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Topic: Micrometeorites

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	The Citizen Scientist - Society for Amateur Scientists
		Micrometeorites (1) are incredibly small bits of iron or nickel-iron of four general shapes: rounded rod, raindrop, sphere or pear as seen in Fig.
		Micrometeorites are formed when material from space is violently incinerated in the upper atmosphere (~100 km altitude) to become meteor debris (2).
		Micrometeorites deposited on a roof will be dislodged by rain or melting snow and will find their way to the gutter system, where the runoff water is collected in plastic buckets placed beneath one or more drain spouts.
	www.sas.org /tcs/weeklyIssues_2005/2005-01-07/project1 (807 words)

	Documentation: Micrometeorites from the South Pole Water Well (S. Taylor)
		Micrometeorites dated between 1100 A.D. to 1500 A.D. were collected from the bottom of the South Pole Water Well in December 1995.
		Micrometeorites are extraterrestrial particles, generally less than 1 mm, that have survived atmospheric entry.
		Micrometeorites form a lag deposit on the well bottom as they are melted out of the ice during continuous drilling of the well.
	nsidc.org /data/docs/agdc/nsidc0113_staylor/index.html (793 words)

	Meteorites - Cambridge University Press (Site not responding. Last check: 2007-11-02)
		From estimates of impact velocity Zook argues that <25% of micrometeorites are asteroidal, the bulk being of cometary origin.
		Micrometeorites were discovered by the “Challenger” oceanographic expedition in the 1870s and correctly identified as extraterrestrial.
		All micrometeorites appear to have been altered or contaminated to some extent during their sojourn in the atmosphere or by their immersion in fresh or salt water or in ice.
	www.cup.cam.ac.uk /catalogue/catalogue.asp?isbn=0521470102&ss=exc (3396 words)

	Elusive micrometeorites may come from dawn of solar system
		These micrometeorites are so small that even when they disintegrate in the atmosphere, they are presently only recordable at high resolution using the very sensitive 430 megahertz radar system at Arecibo Observatory in Puerto Rico.
		One clue leading to the team's hypothesis is the fact that the micrometeorites' orbits do not come close to the major planets or come from the asteroid belt.
		Because the micrometeorites' orbits leave the solar system, Mathews believes the particles may have existed since the creation of the solar system but never became part of any planet.
	www.engr.psu.edu /NewsEvents/EPS/v14n3_1998summer/elusive.htm (520 words)

	Greenand meteorites
		She plans to track the flux of micrometeorites during the past 800 years to see if there is a correlation between the number of micrometeorites and climatic changes during this time.
		A five-micron filter traps any particles of that size or larger, including the micrometeorites, cosmic spherules (tiny particles from space which survived transit through the atmosphere), pollen, dust, obsidian from volcanic ash, and possibly even a rare unknown new particle.
		According to Harvey, micrometeorites can be actual small meteorites that survive the friction of entering the earth's atmosphere.
	www.cwru.edu /pubs/cnews/1998/9-10/greenlnd.htm (654 words)

	Space Studies Board
		Direct measurements of the flux of micrometeorites reaching Earth's surface (Maurette et al., 1991; Hammer and Maurette, 1996; Taylor et al., 1996a), and comparison with the IDP pre-atmospheric flux at 1 AU (Love and Brownlee, 1993), indicate that micrometeorites in the 50- to 500-
		Direct examination of micrometeorites collected in the Antarctic has shown that the proportion of unmelted micrometeorites studied was much larger than predicted by models describing frictional heating of micrometeorites upon atmospheric entry (see, e.g., Hunten, 1997; Maurette, 1998).
		Micrometeorite flux on the melt zone of the west Greenland ice sheet.
	www7.nationalacademies.org /ssb/sssbch6.html (2778 words)

	Micrometeorites
		Micrometeorites are submillimeter extraterrestrial particles that have survived atmospheric entry
		Micrometeorites that fell on the snow hundreds of years ago are now frozen in ice layers under the South Pole station.
		Ongoing work includes determining the compositional distribution of the spherules and using this information to estimate weathering rates for spherules collected from deep-sea sediments that are millions of years old.
	www.crrel.usace.army.mil /es/research/micrometeorites.htm (339 words)

	Micrometeorites (Site not responding. Last check: 2007-11-02)
		Micrometeorites are thought to contribute most of the extraterrestrial matter accreted by the Earth on ten million-year time scales (Peucker-Ehrenbrink 1997, Love and Brownlee 1993, Kyte and Wasson, 1986).
		There are only a few minerals found in micrometeorites and these are determined both by the composition of the particle and by the degree of heating each particle sustained entering the earth’s atmosphere.
		Three types of contaminants are found in the South Pole water well samples: copper spheres (from welding), plastic spheres (from a fire in one of the water hoses) and iron oxide grains (from a pump failure).
	remf.dartmouth.edu /micrometeorites (422 words)

	Educator's Guide to Micrometeorites
		They are actually microscopic and are known as micrometeorites.
		To find the metallic micrometeorites, collect and dry some of the material from a deep bowl at the base of the drain spout.
		Most of the particles are not from space, but the micrometeorites will show signs of their fiery trip through the atmosphere.
	www.solarviews.com /eng/edu/micromet.htm (554 words)

	CRREL news story (9702): Micrometeorites</i> (Site not responding. Last check: 2007-11-02)
		Micrometeorites are extraterrestrial particles less than a millimeter (0.03937 inch) in size.
		Micrometeorites make up most of the 30,000 tons of extraterrestrial material deposited on Earth each year.
		But, although micrometeorites rain down everywhere on the Earth's surface, they are hard to find.
	www.crrel.usace.army.mil /news/news-archives/micrometeorites9703 (713 words)

	[No title] (Site not responding. Last check: 2007-11-02)
		The micrometeorites eventually settle down to the bottom of the ocean where they are mixed with other sediments.
		If the flux of micrometeorites to the earth has remained constant in geological past, then their concentration in sediments can be used to quantitatively evaluate sedimentation rates and the fluxes of different sedimentary components and changes in these fluxes through time.
		This research will test the assumptions that the flux of micrometeorites to the sediments have stayed constant over time and that the micrometeorites in sediments retain their He for time-scales of interest.
	www.cs.utexas.edu /users/yguan/NSFAbstracts/Abstracts/GEO/OCE.GEO.a9402019.txt (231 words)

	Bada_97
		Antarctic ice has been found to be an excellent repository of micrometeorites, and mg size samples can be recovered by melting large amounts (hundreds of tons) of ice.
		Whether micrometeorite material could have supplied the early Earth with a rich inventory of organic compounds is presently unknown.
		Most of the annual infall of micrometeorites and IDPs lands in the ocean where their soluble components would dissolve and accumulate if they were not consumed by organisms.
	exobio.ucsd.edu /bada_97.htm (1750 words)

	Micrometeorites (Site not responding. Last check: 2007-11-02)
		First of all, the largest portion of this material falls into the oceans, and secondly, most of the material that reaches the surface is microscopic, much too small to be noticed.
		In fact, what may be the largest collection of micrometeorites is in the hands of the Cold Regions Research and Engineering Laboratories.
		This is evidence of a micrometeorite's fiery trip through the atmosphere.
	www.teachersource.com /micrometeorites.htm (570 words)

	meteorite
		A good place to find a collection of magnetic (iron containing) micrometeorites is in the dust collected on a gramaphone needle.
		These micrometeorites float in the atmosphere and eventually settle to the ground.
		Metallic micrometeorites are usually iron or iron and nickel and can be collected with a magnet.
	www.mines.edu /Academic/courses/physics/phgn324/CLEA/meteorite.html (1562 words)

	NOVA Online \| Teachers \| Classroom Activity \| Origins: Earth is Born \| PBS
		The majority of the micrometeorites are made of rock, although these are more difficult to identify than metal micrometeorites, which look small, shiny, etched, fl, and more or less round.
		Although micrometeorites come in a range of sizes (from about 10 microns to 500 microns), the smaller sizes are more common.
		The Earth is the third planet from the sun in a system that includes the moon, the sun, eight other planets and their moons, and smaller objects, such as asteroids, and comets.
	www.pbs.org /wgbh/nova/teachers/activities/3111_origins.html (1752 words)

	Elusive Micrometeorites May Come From Dawn of Solar System
		"We can track the micrometeorites' orbits back through time, and most of these tiny rocks appear to originate on the edges of our solar system and not in the trails left by comets," Mathews told attendees today (May 27) at the spring meeting of the American Geophysical Union in Baltimore.
		The researchers have not accurately traced its possible stellar origins yet because that requires a complex back tracking of both the micrometeorites and the solar system as it moves through space.
		While micrometeorites disintegrate at about 60 miles above the earth and weigh only about one microgram, they carry the energy of a 22-caliber bullet.
	www.psu.edu /ur/NEWS/news/micrometeorites.html (634 words)

	Bada_98
		We have concentrated on the detection of a-amino-isobutyric acid (Aib) because it is one of the most abundant amino acids in carbonaceous meteorites and is readily synthesized in abiotic experiments, but it is not one of the amino acids found in the proteins of modern organisms.
		Although adenine and guanine did not sublime in the Murchison heating experiment, there was no evidence of the decomposition of these nucleobases into hypoxanthine and xanthine, respectively.
		The high recovery of amino acids present in the meteorite after exposure to high temperature and the lack of nucleobase decomposition at these temperatures, suggests that a large fraction of these organics in meteorites, especially micrometeorites, may survive the frictional heating associated with atmospheric entry with minimal thermal degradation.
	exobio.ucsd.edu /bada_98.htm (2439 words)

	Greshake et al. 1995
		We have analyzed 20 fine-grained micrometeorites from Antarctica (EUROMET 1994 collection of micro-meteorites) in the range of 200-250 µm and 14 fine-grained 100-150 µm-sized micrometeorites from Devon Is-land, Canada (Canadian Arctic Meteorite Project 1990) for volatile elements by Proton-Induced-X-Ray-Emis-sion.
		In the micrometeorites from Devon Island the concen-trations of all elements up to Mn (condensation temperature 1190 K) except Ni are close to the CI-values.
		Whilst the depletion of Ca is probably preterrestrial the depletion of Ni, S, and Se is attributed to the leaching of sulfides and sulfates in the ice water.
	www.mpi-hd.mpg.de /pixe/mm_ref05.html (699 words)

	Science-Shop > Micrometeorites and the Mysteries of Our Origins (Site not responding. Last check: 2007-11-02)
		Micrometeorites played an essential role in the formation of the atmosphere of the Early Earth and also served as a significant source of activation for organic prebiotic chemistry on mineral surfaces.
		The present book gives a coherent account of this scenario, embedding the more specific results within a broader framework that considers the creation and evolution of the Early Earth.
		The experienced researcher will find this volume to be a modern and compact reference, as well as a source of material for lectures in this field.
	www.wissenschaft-online.de /artikel/831247 (120 words)

	Catch a Falling Star
		This is the home page of the Catch a Falling Star Project, a project designed to improve the public understanding of science and technology by inviting the public, primarily through schools and astronomical societies, to take part in a large-scale scientific experiment.
		Samples will then be sent to me and analysed in order to determine the rate of micrometeorite fallout across the U.K. and its distribution over time.
		Micrometeorites should have the same range of composition as full-size meteorites.
	www.soton.ac.uk /~stargate/cafs (657 words)

	Micrometeorites (Site not responding. Last check: 2007-11-02)
		They are actually small bits of rock and metal that collide with Earth's upper atmosphere and, because of friction, burn up.
		There is an easy way to collect meteorites, but we must be satisfied with finding small metal ones.They are actually microscopic and are known as micrometeorites.
		But dust, plants, pieces of window screens and all other sorts of airborne material also collect there.To find the metallic micrometeorites, collect and dry some of the material from a deep bowl at the base of the drain spout.
	list.terc.edu /pipermail/maine_science/1997-July/000004.html (640 words)

	Dartmouth College Department of Earth Sciences
		I have used multiple techniques to study detonation residues from Army training ranges, micrometeorites that I collect from the South Pole drinking water well, and snow pack processes.
		Matrajt, G., S. Pizzarello, S. Taylor and D. Brownlee (in press) Concentration and variability of the AIB amino acid in polar micrometeorites: implications for the exogenous delivery of amino acids to the primitive Earth, Meteoritics and Planetary Sciences.
		Matrajt G., S. Taylor, G.Flynn, D.E. Brownlee, and D. Joswiak (2003), A nuclear microprobe study of the distribution and concentration of carbo n and nitrogen in Murchison and Tagish Lake meteorites, Antarc tic micrometeorites, and IDPS: Implications for astrobiology, Meteoritics and Planetary Science., 38 (11), 1585-1600.
	www.dartmouth.edu /~earthsci/People/taylor.html (653 words)

	Micrometeorites and the mysteries of our origins
		This book relates an attempt to decrypt the still-obscure first billion years of history of the young Earth, during a cataclysmic period during which our planet was heavily bombarded by bodies ranging in size from that of Mars to 0.1 mm sized tiny micrometeorites.
		It was thus found that micrometeorites played an essential role in the formation of the post-lunar atmosphere.
		They also provided a surprisingly large diversity of reactions in the organic prebiotic chemistry required for the birth of life on our blue planet.
	www.exobio.cnrs.fr /article.php3?id_article=79 (232 words)

	Collecting Micrometeorites
		After several hours (overnight, if you think it will stay dry), roll the sides of the sheet up, tapping the material on the sheet to the center.
		Gently use a brush to sweep the particulate matter into a small container, and then pour it onto a sheet of paper or plastic.
		The micrometeorites will be among the remaining particles.
	www.chevroncars.com /learn/fun-games/collecting-micrometeorites (405 words)

	powell
		Students will learn the meanings of the words: meteors, meteoroids, and micrometeorites.
		Students will learn what shooting stars are, and what they are made of.
		Students will learn where meteoroids come from, and where micrometeorites can be found.
	pirate.shu.edu /~depierjo/star_dust.htm (602 words)

	History: micrometeorites
		Research centered around the study of cosmic dust in the upper atmosphere and in space.
		The analysis of micrometeorites to determine their origin formed the bulk of the research performed over the next decades.
		Efforts included collecting micrometeorites with apparatus flown on high altitude aircraft, balloons, and spacecraft, and analyzing the collected materials using such tools as electron microscopes.
	www.dudleyobservatory.org /History/history_micrometeorites.htm (232 words)

	Orbital airship - Wikipedia, the free encyclopedia
		In the long term, the surface of these objects can be sprayed with a thin-film solar cell, which, while inefficient in energy conversion, would benefit from light weight, simplicity, and the large surface area.
		Several potential problems exist in the design, the largest of which is the threat of micrometeorites.
		As these will frequently impact the airship, it must have an effective self-healing mechanism, without gaining much weight.
	en.wikipedia.org /wiki/Orbital_airship (820 words)

	CNN.com - Learn about the Perseid meteor shower - August 8, 2001
		Challenge students to learn how to collect micrometeorites, and to discover what meteorites reveal about the formation of our solar system.
		Refer students to the following Holt, Rinehhart and Winston site to complete the Collecting Micrometeorites activity.
		Have students write essays explaining how studying elements in meteorites gives scientists insights about the formation of the solar system.
	archives.cnn.com /2001/fyi/lesson.plans/08/08/meteor.shower/index.html (433 words)

	Micrometeorite - webquest (Site not responding. Last check: 2007-11-02)
		Follow the hotlinks to discover how to collect micrometeorites at home.
		Use a field notebook to make notes of each step as you surf the pages.
		At some point, you will want to examine some images (click here) of micrometeorites collected in the Fall of 2001.
	staff.harrisonburg.k12.va.us /~gcorder/mm_main.html (231 words)

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