... We start investigating the results from a non-magnetized (isotropic) plasma, before including the external magnetic field so important for space physics. ... propagating above the electron plasma frequency, w(pe) (reflection point for the waves) . note that, for very high frequencies, both phase and group velocities are equal to light velocity c, and we have electromagnetic wave in free space: even the electrons are unable to respond to the rapidly oscillating electric field! . ...

... Laboratory and theoretical modelling of the UV bump on the interstellar extinction curve is a very popular topic in dusty investigations. ... feature is illustrated by Fig. 10 where the profiles were calculated using the model of graphite spheres. Figure 10: Normalized extinction efficiencies for graphite spheres. ... The lower panel shows the summary extinction of two graphite spheres with radii and (from upper panel) taken in equal proportions. ...

. ___________________________________________________________________ The Electronic Universe Project e-mail: nuts@moo.uoregon.edu

... Aurora over Clouds . ... It is a direction in space that is rich with impressive nebulas. ... Recycling NGC 5291 . ... Following an ancient galaxy-galaxy collision 200 million light-years from Earth, debris from a gas-rich galaxy, NGC 5291, was flung far into intergalactic space. ... Leonids and Friends . ... Leonid meteors rained down on planet Earth this week, the annual shower of dusty debris from the orbit of Comet 55P/Tempel-Tuttle. ... What's the closest active galaxy to planet Earth? ...

... 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 . ...

Russian SHAREABLE DATA CENTER Institute of Solar-Terrestial Physics SB RAS . ... Although their determination is based on the scattering process model, independent check-ups by rocket experiments have shown their correctness in experimental applications. ... Ionospheric data analysis, especially during strong disturbances, cannot be without some other kinds of diagnostic tools. ... The lack of data has always been a challange in this case. ...

... Magnetic fields, subatomic particles, etc., traveling in different directions fill the universe. Do they deflect or otherwise affect one another? If so, isnт??t the information we get from them distorted? ... Neutrino astronomy, which is still in its infancy, is attractive because neutrinos interact so weakly with matter that few of these distorting effects occur. Get instant access to subscriber content on Astronomy.com! ...

Comets are small, fragile, irregularly shaped bodies composed of a mixture of non-volatile grains and frozen gases. ... Most become visible, even in telescopes, only when they get near enough to the Sun for the Sun's radiation to start subliming the volatile gases, which in turn blow away small bits of the solid material. ... Nearly 100 known comets have periods (the time it takes them to make one complete trip around the Sun) five to seven Earth years in length. ...

... COMPUTER SIMULATION OF RADIOWAVE MULTIPLE SCATTERING EFFECTS IN IONOSPHERE USING MONTE-CARLO METHOD . ... Distribution of reflected radiation on the ground is computed. ... Such influence can be remarkable if the scattering is multiple, i.e. the optical thickness for the scattering process is considerably greater than a unit. ... Radiation energy transfer in the slab is modeled by distribution of some particles carring small portions of radiation energy. ... The isotropic plasma approximation is...

... Special Reports Giant space cloud may be powered by black holes 17:57 23 April 2007 NewScientist.com news service David Shiga An enormous cloud of roiling plasma in space may be drawing its energy from black holes, new observations suggest. Such clouds might be sources for the mysterious particles that occasionally crash into Earth's atmosphere at ultra - high speed. ... But higher energy particles in the cloud may be able to escape, he says. ...

... Posts tagged ?particle filter? ... Astronomers have developed their ways of processing signals almost independent to but sometimes collaboratively with engineers, although the fundamental of signal processing is same: extracting information. ... This particular issue of IEEE signal processing magazine may shed lights for astronomers interested in signal processing and statistics outside the astronomical society. IEEE Signal Processing Magazine Jul. ... ArXiv] 3rd week, Dec. ... Entries RSS . ...

... Space Flight . ... It took an accidental dose of cosmic rays to make them fantastic.( ... Air showers ensuing from very-high-energy cosmic rays which can enter EarthтАЩs atmosphere from multiple directions.( ... The latest cosmic ray research:composite sky catalogue using 2 years of Fermi Gamma-ray Space Telescope data.Depicting 1873 objects in total, the brightest patches represent sources with the highest gamma-ray count (at energies greater than 1 billion GeV or electron volts).( ... Astronotes ....

... Epistemology is a part of the study of Philosophy dealing with how we use our senses to know something about the world. ... Yet we know that we can be deceived by our senses. ... If we cannot always trust our senses, how can we ever know anything for certain about the world? ... A branch of epistemology that has come into vogue in the last 10-15 years is the problem of consciousness. ... What relationship is there between our conscious experience and the true nature of the physical world? ...

The space between the planets is far from empty. It contains: electromagnetic radiation (photons); hot plasma (electrons, protons and other ions) a.k.a. the solar wind ; cosmic rays; microscopic dust particles; and magnetic fields (primarily the Sun's). While the Sun 's radiation is obvious, the other components of the interplanetary medium were not discovered until very recently. ... Except near some of the planets, interplanetary space is filled with the Sun's magnetic field. ... Sun .. ...

... Primordial theory review : Dick Bond . Defects and the CMB review : Andy Albrecht . ... Gravitational wave contribution to CMB anisotropies : V.B. Lukash and E.V. Mikheeva . C_l from cosmic strings : Lloyd Knox . Some aspects of CMB anisotropies induced from topological defects : Mairi Sakellariadou . ... CMB anisotropies from scaling sources : Ruth Durrer . ... SZ observations I : Sarah Church . ... Holes in the microwave sky? ... Detecting cosmic strings in the CMB : James Robinson . ...

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... In a solar prominence, charged particles stream up from the Sun, spiraling around magnetic field structures poking out of the solar surface, and ultimately fall back along those structures into the Sun. ... As evolution would predict, animals' eyes sense the colors of light emitted most strongly by the Sun. ... The tiny Moon can completely cover the disk of the Sun, blocking most of the emitted visible light, and reveal the Sun's faint outer atmosphere called the corona...a mass of incandescent gas ...

... Bad Astronomy . Misconceptions . ... Bad Astronomy : The sky is blue because it reflects light from the oceans. Good astronomy : The sky is blue because it is scattering blue light from the sun. ... So everywhere you look you see blue photons, except directly from the Sun, where you'll see all colors. ... The sky does not look blue near the horizon because more yellow photons (and even orange ones right at sunset) are coming from that direction as they get scattered away from the Sun. ...

... 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) . ...

... These trajectories have an initial flight from the Earth to a large distance (of about 1.5 million km), the following passive flight to the Moon's orbit, an approach to the Moon with a decrease of an energy of a particle (spacecraft) selenocentric motion to a negative value and the temporary capture in an elliptic orbit of the Moon's satellite. ... Several trajectories of this type are determined. ... Ivashkin V. V. On optimal trajectories of space flight to the Moon in the Earth--Moon--Sun system. ...