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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 eyes can be exposed to a variety of hazards, such as flying objects (from hand tools or other equipment), small particles (grinding wheels), dusts, splashes of corrosive liquids or metals, injurious lights or heat rays, and poisonous gas fumes. ... Persons who wear corrective eyeglasses can wear mono-goggles over the corrective glasses or safety over glasses. Complete eye protection on certain jobs, such as machining operations, call for the use of side shields on safety glasses. ...

... nonlinear stabilization, the helicity, rotation and small-scale structures influence, the precursors of crisis processes development, the modeling of coherent structures evolution, applications in the natural disasters forecasting, for the helical structures generation in plasmas and astrophysics . ... Large-scale instabilities in hydrodynamics and plasmas . ... The turbulence in plasmas and in the atmosphere and MHD-turbulence . ...

... Energy . ... The free ions and electrons in a plasma behave the same way. Knowing the temperature of the high atmosphere of Earth, or that of the Sun, we can calculate energies expected of ions and electrons found there. However, ions and electrons actually observed in space are often much, much more energetic, and may move at a respectable fraction of the velocity of light (300,000 km/sec or 186,000 miles/sec). ... Typical energy of an electron in the polar aurora. 40,000 ev . ... 50,000 ev . ...

The largest contribution to the fireball-rich Leonid outburst of 1998 has previously been shown to be a component of resonant meteoroids ejected from Comet 55P/Tempel-Tuttle in 1333. By integrating particles with a suitable range of initial orbits, we demonstrate here that the cross section of the arc of resonant particles from 1333 through which the Earth passed in 1998 is quite compact and reflects details of the particles' initial ejection velocities. ...

... The photon temperature now is T p = 2.728 K and the neutrino temperature now is 1.947 K. If neutrinos are massless then we can compute their equivalent mass density using rho = [Q/a 3 ]/c 2 = N n (2\sigma/c)(7/8)g f T n 4 where N n is the number of neutrino species: N n = 6 for 3 types of neutrinos and 3 types of anti-neutrinos. ... Because this behavior is caused by the thermal velocity of the neutrinos, this form of dark matter is called Hot Dark Matter . ...

are denoted by the following symbols and may be taken to have the values below Elementary charge Speed of light in vacuum Planck constant Permeability of vacuum Permittivity of vacuum Unified atomic mass constant Rest mass of proton Rest mass of electron Boltzmann constant Avogadro constant Gravitational ... Write down the expression for the gravitational field, g, at distance r from a point mass of mass m, carefully defining all the terms in your expression. ...

Calibration and Data Reduction . Dark frames are long exposures that are taken with no light incident on the CCDs. ... Observers are cautioned that the calibration provided by the pipeline may not use the most up-to-date dark frames (partly because constructing these may involve data taken after the observation). ... Data to construct improved super-darks is available in the archive with at least 5 long dark exposures being taken weekly. ...

... Комментариев нет 3 августа 2010, 23:15 Blogger , English , Астрономия . Dark Stars and Boosted Dark Matter Annihilation Rates. (arXiv:1008.0348v1 [astro-ph.CO]) : "Dark Stars (DS) may constitute the first phase of stellar evolution, powered by dark matter (DM) annihilation. ... Secondly, we study the dependence of DS properties on the concentration pa- rameter of the initial DM density profile of the halos where the first stars are formed. ...

... The upward propagating HF wave is reflected at a particular height. ... The instabilities seen by the radar shortly after the HF is turned on can be divided into two types according to the degree of sophistication required in the model describing the response to the E field of the HF wave. ... The first kind occurs at a particular height determined by k vector and frequency matching conditions on the HF wave, the low and high frequency plasma waves, and the radar EM wave. ... Incoherent Scatter . ...

Next: The Stopping Radius in Up: ``Ecology'' of Magnetic Rotators Previous: The Environment of the . Now we consider qualitatively the effect of the electromagnetic field of a magnetic rotator on the accreting plasma. ... What is important is that both relativistic particles and magnetic dipole radiation will transfer their momentum and hence exert pressure on the accreting plasma. ... 2) The pressure of the accreting plasma is high enough to permit the plasma to enter the light cylinder . ...

... ATNF Home . About ATNF . ... About ATNF overview . ... Resonant inverse Compton scattering above polar caps: Gap acceleration efficiency for young pulsars . ... Title/Abstract Page: Resonant inverse Compton scattering . ... For a hot polar cap which emits soft photons, RICS can constrain the maximum energies of electrons (or positrons) accelerated in the polar gap in the following two ways: the energy loss competes with acceleration, or by limiting the acceleration length through pair production. ...

Next: Field of View Up: CCD Scientific Performance Previous: Back Illumination . The CCD acts as a storage medium, and with frame times of the order seconds, there is no obvious method of employing prompt co-incidence rejection of charged particle events. ... In conventional CCDs, a m track length results in an equivalent energy deposition of 5 - 6 keV, and significant confusion with X-ray events arises. ... A trade-off between rejection efficiency and spectroscopic efficiency is required. ...

Next: Disk Expansion and Up: The Epsilon Aurigae Previous: Vertical Structure of . ... We model disks with and without central holes and use a variety of midplane opacities and temperatures. ... The eclipse lightcurve was computed on a grid of 505 time steps separated by approximately 1.3 days, for a range of values of the disk scale height, , the inclination, i , and central hole radius, . The opacity parameter, approximately equal to the ``vertical'' optical depth of the disk, is: . ...

... Radio Astronomy . ... ASRAS Board Members . ... To see the most up to date news and events happening with ASRAS log in with your user name and password and then click on the Activities page. ... Messier Marathon (Member Observing) CANCELLED Saturday, April 9, 2016 9:00 PM Location:Farash Center Ionia NY . ... ASRAS Members meeting - Friday May 6 at Farash Center - Ionia NY . ... ASRAS Board members meeting - monday May 9 @ Farash Center Monday, May 9, 2016 7:00 PM Location:Farash Center Ionia NY . ...

Blackholes2 Forum Message . Forums: . ... Firtual Particles Are Not Only Particle Pairs . ... Posted by Richard Ruquist on October 19, 2004 12:03:20 UTC . ... Vacuum production of virtual particle pairs cannot violate the uncertainty principle. ... This theory is dual to the particle theory of gravitons. ... www.astronomy.net . About Astronomy Net | ... Forum posts are Copyright their authors as specified in the heading above the post. "dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" . ...

August, 2012, Odessa, Ukraine EVENTS: Monday, 20.08.2012 Arrival 09.00 ­ 22.00 Registration of participants 20.00 ­ 22.00 Evening session : Astronomical Society news (conference hall of ONU recreation center « Chernomorka ») Tuesday, 21.08.2012 06.03 09.00 09.30 10.45 12.45 13.00 14.30 16.00 16.30 18.00 19.00 19.57 21.00 06.04 09.30 11.00 11.30 13.00 14.30 16.00 16.30 18.30 20.00 19.56 ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ 13.00 10.45 12.45 ... 10 Section 3. ... 14.30 ­ 15.30 Section sessions ­ .. ...

... Readily produced in nuclear reactions and particle collisions, they can easily pass completely through planet Earth without once interacting with any other particle. ... Recent photographs by the spacecraft Mars Global Surveyor, currently in orbit around Mars, show features unusual for Mars yet similar to a dried pond on Earth. ... The quake was the first ever recorded on the Sun, but only because astronomers have only recently figured out when and how to find them using the orbiting SOHO spacecraft...

... Tonight's Sky . ... Search By Name Enter coordinates Use current location . ... News . ... New dark matter detector begins search for invisible particles . ... Dark matter particles, which scientists think rarely interact with other matter, should form individual bubbles in the COUPP-60 tank. ... Dark matter particles can move through the mile and a half of rock under which the laboratory is buried, whereas most other particles cannot. ... But no one has conclusively observed dark matter particles. ...