[meteorite-list] Impact Crater Dynamics in the Laboratory
06/29/2004 10:05:27 PM Mexico Daylight Time Professor Detlef Lohse escribe: Thanks for your nice words. You carefully read the paper. We made the sand flushy to destroy the force chains. In this way hardly any energy is stored in the ground, and the energy of the object is overwhelming. The geophysics community calls this gravity driven. I just talked about this at the Gordon conferences here in Colby, Maine, USA and the geophysicists who were around viewed it favorably. Best regards, Detlef Lohse Dear Meteorite-list, I am forwarding the above friendly response from Dr. Lohse, the physicist from the Netherlands who designed the recent impact experiment and whose area of study is events of singularity. Apparently has just discussed the recent work modeling terrestrial impacts under discussion here at the physics' symposia "Gordon Conference" currently held in the US. In his reply he emphasizes that the ratio of the impactor's energy to that of the potential energy in the ground makes the latter negligible. That's the case expected for the real asteroid impacting events. That suggests to me that it is the first time someone has actually modeled such an energy differential in the laboratory, helping to earn the work the honor of "first scalable impact event created in the laboratory", not to mention the differences they identified vs. videos relating to unique sedimentation and reverse jet they worked the physics out on which are different from liquid models that have been already investigated. For example, it supports the idea that the meteorite winter that helped wipe out the dinosaurs was caused by terrestrial ejecta jetted in reverse along the entry trajectory, rather than from a splash, as most videos would indicate. That was done by an interesting, basically two dimensional cross experiment that I have never seen in a video. But then again you folks in the US are more privileged than much of the rest of the world when it comes to the media. The work also might also be useful to investigate under what impact conditions an earth meteoroid might theoretically be produced, which has previously been a topic of much interest to this group. The goal of this work was clearly not to film any collision which will obviously help one get a handle on collisions in general, such as a drop falling on apuddle, and what happens on a small time scale; it was to reporduce for the first time the energy ratios contemplated for Earth's big extinction events. I hope the 599 other members of the meteorite list will join with me in wishing him congratulations and further encouragement to refine the results on sedimentation patterns and the resulting stress patterns in this interesting impact research, and thanks to Ron Baalke at JPL for the initial post alerting us to this. The list is described at http://www.meteoritecentral.com and has members who are interested in all aspects of meteorites, impacts, for the scientific, hobby and resulting commerce of meteorite trade. Saludos, Doug Dawn N. 25.4° W. 100.2° Mexico __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
RE: [meteorite-list] Extraterrestrial Impact Recreated in the Laboratory
Agree with Craig.. The simpler tests using a drop of milk in a puddle produced much better information. You could see the concentric rings being created (complex ring structure crater) as the central mass sank, upwelled, and sank again. By using the fluid dynamics math on the liquid, and extrapolating to the fluid effects that sand and rock would have, you could understand how the concentric rings were frozen in time, when the energy level dropped low enough so that the material stopped behaving like a fluid, thus producing the multiple rings in the crater, and a domed central uplift in the exact center.. I do not see this behavior modeled well enough in this new test, to call in unique. CharlyV From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, June 29, 2004 6:38 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: [meteorite-list] Extraterrestrial Impact Recreated in the Laboratory ?? I've seen video of this type of test being performeded numerous times on various TV programs on places like The Discovery Channel, etc. So unless I missed something here, what was so special about this test? Craig Hola Craig, I think the special aspects you could be missing is that, the test is far more rigorous than a video on The Discovery Channel! It seems that the Dutch group is quite experienced with integrating mathematical singularity events into coherent explanations, which bridge observations to theory. Like asking how does a bubble really pop and can we predict the volume or pitches of the sound wave produced?. While most of us are happy modeling that with some chewing gum or bubble bath, it sounds like these curious physicists probably can get into the almost philosophical question of how the weakness develops, at what limit it opens up, and where, and how that affects the trajectories of the material that goes flying. Keeping in mind that the holy grail of this sort of work ought to be scalability: In the impactor case of this study, they chose to model the surface of the experiment impact site based on aerated (carefully fluffed) uniform sized particles (sand). The reason for this, it seems, was to create a solid to be impacted which maximized the relative amount of energy the incoming iron impactor had. In other words, rather than create a super accelerated Hulk smashing projectile hitting compacted (higher stored potential energy) earth, in which events are apparently experimentally much more difficult and less reliable to set up on reasonable timescales and energies, it was easier to create a situation where the impact site had a lot less energy. They determined that the granulated impacted materials act somewhat like water and could be mathematically explained by common engineering fluid flow (Euler) equations, which reduced into a special case called a Rayleigh-type equation. This was an intriguing result, in the authors' opinions, as it is theoretically scalable. And scalability is what all of these videos wish they could do. But the fact remains - no one has ever been able to record a major impact event, so a new scalable model has the potential to give us much insight. The authors claimed, further, that a liquid (predictable) model is general not accepted, and these impact events are too easily written off as not reproducible - to random - So being a nice combination of experimental-theoretical physicists, they more rigorously developed the major ideas on the blackboard. It looks like their major result was that the iron tunnels into the site, and after mathematically modeling the tunnel created which collapses, and then solving for that point of first contact in the collapse, they derived equations from this simple experimental design which agreed with the observations of the creation of a splash and more importantly two jets: one forward into the tunnel, and the other exactly reverse, which implications were not covered well in the post (see next paragraph). They then further derived what sort of patterns should be created ... and scaled them up as permitted by their clever model. Their major result here was that the peripheral splash didn't cause most of the material thrown out as (tektites if you believe, or ejecta from earth to become earth meteorites). That honor was shown to be from the reverse jet created upon the not turbulent closing of the tunnel. There was a further observation not mentioned in the initial abstract posted here, that I think is very significant. That is that for a liquid like water, no matter what the entry angle, the resulting jet goes vertical. But in this case, unlike water, it went exactly backward along the entry trajectory. Furthermore, they were able to characterize what layers (call them sediments) ended up where. So the suggestion is that using this type of model to look for different impactites as these predictions go could be a good tool to understand what happened in the
[meteorite-list] Meteor Reported in Australia
http://www.abc.net.au/news/newsitems/200406/s1143829.htm] Meteorite reported in southern WA Australian Broadcasting Corporation June 30, 2004 The Perth Observatory says it has had reports a meteor has crashed near Walpole in Western Australia's south. Witnesses say they saw a large, fiery object zigzagging through the sky at about 5:30pm yesterday. The witnesses say the object left a trail of thick smoke and then they heard a bang. The observatory says it appears the object was travelling somewhere between Perth and Albany in a south-south easterly direction. Walpole resident Heather Burton was in her backyard when she saw the object. She says it was unlike a normal shooting star. A shooting star usually just goes straight across or straight down - this one had these gradual zigzags just coming down, she said. Alex Bevan from the WA Museum says the reports indicate the sightings were the result of a fireball generated by a meteorite. We're certainly picking up reports of a bright fireball and sonic phenomena associated - I'm absolutely sure - with the fall of a meteorite, Dr Bevan said. Dr Bevan says it will be difficult to find where the meteorite landed. Unfortunately there doesn't seem to be as many observations, so actually pinning down where the object landed might be a bit difficult and in that area, the vegetation might mean searching for it would be difficult, he said. __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Mars Global Surveyor Images - June 24-30, 2004
MARS GLOBAL SURVEYOR IMAGES June 24-30, 2004 The following new images taken by the Mars Orbiter Camera (MOC) on the Mars Global Surveyor spacecraft are now available: o South Polar Erosion (Released 24 June 2004) http://www.msss.com/mars_images/moc/2004/06/24/index.html o Pits Near Rhabon Valles (Released 25 June 2004) http://www.msss.com/mars_images/moc/2004/06/25/index.html o Isidis Planitia Features (Released 26 June 2004) http://www.msss.com/mars_images/moc/2004/06/26/index.html o Faulted Sedimentary Rocks (Released 27 June 2004) http://www.msss.com/mars_images/moc/2004/06/27/index.html o Caterpillar Dunes (Released 28 June 2004) http://www.msss.com/mars_images/moc/2004/06/28/index.html o Remnant Layered Rocks (Released 29 June 2004) http://www.msss.com/mars_images/moc/2004/06/29/index.html o Polar Dust Devil Streaks (Released 30 June 2004) http://www.msss.com/mars_images/moc/2004/06/30/index.html All of the Mars Global Surveyor images are archived here: http://www.msss.com/mars_images/moc/index.html Mars Global Surveyor was launched in November 1996 and has been in Mars orbit since September 1997. It began its primary mapping mission on March 8, 1999. Mars Global Surveyor is the first mission in a long-term program of Mars exploration known as the Mars Surveyor Program that is managed by JPL for NASA's Office of Space Science, Washington, DC. Malin Space Science Systems (MSSS) and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO. __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteor Reported in Australia
Zig-zagging = tumbling space junk? MDF http://www.abc.net.au/news/newsitems/200406/s1143829.htm] Meteorite reported in southern WA Australian Broadcasting Corporation June 30, 2004 The Perth Observatory says it has had reports a meteor has crashed near Walpole in Western Australia's south. Witnesses say they saw a large, fiery object zigzagging through the sky at about 5:30pm yesterday. The witnesses say the object left a trail of thick smoke and then they heard a bang. The observatory says it appears the object was travelling somewhere between Perth and Albany in a south-south easterly direction. Walpole resident Heather Burton was in her backyard when she saw the object. She says it was unlike a normal shooting star. A shooting star usually just goes straight across or straight down - this one had these gradual zigzags just coming down, she said. Alex Bevan from the WA Museum says the reports indicate the sightings were the result of a fireball generated by a meteorite. We're certainly picking up reports of a bright fireball and sonic phenomena associated - I'm absolutely sure - with the fall of a meteorite, Dr Bevan said. Dr Bevan says it will be difficult to find where the meteorite landed. Unfortunately there doesn't seem to be as many observations, so actually pinning down where the object landed might be a bit difficult and in that area, the vegetation might mean searching for it would be difficult, he said. __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list -- Marc D. Fries, Ph.D. Postdoctoral Research Associate Carnegie Institution of Washington Geophysical Laboratory 5251 Broad Branch Rd. NW Washington, DC 20015 PH: 202 478 7970 FAX: 202 478 8901 __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteor Reported in Australia
Portales Valley was spinning when it fell, so I think that if the body has a strange angled shape, that it can tumble, or spin while falling, I doubt that it was zig zagging as in changing directions like they suggest. Mike Farmer - Original Message - From: Marc D. Fries [EMAIL PROTECTED] To: Meteorite Mailing List [EMAIL PROTECTED] Sent: Wednesday, June 30, 2004 10:53 AM Subject: Re: [meteorite-list] Meteor Reported in Australia Zig-zagging = tumbling space junk? MDF http://www.abc.net.au/news/newsitems/200406/s1143829.htm] Meteorite reported in southern WA Australian Broadcasting Corporation June 30, 2004 The Perth Observatory says it has had reports a meteor has crashed near Walpole in Western Australia's south. Witnesses say they saw a large, fiery object zigzagging through the sky at about 5:30pm yesterday. The witnesses say the object left a trail of thick smoke and then they heard a bang. The observatory says it appears the object was travelling somewhere between Perth and Albany in a south-south easterly direction. Walpole resident Heather Burton was in her backyard when she saw the object. She says it was unlike a normal shooting star. A shooting star usually just goes straight across or straight down - this one had these gradual zigzags just coming down, she said. Alex Bevan from the WA Museum says the reports indicate the sightings were the result of a fireball generated by a meteorite. We're certainly picking up reports of a bright fireball and sonic phenomena associated - I'm absolutely sure - with the fall of a meteorite, Dr Bevan said. Dr Bevan says it will be difficult to find where the meteorite landed. Unfortunately there doesn't seem to be as many observations, so actually pinning down where the object landed might be a bit difficult and in that area, the vegetation might mean searching for it would be difficult, he said. __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list -- Marc D. Fries, Ph.D. Postdoctoral Research Associate Carnegie Institution of Washington Geophysical Laboratory 5251 Broad Branch Rd. NW Washington, DC 20015 PH: 202 478 7970 FAX: 202 478 8901 __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
RE: [meteorite-list] Extraterrestrial Impact Recreated in theLaboratory
The video that I referred to was of high speed projectile impact testing performed by NASA, so I think they could be considered somewhat rigorous. I'm not saying the tests referred to in Ron's original posting weren't important, but maybe the article just didn't spell out the reasons that it could be considered special. Craig Hola Craig, I think the special aspects you could be missing is that, the test is far more rigorous than a video on The Discovery Channel! __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteor Reported in Australia
In a message dated 6/30/2004 11:57:38 AM Mountain Daylight Time, [EMAIL PROTECTED] writes: Portales Valley was spinning when it fell, so I think that if the body has astrange angled shape, that it can tumble, or spin while falling, I doubtthat it was zig zagging as in changing directions like they suggest.Mike Farmer Hello Mike and List Members: I have seen my fair share of meteors - and can only once remember one deviating from a straight path. It had the SLIGHTEST of ziggs to one side about half way through its flight. This meteor was one of two that were a couple of seconds apart, in parallel paths almost right on top of each other. These are also the only two meteors I have ever heard - with a distinct "woosh" after they passed. They left a trail that lingered about for 30 seconds or so. Now in all fairness, this event happened 30 or so years ago I do have one witness. My sister was there with me and remembers the two meteors. Further details however are lacking in her memory. Juris Breikss [EMAIL PROTECTED] __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteor Reported in Australia
Juris, indeed, most meteors we all know are moving so fast and burn up. These large ones that drop meteorites slow down enough that the air pressures on the body can move it around. I think it would be extremely rare anyway, but with an odd shaped meteorite, and a hard one like an iron, when it slows down enough, I would think that the air can easily force it to rotate and spin. Mike Farmer - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] ; [EMAIL PROTECTED] ; [EMAIL PROTECTED] Sent: Wednesday, June 30, 2004 11:13 AM Subject: Re: [meteorite-list] Meteor Reported in Australia In a message dated 6/30/2004 11:57:38 AM Mountain Daylight Time, [EMAIL PROTECTED] writes: Portales Valley was spinning when it fell, so I think that if the body has astrange angled shape, that it can tumble, or spin while falling, I doubtthat it was zig zagging as in changing directions like they suggest.Mike Farmer Hello Mike and List Members: I have seen my fair share of meteors - and can only once remember one deviating from a straight path. It had the SLIGHTEST of ziggs to one side about half way through its flight. This meteor was one of two that were a couple of seconds apart, in parallel paths almost right on top of each other. These are also the only two meteors I have ever heard - with a distinct "woosh" after they passed. They left a trail that lingered about for 30 seconds or so. Now in all fairness, this event happened 30 or so years ago I do have one witness. My sister was there with me and remembers the two meteors. Further details however are lacking in her memory. Juris Breikss [EMAIL PROTECTED] __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteor Reported in Australia
I guess it comes down to what the eyewitness meant by zig zagging. If we're talking about some corkscrewing motion through the sky then I can believe it was a tumbling meteorite, but if it rapidly changed direction then my vote is for a large, tumbling, very-low-density-by-comparison chunk of expended rocket stage or the like. Cheers, MDF Juris, indeed, most meteors we all know are moving so fast and burn up. These large ones that drop meteorites slow down enough that the air pressures on the body can move it around. I think it would be extremely rare anyway, but with an odd shaped meteorite, and a hard one like an iron, when it slows down enough, I would think that the air can easily force it to rotate and spin. Mike Farmer - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] ; [EMAIL PROTECTED] ; [EMAIL PROTECTED] Sent: Wednesday, June 30, 2004 11:13 AM Subject: Re: [meteorite-list] Meteor Reported in Australia In a message dated 6/30/2004 11:57:38 AM Mountain Daylight Time, [EMAIL PROTECTED] writes: Portales Valley was spinning when it fell, so I think that if the body has a strange angled shape, that it can tumble, or spin while falling, I doubt that it was zig zagging as in changing directions like they suggest. Mike Farmer Hello Mike and List Members: I have seen my fair share of meteors - and can only once remember one deviating from a straight path. It had the SLIGHTEST of ziggs to one side about half way through its flight. This meteor was one of two that were a couple of seconds apart, in parallel paths almost right on top of each other. These are also the only two meteors I have ever heard - with a distinct woosh after they passed. They left a trail that lingered about for 30 seconds or so. Now in all fairness, this event happened 30 or so years ago I do have one witness. My sister was there with me and remembers the two meteors. Further details however are lacking in her memory. Juris Breikss [EMAIL PROTECTED] -- Marc D. Fries, Ph.D. Postdoctoral Research Associate Carnegie Institution of Washington Geophysical Laboratory 5251 Broad Branch Rd. NW Washington, DC 20015 PH: 202 478 7970 FAX: 202 478 8901 __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
Re-2: [meteorite-list] Meteor Reported in Australia
Hello Juris, Mike, and List, with an odd shaped meteorite, and a hard one like an iron, when it slows down enough, I would think that the air can easily force it to rotate and spin. Noblesville (H4) - oriented with well-developed flight markings, 483.7 grams. B.Kinzie saw the meteorite spinning as it passed them, watched it thud into the lawn 3.56 in in front of them and saw the meteorite rock a little as it impacted the lawn. Best regards, Bernd To: [EMAIL PROTECTED] [EMAIL PROTECTED] [EMAIL PROTECTED] [EMAIL PROTECTED] __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Meteor Reported in Australia
... they saw a large, fiery object zigzagging through the sky at about 5:30pm yesterday. Zig-zagging = tumbling space junk? comes down to what the eyewitness meant by zig zagging if it rapidly changed direction ... a large, tumbling, very-low- density-by-comparison chunk of expended rocket stage ... Hello again, As it was about 5:30 p.m., the sun was already low on the horizon. This might support Marc D. Fries's assumption that it was space junk - maybe something metallic that reflected the sunlight at more or less regular intervals while it was tumbling into and out of the incident sunlight. This tumbling motion may have led to the illusion that it was zigzagging. Cheers, Bernd __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Zig zags and spinning
Dear list, Sounds like we are talking about two different phenoma here: rotational spinning and relative translational displacement, or zig zagging. There is a third one to consider, too, spiraling. Spiraling traces zig zagging in that brief moment of surprise, if like most viewers, they see it from the side, and not coming right at them. There is no reason the meteorite can't spiral or truly zig zag coming down, something like the random a "skipping" stone a child throws at the water. The same sort of thing happens as the usually rotating meteorite enters the atmosphere. If the rotation is like a steam roller you'll likely get the true zig zag, but if the meteor is irregular enough then you get the two diminsional spiral version of a zig zag. As the amount of surface area to the air changes direction and intensity while rotating, the upward frictional force varies, causing a truer zig zag for the steam roller type spinner, which has one degree less of orientation than a true oriented projectile that fall in a parabolic arc. On the other hand, if the spin axis isn't perpendicular to the incident trajectory (i.e. not a steam roller), you will get a spiral. Either way they look like gradual zig zags. I have spoken with witnesses to a bolide who independently described the same even as a zig zag in one case, and the other a spiral. They did not have any idea what others reported. They even carefully described to me the sounds accompanying the spiraling cycles: Just like a puttering jalopy which repeats itself every few seconds. If you're in a speeding car and have the pleasure to stick a "karate chop" hand out the window, held straight out, you can zig zag. If you vary the "straight out" part you will feel the pressure to spiral. Harvey in "Find a Falling Star" 1972, was very impressed by cowboy Chharles M. Brown's reflexes in capturing the Pasamonte, New Mexico bolide on film on March 24, 1933, at exactly 5:00 PM. Al Mitterling kindly sent me an image of that picture which doesn't appear in the original edition, though it is discussed a lot. I have taken the liberty of posting kind Al's image of Brown's photo at: http://www.diogenite.com/Pasamonte.jpg where the zig zag is apparent. Still, I need to agree with Mike in the sense that the newspaper sensationalized the whole thing, saying "a fiery object zigzagging across the sky" when the original actual witnesses' quote is much more appropriate in the same article: "gradual zig zags". There was a slightly suggested, unintention little green men aspect of the reporter's description, in my opinion, too. Saludos, Doug Mexico Portales Valley was spinning when it fell, so I think that if the body has a strange angled shape, that it can tumble, or spin while falling, I doubt that it was zig zagging as in changing directions like they suggest. Mike Farmer - Original Message - From: "Marc D. Fries" m.fries at gl.ciw.edu To: "Meteorite Mailing List" meteorite-list at meteoritecentral.com Sent: Wednesday, June 30, 2004 10:53 AM Subject: Re: [meteorite-list] Meteor Reported in Australia Zig-zagging = tumbling space junk? MDF http://www.abc.net.au/news/newsitems/200406/s1143829.htm] Meteorite reported in southern WA Australian Broadcasting Corporation June 30, 2004 The Perth Observatory says it has had reports a meteor has crashed near Walpole in Western Australia's south. Witnesses say they saw a large, fiery object zigzagging through the sky at about 5:30pm yesterday. The witnesses say the object left a trail of thick smoke and then they heard a bang. The observatory says it appears the object was travelling somewhere between Perth and Albany in a south-south easterly direction. Walpole resident Heather Burton was in her backyard when she saw the object. She says it was unlike a normal shooting star. "A shooting star usually just goes straight across or straight down - this one had these gradual zigzags just coming down," she said. Alex Bevan from the WA Museum says the reports indicate the sightings were the result of a fireball generated by a meteorite. "We're certainly picking up reports of a bright fireball and sonic phenomena associated - I'm absolutely sure - with the fall of a meteorite," Dr Bevan said. Dr Bevan says it will be difficult to find where the meteorite landed. "Unfortunately there doesn't seem to be as many observations, so actually pinning down where the object landed might be a bit difficult and in that area, the vegetation might mean searching for it would be difficult," he said. __ Meteorite-list mailing list Meteorite-list at meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Cassini Set to Ring Saturn Today
MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011 http://jpl.convio.net/site/R?i=h8gLqhEOIJ5O-3BCLCXxIg.. Donald Savage (202) 358-1727 NASA Headquarters, Washington Carolina Martinez (818) 354-9382 Jet Propulsion Laboratory, Pasadena, Calif. NEWS RELEASE: 2004-167 June 30, 2004 Cassini Set to Ring Saturn Today After nearly seven years of asking, Are we there yet? the Cassini-Huygens mission is poised to enter Saturn's orbit this evening. Getting into orbit means we have a mission. If we don't get into orbit then we have a flyby and that's not what we are here to do, said Dr. Dennis Matson, project scientist for the Cassini-Huygens mission at NASA's Jet Propulsion Laboratory, Pasadena, Calif. We are confident that the Cassini team will get us there. Although everything on the spacecraft is performing well, mission managers caution that this is not a slam-dunk by any means. There are risks as with any mission. One of those risks is the ring plane crossing. Although this area has been mapped extensively and is believed to be safe, there is still a risk of an impact to the spacecraft. There are three hold-your-breath moments for the mission, said Robert T. Mitchell, program manager for the Cassini-Huygens mission at JPL. The first is when we see the signal coming back after we cross the ring plane in the ascending direction. The second is an indication that the burn has begun at 7:36 p.m. Pacific time (10:36 p.m. EDT). And finally, the signal showing the burn completion at the right time. Another concern is weather that may affect the reception of the signal on Earth. Weather on Earth will not change the outcome of the mission but it will impact whether or not mission controllers will receive a signal during the orbit insertion. Current weather predictions at the Canberra, Australia, station of the Deep Space Network show possible high winds that could effect this evening's operation of that antenna. This evening at 7:11 p.m. PDT (10:11 p.m. EDT), Cassini will cross the ring plane between Saturn's F and G rings. Its antenna will be oriented forward and act as a shield against small particles. At 7:36 p.m. PDT (10:36 p.m. EDT), the spacecraft will begin a critical 96-minute main engine burn. Once the burn is complete the spacecraft will turn and send a signal back to Earth to report how it is doing. Then it will point its cameras and other instruments at the rings. Orbit insertion is sort of like applying your brakes while driving your car downhill, said Mitchell. Although you've got your foot on the brakes, you still pick up speed as a steep gravity pulls you in. During the burn, the spacecraft will change its velocity by 626 meters per second (1,400 miles per hour). Relative to Saturn, at burn start the spacecraft speed is 24.26 kilometers per second (54,270 miles per hour) and at the end of the burn the speed is 30.53 kilometers per second (68,293 miles per hour). Mission managers expect periodic interruptions of the Doppler signal as Cassini passes behind the rings. The team that got the spacecraft to Saturn may be one of the most seasoned teams to work on a large mission like Cassini, mostly due to the fact they have flown the spacecraft for seven years. We've had nearly seven years to iron out the wrinkles, said Julie Webster, spacecraft team chief at JPL. We are ready. In many ways, the most exciting part of the journey is about to begin because we don't know what lies ahead. We've been driving this bus for nearly 3.5 billion kilometers (2.2 billion miles), said Dr. Jeremy Jones, navigation team chief of the Cassini-Huygens mission at JPL. The trip has sort of been like a long car drive, and we can't wait to get out there and explore the sites. In a sense the tour is just beginning. The arrival period provides a unique opportunity for scientists to observe Saturn's rings and the planet itself. The spacecraft's closest approach to Saturn during the entire mission is at 9:03 p.m. PDT. Its distance from the center of Saturn will be 80,230 kilometers (49,850 miles) and 19,980 kilometers (12,400 miles) from the cloud tops. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. JPL designed, developed and assembled the Cassini orbiter. For the latest images and more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini .
Re: [meteorite-list] Meteor Reported in Australia
Mike Farmer wondered: I think it would be extremely rare anyway, but with an odd shaped meteorite, and a hard one like an iron, when it slows down enough, I would think that the air can easily force it to rotate and spin. Hi All, I remember reading about a meteorite that fell through the trunk of a car in Japan a number of years ago. The meteorite was spinning and as it punched through the metal of the trunk lid, it was scored or somehow marked with a screw-thread pattern that was later used to hypothesize about the spin rate of the falling stone. Anyone else remember this and know more about it? Martin __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] re: Meteor Reported in Australia
Zig-zagging = tumbling space junk? MDF Not likely. There is no suitable decay candidate for that date/time/location combination. The last decay warning at the NASA OIG server is for the decay of 1992-088E on June 27, which was a spectaculare one observed from the eastern USA and Canada. No decayers after that date. The next expected decay is in a couple of hours from now, the decay of a piece of Ariane 3 debris (1988-018E). - Marco -- Marco Langbroek Leiden, the Netherlands 52.15896 N, 4.48884 E (WGS 84) e-mail: [EMAIL PROTECTED] website: http://home.wanadoo.nl/marco.langbroek weblog: http://home.wanadoo.nl/marco.langbroek/iss_log.html -- __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
Re-2: [meteorite-list] Meteor Reported in Australia
Martin writes: I remember reading about a meteorite that fell through the trunk of a car in Japan a number of years ago. The meteorite was spinning and as it punched through the metal of the trunk lid, it was scored or somehow marked with a screw-thread pattern that was later used to hypothesize about the spin rate of the falling stone. Anyone else remember this and know more about it? This one? Another Car Conker (Sky Telescope, September 1995, p. 12): Kciichi Sasatani didn't hear the loud bang that announced the arrival of a small stony meteorite outside his home on the night of February 18th. But the retired school director from Neagari, Japan, had no trouble finding the cosmic intruder the next day: it was lying squarely in the deeply punctured trunk cover of his car. Eyewitnesses saw a bright bolide near midnight (14:55 Universal Time) prior to the stone's abrupt landing. The fireball appeared high above the Sea of Japan and traced a steep, south-southeast trajectory toward the coast. About the size of a chicken's egg, the Neagari meteorite broke into at least four pieces upon impact. The largest of these weighs 325 grams. According to Akira lshiwatari (Kanazawa University), the stone is an L6 chondrite, one of the most common types to fall on Earth. But it is very special to Sasatani, who now owns one of only three meteorites known to have struck a vehicle. The most famous predecessor fell in Peekskill, New York, in October 1992 (ST, February 1993, page 26). Less well known is the unfortunate meeting of a 1.8-kilogram stone and a Pontiac coupé in Benld, Illinois, on September 29, 1938 (The Sky, June 1939, page 11). A fourth collision, reported last year near Madrid, Spain, may not have involved a meteorite after all. Cheers, Bernd To: [EMAIL PROTECTED] [EMAIL PROTECTED] __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Re: Meteor Reported in Australia
I wrote: The last decay warning at the NASA OIG server is for the decay of 1992-088E on June 27, which was a spectaculare one observed from the eastern USA and Canada. No decayers after that date. The next expected decay is in a couple of hours from now, the decay of a piece of Ariane 3 debris (1988-018E). Might have been wrong here. Turns out there were two launches that day, at 3:59 UTC and 6:30 UTC, and I do not know whether the first stages of such launches get listed by the OIG as it returns almost immediately after separation. Could be an option, perhaps. - Marco -- Marco Langbroek Dutch Meteor Society (DMS) Leiden, the Netherlands 52.15896 N, 4.48884 E (WGS 84) e-mail: [EMAIL PROTECTED] DMS website: http://www.dmsweb.org priv. website: http://home.wanadoo.nl/marco.langbroek -- __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Ensissheim Ste Marie shows - ADD Acfer and Tanezrouft
Dear All, We have made new pages of our web site in order to put some pictures of Ensisheim and Ste Marie aux Mines Shows, that you can see at: - Ensisheim (English): http://meteoriteshow.free.fr/meteoriteshow%20angl/pages%20navigation/Ensisheim-navbanner-contact.html - Ste Marie (English): http://meteoriteshow.free.fr/meteoriteshow%20angl/pages%20navigation/SteMarie-navbanner-contact.html - Ensisheim (French): http://meteoriteshow.free.fr/meteoriteshow%20fra/pages%20navigation/Ensisheim-navbanner-contact-copyright-fra.html - Ste Marie (French): http://meteoriteshow.free.fr/meteoriteshow%20fra/pages%20navigation/SteMarie-navbanner-contact-copyright-fra.html Bernd and Hanno have already provided a very good report of Ensisheim show and we do not see anything to add as far as comments are concerned, hoping that we will be even more crazy space rocks lovers next year! We have also put on our "for sale" page one slice - and sometime the comlpete main mass - of each Acfer and Tanezrouft meteorite that we recently got classified and announced in the MB #88. This includes some highly shocked ones (up to S6) and fresh ones as well (up to W1). All of them are chondrites: L6, H3-5, H3, LL5, LL6, one L Impact Melt, etc... We have also added a beautiful slice of our C4 anomalous Tanezrouft 057, which displays the main C4 structure, some CAIs and part of a dark inclusion... Please have a look at: http://meteoriteshow.free.fr/meteoriteshow%20fra/pages%20navigation/pieces_en_vente-fra.html Some have a very low TKW and we won't have many slices of those available! Acfer 345 (LL5) and Tanezrouft 067 (L impact melt) are so small and nice, that we do not want to cut more than the type specimen from them. Therefore, we propose the completeremaining masses. Thanks and best wishes, Frederic Beroud Christophe Boucherwww.meteoriteshow.comIMCA #2491 __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Original Meteorite Kills(Fill in Blank) Story Appears in WWW
While waiting in the local cehckup line, I noticed that this week's Weekly World News (WWW) has one of the latest versions of the Falling Meteorite kills (fill in the blank) story. The headline reads, Meteorite Flattens Pope. In the tradition of the Weekly World News, it is quite a shaggy dog story complete with fake photographs. The people, who publish the WWW must be really strange people. Yours, Paul __ Do you Yahoo!? New and Improved Yahoo! Mail - Send 10MB messages! http://promotions.yahoo.com/new_mail __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteor Reported in Australia
G'day List, The way I interpreted this is that it was probably a meteor fragmenting before 'burn-out'. Read this line: A shooting star usually just goes straight across or straight down - this one had these gradual zigzags just coming down," she said. The resultant fragments could be seen as "zig-zags"; kind of like fireworks. I've seen this phenomena a few times myself. Cheers, Jeff KuykenI.M.C.A. #3085www.meteorites.com.au - Original Message - From: Ron Baalke To: Meteorite Mailing List Sent: Thursday, July 01, 2004 3:35 AM Subject: [meteorite-list] Meteor Reported in Australia http://www.abc.net.au/news/newsitems/200406/s1143829.htm]Meteorite reported in southern WAAustralian Broadcasting CorporationJune 30, 2004The Perth Observatory says it has had reports a meteor has crashednear Walpole in Western Australia's south.Witnesses say they saw a large, fiery object zigzagging through thesky at about 5:30pm yesterday.The witnesses say the object left a trail of thick smoke and thenthey heard a bang.The observatory says it appears the object was travelling somewherebetween Perth and Albany in a south-south easterly direction.Walpole resident Heather Burton was in her backyard when she saw theobject.She says it was unlike a normal shooting star."A shooting star usually just goes straight across or straight down- this one had these gradual zigzags just coming down," she said.Alex Bevan from the WA Museum says the reports indicate thesightings were the result of a fireball generated by a meteorite."We're certainly picking up reports of a bright fireball and sonicphenomena associated - I'm absolutely sure - with the fall of ameteorite," Dr Bevan said.Dr Bevan says it will be difficult to find where the meteorite landed."Unfortunately there doesn't seem to be as many observations, soactually pinning down where the object landed might be a bitdifficult and in that area, the vegetation might mean searching forit would be difficult," he said.__Meteorite-list mailing list[EMAIL PROTECTED]http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Perry to Nininger Letter; Jan. 3, 1954
(Stuart Perry to Harvey Nininger letter, Perry's File copy) January 3, 1954 Dear Harvey, Glad to get your letter, and a happy New Year to you and Mrs. Nininger. Your offer of the two meteorites is tremendously interesting, though the money involved is a bit appalling. But I must admit the extraordinary interest and value of both of them. I am writing Ed to see how badly he wants them and as soon as I hear from him I will write you. That must have been a very interesting meeting at Boston. Didn't you have a paper on nickel-free meteorites? If so, I should very much like to know what you said and what you know about it. I have always had a suspicion that there might be Ni-free meteorites, and I can see no reason in metallurgy which there should be iron with less than 6% Ni or none at all. Maybe we should not brush off some of those old analyses showing 3% or 2% nickel. We have been now just two weeks, and it is pleasant as ever. Some pretty cold nights, but the daytime weather is just what we like. With best regards, Sincerely, (Stuart Perry - name is missing as this is the file copy. The original sent to Nininger would have been signed by Perry)Please visit, www.MeteoriteArticles.com, a free on-line archive of meteor and meteorite articles. __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Perry to Nininger Letter; Jan. 11, 1954
(Stuart Perry to Harvey Nininger letter, Perry's File copy) January 11, 1954 Dear Harvey, I have decided that I don't want to buy the two meteorites. I am sorry, but can't see any other way. They represent too much money to buy for my own collection, and if I gave them to the U.S. Museum I could not claim an income tax deduction larger than the amount paid to you, which would mean that the gift would cost me a substantial amount, more than I feel that I want to give to the "cause" this year. I am counting the dollars a little more carefully because I have just made a large contribution to a big hospital fund drive at Adrian, and have some unusually large personal experience items either just paid or soon to be. With warm regards, Sincerely, (Stuart Perry - name is missing as this is the file copy. The original sent to Nininger would have been signed by Perry)Please visit, www.MeteoriteArticles.com, a free on-line archive of meteor and meteorite articles. __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Nininger to Perry Letter; Jan. 25, 1954
(American Meteorite Museum Letterhead) DEVOTED TO RESEARCH AND POPULAR METEORITICS (drawling of Sedona museum) BOX 146, SEDONA, ARIZONA H.H. Nininger, M.S., D.Sc. DIRECTOR Addie D Nininger SECRETARY - TREASURER C.H. Brandmeyer SUPT. OF CONSTRUCTION AND DESIGN January 25, 1954 Mr. S. H. Perry Arizona Inn Tucson, Arizona Dear Stuart: Your letters were on my desk when I returned from the east. I can well understand that the purchase of those two meteorites would constitute a bit of an adjustment somewhere yet I cannot believe that you want to turn the offer down with finality. It is the first time in twenty-two years that we have ever been able to bring ourselves to the point of offering Bruno and I am sure that once we have negotiated our present crisis without disposing of them we shall not soon, if ever, be willing to offer them again. We could accept half down and the other half some months later if that would suit you better. Also, you might wish to purchase only one of the two offered. I have to make a trip to Tucson about the middle of February and I think I shall bring Bruno with me since, as I remember, you have seen only once what I regard as the finest specimen of nickel-iron meteorites in existence. You will be under no obligation to me for the bringing it, if I decide to do so. Regards to Mrs. Perry from both of us. All the papers of the symposium have been submitted for publication to Geochimica et Cosmochimica Acta according to a letter I have just received from the chairman Dr. Uhlig. Sincerely, (signed) H.H. Nininger HHN: AN cc: E.P. Henderson (Mark Note: Page also has written on it 154.8 x 3 = $464.40. This was written in pencil on the letterhead and appears to be a note on the price of the Horse Creek specimen.)Please visit, www.MeteoriteArticles.com, a free on-line archive of meteor and meteorite articles. __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Rocks From Space Picture Of The Day - July 1, 2004
http://www.geocities.com/spacerocksinc/July_1.htmlIMCA#5184 __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] AD: Digital Scale
Hello list, I am running a sale on the 0.1g-600g digital scale I sell for the next 24 hrs. I have sold over 100 of these almost completely to the meteorite community. In fact, it is fair to say a good portion of the meteorite sellers on eBay is using a scale I sold them. I am still using the one I purchased over two years and use daily, For more information on the scale see the following link: http://www.meteoritearticles.com/scale.html The scale retails at $159.99, in Tucson and Denverthey were selling for $129.99 (one of the large mineral dealers sell them). I have been selling the scalefor $85.99, order now and I will make the scale down to $80.00. E-mail off list if interest, Mark Bostick www.meteoritearticles.com __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Cassini is in orbit around Saturn!
Woohoo! __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Original Meteorite Kills(Fill in Blank) StoryAppears in WWW
Hi, All, The people who publish WWW are like all the other checkout tabloid publishers, cynical Brits who rightly believe that there is no limit to how rich you can become by underestimating the intelligence of the average American. The really strange people are the ones who READ the Weekly World News! Sterling Webb - Paul H wrote: While waiting in the local cehckup line, I noticed that this week's Weekly World News (WWW) has one of the latest versions of the Falling Meteorite kills (fill in the blank) story. The headline reads, Meteorite Flattens Pope. In the tradition of the Weekly World News, it is quite a shaggy dog story complete with fake photographs. The people, who publish the WWW must be really strange people. Yours, Paul __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Ad, Sale, e-bay
Gretings List, I've just listed two very nice endpieces of Park Forest on ebay. Starting price is just $7.00 per gram. See: http://members.ebay.com/aboutme/anorthosite thanx, Steve = Steve Witt IMCA #9020 http://www.meteoritecollectors.org __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
