Cosmic dust 2178570 221172310 2008-06-23T10:26:14Z Kurtan 1037786 blue link {{Redirect|Space dust}} [[Image:Porous chondriteIDP.jpg|thumb|250px|right|Porous chondrite interplanetary dust particle. Courtesy of E.K. Jessberger, Institut für Planetologie, Münster, Germany, and Don Brownlee, University of Washington, Seattle, under a cc-a-2.5 license.]] '''Cosmic dust''' is a type of [[dust]] composed of particles in space which are a few [[molecules]] to 0.1 mm in size. Cosmic dust can be further distinguished by its astronomical location; for example: [[intergalactic dust]], interstellar dust, circumplanetary dust, dust clouds around other stars, and the major interplanetary dust components to our own [[Interplanetary dust cloud|zodiacal dust complex]] (seen in visible light as the [[zodiacal light]]): [[Comet dust]], asteroidal dust plus some of the less significant contributors: [[Kuiper belt]] dust, interstellar dust passing through our solar system, and [[beta meteoroid]]s. Cosmic dust was once solely an annoyance to astronomers, as it obscures objects they wish to observe. When [[infrared astronomy]] began, those so-called annoying dust particles were observed to be significant and vital components of astrophysical processes. For example, Cosmic Dust can drive the mass loss when a [[star]] is [[Stellar evolution#The later years and death of stars|nearing the end of its life]], play a part in the early stages of [[star formation]], and form [[planet]]s. In our own [[solar system]], dust plays a major role in the [[zodiacal light]], [[Saturn (planet)|Saturn]]'s [[B Ring]] [[spokes]], the outer diffuse [[planetary ring]]s at [[Jupiter]], Saturn, [[Uranus]] and [[Neptune]], the resonant dust ring at the Earth, and [[comet]]s. The study of dust is a many-faceted research topic that brings together different scientific fields: [[physics]] ([[solid state physics|solid-state]], [[electromagnetism|electromagnetic theory]], surface physics, [[statistical physics]], [[thermal physics]]), ([[fractal]] mathematics), chemistry ([[chemical reaction]]s on grain surfaces), [[meteoritics]], as well as every branch of [[astronomy]] and [[astrophysics]].<ref name=Grün> {{cite book |author=Eberhard Grün |title=Interplanetary dust |year= 2001 |publisher=Springer |location=Berlin |isbn=3540420673 |url=http://books.google.com/books?id=iWRKx_QulUcC&pg=PA333&dq=astronomy++pressure+interplanetary&lr=&as_brr=0&sig=5Zv1stkwvM6tNujqpxK-CchTlWI#PPA1,M1}} </ref> These disparate research areas can be linked by the following theme: the cosmic dust particles evolve cyclically; chemically, physically and dynamically. The evolution of dust traces out paths in which the universe recycles material, in processes analogous to the daily recycling steps with which many people are familiar: production, storage, processing, collection, consumption, and discarding. Observations and measurements of cosmic dust in different regions provide an important insight into the universe's recycling processes; in the clouds of the diffuse [[interstellar medium]], in [[molecular cloud]]s, in the [[circumstellar dust]] of [[young stellar object]]s, and in [[planetary systems]] such as our own [[solar system]], where astronomers consider dust as in its most recycled state. The astronomers accumulate observational ‘snapshots’ of dust at different stages of its life and, over time, form a more complete movie of the universe's complicated recycling steps. The detection of cosmic dust points to another facet of cosmic dust research: dust acting as [[photon]]s. Once cosmic dust is detected, the scientific problem to be solved is an [[inverse problem]] to determine what processes brought that encoded photon-like object (dust) to the detector. Parameters such the particle's initial motion, material properties, intervening [[Plasma (physics)|plasma]] and [[magnetic field]] determined the dust particle's arrival at the dust detector. Slightly changing any of these parameters can give significantly different dust dynamical behavior. Therefore one can learn about where that object came from, and what is (in) the intervening medium. ==Detection methods== Cosmic dust can be detected by indirect methods utilizing the [[Electromagnetic radiation|radiative]] properties of cosmic dust. Cosmic dust can also be detected directly ('in-situ') using a variety of collection methods and from a variety of collection locations. At the Earth, generally, an average of 40 tons per day of extraterrestrial material falls to the Earth<ref>{{cite conference | author=Leinert C.; Gruen E.| title=Interplanetary Dust | booktitle=Physics and Chemistry in Space (R. Schwenn and E. Marsch eds.) | year=1990 |publisher=Springer-Verlag | pages=204--275}}</ref>. The Earth-falling dust particles are collected in the Earth's atmosphere using plate collectors under the wings of stratospheric-flying [[NASA]] [[fixed-wing aircraft|airplanes]] and collected from surface deposits on the large Earth ice-masses (Antarctica and Greenland / the Arctic) and in deep-sea sediments. Don Brownlee at the University of Washington in Seattle first reliably identified the extraterrestrial nature of collected dust particles in the later 1970s. Another source is the meteorites, which contain [[#Stardust|stardust]] extracted from them (see below). Stardust grains are solid refractory pieces of individual presolar stars. They are recognized by their extreme isotopic compositions, which can only be isotopic compositions within evolved stars, prior to any mixing with the interstellar medium. These grains condensed from the stellar matter as it cooled while leaving the star. In interplanetary space, dust detectors on planetary spacecraft have been built and flown , some are presently flying, and more are presently being built to fly. The large orbital velocities of dust particles in interplanetary space (typically 10-40 km/s) make intact particle capture problematic. Instead, in-situ dust detectors are generally devised to measure parameters associated with the high-velocity impact of dust particles on the instrument, and then derive physical properties of the particles (usually mass and velocity) through laboratory calibration (i.e. impacting accelerated particles with known properties onto a laboratory replica of the dust detector). Over the years dust detectors have measured, among others, the impact light flash, acoustic signal and impact ionisation. Recently the dust instrument on [[Stardust Mission|Stardust]] captured particles intact in low-density aerogel. Dust detectors in the past flew on the [[HEOS-2]], [[Helios]], [[Pioneer 10]], [[Pioneer 11]], [[Giotto mission|Giotto]], and [[Galileo spacecraft|Galileo]] space missions, on the Earth-orbiting [[LDEF]], [[EURECA]], and Gorid satellites, and some scientists have utilized the [[Voyager program|Voyager 1,2]] spacecraft as giant [[Langmuir probe]]s to directly sample the cosmic dust. Presently dust detectors are flying on the [[Ulysses probe|Ulysses]], [[Cassini-Huygens Mission|Cassini]], [[Proba]], [[Rosetta space probe|Rosetta]], [[Stardust Mission|Stardust]], and the [[New Horizons]] spacecraft. The collected dust at Earth or collected further in space and returned by sample-return space missions is then analyzed by dust scientists in their respective laboratories all over the world. One large storage facility for cosmic dust exists at the NASA Houston JSC. Infrared light can penetrate the cosmic dust clouds, allowing us to peer into regions of star formation and the centers of galaxies. [[NASA]]'s [http://www.spitzer.caltech.edu/about/index.shtml Spitzer Space Telescope] is the largest infrared telescope ever launched into space. The Spitzer Space Telescope (formerly SIRTF, the Space Infrared Telescope Facility) was launched into space by a Delta rocket from Cape Canaveral, Florida on 25 August 2003. During its mission, Spitzer will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space between wavelengths of 3 and 180 micrometres. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground. The findings from the Spitzer already revitalized the studies of cosmic dust. A [http://adsabs.harvard.edu/abs/2007ApJ...668L.107M recent report] from a Spitzer team shows some evidence that cosmic dust is formed near a supermassive black hole. ==Radiative properties of cosmic dust== A dust particle interacts with [[electromagnetic radiation]] in a way that depends on its [[cross section (geometry)|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''. Furthermore, we have to specify whether the emissivity process is [[Extinction (astronomy)|extinction]], [[scattering]], or [[absorption]]. In the radiation emission curves, several important signatures identify the composition of the emitting or absorbing dust particles. Dust particles can scatter light nonuniformly. Forward-scattered light means that light is redirected slightly by [[diffraction]] off its path from the star/sunlight, and back-scattered light is reflected light. The scattering and extinction ("dimming") of the radiation gives useful information about the dust grain sizes. For example, if the object(s) in one's data is many times brighter in forward-scattered visible light than in back-scattered visible light, then we know that a significant fraction of the particles are about a micrometer in diameter. The scattering of light from dust grains in long exposure visible photographs is quite noticeable in [[reflection nebula]]s, and gives clues about the individual particle's light-scattering properties. In x-ray wavelengths, many scientists are investigating the scattering of x-rays by interstellar dust, and some have suggested that astronomical x-ray sources would possess diffuse haloes, due to the dust. ==Stardust== Stardust grains (see also [[presolar grains]]) are contained within meteorites, from which they are extracted in terrestrial laboratories. So-called [[carbonaceous chondrites]] are especially fertile reservoirs of stardust. Each stardust grain existed before the earth was formed. The meteorites have preserved the previously interstellar stardust grains since that time. ''Stardust'' is a scientific term rather than a poetic one, referring to refractory dust grains that condensed from cooling ejected gases from individual presolar stars. Many different types of stardust have been identified by laboratory measurements of the highly unusual isotopic composition of the chemical elements that comprise each stardust grain. Many new aspects of [[nucleosynthesis]] have been discovered from those isotopic ratios <ref>{{cite journal | author=D. D. Clayton and L. R. Nittler | title = Astrophysics with Presolar Stardust | journal=ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS | volume=42 | year=2004 | pages=39–78 | doi = 10.1146/annurev.astro.42.053102.134022 }}</ref>. The following website http://www.dtm.ciw.edu/lrn/psg_main.html contains an excellent introduction to, and photographs of, many differing types of stardust. An important property of stardust is the hard, refractory, high-temperature nature of the grains. Prominent are [[silicon carbide]], [[graphite]], [[aluminum oxide]], [[aluminum spinel]], and other such grains that would condense at high temperature from a cooling gas, such as in stellar winds or in the decompression of the inside of a [[supernova]]. They differ greatly from the solids formed at low temperature within the interstellar medium. Also important are their extreme isotopic compositions, which are expected to exist nowhere in the interstellar medium. This also suggests that the stardust condensed from the gases of individual stars before the [[isotope]]s could be diluted by mixing with the interstellar medium. These allow the source stars to be identified. For example, the heavy elements within the SiC grains are almost pure [[s process]] isotopes, fitting their condensation within [[Asymptotic Giant Branch | AGB]] star red giant winds inasmuch as the AGB stars are the main source of s process [[nucleosynthesis]] and have atmospheres observed by astronomers to be highly enriched in dredged-up s process elements. Another dramatic example comes from the supernova condensates, usually shortened by acronym to SUNOCON to distinguish them from other stardust condensed within stellar atmospheres. SUNOCONs show evidence that they condensed containing abundant radioactive 44Ti, which has a 65 yr halflife. It was thus still alive when the SUNOCON condensed within the expanding supernova interior but would have been extinct after mixing with the interstellar gas. Its discovery proved the prediction from 1975 to identify SUNOCONs in this way. But SiC SUNOCONs are only about 1% as numerous as are SiC stardust. Exciting as stardust is, it is but a modest fraction of the condensed cosmic dust. It seems that stardust is less than 0.1% of the mass of total interstellar solids. Its interest lies in the new information that it has brought to the sciences of [[stellar evolution]] and [[nucleosynthesis]]. A fascinating aspect to human culture is the study within terrestrial laboratories of solids that existed before the earth existed. This was once thought impossible, especially in the decades when cosmochemists were confident that the solar system began as a hot gas virtually devoid of any remaining solids, which would have been vaporized by high temperature. The very existence of stardust shows that that historic picture was incorrect. ==Some bulk properties of cosmic dust== [[Image:Smooth chondriteIDP.jpg|thumb|250px|left|Smooth chondrite interplanetary dust particle. Courtesy of E.K. Jessberger, Institut für Planetologie, Münster, Germany, and on Brownlee, University of Washington, Seattle, under a cc-a-2.5 license.]] Cosmic dust is made of dust grains and aggregates of dust grains. These particles are irregularly-shaped with [[porosity]] ranging from ''fluffy'' to ''compact''. The composition, size, and other properties depends on where the dust is found, and conversely, a compositional analysis of a dust particle can reveal the much about the dust particle's origin. General diffuse [[interstellar medium]] dust, dust grains in [[interstellar clouds|dense clouds]], [[planetary rings]] dust, and [[circumstellar dust]], are each different in their characteristics. For example, grains in dense clouds have acquired a mantle of ice and on average are larger than dust particles in the diffuse interstellar medium. ''Interplanetary dust particles'' (IDPs) are generally larger still. [[Image:IDPmajorelements.jpg|thumb|350px|right|Major elements of 200 stratospheric interplanetary dust particles. Courtesy of Thomas Stephan, Institut für Planetologie, Münster, Germany, under a cc-a-2.5 license.]] Most of the influx of extraterrestrial matter that falls onto the Earth is dominated by meteoroids with diameters in the range 50 to 500 micrometers, of average density 2.0 g/cm³ (with porosity about 40%). The densities of most IDPs [[Interplanetary_dust_cloud#Collecting_interplanetary_dust_on_earth|captured]] in the earth's [[stratosphere]] range between 1 and 3 g/cm³, with an average [[density]] at about 2.0 g/cm³.<ref>{{cite journal | author=Love S. G., Joswiak D. J., and Brownlee D. E. | title=Densities of stratospheric micrometeorites | journal=Icarus | year=1992 | volume=111 | pages=227–236 | doi=10.1006/icar.1994.1142}}</ref> Other specific dust properties: *In ''circumstellar dust'', astronomers have found molecular signatures of CO, silicon carbide, amorphous silicate, polycyclic aromatic hydrocarbons, water ice, and polyformaldehyde, among others. (In the diffuse interstellar medium, there is evidence for silicate and carbon grains.) *''[[Comet dust|Cometary dust]]'' is generally different (with overlap) from ''[[asteroid dust|asteroidal dust]]''. Asteroidal dust resembles [[carbonaceous chondrite|carbonaceous chondritic meteorites]], and cometary dust resembles [[interstellar dust|interstellar grains]], which can include the elements: silicates, [[polycyclic aromatic hydrocarbon]]s, and water ice. ==Dust grain formation== The large grains start with the silicate particles forming in the atmospheres of cool stars, and carbon grains in the atmospheres of cool [[carbon star]]s. Stars, which have evolved off the [[main sequence]], and which have entered the [[giant star|giant]] phase of their evolution, are a major source of dust grains in galaxies. ''Star dust'', sung and written in the popular media, is a colloquial term referring to the birthplace of most dust grains in the Universe. If one indeed traces the origin of the elements out of which our bodies are made, we ''are'' star dust. Astronomers know that the dust is formed in the envelopes of late-evolved stars from specific observational signatures. An (infrared) 9.7 micrometre emission silicate signature is observed for cool evolved (oxygen-rich giant) stars. And an (infrared) 11.5 micrometre emission silicon carbide signature is observed for cool evolved (carbon-rich giant) stars. These help provide evidence that the small silicate particles in space came from the outer envelopes (ejecta) of these stars.<ref>{{cite journal | author=Humphreys, Roberta M.; Strecker, Donald W.; Ney, E. P. | title=Spectroscopic and Photometric Observations of M Supergiants in Carina | journal=Astrophysical Journal | year=1972 | volume=172 | pages=75 | doi=10.1086/151329}}</ref>{{Ref|Evans94|label|backEvans94 pg 164-167}} It is believed that conditions in interstellar space are generally not suitable for the formation of silicate cores. The arguments are that: given an observed typical grain diameter ''a'', the time for a grain to attain ''a'', and given the temperature of interstellar gas, it would take considerably longer than the age of the universe for interstellar grains to form {{Ref|Evans94|label|backEvans pg 147-148}}. Furthermore, grains are seen to form in the vicinity of nearby stars in real-time, meaning in a) [[nova]] and [[supernova]] ejecta, and b) R Coronae Borealis, which seem to eject discrete clouds containing both gas and dust. Most dust in our solar system is highly processed dust, recycled from the material out of which our solar system formed and subsequently collected in the planetesimals, and leftover solid material (for example: [[comet]]s and [[asteroid]]s), and reformed in each of those bodies' collisional lifetimes. During our solar system's formation history, the most abundant element was (and still is) H<sub>2</sub>. The metallic elements: magnesium, silicon, and iron, which are the principal ingredients of rocky planets, condensed into solids at the highest temperatures. The range of elements of the solar nebula between H<sub>2</sub> and (Mg, Si, Fe) is not known well (Wood, J., 1999). Some molecules such as CO, N<sub>2</sub>, NH<sub>3</sub>, and free oxygen, existed in a gas phase. Some molecules, for example, graphite (C) and SiC condensed into solid grains. Some molecules also formed complex organic compounds and some molecules formed frozen ice mantles, of which either could coat the "refractory" (Mg, Si, Fe) grain cores. The formation of these molecules was determined, in large part, by the temperature of the solar nebula. Since the temperature of the solar nebula decreased with heliocentric distance, scientists can infer a dust grain's origin(s) with knowledge of the grain's materials. Some materials could only have been formed at high temperatures, while other grain materials could only have been formed at much lower temperatures. The materials in a single interplanetary dust particle often show that the grain elements formed in different locations and at different times in the solar nebula. Most of the matter present in the original solar nebula has since disappeared; drawn into the Sun, expelled into interstellar space, or reprocessed, for example, as part of the planets, asteroids or comets. Due to their highly-processed nature, IDPs are fine-grained mixtures of thousands to millions of mineral grains and [[amorphous]] components. We can picture an IDP as a "matrix" of material with embedded elements which were formed at different times and places in the [[solar nebula]] and before our solar nebula's formation. Examples of embedded elements in cosmic dust are [[Glass with Embedded Metal and Sulfides|GEMS]], [[chondrule]]s, and [[Calcium-Aluminum-Inclusions|CAI]]s. ==A Dusty Trail from the Solar Nebula to Earth== [[Image:Grapsdustytrail.jpg|thumb|400px|right|A dusty trail from the early solar system to carbonaceous dust today. Courtesy of Amara Graps, Planetary Science Institute, Tucson, Arizona, released to the public domain.]] The arrows in the adjacent diagram show one possible path from a collected interplanetary dust particle back to the early stages of the solar nebula. We can follow the trail to the right in the diagram to the IDPs that contain the most volatile and primitive elements. The trail takes us first from interplanetary dust particles to chondritic interplanetary dust particles. Planetary scientists classify chondritic IDPs in terms of their diminishing degree of oxidation so that they fall into three major groups: the carbonaneous, the ordinary, and the enstatite chondrites. As the name implies, the carbonaceous chondrites are rich in carbon, and many have anomalies in the isotopic abundances of H, C, N, and O (Jessberger, 2000). From the carbonaceous chondrites, we follow the trail to the most primitive materials. They are almost completely oxidized and contain the most low condensation temperature elements ("volatile" elements) and the largest amount of organic compounds. Therefore, dust particles with these elements are thought to be formed in the early life of our solar system. Why? The volatile elements have never seen temperatures above about 500 K, therefore, one can conclude that the IDP grain "matrix" consists of some very primitive solar system material. Such a scenario is true in the case of comet dust<ref>{{cite conference | author=Gruen, Eberhard | title=Interplanetary Dust and the Zodiacal Cloud | booktitle=Encyclopedia of the Solar System | year=1999 | pages=XX}}</ref>. We can learn more about these particles' origin, by examining their surfaces. If we examine, in the laboratory, dust particles' density of solar flare tracks, their amorphous rims, and the spallogenic isotopes from cosmic rays (Flynn, 1996), then we have good clues for how long a particle has been travelling in space. Nuclear damage tracks are caused by the ion flux from solar flares. Solar wind ions impacting on the particle's surface produce amorphous radiation damaged rims on the particle's surface. And spallogenic nuclei are produced by galactic and solar cosmic rays. A dust particle that originates in the Kuiper Belt at 40AU would have many more times the density of tracks, thicker amorphous rims and higher integrated doses than a dust particle originating in the main-asteroid belt. ==Dust grain destruction== How are the interstellar grains destroyed? There are several [[ultraviolet]] processes which lead to grain "explosions"<ref>{{cite journal | author=d'hendecourt, L. B.; Allamandola, L. J.; Greenberg, J. M. | title=The volatile element enrichment of chondritic interplanetary dust particles | journal=Astronomy and Astrophysics | year=1985 | volume=152| pages=130–150}}</ref><ref>{{cite journal | author=Greenberg, J. M. | title=Radical formation, chemical processing, and explosion of interstellar grains | journal=Astrophysics and Space Science (Symposium on Solid State Astrophysics, University College, Cardiff, Wales, July 9-12, 1974.)| year=1976 | volume=139 | pages=9–18}}</ref>. In addition, evaporation, [[sputtering]] (when an atom or ion strikes the surface of a solid with enough momentum to eject atoms from it), and grain-grain collisions have a major influence on the grain size distribution. {{Ref|Evans94|label|backEvans}} These destructive processes happen in a variety of places. Some grains are destroyed in the supernovae/novae explosion (and others are formed afterwards). Some of the dust is ejected out of the [[Protostar|protostellar]] disk in the strong stellar winds that occur during a protostar's active [[T Tauri star|T Tauri]] phase and may be destroyed when passing through shocks, e.g. in [[Herbig-Haro objects]]. Plus there are some gas-phase processes in a dense cloud where ultraviolet photons eject energetic electrons from the grains into the gas. Dust grains incorporated into stars are also destroyed, but only a relatively small fraction of the mass of a star-forming cloud actually ends up in stars. This means a typical grain goes through many [[molecular cloud]]s and has mantles added and removed many times before the grain core is destroyed. ==Some "dusty" clouds in the universe== Our solar system has its own [[interplanetary dust cloud]]; extrasolar systems too. There are different types of nebulae with different physical causes and processes. One might see these classifications: *[[diffuse nebula]] *infrared (IR) [[reflection nebula]] *[[supernova remnant]] *[[molecular cloud]] *[[H II region|HII region]]s *[[photodissociation region]]s Distinctions between those types of nebula are that different radiation processes are at work. For example, H II regions, like the [[Orion Nebula]], where a lot of star-formation is taking place, are characterized as thermal emission nebulae. Supernova remnants, on the other hand, like the [[Crab Nebula]], are characterized as nonthermal emission ([[synchrotron radiation]]). Some of the better known dusty regions in the universe are the diffuse nebula in the Messier catalog, for example: [[Crab Nebula|M1]], [[Messier 8|M8]], [[Eagle Nebula|M16]], [[Omega Nebula|M17]], [[Trifid Nebula|M20]], [[Orion Nebula|M42]], [[M43 (nebula)|M43]] [http://seds.lpl.arizona.edu/messier/Messier.html Messier Catalog] Some larger 'dusty' catalogs that you can access from the NSSDC, CDS, and perhaps other places are: *Sharpless (1959) A Catalogue of HII Regions *Lynds (1965) Catalogue of Bright Nebulae *Lunds (1962) Catalogue of Dark Nebulae *van den Bergh (1966) Catalogue of Reflection Nebulae *Green (1988) Rev. Reference Cat. of Galactic SNRs at *[http://nssdc.gsfc.nasa.gov/ The National Space Sciences Data Center (NSSDC)] *[http://cdsweb.u-strasbg.fr/htbin/myqcat3?V/70A/ CDS Online Catalogs] ==Images== <gallery> Image:Comet_dust_microscopic_photo.jpg|Comet dust Image:Asteroids_dust_microscopic_photo.jpg|Asteroidal dust Image:Plane_to_collect_Space_dust.jpg|NASA airplane collector plate Image:Space_dust_collecting_pool.jpg|Collecting pool </gallery> ==References== {{reflist}} {{Note|Evans94|backEvans94}} {{cite book | author=Evans, Aneurin | title=The Dusty Universe | publisher=Ellis Horwood | year=1994}} {{Note|Jess92|backJess92}} {{cite journal | author=Jessberger, Elmar K.; Bohsung, Joerg; Chakaveh, Sepideh; Traxel, Kurt | title=The volatile element enrichment of chondritic interplanetary dust particles | journal=Earth and Planetary Science Letters | year=August 1992 | volume=112, No. 1-4 | pages=91–99}} ==External links== *[http://www.mpi-hd.mpg.de/dustgroup/gloss.html Cosmic Dust Glossary] [[Category:Astronomical objects]] [[Category:Galactic astronomy]] [[Category:Planetary science]] [[bg:Космически прах]] [[da:Kosmisk støv]] [[de:Interstellarer Staub]] [[es:Polvo interestelar]] [[fr:Poussière interstellaire]] [[ja:宇宙塵]] [[pl:Pył kosmiczny]] [[pt:Poeira interestelar]] [[ru:Космическая пыль]] [[th:ฝุ่นคอสมิก]] [[vi:Bụi vũ trụ]]