­ gas atmosphere, created by interaction of interplanetary medium with dispersed product of collisional evolution of asteroid. By interaction of an asteroid ­ rubble pile with interplanetary medium structures asteroid can increase its brightness on account of blowed up dust simulating phenomenon of distant comet's brightening. ...