Re: [meteorite-list] Further thoughts
Hi Chris, Bob, Listees, Just to expand a little on what Chris says (he speaks from a great deal of observational experience), Bob, let's pose a few thoughts for indirect musing... If meteorites had volatiles that were subject to violent expansions, why don't all potential meteorites just turn into powder blasts? It is plausible that this happens to some cometary particles, btw. Think of where and how the meteoroid formed that is responsible for the 'rites in our collections. If it has chondrules, for example, which have metamorphized even slightly due to thermal effects - do you think it has been hotter at some point in its life considering the Earth's atmosphere never alters the matrix (insides) of the meteorites we recover? Not only has it been hotter - but it also was formed at low pressure if it is a chondrite. Why can we say the latter? If it formed hot and relatively low pressure or space, would there be many volitiles? Which are the meteorites represented in our collections that are chondrites and thermally altered? H3.X (X0), H4, H5, H6, H7. L3.X(X0), L4, L5, L6, L7 Feldspar formed from glasses is a common component in these meteorites - at what temperature does this reaction begin to occur? Indeed - they are mostly thought to have formed between 500 and 900 degres CENTIGRADE, a range which which reaches over 1650 F. If they are achondrites, what can we say? How did they get that way? By melting and essentially a process of sedimention + a little crystalization now and then? How hot do we need to be to melt silicates? HOT! Same story, but even hotter for the iron melt that leads to irons. If the silicates separated in this differentiation - do you suspect the gasses mostly did and bubbled out too? So what does that leave? Mostly a few carbonaceous things that carry water, amino acids and boozes. Let's say we instantly dropped a few of them in an oven at 3000 C. They are just rocks. Do you think they would blow up and hurl pieces in all directions and dent the insides of the oven from impacts? Or would they likely just form fissures where any volitile would just slither out of the nooks and cranies and cracks saying p? Jim has written of the blow torch test of a tektite. If something looks like a tektite but he isn't sure, he puts it under a real hot torch. Obsidian turns into Pumice complete with pores and fissures. (tektites usually don't).While safety glasses would be a good idea, the rocks don't turn into firecrackers. (Though I heard certain petrified wood rocks from Texas provide entertainment to pyros and explosive nuts if you like this thought). How far do you think a rock splitting open would hurl all the fragments? Especially if it is going over 10,000 mph forward? If we could really make decent bombs by just heating rocks to 3000 degrees, the military certainly has been wasting a lot of RD money-) All the above hypotheses ignore whay Chris has pointed out. Ablation is a very efficient process. Even in irons which conducrt heat really well, we have quite shallow heat affected zones. I completely agree with Chris, though I would prefer to say that 10,000 mph breath cools down the porridge quickly. How could a hot liquid persist so long on a slippery surface at that speed? Ablation therefore can be seen to be a surface phenomenon in meteorite after meteorite by just looking at the thickness of the fusion rind. Chris' comments are also right on regarding the temperatures of meteoroids in space (and he is assuming they are in Sunlight at about 1 AU). Here's a foolish comment of mine to think about. Did you by chance see an old Star Trek episode called For the World is Hollow and I have Touched the Sky? Do you think a mesosiderite with eucrite inclusions named Yonada at 1 AU would be an mild temperatured world to hollow out and and spend some time in a pinch (but not a nova)? I do...Natira, dear? Best wishes and good health, Doug -Original Message- From: Chris Peterson [EMAIL PROTECTED] To: Meteorite-list@meteoritecentral.com Sent: Wed, 19 Mar 2008 11:53 pm Subject: Re: [meteorite-list] Further thoughts Hi Bob- Even small meteoroids don't heat up inside during their brief meteor phase. Ablation is simply too efficient at carrying away heat. Also, it's doubtful any significant gas pockets exist in meteoroids. There are quite a few videos of meteors breaking up, and they don't seem to show anything like true explosions. I've recorded perhaps 100 events bright enough to show fragmentation, and the fragments always appear to continue along substantially the same path. BTW, the space environment isn't particularly cold. The interior of meteoroids varies from tens of degrees below freezing to tens of degrees above. Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message
[meteorite-list] Rocks from Space Picture of the Day - March 20, 2008
http://www.rocksfromspace.org/March_20_2008.html **Create a Home Theater Like the Pros. Watch the video on AOL Home. (http://home.aol.com/diy/home-improvement-eric-stromer?video=15?ncid=aolhom000301) __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Rocks from Space Picture of the Day - March 20, 2008
OHHH YEAAA Jerry Flaherty - Original Message - From: [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Thursday, March 20, 2008 6:07 AM Subject: [meteorite-list] Rocks from Space Picture of the Day - March 20, 2008 http://www.rocksfromspace.org/March_20_2008.html **Create a Home Theater Like the Pros. Watch the video on AOL Home. (http://home.aol.com/diy/home-improvement-eric-stromer?video=15?ncid=aolhom000301) __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] AD - Ebay Auctions ending
Good Morning All I have auctions ending tonight, ebay ID catchafallingstar.com. ALL started just at 99 Cents!!! http://search.ebay.com/_W0QQsassZcatchafallingstar.com Full recap with photos on Paul and Jim's website: http://www.meteorite.com/meteorites/ebay/catch_a_falling_star_meteorites.htm Thanks for looking Jim Strope 421 Fourth Street Glen Dale, WV 26038 http://www.catchafallingstar.com __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Videos from Bologna Show
here 3 videos from the Bologna Mineral Show with meteorite exhibition http://www.youtube.com/watch?v=35ISBChOBbk http://www.youtube.com/watch?v=35-YY4jV53E http://www.youtube.com/watch?v=ODjXAbfhR58 matteo __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Wanted to Buy : Superb Pallasite! (UPDATE)
Hi Everyone! I have received an overwhelming flood of responses to my request for a superb of example of pallasite. :) Some of you have some SPECTACULAR pieces of pallasite available and it's very hard to pick just ONE! If I had millions of dollars, I'd buy them all! (seriously) Currently I am conferring with my friend and buyer who is financing this little meteoritical expedition into the marketplace. We are examining all of the offers and responses we received and will be making a purchase sometime today or tomorrow. I would like to thank everyone for the kind offers and say that we have received all the offers we need and will be making a decision very soon. Thanks again! MikeG Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Microscope cross polarized light meteorite examination and new retardation plate
Hi list, Not all of you have interest in Microscopic examination of meteorites to the point of wanting to talk about retardation wave plates but this is cool and interesting. The Sony Play Station 3 uses a Blue Ray disk reader. These devices have a laser diode that emits light at 405nm (Violet) as well as one that operates at 660nm (Red) combined with 780nm (Near IR). This combination through one reading lens (objective) requires some cool optics. In the combination of cube polarizers there is a quarter wave plate that produces violet, blue (and more) hues like no other retardation plate I have tried. The plate is small (5mm) but that is big enough to use on a microscope if you apply a little ingenuity. If you are interested in what some of these micrographs look like, email me. I plan to do a Meteorite Times, Micro Vision article on this but that may be a couple months out. Right now I am working with a beautiful thin section of NWA 2977 (Lunar) where the material was supplied by Jim Strope and the thins were arranged (To his new standard of 1/4 micron DPU) by Jeff Hodges. You have got to see this. I can draw out complex structures that are completely hidden in ordinary cross polarized light. Tom Phillips **Create a Home Theater Like the Pros. Watch the video on AOL Home. (http://home.aol.com/diy/home-improvement-eric-stromer?video=15?ncid=aolhom000301) __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] HELP!
Due to great enthusiasm of the list, Dinner With Michael Blood has Already surpassed the price of Dinner with Michael Casper on eBay. Thanks to all you enthusiastic bidders. However, it seems Michael C is out for revenge and has taken The lead in the bidding and is planning on taking ME to dinner! HELP! Michael http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=110234305503ssPageName=A DME:L:DSS:US:1123 __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] HELP!
I really wanted to help but I have already stated how I'm disqualified. : ) I'd order something big. Mike On Mar 20, 2008, at 11:19 AM, Michael L Blood wrote: Due to great enthusiasm of the list, Dinner With Michael Blood has Already surpassed the price of Dinner with Michael Casper on eBay. Thanks to all you enthusiastic bidders. However, it seems Michael C is out for revenge and has taken The lead in the bidding and is planning on taking ME to dinner! HELP! Michael http://cgi.ebay.com/ws/eBayISAPI.dll? ViewItemitem=110234305503ssPageName=A DME:L:DSS:US:1123 __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Mars Odyssey Finds New Clues to Guide the Search for Life on Mars
March 20, 2008 Dwayne Brown Headquarters, Washington 202-358-1726 [EMAIL PROTECTED] Guy Webster Jet Propulsion Laboratory, Pasadena, Calif. 818-354-6278 [EMAIL PROTECTED] Robert Burnham Arizona State University, Tempe 480-458-8207 [EMAIL PROTECTED] Tara Hicks-Johnson University of Hawaii, Manoa 808- 956-3151 [EMAIL PROTECTED] RELEASE: 08-084 NASA MISSION FINDS NEW CLUES TO GUIDE THE SEARCH FOR LIFE ON MARS WASHINGTON - NASA's Mars Odyssey orbiter has found evidence of salt deposits. These deposits point to places where water once was abundant and where evidence might exist of possible Martian life from the Red Planet's past. A team led by Mikki Osterloo of the University of Hawaii, Honolulu, found approximately 200 places on southern Mars that show spectral characteristics consistent with chloride minerals. Chloride is part of many types of salt, such as sodium chloride or table salt. The sites range from about half of a square mile to 25 times that size. They could come from groundwater reaching the surface in low spots, Osterloo said. The water would evaporate and leave mineral deposits, which build up over years. The sites are disconnected, so they are unlikely to be the remnants of a global ocean. Scientists used Odyssey's Thermal Emission Imaging System, a camera designed and operated by Arizona State University, Tempe, to take images in a range of visible light and infrared wavelengths. Thermal infrared wavelengths are useful for identifying different mineral and rock types on the Martian surface. Osterloo found the sites by looking through thousands of images processed to reveal, in false colors, compositional differences on the Martian surface. Plotted on a Mars map, the chloride sites appear only in the southern highlands, the most ancient rocks on Mars. Osterloo and seven co-authors report the findings in this week's issue of the journal Science. Many of the deposits lie in basins with channels leading into them, said Philip Christensen, co-author and principal investigator for the camera at Arizona State University. This is the kind of feature, like salt-pan deposits on Earth, that's consistent with water flowing in over a long time. Scientists think the salt deposits formed approximately 3.5 to 3.9 billion years ago. Several lines of evidence suggest Mars then had intermittent periods with substantially wetter and warmer conditions than today's dry, frigid climate. Scientists looking for evidence of past life on Mars have focused mainly on a handful of places that show evidence of clay or sulfate minerals. Clays indicate weathering by water, and sulfates may have formed by water evaporation. The new research, however, suggests an alternative mineral target to explore for biological remains. By their nature, salt deposits point to a lot of water, which potentially could remain standing in pools as it evaporates. said Christensen. That's crucial. For life, it's all about a habitat that endures for some time. Whether life ever has existed on Mars is the biggest scientific question driving Mars research. On Earth, salt is good at preserving organic material. Bacteria have been revived in the laboratory after being preserved in salt deposits for millions of years. This discovery demonstrates the continuing value of the Odyssey science mission, now entering its seventh year. The more we look at Mars, the more fascinating a place it becomes, said Jeffrey Plaut, Odyssey project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. This is a wonderful and scientifically exciting result obtained from a relatively low cost NASA Mars orbiter mission which still has years of life left., said Alan Stern, associate administrator for NASA's Science Mission Directorate in Washington. Hold on to your hats, more exciting results from Mars are sure to be coming. For additional information about Odyssey, visit: http://www.nasa.gov/mission_pages/odyssey -end- __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Further thoughts-Observations
I have to respectfully disagree Doug. I'd agree more with you had I not witnessed it myself. I believe there might be an unconsidered chemical source to drive an explosion. The Maryville Bolide(1983), which I was lucky to observe may have been an aberration from the norm on several levels( e.g. calculations indicate it was still incandescent between 3-4 miles when conventional wisdom places the max altitude for incandescence at 5 miles above sea level)but none-the-less it expanded explosively in all directions formaing a slightly squat turnip-shapped fire/smoke ball. This meteorite was likely still traveling 1-2 or more kilos per second when it first appeared in front of me. When it bolided, there was a visible smoke trail of a fragment that was ejected up and out at 45-60° leaving 3 distinct doglegs of smoke trails as it went up, out, then started down. An area of secondary crust was found on the only recovered mass suggesting that may have been the source of the wayward fragment. Many questions remained about this fall. Owing to an early morning entry with both cosmic velocity and meeting Earth's 15kps(?) orbital velocity combined, it was screaming fast. The size of the bolide/smoke sphere was estimated between 400-1200 ft in diameter. This seems rather large for the approx. 1kg stone which was recovered. The fall was very close to a large lake so we could never be confidant if the recovered stone was truly the surviving/main mass or if it was the fragment observed ejected from the upper hemisphere of the bolide. In that we know factually little and only weakly theoretically-- about the actual expansion mechanism aka explosive disruption, I believe that there is a case to be made for an explosion--i.e. rapidly expanding, gas-driven, wave front which is moving at or near shock wave velocities of chemical explosives or propellant burn speeds-- even if we are unsure of the mechanism that expands the fireball to many diameters of the original smoke/incandescent trail. Be it recalled that when air suspended, combustible particles such as coal dust or wheat flour are ignited, they act as explosives and can collapse large structures or mine shafts. The nano-gram sized particles of a extensive disruption when suddenly exposed to oxygen might be a sufficient chemical explosive mechanism. For example, metallic iron, shearing at apart at plasma temperatures, might be literally burned in the higher oxygen levels of the lower atmosphere and the rapid expansion of the fireball could be driven by a burning iron fog--meeting the definition of explosive. Regards, Elton --- [EMAIL PROTECTED] wrote: Pete wrote: Some will be blown up and some will be blown down. I believe this is a common misconception for many in the meteorite community and common thought. I don't think anything is blowing up. Simply fragmenting. Each part of the original whole maintains its portion of momentum upon fragmentation. The direction of the momentum is along the angle of entry. There is no blowing up in that sense of a bomb which propells fragments in all directions as there is no internal source of energy (like in a chemical explosive). __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] UM-Led Team Finds Oldest Known Asteroids
Contact: Lee Tune, 1-301-405-4679 [EMAIL PROTECTED] UM-Led Team Finds Oldest Known Asteroids March 20, 2008 COLLEGE PARK, Md. -- Using visible and infrared data collected from telescopes on Hawaii's Mauna Kea, a team of scientists, led by the University of Maryland's Jessica Sunshine, have identified three asteroids that appear to be among our Solar System's oldest objects. Evidence indicates that these ancient asteroids are relatively unchanged since they formed some 4.55 billion years ago and are older than the oldest meteorites ever found on Earth, say Maryland's Sunshine and colleagues from the City University of New York, the Smithsonian Institution, and the University of Hawaii. Their findings are published in this week's edition of Science Express. We have identified asteroids that are not represented in our meteorite collection and which date from the earliest periods of the Solar System, said Sunshine, a senior research scientist in the University of Maryland's department of astronomy. These asteroids are prime candidates for future space missions that could collect and return samples to Earth providing a more detailed understanding of the Solar System's first few millions of years. In the Beginning At the beginning of the Solar System, there was just a disk-shaped cloud of hot gas, the solar nebula. When gasses on the edge of the early nebula began to cool, the first materials to condense into solid particles were rich in the elements calcium and aluminum. As the gasses cooled further, other materials also began to condense. Eventually the different types of solid particles clumped together to form the common building blocks of comets, asteroids, and planets. Astronomers have thought that at least some of the Solar System's oldest asteroids should be more enriched in calcium and aluminum, but, until the current study, none had been identified. Meteorites found on Earth do contain small amounts of these earliest condensing materials. As seen in meteorites, these bright white ancient materials, the so-called calcium, aluminum-rich inclusions, or CAIs, can be as large as a centimeter in diameter. Scientists, in fact, long have used the age of CAIs to define the age of the Solar System. The fall of the Allende meteorite in 1969 initiated a revolution in the study of the early Solar System, said Tim McCoy, curator of the national meteorite collection at the Smithsonian's National Museum of Natural History. It was at that time scientists first recognized that the remarkable white inclusions -- later called calcium, aluminum-rich inclusions-- which were found in this meteorite, matched many of the properties expected of early Solar System condensates. I find it amazing that it took us nearly 40 years to collect spectra of these [CAI-rich] objects and that those spectra would now initiate another revolution, pointing us to the asteroids that record this earliest stage in the history of our Solar System, said McCoy. Sunshine and McCoy, with colleagues Harold Connolly, Jr, City University of New York; Bobby Bus, Institute for Astronomy, University of Hawaii, Hilo; and Lauren La Croix, Smithsonian Institution, used the SpeX instrument at the NASA Infrared Telescope Facility in Hawaii to look at the surface of asteroids for evidence of the presence of such early bits of high-temperature rock. In particular, they looked for spectral fingerprints indicative of the presence of CAIs. Because different minerals have different reflective properties, the spectrum, or color of light reflected from a surface, reveals information about its composition enabling telescopic compositional analysis. In their paper, Sunshine and colleagues quantitatively compare the spectral signatures of asteroid surfaces and CAIs in meteorites from the Smithsonian's National Museum of Natural History collection. Several CAI-rich asteroids have been identified that contain 2-3 times more CAI material than any known meteorite, Sunshine said. Thus it appears ancient asteroids have indeed survived, and we know where they are. This research was supported by NASA and the National Science Foundation (NSF). Making a Deep Impact on Space Exploration University of Maryland scientists and engineers are at the forefront of many efforts to explore our Solar System and the universe beyond it. Maryland astronomers have led or participated in many Solar System missions, including: Deep Impact and its current follow-on mission EPOXI; the Dawn mission to study dwarf planet Ceres and asteroid Vesta; and the NEAR spacecraft that in 2000 became the first to orbit, and then land on, an asteroid. Scientists of the university's space physics group have built sensors for some 13 spacecraft, including the two Voyager spacecraft, now exploring the outer edge of the Solar System; the Cassini mission (Saturn); the Ulysses probe to the solar poles; and near-Earth missions such as Geotail and the Solar Anomalous and Magnetospheric Particle
Re: [meteorite-list] Further thoughts-Observations
Hi Elton- I don't see that any sort of explosion- especially not chemical- is required to explain what you saw. There is a significant difference between sending material in all directions relative to the point of breakup, and imparting some lateral velocity. The former requires more energy than can be reasonably explained- at least several times the parent body mass in TNT. But it's certainly possible that with the right sort of breakup (especially at low altitude), aerodynamics could produce components that fly off the original path somewhat (but still with much of the original forward velocity component). Combine that with an expanding smoke cloud (where all forward momentum has been lost), and I imaging a striking explosion effect. I see nothing about your description of the Maryville fireball that contradicts this explanation. In fact, videos of fragmenting meteors and of decaying space junk do show components with some lateral velocity component. It's just not common for that amount to be very much. Of course, if a fireball has a large motion component towards the observer, the terminal explosion may appear to radiate outwards in all directions even though all the material is still traveling along substantially the same path. We should also take care to distinguish between what might be possible in exotic cases from what is typical. We all know that small meteors don't reach the ground with hypersonic velocity. Well, except for one. While we can't say for certain that there isn't a set of conditions that might cause meteor components to be propelled from the parent at radical angles and high velocities, we can say with absolute confidence that any such event is very rare, and certainly doesn't represent a typical fireball/meteorite fall. Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message - From: Mr EMan [EMAIL PROTECTED] To: [EMAIL PROTECTED]; [EMAIL PROTECTED]; Meteorite-list@meteoritecentral.com Sent: Thursday, March 20, 2008 4:16 PM Subject: Re: [meteorite-list] Further thoughts-Observations I have to respectfully disagree Doug. I'd agree more with you had I not witnessed it myself. I believe there might be an unconsidered chemical source to drive an explosion. The Maryville Bolide(1983), which I was lucky to observe may have been an aberration from the norm on several levels( e.g. calculations indicate it was still incandescent between 3-4 miles when conventional wisdom places the max altitude for incandescence at 5 miles above sea level)but none-the-less it expanded explosively in all directions formaing a slightly squat turnip-shapped fire/smoke ball. This meteorite was likely still traveling 1-2 or more kilos per second when it first appeared in front of me. When it bolided, there was a visible smoke trail of a fragment that was ejected up and out at 45-60° leaving 3 distinct doglegs of smoke trails as it went up, out, then started down. An area of secondary crust was found on the only recovered mass suggesting that may have been the source of the wayward fragment. Many questions remained about this fall. Owing to an early morning entry with both cosmic velocity and meeting Earth's 15kps(?) orbital velocity combined, it was screaming fast. The size of the bolide/smoke sphere was estimated between 400-1200 ft in diameter. This seems rather large for the approx. 1kg stone which was recovered. The fall was very close to a large lake so we could never be confidant if the recovered stone was truly the surviving/main mass or if it was the fragment observed ejected from the upper hemisphere of the bolide. In that we know factually little and only weakly theoretically-- about the actual expansion mechanism aka explosive disruption, I believe that there is a case to be made for an explosion--i.e. rapidly expanding, gas-driven, wave front which is moving at or near shock wave velocities of chemical explosives or propellant burn speeds-- even if we are unsure of the mechanism that expands the fireball to many diameters of the original smoke/incandescent trail. Be it recalled that when air suspended, combustible particles such as coal dust or wheat flour are ignited, they act as explosives and can collapse large structures or mine shafts. The nano-gram sized particles of a extensive disruption when suddenly exposed to oxygen might be a sufficient chemical explosive mechanism. For example, metallic iron, shearing at apart at plasma temperatures, might be literally burned in the higher oxygen levels of the lower atmosphere and the rapid expansion of the fireball could be driven by a burning iron fog--meeting the definition of explosive. Regards, Elton __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] UM-Led Team Finds Oldest Known Asteroids
Hi, All, A very coy press release. What are the three asteroids? Where are they in the solar system? and a host of other questions go unanswered. They're large, 50km to 100km in diameter says the abstract: Calcium-, aluminum-rich inclusions (CAIs) occur in all classes of chondritic meteorites and contain refractory minerals predicted to be the first condensates from the solar nebula. Near infrared spectra of CAIs have strong 2 µm absorptions, attributed to FeO-bearing aluminous spinel. Similar absorptions are present in telescopic spectra of several asteroids; modeling indicates these contain ~30±10% CAIs, 2-3 times that of any meteorite. Survival of these undifferentiated, large (50-100 km diameter) CAI-rich bodies argues that they may have formed before the injection of radiogenic 26Al into the Solar System. They have also experienced only modest post-accretionary alteration. Thus, these asteroids have higher concentrations of CAI material, are likely less altered, and are more ancient than any known sample in our meteorite collection, making them prime candidates for sample return. The three asteroids are: 234 Barbara, 387 Aquitania, and 980 Anacostia. They think that 2448 Sholokhov is possibly a weathered example. The last three are members of the Watsonia family, with orbits that range from 2 to 3 AU. Anybody got an unclassified NWA that's 30% to 40% CAI's?! Sterling - Original Message - From: Ron Baalke [EMAIL PROTECTED] To: Meteorite Mailing List meteorite-list@meteoritecentral.com Sent: Thursday, March 20, 2008 6:39 PM Subject: [meteorite-list] UM-Led Team Finds Oldest Known Asteroids Contact: Lee Tune, 1-301-405-4679 [EMAIL PROTECTED] UM-Led Team Finds Oldest Known Asteroids March 20, 2008 COLLEGE PARK, Md. -- Using visible and infrared data collected from telescopes on Hawaii's Mauna Kea, a team of scientists, led by the University of Maryland's Jessica Sunshine, have identified three asteroids that appear to be among our Solar System's oldest objects. Evidence indicates that these ancient asteroids are relatively unchanged since they formed some 4.55 billion years ago and are older than the oldest meteorites ever found on Earth, say Maryland's Sunshine and colleagues from the City University of New York, the Smithsonian Institution, and the University of Hawaii. Their findings are published in this week's edition of Science Express. We have identified asteroids that are not represented in our meteorite collection and which date from the earliest periods of the Solar System, said Sunshine, a senior research scientist in the University of Maryland's department of astronomy. These asteroids are prime candidates for future space missions that could collect and return samples to Earth providing a more detailed understanding of the Solar System's first few millions of years. In the Beginning At the beginning of the Solar System, there was just a disk-shaped cloud of hot gas, the solar nebula. When gasses on the edge of the early nebula began to cool, the first materials to condense into solid particles were rich in the elements calcium and aluminum. As the gasses cooled further, other materials also began to condense. Eventually the different types of solid particles clumped together to form the common building blocks of comets, asteroids, and planets. Astronomers have thought that at least some of the Solar System's oldest asteroids should be more enriched in calcium and aluminum, but, until the current study, none had been identified. Meteorites found on Earth do contain small amounts of these earliest condensing materials. As seen in meteorites, these bright white ancient materials, the so-called calcium, aluminum-rich inclusions, or CAIs, can be as large as a centimeter in diameter. Scientists, in fact, long have used the age of CAIs to define the age of the Solar System. The fall of the Allende meteorite in 1969 initiated a revolution in the study of the early Solar System, said Tim McCoy, curator of the national meteorite collection at the Smithsonian's National Museum of Natural History. It was at that time scientists first recognized that the remarkable white inclusions -- later called calcium, aluminum-rich inclusions-- which were found in this meteorite, matched many of the properties expected of early Solar System condensates. I find it amazing that it took us nearly 40 years to collect spectra of these [CAI-rich] objects and that those spectra would now initiate another revolution, pointing us to the asteroids that record this earliest stage in the history of our Solar System, said McCoy. Sunshine and McCoy, with colleagues Harold Connolly, Jr, City University of New York; Bobby Bus, Institute for Astronomy, University of Hawaii, Hilo; and Lauren La Croix, Smithsonian Institution, used the SpeX instrument at the NASA Infrared Telescope Facility in Hawaii to look
Re: [meteorite-list] HELP!
Be very careful about bidding on this auction. I've seen this dude eat and he'll set you back a fortune just for the appetizers;-) Best and with tongue in cheek, John Gwilliam At 10:19 AM 3/20/2008, Michael L Blood wrote: Due to great enthusiasm of the list, Dinner With Michael Blood has Already surpassed the price of Dinner with Michael Casper on eBay. Thanks to all you enthusiastic bidders. However, it seems Michael C is out for revenge and has taken The lead in the bidding and is planning on taking ME to dinner! HELP! Michael http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=110234305503ssPageName=A DME:L:DSS:US:1123 __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Oldest Known Asteroids
The three asteroids are: 234 Barbara, 387 Aquitania, and 980 Anacostia. They think that 2448 Sholokhov is possibly a weathered example. The last three are members of the Watsonia family, with orbits that range from 2 to 3 AU. http://en.wikipedia.org/wiki/234_Barbara 234 Barbara is a typical Main belt asteroid. It is classified as an S-type asteroid. It was discovered by C. H. F. Peters on August 12, 1883 in Clinton, New York. It ranges from 1.8 AU to 2.97 AU, period of 3.69 years, and is 44 km in diameter, rotates every 26.5 hours and has an albedo of 0.227 http://en.wikipedia.org/wiki/387_Aquitania 387 Aquitania is a fairly large Main belt asteroid. It is classified as an S-type asteroid. It was discovered by F. Courty on March 5, 1894 in Bordeaux. It ranges from 2.74 AU to 3.39 AU in a period of 4.53 years. It has a diameter of 101 km. http://en.wikipedia.org/wiki/980_Anacostia Discovered by G. H. Peters Nov. 21, 1921. It ranges from 2.74 AU to 3.294 AU in a period of 4.539 years. No diameter is given. Sterling K. Webb __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] gold coin for meteorites
Hi list.It seems a trade between me and a very prominent meteorite person fell thru after we had agreed to trade.Well that fell thru and once again I have my 1892 $10 gold piece I will trade for meteorites if interested please email me off list.Thanks for your time. Steve R.Arnold,chicago,Ill,Usa!! The Asteroid Belt! http://chicagometeorites.net/ Collecting Meteorites since 06/19/1999 Ebay I.D. Illinoismeteorites Never miss a thing. Make Yahoo your home page. http://www.yahoo.com/r/hs __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
