Re: [meteorite-list] Planet V (for Five)
Hi, David, List, Not unexpectedly, I agree that HED-Mesosiderites are all out of one connected origin. This is not a new notion. Digging around, I found this quote from the early 70's. "It is a reasonable working hypothesis that there is a close genetic relationship among the eucrites, howardites and mesosiderites." (John S. Lewis) The use of oxygen isotope ratio slopes is pretty definite, but listening to the occasional oxygen isotope spat that happens on this List, it seems to me that people may take them for more definite than they are. With all the other elements, we are dealing with isotopes present only in solid phases -- they ain't going anywhere. But in early system formation times, oxygen is present both in the solid phases of various minerals AND in possible gaseous phases which can (and often do) undergo exchanges with solid material. So, it's always possible that the oxygen now present in one rock had two sources, each from differing times and conditions. There's no way to distinguish dual sources. We have to regard O-ratios as reliable but tricky, like somebody who's usually completely honest but once in a while will tell you a totally unbelievable whopper with a perfectly straight face. Maybe the E chondrites are one of those tall tales. They're certainly not Earthly in any other way, and very depleted in volatiles, while the Earth is volatile-rich, some of which are suspected of having been added to the mix from a separate source. (I guess I have my metaphors mixed; perhaps the E chondrites are honest and the Earth is fibbing.) Maybe that's it. It's funny the way the pieces of one argument tie in to another. If the solar nebula was very sharply zoned because there was little mixing, why, the O-isotope data would be like a street address or a file location on a hard drive. If you belong to the super high mass density school (more mixed), the O-isotope data would be more like random gossip. The fact that O-isotopes are as reliable as they are puts a constraint on how much or little mixing there could have been. Planet V is just one hypothesis to fit the (now) pretty well proven fact of the Late Bombardment. When the evidence for the LHB showed up in the 1970's, there were a fair number of people convinced that it must be a mistake or a wrong number. But since it seems to have really happened, the only explanation is that something big got loose and went on a collision rampage. Whether it was this particular object (Planet V) or some other object with a different origin and characteristics remains to be seen. I was just impressed with how many other things fit with Chambers' Planet V notion. Chambers' field is celestial mechanics; he just searched for a solar orbit in the area that seemed stable (no obvious resonances or other problems) but became unstable after 600 million years, at the time we need something to come loose. He found one. I suspect it's up to others to fill in its physical characteristics. The Dawn mission is wonderful, and its ion engines are wonderful, blah, blah, but... so slow. I have to wait until 2011 to see Ceres? I'm a mental primitive; I want to LOOK at it. I had to Google deep to find out how sharp a resolution the camera on the Dawn mission is: http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=DAWN&ex=1 The camera field of view is 5.5 x 5.5 degrees with a resolution of 9.3 m/pixel (175 pixels per mile) at a distance of 100 km. (Nine meters per pixel is about what the MRO test images got from high orbit, remarkably detailed.) There are two identical cameras aboard. They will be busy. I calculate the surface area of Ceres as 1,153,700 square miles! That's 35 GigaPixels. (The land area of the US is 3,537,438 square miles counting Alaska and Hawaii; Ceres is about a third of a US.) Vesta is "only" about 880,000 square miles! (27 GigaPixels) I said "about" because it's a tri-axial oblate spheroid. (Anybody got the area formula for that?) It'll be worth waiting for! Sterling K. Webb - Original Message - From: "David Weir" <[EMAIL PROTECTED]> To: "Sterling K. Webb" <[EMAIL PROTECTED]> Cc: "Meteorite List" Sent: Friday, April 28, 2006 12:28 PM Subject: Re: [meteorite-list] Planet V (for Five) Sterling K. Webb wrote: Maybe it hit Planet V-for-Five. Maybe it WAS Planet V-for-Five or a good chunk of it. Or a satellite of Planet V-for-Five dragged along for the ride when its orbit became unstable. Or... I look at my little chunks of mesosiderite with new respect. I sidle up to them at the bar and buy them a drink in the hope that they will tell me their life story... Sterling, It may be just another one of those O-isotope coincidences, like the fact that E chondri
Re: [meteorite-list] Planet V (for Five)
Sterling K. Webb wrote: Maybe it hit Planet V-for-Five. Maybe it WAS Planet V-for-Five or a good chunk of it. Or a satellite of Planet V-for-Five dragged along for the ride when its orbit became unstable. Or... I look at my little chunks of mesosiderite with new respect. I sidle up to them at the bar and buy them a drink in the hope that they will tell me their life story... Sterling, It may be just another one of those O-isotope coincidences, like the fact that E chondrites have O-isotopic values that are indistinguishable from those of the Earth, or that brachinites have values that are identical to the HEDs, but a new O-isotope study by Greenwood et al. (http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1768.pdf) of numerous mesosiderites demonstrates that their oxygen isotopic values are almost identical to those of the HED clan, which suggests that there may be a genetic link between them. The results suggest that both HEDs and mesosiderites may be derived from Vesta; or, if you want to speculate like me - I think the arrival of Dawn (in Sept. 2011) will reveal that HED and MES meteorites were derived from a separate, significantly disrupted, Vesta-like PB. This latter possibility may leave the door open for a possible Planet V origin for these two groups. David __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Planet V (for Five)
Hi, All, Well, sure, if as the author states, "we believe that such a big object never existed in the outer solar system," then you have to find something else. That's because he belongs to the High Mass Density Nebula School and not the Low Mass Density Nebula School. If you have high mass, the planets accrete in a big hurry from small planetesimals and it's all over quick. If you have low mass, accretion takes longer and it needs lots of big planetesimals. If you have high mass, though, the nebular gas is there while the planets are accreting, and the drag of trying to shove a blanking Jupiter (and all the planets) through a thick cloud makes so much drag that they spiral rapidly into the Sun and vanish. So, something (who knows what?) has to blow off the entire mass of the nebula in the nick of time and save the planets and push them back out again. The biggest difficulty is that this kind of accretion would produce planets that are all very much alike, since they accrete from small planetesimals that are all remarkably similiar because a high mass nebula is well mixed. It would produce planets far more alike than the planets we've actually got, which look more and more different the more we learn about them. You can see that High Mass theories have problems. It was not a popular theory at all until... TaDa! We discover all these 100+ extrasolar planets and, OMG! There are Jupiters and Super-Jupiters orbiting closer to their Suns than Mercury... Suddenly, the High Mass Density Nebula Theories are the chic new thing and everybody wants one! Of course, this kind of solar system generates the biggest best signal for detection by the method being used and a solar system like ours wouldn't register at all. And sure enough, if you plot the discoveries versus their distances you can see that these are highly biased samples. There are more discoveries at greater distances instead of less, which means a great volume of stars is likely to contain some even more extreme systems than a small volume. They represent less than 4% of the selected likely targets. I think they're the oddballs, and the other 96+% all have solar systems that are "normal," whatever that is. At least they don't have 10-Jupiter mass planets orbiting only 20-30 million kilometers off the star! Anyway, you got any idea just how close Jupiter would have to be to Uranus to roll it over? Like eighteen-wheelers playing Chicken on dirt road, raised to 100th power... Like all the rest of the High Mass Density Nebula theory, it requires some very close calls and lots of lucky coincidences. As Bohr said to Pauli, "We all agree that your theory is crazy. Now we're arguing about whether or not it's crazy enough to be true!" No big objects in the outer Solar System!? Sterling K. Webb - Original Message - From: "Darren Garrison" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Cc: Sent: Thursday, April 27, 2006 9:29 PM Subject: Re: [meteorite-list] Planet V (for Five) On Thu, 27 Apr 2006 19:49:55 -0500, you wrote: Even Jupiter has a three-degree tilt. Ya know its gonna take a good whack upside the planet to tilt Jupiter! Uranus is tilted over on its side; it takes an impact with an Earth mass object to deliver that amount of change in momentum. Or maybe not: http://www.msnbc.msn.com/id/12498416/ Early gravitational pull tilted the big planets New theory departs from earlier idea that tilts were caused by impacts Updated: 3:59 p.m. ET April 26, 2006 WASHINGTON - An early gravitational dance made the giant planets tilt the way they do - which is different from the way Earth and the other smaller planets tilt, an astronomer reported on Wednesday. The shift probably happened billions of years ago when the bigger planets in our solar system were closer together than they are now, and the gravity of each one exerted a pull on the others, said Adrian Brunini of the Facultad de Ciencias Astronomicas y Geofisicas in Buenos Aires. This "neutral gravitational interaction" caused Jupiter, Saturn, Uranus and Neptune to have tilted axes that were determined as they moved through the solar system to take their current positions far from the sun, Brunini said in a telephone interview. This is a departure from an earlier theory that holds that the massive planets' tilts - or obliquities, as astronomers call them - were caused by collisions with Earth-sized space rocks during the early period of the solar system. "This model has some problems that were not clear how to solve," Brunini said. "For example, we believe that such a big object never existed in the outer solar system." In research published in the current edition of the journal Nature, Brunini used numerical models to show that the outer planets&#x
Re: [meteorite-list] Planet V (for Five)
efore it was disrupted 3.9 billion years ago. (The diffusion of nickel in the iron in mesosiderites yields a cooling rate of one degree every 500,000 years -- very slow.) Maybe it hit Planet V-for-Five. Maybe it WAS Planet V-for-Five or a good chunk of it. Or a satellite of Planet V-for-Five dragged along for the ride when its orbit became unstable. Or... I look at my little chunks of mesosiderite with new respect. I sidle up to them at the bar and buy them a drink in the hope that they will tell me their life story... Sterling K. Webb -- - Original Message - From: "Darren Garrison" <[EMAIL PROTECTED]> To: "Sterling K. Webb" <[EMAIL PROTECTED]> Cc: Sent: Thursday, April 27, 2006 9:14 AM Subject: Re: [meteorite-list] Planet V (for Five) On Wed, 26 Apr 2006 20:05:52 -0500, you wrote... And, if you're looking for other unexplained facts to tuck into the envelope, there's the anomalous slow, backward rotation of Venus (a "day" longer than its "year"), for which repeated close encounters with a large body has been suggested as a cause. Planet V? Cough-Velikovsky-cough. __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Planet V (for Five)
Hello list For those people recently who wereharping on about the apparent disintegration of this list, this is an example of the sort of gem which I find make it all worth while. I like a lot of what is in this post and wish I had the celestial mechanics ability (and time too) to work on it (With a healthy dollop of simulation programming thrown in too) I will restric myself to one thought to raise regarding this topic and this is; Did all trace of this planet disappear? Does anyone have any idea where NWA3133 may fit into the picture? Rob McCafferty --- "Sterling K. Webb" <[EMAIL PROTECTED]> wrote: > Hi, List, > > With several stories being posted about the new > research on lunar return samples showing that there > was indeed a Late Heavy Bombardment with a sharp > peak after a quiet period, instead of the Final > Flurry > of an ongoing bombardment, I realized that the > Planet V > hypothesis put forward several years ago to account > for the LHB also ties in with several other new > developments. > > The Asteroid Belt "should be" a zone of > relatively > similar objects in relatively circular, non-inclined > orbits; > that's what ALL the Solar System formation theories > would predict, despite the differing formation > mechanisms they propose. > > But, of course the "real" Asteroid Belt isn't > like > that. There are a wide variety of compositions, like > iron asteroids (that could never have formed that > far > out), dry asteroids, wet asteroids, carbonaceous > asteroids, differentiated asteroids, > non-differentiated > asteroids, asteroids with diamonds, asteroids that > smell > like bubble gum... You name it. In short, every > oddball composition we know from meteorites. > > The SRI published a computer simulation earlier > this year (about which Ron Baalke posted to The > List) > that suggests the Asteroid Zone is full of objects > that formed elsewhere in the Solar System (like iron > asteroids) because they were ALL deflected there > from > other parts of the Solar System. It is silent on > what > did the deflecting, but the simulations seems to > show > that's the only way they could get there > > And, there are asteroid "families" with very > distinctive > eccentric and inclined orbits, grouped together. The > "delta-V" required to drive asteroids into those > orbits > requires repeated close encounters with a body > larger > than Mars (about 1 to 4 Mars masses). This > observation > is decades old, but no one has ever suggested, > again, > what did the deflecting, or when. > > Below is a news story about Chambers and > Lissauer's > Planet V (for Five) hypothesis, which they offer as > an > explanation for the Late Lunar Bombardment, but it > seems to me that the hypothesis may have "legs," as > they say, and that the other unexplained conditions > described above offer some confirmatory > implications. > > And, if you're looking for other unexplained > facts > to tuck into the envelope, there's the anomalous > slow, > backward rotation of Venus (a "day" longer than its > "year"), for which repeated close encounters with a > large body has been suggested as a cause. Planet V? > > And last, there's the mantle-stripping Big Splat > > on Mercury. We've always "assumed" that it took > place as early as our own Moon-forming Big Impact, > but it could have happened at 3.8 to 3.9 billion > years > ago instead, the final outcome of Planet V's rogue > career. Guess we have to wait for that Mercury > Sample Return Mission to find out... > > Here's the only Chambers paper on the hypothesis > that I could get to, for free anyway: > http://www.lpi.usra.edu/meetings/lpsc2002/pdf/1093.pdf > > There's an Australian paper that tries to > duplicate > the results of Chambers and Lissauer, but can't. > http://eo.ucar.edu/staff/dward/sao/dward617paper.pdf > > Its flaw is that it makes Planet V a puny little > thing, about 5 to 8 times too small to do the job. > But then, so does Chambers, because he wants > Planet V to end up crashing into the Sun, a silly > notion whose attractions I am blind to. I like the > Big Splat. > > But I understand his problem. If you're going > to stick another planet in the Solar System to > account for all these things, why, you have to get > rid > of it somehow since it doesn't seem to be around > any more! > > Mercury makes a perfectly good "hit man." > > > Sterling K. Webb > -- > > http://www.space.com/scienceastronomy/solarsystem/fifth_planet_020318.html > > Long-Destroyed Fifth Planet May Have Caused > Lunar Cataclysm, Researchers Say > By Leonard David, Senior Space Writer > posted: 03:00 pm ET, 18 March 2002 > > HOUSTON, TEXAS -- Our solar system may have had a > fifth terrestrial planet, one that was swallowed up > by the Sun. > But before it was destroyed, the now > missing-in-action > world made a mess of things. >
