Re: [meteorite-list] Earth Trojan asteroids
Hi, Rob, Doug, List Why am I always digging myself out of holes that I apparently made with my own mouth? Well, better than extracting one's own feet from that same mouth, I guess. There are many definitions of phase angle. Leaving out the ones that apply to periodic and wave functions, I find: 1. The angle between the incident sunlight and the viewing direction when looking at an illuminated surface. Low phase angles result in relatively few shadows being cast by the surface relief. 2. The angle between the Sun, an object, and an observer. 0 degrees phase means the Sun is behind the observer. 3. The angle between a line from the Sun to the center of a body and a line from the spacecraft to the center of the same body. 4. For a solar system object besides the earth and sun, the angle between the earth and the sun (or the earth's elongation from the sun) as seen from that third object. The phase angle is given in ephemerides on IAU Circulars and Minor Planet Circulars is denoted by either of the lower-case Greek letters beta or phi. 5. The phase angle states the phase of a celestial body, i.e. the illuminated fraction of it as it can be seen from the Earth. Of course, you might note that I NEVER said phase angle. I merely used the word phase (simplified version of definition #5) in its most direct sense, as in, What is the phase of the Moon tonight? And 2/3rds means that 2/3rds of a sphere at the Trojan point would be illuminated and 1/3rd would be dark) as viewed from the Earth. And, considering that the shape of an asteroid is often not only NOT a sphere, but usually mathematically impossible to characterize, we fall invariably back on terms like potato, lumpy potato, or it looks like a butternut squash to me. And since the curve of this varying reflectance would also depend on its rotational period in all axes, any compositional differences on its surface, and the number of shiny new UFO's parked on it for scheduled maintenance that day, I did not feel that it was a strictly predictable quantity. And while an asteroid would dim by a factor of 2.512 to the .64th power from opposition to the Trojan position, since we don't have the foggiest notion what its albedo would be (except that we casually assume it to be like most NEA's or in their range), it is a result of very high precision and only slight accuracy. In ancient days long gone, I used to set up little problems for the mid-1980's computers that ran MicroSoft Basic Vers. 4.21, in which the answer to 2 + 2 would come out 3.997547563954. Highly precise; not very accurate. The two are not the same. I had a lot of fun writing an arithmetic program in BASIC which converted numerical imputs to $tring functions, then digit by digit performing the same grade school arithmetic every child learns, constructing the answer as $tring functions again, with callable subroutines for each (addition, subtraction, etc., even roots) arithmetical operation. In that era of big 16-bit processors and horrendous floating point errors, people would stare at an old Kapro CPM machine churning out solutions (like the square root of 2) to 998 decimal points of accuracy like it was the Second Coming. They get all excited and yell, What algorithm are you using? Arithmetic, I'd answer. No, I know it's doing arithmetic, but what's the algorithm? No, I reply, you don't get it. The algorithm is ARITHMETIC. That's all I'd say. They'd figure it out sooner or later, but it was always fun to watch the struggle to absorb the obvious. However, you are dead right about Jupiter's Trojans. I screwed the pooch on that one. Too late at night, wrong column of figures, bad eyes, just-plain-dumb, all factor in... Oh, don't forget old data, too JUPITER TROJANS EAST a = 4.90 to 5.37 AU e 0.30 and i 40° Lagrangian point L4 of Jupiter: NUMBER KNOWN AS OF MAY 20, 2004: 525 ESTIMATED TOTAL: 1039 JUPITER TROJANS WEST a = 4.96 to 5.36 AU e 0.28 and i 44° Lagrangian point L5 of Jupiter NUMBER KNOWN AS OF MAY 20, 2004: 352 ESTIMATED TOTAL: 628 And I can't even figure where I got the 149 number from, now. Pleasant that we're over last year's estimated total already. Congratulations on SEVEN Trojans! But there is something that bothers me... Always a big fan of the Iliad, even BEFORE it was a movie with Brad Pitt, I can't recall the names of 1783 Trojan characters in the Iliad! In fact, I count only: Hector, Priam, Hecuba, Paris (also known as Alexander), Helen (of course, she's a Trojan now...), Aeneas, Andromache, Astyanax, Polydamas, Glaucus, Agenor, Dolon, Pandarus, Antenor, Sarpedon, Chryseis, Briseis, and Chryses. Not a cast of thousands... Where do folks come up another 1765 Trojan names? Third soldier from the left in the last row in the Battle in Book Ten? Just make'em up? Greekify your children's names? Just leave it to some gentlemen in Paris at
[meteorite-list] AD - ebay auctions ending soon!
Hello List, i got some auctions ending soon, some of them are still at 1€ Theres a cute brahin with some shining through olivines and much more... If you like take a look here: http://cgi6.ebay.de/ws/eBayISAPI.dll?ViewSellersOtherItemsuserid=gipometeoritesinclude=0sort=3rows=25since=-1rd=1 Thanks for your interest! Carsten __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Earth Trojan asteroids
Sterling: Always a big fan of the Iliad, even BEFORE it was a movie with Brad Pitt, I can't recall the names of 1783 Trojan characters in the Iliad! Hola Sterling, for one thing, they cheat, because the L4 are the Greeks and the L5 are the Trojans, with a few glaring errors (Hektor is L4). So they should really be called the Greco-Ilium asteroids! Here;s where they seem to be at, lots of names and many more are only numbers and even more are just coded for year for the time being (looks like twpo more are already there = 1785 now): http://cfa-www.harvard.edu/iau/lists/JupiterTrojans.html The last one listed there with a name was (85030) Admetos. But it was discovered in 1960. From the Iliad, a homage to all the fleets great and small and lots of people...In the Book of Ships Fleets (Book II) Admetos is mentioned as king and father of a princely commander of a small fleet of 11 ships from Pherai (who fought with the Greeks) (L4, checks ok): And of them that dwelt in Pherai by the Boibeian mere, in Boibe and Glaphyre and stablished Iolkos, of them, even eleven ships, Admetos' dear son was leader, Eumelos whom Alkestis, fair among women, bare to Admetos, she that was most beauteous to look upon of the daughters of Pelias. This was really an epic war ... with literally hundreds of names - maybe enough for the moment with a little liberal research (i.e., you know one ally, of the dozens, just do a little research and more names mentioned or not in the Illiad will be recorded somewhere...Achilles alone commanded 50 ships, and he was just one of about 50 groups...each with a fierce pride) Here's one from 1998: (21602) Ialmenus, son of mighty Ares' galavanting who layed with the stately maiden Astyoche, again from the Book II of Ships: And they that dwelt in Aspledon and Orchomenos of the Minyai were led of Askalaphos and Ialmenus, sons of Ares, whom Astyoche conceived of the mighty god in the palace of Aktor son of Azeus, having entered her upper chamber, a stately maiden; for mighty Ares lay with her privily. And with them sailed thirty hollow ships. But as you can see from the list, there can't be more than about 200 named so far... Saludos, Doug Sterling W. wrote: Always a big fan of the Iliad, even BEFORE it was a movie with Brad Pitt, I can't recall the names of 1783 Trojan characters in the Iliad! In fact, I count only: Hector, Priam, Hecuba, Paris (also known as “Alexander”), Helen (of course, she's a Trojan now...), Aeneas, Andromache, Astyanax, Polydamas, Glaucus, Agenor, Dolon, Pandarus, Antenor, Sarpedon, Chryseis, Briseis, and Chryses. Not a cast of thousands... Where do folks come up another 1765 Trojan names? Third soldier from the left in the last row in the Battle in Book Ten? Just make'em up? Greekify your children's names? Just leave it to some gentlemen in Paris at IAU to do it? Give'em numbers? Buy one of those 5000 Names for Your Child books, written in Greek? What?! __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] AD - Ebay auctions ending tonight
Hi All... My ebay auctions including the new Winonaite are ending tonight under user name catchafallingstar.com Or go to the following link and scroll to the bottom of the page: http://cgi3.ebay.com/ws/eBayISAPI.dll?ViewUserPageuserid=catchafallingstar.com Thanks for looking and have a great weekend... Jim Strope 421 Fourth Street Glen Dale, WV 26038 http://www.catchafallingstar.com __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Earth Trojan asteroids
Francis and List, could someone help me with the L4, L5 points?? Jerry Flaherty - Original Message - From: Francis Graham [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Friday, June 24, 2005 6:21 PM Subject: Re: [meteorite-list] Earth Trojan asteroids MOON Trojan objects exist. They are the Kordylewski clouds, small faint patches of dust, at the L4 and L5 points of the Earth-Moon system (not Earth-sun system). The Kordylewski clouds have been photographed, and have even been seen by the naked eye under total dark skies. They may be variable in their mass and integrated visual magnitude. Very little has been studied about them, very little is known about their possible variability, nobody has anything like a reflectance spectrum of the dust. They remain the closest things about which so little is known. They could well be the subject of study of any of you who wish to make a contribution to science. One thing is known: unless you are under skies so dark the Milky Way is a BRILLIANT band of light, and the Gegenschein is easy, and the zodiacal light is an obvious swath, unless you are under those kinds of dark skies, you have NO hope of seeing the Kordylewski clouds. Francis Graham --- [EMAIL PROTECTED] wrote: Hola Rob, Wouldn't that be = 2/3's (gibbous) phase = about 66% illumination, and a maximum average sky angle of a comfortable,high 60 degrees max observed angle (+/- the oscillation) ... checking they're equilateral triangles, though intuition might be wrong? Saludos, Doug En un mensaje con fecha 06/23/2005 6:21:15 PM Mexico Daylight Time, [EMAIL PROTECTED] escribe: Certainly astronomers have tried, but small objects at L4 and L5 would be hard to see due to a combination of range (150 million km), poorer phase angle, and a maximum sky elevation of perhaps 45 degrees at astronomical twilight -- lower when the sky is darker. It would be an interesting exercise to compute the maximum size an Earth Trojan could be and still have managed to go undetected. --Rob __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Discover Yahoo! Use Yahoo! to plan a weekend, have fun online and more. Check it out! http://discover.yahoo.com/ __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Meteoritical Bulletin 89
G'day List, I was just taking a look through the Meteoritical Society website and it looks as if Bulletin 89 was finalised yesterday. I noticed the new edition also has a nice colour photograph of John Birdsell's NWA 2428. http://www.meteoriticalsociety.org/bulletin/mb89.pdf Cheers, Jeff Kuyken I.M.C.A. #3085 www.meteorites.com.au __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] New AZ find main mass, AD
Hello John and list, Here is a photo of the inside of a 15 gram piece I cut a while back, unpolished. http://www.nuggetshooter.com/fimage/DSCF0311.jpg Now about the slices, perhaps and if the main mass does not tickle anyone's fancy I may have it sliced up and offer it that way. I do have a couple in the 30 to 60 gram size I may cut and offer at a later date. I also plan to have a few thin sections made Bill - Original Message - From: JKGwilliam [EMAIL PROTECTED] To: Bill Southern [EMAIL PROTECTED]; Meteorite-list@meteoritecentral.com Sent: Friday, June 24, 2005 6:26 PM Subject: Re: [meteorite-list] New AZ find main mass, AD Hello Bill, Can you show us a picture of the interior of your new meteorite? Seems like I saw a picture of a part slice a while back but can't remember where to find it. Also, is there a possibility that you will be offer slices of this new Arizona chondrite? I know that several of us that specialize in Arizona meteorites would like to own one. Congratulations again on your new find. I'm thinking it might be worth the price just to get the proposed name so I can narrow down wher to hunt for more;-) Best, John Gwilliam At 05:20 PM 6/24/2005, Bill Southern wrote: Hello List, As many of you know I made a new chondrite find in January here in Arizona and it has been classified as a L5, S1, W3 by Lora Bleacher at ASU. This meteorite will be in the next bulletin pending acceptance. I have been hunting the area for 6 months now and have found only 840 grams or so with the main mass being 465 grams. I was hoping to get into more and still may who knows, but I have put in some serious time hunting with some help with no more found and a very large area of very rough country has been pretty well covered both by eye and metal detecting... All that I have so far is from the same specimen and found in a 25 x 50 foot area (or so). I have decided to sell the main mass (465 grams) to help out the ol' household cash flow so I will offer it here to the first one to offer $5.00 per gram I will wait 3 days before I follow other avenues. Here is a link to a photo of the specimen next to the second largest (164 g). The buyer will also be told the name (proposed) of the new AZ find that I have not so far released as I am still hunting the area. There are several here at the list that can give you a reference if you have any questions about me: John B. John Gwilliam Larry Sloan and a few others. If interested please contact me off list and click the link for a photo. http://www.nuggetshooter.com/fimage/Newfinda1-13-2005.jpg Best Regards, Bill Southern IMCA 1552 __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] OT: WorldWind
Has anyone been having trouble getting WorldWind to refresh lately? I used it a couple of weeks ago to look at our local cloud cover, and thought it looked unrepresentative (we were 80% overcast at the time, and I was trying to decide if it was safe to hang out the wash.) As it turned out, I had to run to bring in the laundry, as we got some unanticipated showers. For the last week, we have been looking at the same motionless strip of clouds over Haleakala. Are they still updating the views, or has there been a shutdown or breakdown? Tracy Latimer __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] (AD) summer iron meteorite sale
Hi list,because it has been so hot out, I have cooled down the prices on my sale.3 things have sold,with 5 items left.I also have added a 21 gram small sikote-alin with a hole for $45.00.Pics on demand.I am in the process of getting a larger one.Sikotes do not rust. steve Steve R.Arnold, Chicago, IL, 60120 Illinois Meteorites,Ltd! website url http://stormbringer60120.tripod.com __ Yahoo! Mail Stay connected, organized, and protected. Take the tour: http://tour.mail.yahoo.com/mailtour.html __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Earth Trojan asteroids
Jerry F. wrote: Francis and List, could someone help me with the L4, L5 points?? Jerry Flaherty Hola Jerry, L4 and L5: These two zones (it would be a point if it were unstable, but you will see that they are stable and hence, zones) are one AU in front of Earth or 1 AU behind Earth. They are stable: In the case of going co-orbital exactly 1 AU in front of Earth in our orbit (L4), or co-orbital 1 AU behind (L5), Earth, or anything of reasonable planetary size will either pull it back or drag it along. If it is wanders by being pulled back from L4, it gets pushed in an arc right into the Sun, and if it gets dragged along, it gets pulled away from the Sun outwards (both pull and push tangents from 1 AU around Earth are directed exactly into or away from the Sun - draw two equal circles, each that pass through the center of the other to convince yourself). Well hypothetically pushing it into the Sun in front, and then the Sun speeds it up and presto it gets sent right back to where it started from, and when Earth pulls it along then presto the extra distance pulled outward from the Sun slows it down, and the hypothetical deviation pull from Earth is compensated and it falls back into its place - a stable equilibrium. If you like algebra trig instead of my handwaving summary, it is done here: _http://www-spof.gsfc.nasa.gov/stargaze/Slagrng2.htm_ (http://www-spof.gsfc.nasa.gov/stargaze/Slagrng2.htm) and more elegantly here: _http://www-spof.gsfc.nasa.gov/stargaze/Slagrng3.htm_ (http://www-spof.gsfc.nasa.gov/stargaze/Slagrng3.htm) Each object has the property, on the case of the Earth-Sun-object, that they have an orbit of one Earth year, locked-step in a dance with Earth until a collision or huge comet/asteroid or even another star happens by...and 60 degrees is a magic number because it creates the equilateral triangle of connections among the three masses - which is why all the planets could have these regardless of size, within reason. Of course, it you placed it exactly at the point L4 or L5 itself and the Universe were just three bodies, it would stand still. But due to influences of other planets and significant asteroids, you can get little halo like oscillatory orbits around the frame of reference of the L-point. Just like pushing a pendulum -it doesn't stop... Pluto wouldn't be a likely candidate to have Pluto Trojans in my opinion since Neptune gravity rules out there, for example...but: did you know that Pluto makes two orbits for every three of Neptunes? It's reasoning just like thiscatching up loss and pushing back gain equilibrium and that is why those two planets will never collide. Saludos, Doug - Original Message - From: Francis Graham [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Friday, June 24, 2005 6:21 PM Subject: Re: [meteorite-list] Earth Trojan asteroids MOON Trojan objects exist. They are the Kordylewski clouds, small faint patches of dust, at the L4 and L5 points of the Earth-Moon system (not Earth-sun system). The Kordylewski clouds have been photographed, and have even been seen by the naked eye under total dark skies. They may be variable in their mass and integrated visual magnitude. Very little has been studied about them, very little is known about their possible variability, nobody has anything like a reflectance spectrum of the dust. They remain the closest things about which so little is known. They could well be the subject of study of any of you who wish to make a contribution to science. One thing is known: unless you are under skies so dark the Milky Way is a BRILLIANT band of light, and the Gegenschein is easy, and the zodiacal light is an obvious swath, unless you are under those kinds of dark skies, you have NO hope of seeing the Kordylewski clouds. Francis Graham --- [EMAIL PROTECTED] wrote: Hola Rob, Wouldn't that be = 2/3's (gibbous) phase = about 66% illumination, and a maximum average sky angle of a comfortable,high 60 degrees max observed angle (+/- the oscillation) ... checking they're equilateral triangles, though intuition might be wrong? Saludos, Doug En un mensaje con fecha 06/23/2005 6:21:15 PM Mexico Daylight Time, [EMAIL PROTECTED] escribe: Certainly astronomers have tried, but small objects at L4 and L5 would be hard to see due to a combination of range (150 million km), poorer phase angle, and a maximum sky elevation of perhaps 45 degrees at astronomical twilight -- lower when the sky is darker. It would be an interesting exercise to compute the maximum size an Earth Trojan could be and still have managed to go undetected. --Rob __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Re: AM Meteorite Museum in Postcards
Mike Jensen posted: http://jensenmeteorites.com/Postcards/american_meteorite_museum.htm Dear Mike: I'm slow in commenting on this, but wanted to commend you on a really excellent job of collecting and presenting these rare and interesting postcards. A great addition to the literature on the AMM. Well done! Geoff N. __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Earth Trojan asteroids
Ah HAH!! I think. Thank you and thank you cause you've answered both questions. Billiards on a planetary scale. No wonder I never made it in a pool hall!! Jerry - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED]; [EMAIL PROTECTED]; meteorite-list@meteoritecentral.com Sent: Saturday, June 25, 2005 3:45 PM Subject: Re: [meteorite-list] Earth Trojan asteroids Jerry F. wrote: Francis and List, could someone help me with the L4, L5 points?? Jerry Flaherty Hola Jerry, L4 and L5: These two zones (it would be a point if it were unstable, but you will see that they are stable and hence, zones) are one AU in front of Earth or 1 AU behind Earth. They are stable: In the case of going co-orbital exactly 1 AU in front of Earth in our orbit (L4), or co-orbital 1 AU behind (L5), Earth, or anything of reasonable planetary size will either pull it back or drag it along. If it is wanders by being pulled back from L4, it gets pushed in an arc right into the Sun, and if it gets dragged along, it gets pulled away from the Sun outwards (both pull and push tangents from 1 AU around Earth are directed exactly into or away from the Sun - draw two equal circles, each that pass through the center of the other to convince yourself). Well hypothetically pushing it into the Sun in front, and then the Sun speeds it up and presto it gets sent right back to where it started from, and when Earth pulls it along then presto the extra distance pulled outward from the Sun slows it down, and the hypothetical deviation pull from Earth is compensated and it falls back into its place - a stable equilibrium. If you like algebra trig instead of my handwaving summary, it is done here: _http://www-spof.gsfc.nasa.gov/stargaze/Slagrng2.htm_ (http://www-spof.gsfc.nasa.gov/stargaze/Slagrng2.htm) and more elegantly here: _http://www-spof.gsfc.nasa.gov/stargaze/Slagrng3.htm_ (http://www-spof.gsfc.nasa.gov/stargaze/Slagrng3.htm) Each object has the property, on the case of the Earth-Sun-object, that they have an orbit of one Earth year, locked-step in a dance with Earth until a collision or huge comet/asteroid or even another star happens by...and 60 degrees is a magic number because it creates the equilateral triangle of connections among the three masses - which is why all the planets could have these regardless of size, within reason. Of course, it you placed it exactly at the point L4 or L5 itself and the Universe were just three bodies, it would stand still. But due to influences of other planets and significant asteroids, you can get little halo like oscillatory orbits around the frame of reference of the L-point. Just like pushing a pendulum -it doesn't stop... Pluto wouldn't be a likely candidate to have Pluto Trojans in my opinion since Neptune gravity rules out there, for example...but: did you know that Pluto makes two orbits for every three of Neptunes? It's reasoning just like thiscatching up loss and pushing back gain equilibrium and that is why those two planets will never collide. Saludos, Doug - Original Message - From: Francis Graham [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Friday, June 24, 2005 6:21 PM Subject: Re: [meteorite-list] Earth Trojan asteroids MOON Trojan objects exist. They are the Kordylewski clouds, small faint patches of dust, at the L4 and L5 points of the Earth-Moon system (not Earth-sun system). The Kordylewski clouds have been photographed, and have even been seen by the naked eye under total dark skies. They may be variable in their mass and integrated visual magnitude. Very little has been studied about them, very little is known about their possible variability, nobody has anything like a reflectance spectrum of the dust. They remain the closest things about which so little is known. They could well be the subject of study of any of you who wish to make a contribution to science. One thing is known: unless you are under skies so dark the Milky Way is a BRILLIANT band of light, and the Gegenschein is easy, and the zodiacal light is an obvious swath, unless you are under those kinds of dark skies, you have NO hope of seeing the Kordylewski clouds. Francis Graham --- [EMAIL PROTECTED] wrote: Hola Rob, Wouldn't that be = 2/3's (gibbous) phase = about 66% illumination, and a maximum average sky angle of a comfortable,high 60 degrees max observed angle (+/- the oscillation) ... checking they're equilateral triangles, though intuition might be wrong? Saludos, Doug En un mensaje con fecha 06/23/2005 6:21:15 PM Mexico Daylight Time, [EMAIL PROTECTED] escribe: Certainly astronomers have tried, but small objects at L4 and L5 would be hard to see due to a combination of range (150 million km), poorer phase angle, and a
Re: [meteorite-list] Earth Trojan asteroids
Ok, 60 deg preceeding[L4], 60deg following[L5]. What's the significance of 60deg or 120 or 240?? Any math clue? struggling to follow, I've got to be an L5, Jerry - Original Message - From: Dawn Gerald Flaherty [EMAIL PROTECTED] To: Francis Graham [EMAIL PROTECTED]; meteorite-list@meteoritecentral.com Sent: Saturday, June 25, 2005 8:28 AM Subject: Re: [meteorite-list] Earth Trojan asteroids Francis and List, could someone help me with the L4, L5 points?? Jerry Flaherty - Original Message - From: Francis Graham [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Friday, June 24, 2005 6:21 PM Subject: Re: [meteorite-list] Earth Trojan asteroids MOON Trojan objects exist. They are the Kordylewski clouds, small faint patches of dust, at the L4 and L5 points of the Earth-Moon system (not Earth-sun system). The Kordylewski clouds have been photographed, and have even been seen by the naked eye under total dark skies. They may be variable in their mass and integrated visual magnitude. Very little has been studied about them, very little is known about their possible variability, nobody has anything like a reflectance spectrum of the dust. They remain the closest things about which so little is known. They could well be the subject of study of any of you who wish to make a contribution to science. One thing is known: unless you are under skies so dark the Milky Way is a BRILLIANT band of light, and the Gegenschein is easy, and the zodiacal light is an obvious swath, unless you are under those kinds of dark skies, you have NO hope of seeing the Kordylewski clouds. Francis Graham --- [EMAIL PROTECTED] wrote: Hola Rob, Wouldn't that be = 2/3's (gibbous) phase = about 66% illumination, and a maximum average sky angle of a comfortable,high 60 degrees max observed angle (+/- the oscillation) ... checking they're equilateral triangles, though intuition might be wrong? Saludos, Doug En un mensaje con fecha 06/23/2005 6:21:15 PM Mexico Daylight Time, [EMAIL PROTECTED] escribe: Certainly astronomers have tried, but small objects at L4 and L5 would be hard to see due to a combination of range (150 million km), poorer phase angle, and a maximum sky elevation of perhaps 45 degrees at astronomical twilight -- lower when the sky is darker. It would be an interesting exercise to compute the maximum size an Earth Trojan could be and still have managed to go undetected. --Rob __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Discover Yahoo! Use Yahoo! to plan a weekend, have fun online and more. Check it out! http://discover.yahoo.com/ __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Earth Trojan asteroids
On Sat, 25 Jun 2005 22:08:46 -0400, Dawn Gerald Flaherty [EMAIL PROTECTED] wrote: Ok, 60 deg preceeding[L4], 60deg following[L5]. What's the significance of 60deg or 120 or 240?? Any math clue? struggling to follow, I've got to be an L5, Jerry Look at http://www.physics.montana.edu/faculty/cornish/lagrange.html __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Earth Trojan asteroids
Jerry F. wrote: Billiards on a planetary scale. No wonder I never made it in a pool hall!! Jeje, Hola Jerry, Yes, if the counterpart balls in the pool hall had a sort of magnetic attraction that could transfer momentum without touching (i.e, gravity) Another way to think of these two points are as the corners behind the refrigerator that no matter how you sweep out the lint you always get frustrated in those naughty corners as the more you try to get them out the more they get swept further in. 'S'matter? Never seen cleaning behind the fridge, either?:) The interesting thing about them is, which I haven't seen mentioned yet...p-robably the L4 and L5 Earth-Moon points (that dust Francis was talking about) contain most of the history of the formation of the Moon, and in the case of the Earth, Most of the history of the formation of the Earth. These are the meteoroids that AREN'T swept up by the planets...A new NASA mission is planned called the Spring-Cleaning-Day:) Now to see Mercury Venus and the Moon, it's my longitudes turn! Future sale: Spring-Cleaning Meteoroid Dust Sale Saludos, Doug __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Dean Bessey material from a new supllier - what is it ? (probable LL4 or 5)
With the help of John Kashuba from California who also bought a piece of this meteorite, it appears that my nice Diogenite is more like a LL4 or maybe even LL5. That would explain the metal, and lack of apparent chondrules on the weathered surface. But the crust so, so nice. :) I'm so good at this... :( I need to stick to what I know or don't know, and not guess anymore. Thanx to John K who exposed a surface for visual analysis. One of John's pics is below. A very nice amphoterite. http://i19.photobucket.com/albums/b164/gabbroman/Bessey_R_205_Low_magnetic_22g_ground.jpg JD -- Original message from [EMAIL PROTECTED]: -- Hello all, This morning I finally got to look at a new fragment of a meteorite that Dean Bessey sold as an un-cut, unclassified meteorite that is probably an LL. He sold about 5 small pieces an I bought one of them for about $5/g. The material was from a new supplier, making it somewhat unique in Dean's eyes. The fragment has a nice black melted crust, not unlike many HED meteorites. There is a pull with a strong magnet similar to an LL. Not weak, but not strong like an L. There are no signs of chondrules on the slightly brown-weathered broken faces. Looks like a fair amount of orthopyroxene sticking through. To me it is a nice Diogenite, but I have yet to cut it. I was wondering if anyone else who bought a piece has studied it enough to come to a conclusion? Has anyone cut it yet either ? Curious, but not ready to cut. John __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Earth Trojan asteroids
Doug you and Sterling have to take this show on the ROAD!! Look at where Click and Clack the Tapit brothers have climbed in NPR annals! Jerry - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED]; [EMAIL PROTECTED]; meteorite-list@meteoritecentral.com Sent: Saturday, June 25, 2005 3:45 PM Subject: Re: [meteorite-list] Earth Trojan asteroids Jerry F. wrote: Francis and List, could someone help me with the L4, L5 points?? Jerry Flaherty Hola Jerry, L4 and L5: These two zones (it would be a point if it were unstable, but you will see that they are stable and hence, zones) are one AU in front of Earth or 1 AU behind Earth. They are stable: In the case of going co-orbital exactly 1 AU in front of Earth in our orbit (L4), or co-orbital 1 AU behind (L5), Earth, or anything of reasonable planetary size will either pull it back or drag it along. If it is wanders by being pulled back from L4, it gets pushed in an arc right into the Sun, and if it gets dragged along, it gets pulled away from the Sun outwards (both pull and push tangents from 1 AU around Earth are directed exactly into or away from the Sun - draw two equal circles, each that pass through the center of the other to convince yourself). Well hypothetically pushing it into the Sun in front, and then the Sun speeds it up and presto it gets sent right back to where it started from, and when Earth pulls it along then presto the extra distance pulled outward from the Sun slows it down, and the hypothetical deviation pull from Earth is compensated and it falls back into its place - a stable equilibrium. If you like algebra trig instead of my handwaving summary, it is done here: _http://www-spof.gsfc.nasa.gov/stargaze/Slagrng2.htm_ (http://www-spof.gsfc.nasa.gov/stargaze/Slagrng2.htm) and more elegantly here: _http://www-spof.gsfc.nasa.gov/stargaze/Slagrng3.htm_ (http://www-spof.gsfc.nasa.gov/stargaze/Slagrng3.htm) Each object has the property, on the case of the Earth-Sun-object, that they have an orbit of one Earth year, locked-step in a dance with Earth until a collision or huge comet/asteroid or even another star happens by...and 60 degrees is a magic number because it creates the equilateral triangle of connections among the three masses - which is why all the planets could have these regardless of size, within reason. Of course, it you placed it exactly at the point L4 or L5 itself and the Universe were just three bodies, it would stand still. But due to influences of other planets and significant asteroids, you can get little halo like oscillatory orbits around the frame of reference of the L-point. Just like pushing a pendulum -it doesn't stop... Pluto wouldn't be a likely candidate to have Pluto Trojans in my opinion since Neptune gravity rules out there, for example...but: did you know that Pluto makes two orbits for every three of Neptunes? It's reasoning just like thiscatching up loss and pushing back gain equilibrium and that is why those two planets will never collide. Saludos, Doug - Original Message - From: Francis Graham [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Friday, June 24, 2005 6:21 PM Subject: Re: [meteorite-list] Earth Trojan asteroids MOON Trojan objects exist. They are the Kordylewski clouds, small faint patches of dust, at the L4 and L5 points of the Earth-Moon system (not Earth-sun system). The Kordylewski clouds have been photographed, and have even been seen by the naked eye under total dark skies. They may be variable in their mass and integrated visual magnitude. Very little has been studied about them, very little is known about their possible variability, nobody has anything like a reflectance spectrum of the dust. They remain the closest things about which so little is known. They could well be the subject of study of any of you who wish to make a contribution to science. One thing is known: unless you are under skies so dark the Milky Way is a BRILLIANT band of light, and the Gegenschein is easy, and the zodiacal light is an obvious swath, unless you are under those kinds of dark skies, you have NO hope of seeing the Kordylewski clouds. Francis Graham --- [EMAIL PROTECTED] wrote: Hola Rob, Wouldn't that be = 2/3's (gibbous) phase = about 66% illumination, and a maximum average sky angle of a comfortable,high 60 degrees max observed angle (+/- the oscillation) ... checking they're equilateral triangles, though intuition might be wrong? Saludos, Doug En un mensaje con fecha 06/23/2005 6:21:15 PM Mexico Daylight Time, [EMAIL PROTECTED] escribe: Certainly astronomers have tried, but small objects at L4 and L5 would be hard to see due to a combination of range (150 million km), poorer phase angle, and a maximum sky
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