Re: [meteorite-list] fire flies or flying fires
to the core, when did that happen? After 4500 mya (complete first Earth) but before 4450 mya (lunar crystal), right? Or at 4500 mya, at the very last minute? Why is the happy zircon so happy? And when it find a time and place to be happy in at 4404 mya? If the 4450 mya lunar crystal is a lucky inclusion (like the zircon?) was there a happy Earth that got whacked by another planetoid and the lucky zircon is a chance survivor? The pro-zircon forces are in favor of a totally Cool Early Earth (I think it's pretty cool, myself). The Earth-Moon Impact crowd insist that their Early Earth be served Molten Hot Twice. Am I the only one to see a problem here? NO Hadean Epoch? TWO Hadean Epochs? The happy zircon is also a funny zircon. Even it's a tiny crystal, other probe spots on it are younger than the 4404 mya spot, even though it's one crystal. Contacting zircons in the one little rock the crystal is included in are as young as 3300 mya. There's no this one whole microscopic crystal is 4404 mya object. It has had a complicated life for a happy zircon. It's clear the happy zircon is a triumph of micro-probe dating, but what is it proof of? And the Moon? We know how long it would take the lunar mantle to crystallize and we know how long again before the core solidified, but WHEN does that timeline start? The Earth-Moon Impact crowd say the Moon was complete by 4440 mya but about how long it took to assemble, there is silence and a few mutters, a couple of days say some, 100 million years say some. The models are dynamically incomplete. So sorry. Recent remodeling says it was more likely quick, but then we want it, need it, to be quick. We are still quarreling about the Late Collisional Bombardment, whether there was one or not, for heaven's sake. Stitching together the happy zircon timeline, the Earth-Moon impact timeline, the planetesimal and accretion timeline, and all the other timelines is not complete. We're still looking for the needle and thread. Oddities abound. Every living thing on Earth has the same little snippet of 16S ribosomal RNA gene (in various related mutated versions). What is it good for? Why, metabolizing sulfur for energy! We all get our go from sulfur, right? No. The critters that need it are the archaic sulfur eating bacteria in deep sea hot mineral vents, and some biologists suggest that its universality arises from an early extinction of ALL life but them, and that life had to start all over again. Earth-Moon impact, anyone? After the happy zircon? This stitching is like making a crazy quilt. Drives me crazy, anyway. I'm a lot more certain about the predominance of near side ancient basins, though. We're doomed to disagree, Chris, you (CalTech) and me (MIT). Sterling K. Webb - Chris Peterson wrote: Hi Sterling- I'm don't agree with your argument for basaltic maria on the Earth side of the Moon. There are plenty of big impact craters on the far side. The difference is that the lunar crust is 40km thicker on the far side than on the near side (100km vs 60km). It takes a heck of a lot bigger impact to punch through the far side crust to the (once) molten interior. Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message - From: Sterling K. Webb [EMAIL PROTECTED] To: Chris Peterson [EMAIL PROTECTED]; Meteorite-list@meteoritecentral.com; Dawn Gerald Flaherty [EMAIL PROTECTED]; Graham Christensen [EMAIL PROTECTED] Sent: Sunday, June 26, 2005 7:26 PM Subject: Re: [meteorite-list] fire flies or flying fires Basically, anything orbiting the Earth inside the Moon's orbit is long-term unstable because the Moon perturbs inner objects to increase their eccentricity without limit until they smack into... the Moon! This is why all the gigantic lava-flowed impact basins are on the side of the Moon that faces the Earth and there's so few on the far side. Most of those ancient huge impactors were probably in orbit around the Earth back in its wild and woolly youth! __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] fire flies or flying fires
Hi Sterling- Yeah, I guess you're right, we're doomed to disagree g. (Did you see the cleverly packaged MIT T-shirts distributed to MIT freshman at last years orientation? The ones that nobody noticed until too late had Because not everyone can go to Caltech printed on the back?) I take exception to your point that the Moon obviously has a uniform crust early on. This isn't obvious at all, and nobody has a good explanation for why the Moon does not now have a uniform crust. This feature does not fall out of any models. Gravity does not obviously explain why the crust should be thinner towards the Earth. If the crust thickness variation developed early (and the maria are certainly old) this would explain the reason that maria are only present on one side. Since it is likely that the Moon was not yet tidally locked when the basins formed, I don't see the effects of the Earth as having contributed in an obvious way to their formation. Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message - From: Sterling K. Webb [EMAIL PROTECTED] To: Chris Peterson [EMAIL PROTECTED]; Meteorite-list@meteoritecentral.com; Dawn Gerald Flaherty [EMAIL PROTECTED] Sent: Monday, June 27, 2005 3:55 AM Subject: Re: [meteorite-list] fire flies or flying fires Hi, There are a variety of questions involved. First, there is to the problem of identifying what constitutes a basin as the earliest basins are relicts of the earliest impacts and are obscured to a greater or lesser degree by later large basin forming impacts. Most selenologists think Procellarum is the most ancient relict basin overlaid by the later Imbrium, Serenitatis, Tranquilitatis, Humorium and Nubium basins. If Procellarum is a basin, it would be the largest on the Moon at 3200 km (near side), followed by South Polar basin at 2500 km (on the edge but mostly near side), followed by Imbrium at 1160 km (near side), Crisium at 1060 km (near side), Orientale at 930 km (on the edge, side), down through a long list sorted by size, until you arrive at the Keeler-Heavyside basin at 780 km (far side). The size of the basin is not linearly related to the size of the impactor, as the state of the Moon was changing throughout the period of bombardment. The crust, its distribution and other characteristics, the mantle, the core, were continually evolving over the basin-impact period. Obviously, when the Moon was mostly molten and starting to differentiate, the crust was a new thin skin everywhere. Procellarum, if a basin, formed within the Moon's first 150 million years, before (during?) mantle crystallization and would not have required as large an impactor as later basins of lesser size. At this point the differential crust thickness and the eccentric mass center lay (mostly?) in the Moon's future. The gravitational effects that displaced the Moon's center of mass toward the Earth only take effect after cooling and differentiation has progressed to a sufficiently great degree and the crust differential only develops late or after that mass center shift is mostly complete, then it freezes in place. Imbrium, the second largest basin, formed when the Moon was 600 million years old (?), is thought by many to have been the target of the largest impact object of the Moon's history, well after the crust differential had developed. Indeed, Imbrium appears to be one of the youngest basins in the solar system, hence requiring a stupendous whack from an object large enough to be a respectable little moon itself. Another young (or later, whichever you prefer) giant basin is Caloris on Mercury, larger at 3700 km, whose impactor came close to breaking the planet, as the vast stretch of chaotic terrain on the opposition point on Mercury's surface shows. Planet breakers, not a happy concept. However, the point of all this is that ancient basins are identifiable even when overlaid by one or several or many later basins (like Procellarum is). The far side shows no traces, however faint, of former gigantic relict basins to rival those of the near side or the poles. There was far less magna upwelling on the far side to obliterate traces of relict basins. The thick crust protects relict basins from obliteration because it is harder to form new large basins on (or is the word in?). Yet, the central far side is the most depleted in traces of ancient basins, implying far fewer impacts. Large ringed craters / small basins are pretty much the same thing and in uniform distribution. The Moon has a huge number of them and every smaller size of impact, but giant ancient basins? Near side is the spot where the action was. We also have to distinguish between ringed basins formed in an already stiffened crust and flood basins formed by large upwellings alone, although Procellarum is so old it's hard to tell, it doesn't
Re: [meteorite-list] fire flies or flying fires
Hi, Again, it's all in the timing. But you made me re-think some things. Like Newton, you form no hypotheses. I, on the other hand, am a hypothesizing fool. If the Moon is a molten liquid drop of uniform density (undifferentiated), then Earth's gravity distorts it into a spheroid, and cooling and differentiation take place in an egg-shaped Moon, creating a thick equatorial crust and thin polar crust with a centered core until the Moon is cooled. So, it didn't happen that way. So, it was only when mass concentrated toward to the Moon's center (after at least partial differentiation) that the warm gooey center was tugged and shifted toward the Earth, moving easily in the hot liquid and slush. Now the internal heat has two different length of cooling paths to nearside and farside centers. The nearside cools faster and the mantle crystallizes sooner: thinner crust. The farside cools more slowly and the crust continues to thicken until the mantle separates: thicker crust. As the interior stiffens up, it forces the off-center core back, almost but not all the way back, towards the center. But I'm worried about my little pet theory, It doesn't look so healthy as it did last night (more research). There are spots in Crisium where the crust thickness is essentially zero and north of Korolev it's up to 107 km thick. That's a little extreme. The Moon is, to generalize, lumpy and uneven, and the crust differential, which I had always though of as relatively uniform, is far from it. There are spots on the farside where the crust is as thin as the thickest parts of the nearside crust. My pet theory might have to go the pet theory hospital... This argument depends on a fully locked rotation rate from the very start. The fact is, we don't know about that. There are no clues. Present librations and precessions are all accountable for by gravity and orbital parameters; there are no residual motions. 4500 million years is a long time... Even the truly odd thing, the Moon's orbital inclination to the Earth, can now be accounted for by the collision model as presently refined. It seems the debris disk's gravity waves can incrementally crank up the inclination to 15 degrees or more (and the Moon's is only 5). Interestingly enough, for this scenario to work, they say, the Moon has to accrete on the outermost edge of its accretion disk around the Earth, which would certainly account for nearside preferential impacts. (That one just fell in my lap!) I think accretion in orbit virtually guarantees a lock. The Moon is orbiting initially very, very close to the Earth, and we outweigh the opponent 80 to one. The fight is fixed. The smart money is down. But the model, in its present highly tweaked state, is still primitive. Its equation of state, which underlies the whole thing, is crude and simplistic, says Jay Melosh. Currently, the model only works if the Big Impact happens while the Earth is still assembling, at about half its present mass, and Moon formation is part of the accretion process. This puts it on the timeline at about 4530-4540 mya. A breathing space for the happy zircon? If impact happens later, there's too much angular momentum in the system for it to work unless you compensate with a larger and larger impactor. Oddly enough, after last night, I was thinking about angular momentum. (Really, I was, that's why it's odd.) There really is no reason why any terrestrial planet should any angular momentum to speak of. Accrete a planet by rocky impacts with totally randomized force vectors and you get NO residual angular momentum. Everything cancels out (always neat). The giant planets, formed by a different mechanism than rocky accretion, all spun up nicely, the bigger the faster. Mercury and Venus have very little angular momentum. It's pitiful. Mars has more. My theory on that is that Mars accreted on the inner edge of a reduced accretion disk because the newly fattened-up Earth Moon system was increasingly stealing of Mars' planetesimals on the sunward side. Because Mars accreted more from the outward side, the impact vectors were prograde preferential and added angular momentum to the Mars system. Maybe our Big Impactor was the largest proto-Mars planetesimal and we stole it. Maybe the Earth was trudging toward being a small warm dry planet and Mars was on the road to being big and wet and cool, teeming with life and firmly believing itself to be the Center of the Universe, when suddenly, its glorious destiny was snatched away by that sneaky little Earth! No wonder the Martians hate us! That's probably why they're always doing that War of the Worlds thing of theirs. They're only reclaiming what was rightfully theirs... Being minds vast and cool and unsympathetic, as Wells says, their superior computer simulations have demonstrated it to be true beyond all possible doubt. With planet-wide super-cooled quantum-state computers, their
Re: [meteorite-list] fire flies or flying fires
I suppose I shouldn't keep encouraging all this OT[as perceived by some] BUT [and I'm sure I'll get some diagreement] you certainly can't buy this kind of entertainment or it isn't easily available on the BOOB TUBE. Take it from a connoisseur[or is that a kind of sewer] of Direct TV. Jerry Flaherty - Original Message - From: Sterling K. Webb [EMAIL PROTECTED] To: Chris Peterson [EMAIL PROTECTED]; Meteorite-list@meteoritecentral.com; Dawn Gerald Flaherty [EMAIL PROTECTED]; Graham Christensen [EMAIL PROTECTED] Sent: Monday, June 27, 2005 7:48 PM Subject: Re: [meteorite-list] fire flies or flying fires Hi, Again, it's all in the timing. But you made me re-think some things. Like Newton, you form no hypotheses. I, on the other hand, am a hypothesizing fool. If the Moon is a molten liquid drop of uniform density (undifferentiated), then Earth's gravity distorts it into a spheroid, and cooling and differentiation take place in an egg-shaped Moon, creating a thick equatorial crust and thin polar crust with a centered core until the Moon is cooled. So, it didn't happen that way. So, it was only when mass concentrated toward to the Moon's center (after at least partial differentiation) that the warm gooey center was tugged and shifted toward the Earth, moving easily in the hot liquid and slush. Now the internal heat has two different length of cooling paths to nearside and farside centers. The nearside cools faster and the mantle crystallizes sooner: thinner crust. The farside cools more slowly and the crust continues to thicken until the mantle separates: thicker crust. As the interior stiffens up, it forces the off-center core back, almost but not all the way back, towards the center. But I'm worried about my little pet theory, It doesn't look so healthy as it did last night (more research). There are spots in Crisium where the crust thickness is essentially zero and north of Korolev it's up to 107 km thick. That's a little extreme. The Moon is, to generalize, lumpy and uneven, and the crust differential, which I had always though of as relatively uniform, is far from it. There are spots on the farside where the crust is as thin as the thickest parts of the nearside crust. My pet theory might have to go the pet theory hospital... This argument depends on a fully locked rotation rate from the very start. The fact is, we don't know about that. There are no clues. Present librations and precessions are all accountable for by gravity and orbital parameters; there are no residual motions. 4500 million years is a long time... Even the truly odd thing, the Moon's orbital inclination to the Earth, can now be accounted for by the collision model as presently refined. It seems the debris disk's gravity waves can incrementally crank up the inclination to 15 degrees or more (and the Moon's is only 5). Interestingly enough, for this scenario to work, they say, the Moon has to accrete on the outermost edge of its accretion disk around the Earth, which would certainly account for nearside preferential impacts. (That one just fell in my lap!) I think accretion in orbit virtually guarantees a lock. The Moon is orbiting initially very, very close to the Earth, and we outweigh the opponent 80 to one. The fight is fixed. The smart money is down. But the model, in its present highly tweaked state, is still primitive. Its equation of state, which underlies the whole thing, is crude and simplistic, says Jay Melosh. Currently, the model only works if the Big Impact happens while the Earth is still assembling, at about half its present mass, and Moon formation is part of the accretion process. This puts it on the timeline at about 4530-4540 mya. A breathing space for the happy zircon? If impact happens later, there's too much angular momentum in the system for it to work unless you compensate with a larger and larger impactor. Oddly enough, after last night, I was thinking about angular momentum. (Really, I was, that's why it's odd.) There really is no reason why any terrestrial planet should any angular momentum to speak of. Accrete a planet by rocky impacts with totally randomized force vectors and you get NO residual angular momentum. Everything cancels out (always neat). The giant planets, formed by a different mechanism than rocky accretion, all spun up nicely, the bigger the faster. Mercury and Venus have very little angular momentum. It's pitiful. Mars has more. My theory on that is that Mars accreted on the inner edge of a reduced accretion disk because the newly fattened-up Earth Moon system was increasingly stealing of Mars' planetesimals on the sunward side. Because Mars accreted more from the outward side, the impact vectors were prograde preferential and added angular momentum to the Mars system. Maybe our Big Impactor was the largest proto-Mars planetesimal and we stole
[meteorite-list] fire flies or flying fires
List, I once asked the List if the Earth could have as yet undetected FAINT[obviously faint enough to have as yet evaded detection] debris rings. I don't mean to beat a dead horse here but, I'll ask the list again to consider this possibility given the various optical phenomena [Kordylewski Clouds, Lagrangian Points,] yet fully explained and the difficulties observing potential rings due to Solar interference for one. By way of a poor analogy, Flying Gnats glow bright when their angle to the sun and our eye are fortunate. At other times of the day you'll swallow or breathe them before you ever see them. Swallows dart around feasting on these tiny critters all day long as they make flight adjustments to highlight their prey. Points of observation are everything. Hope I don't raise anyone's ire. Just love to speculate for fun and profit!! Jerry __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] fire flies or flying fires
I doubt there is a stable solution for a ring system in a binary planet system like the Earth/Moon, unless possibly they are very close to the Earth. But if they are close to the Earth, they would show up by interacting with geosynchronous satellites. AFAIK there is no difference in meteorite/micrometeorite impact risk for geosynchronous satellites versus those in other orbits. Not sure what connection you are suggesting between a ring system and debris collecting at Lagrangian points. Those seem unrelated to me. Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message - From: Dawn Gerald Flaherty [EMAIL PROTECTED] To: Meteorite-list@meteoritecentral.com Sent: Sunday, June 26, 2005 6:28 PM Subject: [meteorite-list] fire flies or flying fires List, I once asked the List if the Earth could have as yet undetected FAINT[obviously faint enough to have as yet evaded detection] debris rings. I don't mean to beat a dead horse here but, I'll ask the list again to consider this possibility given the various optical phenomena [Kordylewski Clouds, Lagrangian Points,] yet fully explained and the difficulties observing potential rings due to Solar interference for one. By way of a poor analogy, Flying Gnats glow bright when their angle to the sun and our eye are fortunate. At other times of the day you'll swallow or breathe them before you ever see them. Swallows dart around feasting on these tiny critters all day long as they make flight adjustments to highlight their prey. Points of observation are everything. Hope I don't raise anyone's ire. Just love to speculate for fun and profit!! Jerry __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] fire flies or flying fires
Hi Chris and List, I'm sure there is no connection with the Larangian points then. I do appreciate your response, and yes the Earth/Moon system, being somewhat unique, might mitigate against any such system. Just thought I'd ask one more time to get it out of my system. Thanks. Jerry - Original Message - From: Chris Peterson [EMAIL PROTECTED] To: Meteorite-list@meteoritecentral.com Sent: Sunday, June 26, 2005 8:46 PM Subject: Re: [meteorite-list] fire flies or flying fires I doubt there is a stable solution for a ring system in a binary planet system like the Earth/Moon, unless possibly they are very close to the Earth. But if they are close to the Earth, they would show up by interacting with geosynchronous satellites. AFAIK there is no difference in meteorite/micrometeorite impact risk for geosynchronous satellites versus those in other orbits. Not sure what connection you are suggesting between a ring system and debris collecting at Lagrangian points. Those seem unrelated to me. Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message - From: Dawn Gerald Flaherty [EMAIL PROTECTED] To: Meteorite-list@meteoritecentral.com Sent: Sunday, June 26, 2005 6:28 PM Subject: [meteorite-list] fire flies or flying fires List, I once asked the List if the Earth could have as yet undetected FAINT[obviously faint enough to have as yet evaded detection] debris rings. I don't mean to beat a dead horse here but, I'll ask the list again to consider this possibility given the various optical phenomena [Kordylewski Clouds, Lagrangian Points,] yet fully explained and the difficulties observing potential rings due to Solar interference for one. By way of a poor analogy, Flying Gnats glow bright when their angle to the sun and our eye are fortunate. At other times of the day you'll swallow or breathe them before you ever see them. Swallows dart around feasting on these tiny critters all day long as they make flight adjustments to highlight their prey. Points of observation are everything. Hope I don't raise anyone's ire. Just love to speculate for fun and profit!! Jerry __ 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] fire flies or flying fires
Hi, Ring systems (former ones, anyway) have been proposed for the Earth. Go to archives or your own Inbox if you keep as much stuff as I do, and find a two part post by Graham Christensen of The Formation of Tektites from a Terrestrial Ring Arc By J. Hayawardena on March 27 of this year (2005). John O'Keefe postulated a ring system for the Eocene (35 million years ago) that went into orbital decay (forming tektites with each breakup). Hayawardena's ideas are more elaborate. O'Keefe was inspired to his idea by the phenomenon of the Chant Trace of 1913 which appears to have been the sub-orbital decay of many small bodies in a ring around the entire planet, creating one of the largest and most unusual meteor displays of all time. It actually happened, but is largely unexplained. I posted a long description of the Chant Trace event on March 26, 2005, and Graham (it was new to him!) posted the Hayawardena piece (it was new to me!) the next day! Basically, anything orbiting the Earth inside the Moon's orbit is long-term unstable because the Moon perturbs inner objects to increase their eccentricity without limit until they smack into... the Moon! This is why all the gigantic lava-flowed impact basins are on the side of the Moon that faces the Earth and there's so few on the far side. Most of those ancient huge impactors were probably in orbit around the Earth back in its wild and woolly youth! No picture of the Earth taken by any spacecraft near and far away in any wavelength of light or radar shows any traces of an extended dust ring, which is why I kind of doubt any exists. But I do like the thought of a stroll down the beach of an Eocene night by the brighter than moonlight glow of The Rings! Even if they are imaginary... Sterling K. Webb Chris Peterson wrote: I doubt there is a stable solution for a ring system in a binary planet system like the Earth/Moon, unless possibly they are very close to the Earth. But if they are close to the Earth, they would show up by interacting with geosynchronous satellites. AFAIK there is no difference in meteorite/micrometeorite impact risk for geosynchronous satellites versus those in other orbits. Not sure what connection you are suggesting between a ring system and debris collecting at Lagrangian points. Those seem unrelated to me. Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message - From: Dawn Gerald Flaherty [EMAIL PROTECTED] To: Meteorite-list@meteoritecentral.com Sent: Sunday, June 26, 2005 6:28 PM Subject: [meteorite-list] fire flies or flying fires List, I once asked the List if the Earth could have as yet undetected FAINT[obviously faint enough to have as yet evaded detection] debris rings. I don't mean to beat a dead horse here but, I'll ask the list again to consider this possibility given the various optical phenomena [Kordylewski Clouds, Lagrangian Points,] yet fully explained and the difficulties observing potential rings due to Solar interference for one. By way of a poor analogy, Flying Gnats glow bright when their angle to the sun and our eye are fortunate. At other times of the day you'll swallow or breathe them before you ever see them. Swallows dart around feasting on these tiny critters all day long as they make flight adjustments to highlight their prey. Points of observation are everything. Hope I don't raise anyone's ire. Just love to speculate for fun and profit!! Jerry __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] fire flies or flying fires
Thank you Sterling. precise, succinct and poignant as usual. Jerry Flaherty - Original Message - From: Sterling K. Webb [EMAIL PROTECTED] To: Chris Peterson [EMAIL PROTECTED]; Meteorite-list@meteoritecentral.com; Dawn Gerald Flaherty [EMAIL PROTECTED]; Graham Christensen [EMAIL PROTECTED] Sent: Sunday, June 26, 2005 9:26 PM Subject: Re: [meteorite-list] fire flies or flying fires Hi, Ring systems (former ones, anyway) have been proposed for the Earth. Go to archives or your own Inbox if you keep as much stuff as I do, and find a two part post by Graham Christensen of The Formation of Tektites from a Terrestrial Ring Arc By J. Hayawardena on March 27 of this year (2005). John O'Keefe postulated a ring system for the Eocene (35 million years ago) that went into orbital decay (forming tektites with each breakup). Hayawardena's ideas are more elaborate. O'Keefe was inspired to his idea by the phenomenon of the Chant Trace of 1913 which appears to have been the sub-orbital decay of many small bodies in a ring around the entire planet, creating one of the largest and most unusual meteor displays of all time. It actually happened, but is largely unexplained. I posted a long description of the Chant Trace event on March 26, 2005, and Graham (it was new to him!) posted the Hayawardena piece (it was new to me!) the next day! Basically, anything orbiting the Earth inside the Moon's orbit is long-term unstable because the Moon perturbs inner objects to increase their eccentricity without limit until they smack into... the Moon! This is why all the gigantic lava-flowed impact basins are on the side of the Moon that faces the Earth and there's so few on the far side. Most of those ancient huge impactors were probably in orbit around the Earth back in its wild and woolly youth! No picture of the Earth taken by any spacecraft near and far away in any wavelength of light or radar shows any traces of an extended dust ring, which is why I kind of doubt any exists. But I do like the thought of a stroll down the beach of an Eocene night by the brighter than moonlight glow of The Rings! Even if they are imaginary... Sterling K. Webb Chris Peterson wrote: I doubt there is a stable solution for a ring system in a binary planet system like the Earth/Moon, unless possibly they are very close to the Earth. But if they are close to the Earth, they would show up by interacting with geosynchronous satellites. AFAIK there is no difference in meteorite/micrometeorite impact risk for geosynchronous satellites versus those in other orbits. Not sure what connection you are suggesting between a ring system and debris collecting at Lagrangian points. Those seem unrelated to me. Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message - From: Dawn Gerald Flaherty [EMAIL PROTECTED] To: Meteorite-list@meteoritecentral.com Sent: Sunday, June 26, 2005 6:28 PM Subject: [meteorite-list] fire flies or flying fires List, I once asked the List if the Earth could have as yet undetected FAINT[obviously faint enough to have as yet evaded detection] debris rings. I don't mean to beat a dead horse here but, I'll ask the list again to consider this possibility given the various optical phenomena [Kordylewski Clouds, Lagrangian Points,] yet fully explained and the difficulties observing potential rings due to Solar interference for one. By way of a poor analogy, Flying Gnats glow bright when their angle to the sun and our eye are fortunate. At other times of the day you'll swallow or breathe them before you ever see them. Swallows dart around feasting on these tiny critters all day long as they make flight adjustments to highlight their prey. Points of observation are everything. Hope I don't raise anyone's ire. Just love to speculate for fun and profit!! Jerry __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
