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Topic: Cosmic dust


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In the News (Tue 23 Apr 19)

  
  cosmic dust
Interstellar dust particles strongly absorb, scatter, and polarize visible light at wavelengths comparable to their size, reemitting the light in the far-infrared region of the spectrum.
Elliptical galaxies have less dust than our galaxy (but are not dust-free), while some galaxies are experiencing such tremendous episodes of star formation that the dust in them converts nearly all the visible light into infrared, resulting in an ultra-luminous infrared galaxy.
"Cosmic dust in manganese nodules" (Jacques Jedwab, Free University of Brussels)
www.daviddarling.info /encyclopedia/C/cosmicdust.html   (642 words)

  
 Cosmic dust - Wikipedia, the free encyclopedia
Cosmic dust used to be an annoyance to astronomers because of the way that the dust obscures the object that they wish to observe.
Cosmic dust is dust grains and agreggates of dust grains.
A dust particle interacts with electromagnetic radiation in a way that depends on its cross section, the wavelength of the electromagnetic radiation, and on the nature of the grain: its refractive index, size, etc. The radiation process for an individual grain is called its emissivity, dependent on the grain's efficiency factor.
en.wikipedia.org /wiki/Cosmic_dust   (1628 words)

  
 Cosmic dust bunnies | csmonitor.com
Cosmic dust is constantly raining down on the Earth from space, and in an average year, we pick up about 40,000 tons of the stuff.
Cosmic dust forms far out in space, possibly from the residue of a supernova explosion, or in the upper atmosphere of a giant, cool star.
Cosmic dust may even be leftover bits of the dust cloud that formed the Earth itself, and as such, may give us clues about how the whole process worked.
www.csmonitor.com /2003/0418/p25s02-stss.html   (1611 words)

  
 Cosmic Dust and its Evolution
Dust scientists now know that some origins of the in-situ dust is interstellar, as well as interplanetary, deduced by arguments that the particles have hyperbolic orbit trajectories that are compatible with the flow of interstellar gas.
Before the dust grains settle into a midplane region, (and before the T-Tauri phase of the protostar) the homogenized distribution of the grains are a primary cause of opacity, leading to steep temperature gradients and convection and turbulence.
Greenberg, J. Mayo and J.I. Hage, (1990) "From Interstellar Dust to Comets: A Unification of Observational Constraints," ApJ 361, 260-274.
www.tass-survey.org /richmond/answers/dust.html   (4900 words)

  
 JPL.NASA.GOV: Feature Stories
Dust devil vortices form when the air is fairly calm and the ground is heated by sunlight--this heats the air immediately above ground.
All that extra dust on the ground means that the dust devils leave tracks behind them where they have either picked up dust or disturbed the dust lying about on the surface.
Dust devils give me a chill when I see them out in nature on Earth--they often seem to have a mind of their own.
www.jpl.nasa.gov /news/features.cfm?feature=519   (1724 words)

  
 Stratospheric Dust
The ultra-clean Cosmic Dust Laboratory, established in 1981 to handle particles one-tenth the diameter of a human hair, curates over 2000 cosmic dust particles and distributes samples to over 30 investigators.
Cosmic dust grains include our only samples from comets, probably containing material in the same condition as when the solar system began to form.
The terrestrial dust and spacecraft debris particles are of considerable interest to atmospheric scientists and climatologists, since they influence some global atmospheric reactions.
www-curator.jsc.nasa.gov /curator/dust/dust.htm   (202 words)

  
 Guardian | Cosmic dust culprit unmasked
British astronomers have solved one of the darker riddles of the universe - the culprit behind the gargantuan clouds of cosmic dust.
The conclusion is that cosmic dust is made and then spread by supernovae.
The dust and debris from the explosion is still travelling outwards at 10,000km a second.
www.guardian.co.uk /print/0,3858,4714155-103616,00.html   (268 words)

  
 Joint Astronomy Centre   (Site not responding. Last check: 2007-10-14)
The amount of dust was a thousand times what had been previously detected, suggesting that these powerful explosions are one of the most efficient ways to create cosmic dust.
Since these are the ingredients of cosmic dust grains, it was suspected that supernovae might be important in explaining the origin of dust.
Dust grains block half of all the visible light from stars and galaxies, but this dusty cloud has a silver lining as they also shine this stolen starlight back out as far-infrared and submillimetre waves (at wavelengths between 0.1 and 1 millimetre).
outreach.jach.hawaii.edu /pressroom/2003_casa   (1391 words)

  
 BBC NEWS | Wales | Origin of cosmic dust discovered
Astronomers had thought space dust was mostly made in the winds from cool, giant stars in the late stages of their lives.
Researchers used the Scuba instrument on the James Clerk Maxwell Telescope to hunt for dust in the remains of a star called Cassiopeia A, which is 11,000 light-years distant and exploded 320 years ago as viewed from Earth.
Cosmic dust consists of tiny particles of solid material floating around in the space between the stars, but unlike house dust, it more closely resembles cigarette smoke and blocks out half of the light given off by stars and galaxies.
news.bbc.co.uk /1/hi/wales/3072121.stm   (403 words)

  
 Cassini-Huygens: Spacecraft-Instruments-Cosmic Dust Analyzer (CDA)
Giovanni Cassini was the first to recognize dust in interplanetary space through his telescopic observations in the 17th century and his recognition of the presence of dust around the sun.
Finding out the origins of this cosmic dust, what it is made of and how it may affect life on Earth has been an ongoing program of research and exploration ever since.
The Cosmic Dust Analyzer onboard the Cassini orbiter is ultimately designed to help discover more about these mysterious particles, and significantly add to the knowledge of the materials in other celestial bodies and potentially more about the origins of the universe.
saturn.jpl.nasa.gov /spacecraft/instruments-cassini-cda.cfm   (467 words)

  
 Cosmic Dust and Planetary Systems
Dust and meteoroids are important subjects to study the evolution of small bodies in planetary systems.
Dust properties and evolution as well as interactions with the cosmic plasma environment are studied through many different ways: astronomical and meteor observations, in-situ measurements from spacecraft of dust and plasma phenomena connected to the interaction with dust particles, and laboratory analysis.
We invite the submission of abstracts on observational, experimental and theoretical aspects of cosmic dust studies and dust-plasma interactions in cosmic and atmospheric environments, as well as on extra-solar planet detection and on studies of extra-solar planetary systems.
www.asiaoceania-conference.org /Ps/ps1.htm   (166 words)

  
 2002 News Releases - Stardust Spacecraft Reaches for Cosmic Dust
This dust, passing through the solar system like a wind, is made of particles smaller than one-hundredth the width of a human hair.
Comparing the ancient and newer types of dust may provide clues to the evolutionary changes in the galaxy and the composition of the early galaxy.
The interstellar dust stream differs from the solar wind in that the solar wind is made of individual atoms, while the interstellar dust is made of small particles of rocks with complex compositions.
www.jpl.nasa.gov /releases/2002/release_2002_158.html   (570 words)

  
 SPACE.com -- Comet Collisions Help Generate Puzzling Cosmic Rays, Study Shows
Anomalous cosmic rays are so named because they form in the relative vicinity of the Earth, near the sun, and have lower energy than galactic and intergalactic cosmic rays, which form in the far reaches of the galaxy and beyond.
Cosmic rays move throughout the universe at light speed and constantly bombard the Earth.
Recent observations of anomalous cosmic rays are puzzling because of the unexpected presence of iron, silicon and carbon.
www.space.com /scienceastronomy/comet_collisions_021105.html   (652 words)

  
 APOD: 2003 July 6 - Fractal Interstellar Dust Up Close   (Site not responding. Last check: 2007-10-14)
Dust usually shows its presence by blocking out light emitted from stars or nebulae behind it, sometimes creating the illusion of a horse's head or a sombrero hat.
Interstellar dust grains are composed mostly of carbon, silicon, and oxygen and are usually less than about 1/1000 of a millimeter across.
Recent work indicates that most dust grains are not spherical.
antwrp.gsfc.nasa.gov /apod/ap030706.html   (158 words)

  
 Scientists solve mystery of cosmic dust | Mid Wales Online
Originally astronomers thought that dust was mostly made in the winds from cool, giant stars in the late stages of their lives.
Cosmic dust consists of tiny particles of solid material floating around in the space between the stars.
As these are also the elements making up dust grains, supernovae have long been a prime suspect in the mystery of the origin of cosmic dust.
www.midwalesonline.co.uk /news.cfm?id=6486   (754 words)

  
 SPACE.com -- Exploding Stars Create Clouds of Cosmic Dust
SCUBA detected a shell of cosmic dust about 12 light-years across in Cassiopeia A. The fl and dark blue colors represent fainter emission; light blue and white show brighter areas of dust.
Heavier stuff -- dust, metals and all the other ingredients needed to make planets, plants and people -- was forged in stars and, especially, in the catastrophic explosions of the most massive stars.
"Dust has been swept under the cosmic carpet -- for years astronomers have treated it as a nuisance because of the way it hides the light from the stars," said Cardiff's Loretta Dunne, who led the new research.
www.space.com /scienceastronomy/supernova_dust_030731.html   (706 words)

  
 Obscuration by Diffuse Cosmic Dust   (Site not responding. Last check: 2007-10-14)
Previous studies investigating the effects of foreground dust on background sources assumed dust to be ``compactly'' distributed, ie.
Galaxy clusters are a likely location for ``large-scale'' diffusely distributed dust, and its effect on the counts of background sources is explored.
We also explore the implications of a hypothesised diffuse intergalactic dust component uniformly distributed to high redshift with comoving mass density equal to that associated with local galaxies.
www.atnf.csiro.au /pasa/15_3/masci/paper   (177 words)

  
 Interplanetary Dust Particle.
After arguing for decades that the accretion rate of interplanetary dust particles (IDPs) to the moon and earth contradicts the accepted, multibillion-year age of the solar system, young-earthers have now for the most part abandoned the argument (Snelling and Rush, 1993).
This dust is thought to be derived from collisions of asteroidal material and from comets (e.g.
The effects of sampling artifacts on cosmic dust flux estimates: a reevaluation of nonvolatile tracers (Os, Ir), Geochimica et Cosmochimica Acta 64, pp.
www.geocities.com /earthhistory/idp.htm   (1222 words)

  
 Austin, Daniel E. (2002-11-05) Impact-ionization mass spectrometry of cosmic dust. ...
In situ characterization of cosmic dust grains typically involves impact-ionization time-of-flight mass spectrometry.
Dust particles hit the 65-cm2 target plate and are partially ionized by the impact.
The implications of this ionization effect are discussed in relation to interpretation of mass spectra from other in situ dust analyzers.
etd.caltech.edu /etd/available/etd-11072002-135150   (385 words)

  
 News in Science - Cosmic dust may change climate - 25/08/2005
Cosmic dust from meteors could have a bigger impact on our climate than once thought, scientists say.
Klekociuk says the house-sized meteor that had been orbiting between Venus and the Earth disintegrated into cosmic dust as it entered the atmosphere in September 2004, south of South Africa and about 7000 kilometres from the Davis base.
Dust has the potential to warm or cool the Earth depending on the size and composition of the particles.
www.abc.net.au /science/news/stories/s1442917.htm   (527 words)

  
 [39.02] On Computational Methods for Calculating Light Scattering by Cosmic Dust   (Site not responding. Last check: 2007-10-14)
Cosmic dust is almost everywhere in the solar system: on the surfaces of atmosphereless bodies, in the interplanetary space, and in the cometary comae.
Dust plays an important role in star-forming regions, and is present in protostars, young stellar objects, up to main-sequence stars.
However, there are significant variations in the structure of dust, arising, e.g., from different material parameters such as the complex refractive index or the geometry by which some dust aggregate has been built of constituent particles.
www.aas.org /publications/baas/v33n3/dps2001/314.htm   (355 words)

  
 ASP: Collecting Cosmic Dust   (Site not responding. Last check: 2007-10-14)
This scanning electron microscope image shows an interplanetary dust particle known as a "cosmic sphere." It measures 300 microns across, about three times the width of a human hair.
Scientists go to Antarctica, the stratosphere, and the seafloor to collect material more precious than gold, dust that tells how the stuff of life was brought to Earth.
These micrometeorites, also known as "interplanetary dust particles," are shed by asteroids banging into one another, and by comets evaporating as they wander too close to the Sun.
www.astrosociety.org /pubs/mercury/30_06/cosmicdust.html   (413 words)

  
 Specific Arguments - Moon Dust
Pettersson's upper estimate for the influx of cosmic dust, a figure he considered risky, was based on particles he collected from two filtration units in the Hawaiian Islands.
The low value for the accretion rate for the small particles is not adequate to produce large scale dust erosion or to form deep layers of dust on the moon, for the flux has probably remained fairly constant during the past several billion years." (p.
Results from the early microphone-type dust detectors (recording clicks as bits of space dust struck at high speeds) were compared with penetration detectors (which recorded holes punched in thin foil).
www.infidels.org /library/modern/dave_matson/young-earth/specific_arguments/moon_dust.html   (2834 words)

  
 USATODAY.com - Source of cosmic dust found   (Site not responding. Last check: 2007-10-14)
Now, Andrew Klekociuk of the Australian Antarctic Division and his colleagues have studied the dust cloud from a recent large meteoroid and determined that the dust particles are actually 10 to 20 micrometers – a thousand times larger than previously thought.
Previously, it was thought that large dust particles from meteoroids were only formed as the particles in the cloud coagulate over a period of weeks, eventually settling on the Earth.
Depending on their size and overall number, cosmic dust and other particles in the atmosphere have the potential to change Earth's climate.
www.usatoday.com /tech/science/space/2005-08-29-cosmic-dust_x.htm   (679 words)

  
 Cosmic dust
On its journey around the sun, the earth constantly gathers extra-terrestrial material in the form of atoms, dust and larger bodies sometimes weighing in excess of 10,000,000 tonnes.
Some 10 atoms of galactic cosmic radiation hit the earth per cm2 and second, the major part of which is attributable to the solar wind.
Meteors (from particles ranging in size from one millimetre to a centimetre) occur on average every 30 seconds and meteorites fall only a few times per year.
www.nhm-wien.ac.at /NHM/Mineral/Kosmicduste.htm   (218 words)

  
 Whitley Strieber's Unknown Country
We're at the beginning of a ten-year-long cosmic dust storm and we don't know what the consequences will be.
Cosmic dust bombardment in the past may have caused ice ages and mass extinctions.
One way to find out how the dust will affect us will be to analyze deep polar ice cores for the presence of cosmic dust and compare dust storms of the past with periods of mass extinction.
www.unknowncountry.com /news?id=2990   (224 words)

  
 Science News: Dusting the galaxy - cosmic dust
Cosmic dust is one of the two major inhabitants of interstellar space in our and other galaxies (gas clouds are the other).
In visible light the dust manifests its presence in a negative, subtractional way by absorbing light and so dimming and reddening the appearance of stars.
From all this Mauche and Gorenstein could calculate that approximately all of the silicon, magnesium and iron and 60 percent of the carbon in the interstellar medium is locked up in dust grains.
www.findarticles.com /p/articles/mi_m1200/is_v128/ai_3869769   (451 words)

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