[meteorite-list] comet holmes
It's still naked eye near Algol in dark skys Jerry Flaherty __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes, always the same........
Excellent vintage, Dr. Watson! ...Holmes cocked his eye at me, leaning back on the cushions with a pleased and yet critical face, like a connoisseur who has just taken his first sip of a comet vintage. Ref: The Memoirs Of Sherlock Holmes, The Stock-Broker's Clerk (1894) by Arthur Conan Doyle Cheers! Doug - Original Message - From: Martin Altmann [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Thursday, November 22, 2007 1:46 AM Subject: [meteorite-list] Comet Holmes, always the same Hi, found a photo of Holmes of 1892. Looks the same as today! http://kuerzer.de/watson1892 1st picture, down right. __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes, always the same........
All periodic comets eventually lose their volatiles. The result is an extinct comet, although nobody knows exactly what that means... an asteroid? a loose clump of rocky material? There are asteroids which are believed to be extinct comets (3200 Phaethon, for instance, the parent body of the Geminids). Holmes is a Jupiter class comet, which means it isn't in a particularly stable orbit. It's probably only been in the inner Solar System for a few thousand years, maybe less. It also doesn't seem particularly active in general- the two known outbursts excepted. But anytime it's at all active, it is losing material, and it can't do that forever. It could also be perturbed into an orbit keeping it far from the Sun, in which case it would never be active and therefore wouldn't lose more material, or much closer (or even into) to the Sun, in which case it would rapidly lose its volatiles. Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message - From: Ron [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Thursday, November 22, 2007 9:06 AM Subject: Re: [meteorite-list] Comet Holmes, always the same Hi, I saw the picture of Comet Holmes, listed as 1892. Does it, or will it ever dissipatate? Ron __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes, always the same........
Hi, I saw the picture of Comet Holmes, listed as 1892. Does it, or will it ever dissipatate? Ron Hi, found a photo of Holmes of 1892. Looks the same as today! http://kuerzer.de/watson1892 1st picture, down right. __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes, always the same........
Happy Thanksgiving to our American colleagues - and holiday blessing to our international colleagues. Do not forget that Murchison is thought by some in the community to be a leading candidate as a dead comet due to its 98 known amino acids and 13% water by volume. I for one love the smell of my Murchison that I keep under a bell jar - it truly smells like a cognac. All the best, Greg Redfern NASA JPL Solar System Ambassador http://www2.jpl.nasa.gov/ambassador/index.html WHAT'S UP?: THE SPACE PLACE http://www.wtopnews.com/?sid=600113nid=421 -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Chris Peterson Sent: Thursday, November 22, 2007 11:23 AM To: meteorite-list@meteoritecentral.com Subject: Re: [meteorite-list] Comet Holmes, always the same All periodic comets eventually lose their volatiles. The result is an extinct comet, although nobody knows exactly what that means... an asteroid? a loose clump of rocky material? There are asteroids which are believed to be extinct comets (3200 Phaethon, for instance, the parent body of the Geminids). Holmes is a Jupiter class comet, which means it isn't in a particularly stable orbit. It's probably only been in the inner Solar System for a few thousand years, maybe less. It also doesn't seem particularly active in general- the two known outbursts excepted. But anytime it's at all active, it is losing material, and it can't do that forever. It could also be perturbed into an orbit keeping it far from the Sun, in which case it would never be active and therefore wouldn't lose more material, or much closer (or even into) to the Sun, in which case it would rapidly lose its volatiles. Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message - From: Ron [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Thursday, November 22, 2007 9:06 AM Subject: Re: [meteorite-list] Comet Holmes, always the same Hi, I saw the picture of Comet Holmes, listed as 1892. Does it, or will it ever dissipatate? Ron __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes, always the same........
Hi, Ron, Holmes had its first known (or noticed) outburst in 1892, which was why it was discovered. That outburst faded, then there was another similarly bright outburst 60 days later, which also faded. The next time around, 7 years later, it was pretty dim, and got dimmer. It got so faint, it was lost in 1913, until the 1960's when it was found again, but only by a big 'scope trying to recover it. This year's outburst is the first since 1892-3, 105 years ago. What it will do next is problematic and not really predictable. Some observers think a big chunk of the nucleus broke away to cause this outburst, but attempts to image it, even by the Hubble, have not located the chunk. Holmes could just outgas all its volatiles and go dead, yes, but Comet Holmes can easily spare the material that it's spewing into the coma. The volume of the nucleus is roughly 20,500,000,000 cubic meters. If it's all ice (with a density of 1.0), that's 20,500,000,000 tons! If half rock and half ice: 30 billion tons. The coma of Comet Holmes, so thin you can see stars through it, only has a few dozen million tons of ice and dust in it. Of course, this material is out-flowing, so over the course of a very long outburst (100 days?), the Comet might lose from a few hundred million tons up to a billion tons of itself. That's 1% up to 5% of its mass. We could all stand to lose 5% of our mass (and by the end of the holidays, maybe more). Whatever caused the 1892 outburst, the Comet remained stable for 105 years. The result of this outburst? Nobody knows. It could go dark for a few centuries, or have a glorious outburst every seven years at each perihelion passage or something inbetween. It's what makes watching the Universe fun. Sterling K. Webb - - Original Message - From: Ron [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Thursday, November 22, 2007 10:06 AM Subject: Re: [meteorite-list] Comet Holmes, always the same Hi, I saw the picture of Comet Holmes, listed as 1892. Does it, or will it ever dissipatate? Ron Hi, found a photo of Holmes of 1892. Looks the same as today! http://kuerzer.de/watson1892 1st picture, down right. __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Comet Holmes, always the same........
Hi, found a photo of Holmes of 1892. Looks the same as today! http://kuerzer.de/watson1892 1st picture, down right. __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes/Parent bodies?
G'day Graham, Here's a list I compiled some years ago from various posts to the list following a large a origins/parent-body thread. I'm not sure if those discussions are still in the archives though. www.meteorites.com.au/oddsends/origin.html Cheers, Jeff - Original Message - From: ensoramanda To: MeteoriteList Sent: Wed Nov 7 04:23:56 2007 Subject: Re: [meteorite-list] Comet Holmes/Parent bodies? Hi Al, All, Nice shots for first attemptI hav'nt had a go for ages...you've inspired me to give it a try whilst there is something special about. You also made me wonder about parent bodies when considering if there might be bits of Holmes about. I am not sure if this has been discussed on the list before much...but wondered if there was any more recent research that indicated more about where all our collections have come from? I have read about various possibilities, matching various classifications of meteorite with various asteroids and suggestions that certain ones might be cometary material...but is there an up to date simple summary or list that matches them up as far as current thinking can? Anyone know? Regards, Graham Ensor __ 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] Comet Holmes/Parent bodies?
Hi Graham and all, Here is a listing of possible parent bodies to our meteorites. If anyone has a more complete listing and would care to share it with me on or off list I would appreciate it. I am sure there a quite a number of suspect parent bodies but not enough data to support a pairing. Best! Comets have also been suggested to be sources for some meteorites but a few problems exist to determine this. First very little is know about comets (though we are just now finding out more) Two no photographs from a network of cameras of material has been taken to show a relationship of material to comets. The streaks of light during a meteor shower represent only minor particles the size of dust or perhaps a bit larger. So currently the jury is still out on pinning meteorite falls to known comets or cometary debris. A Listing of Known and Possible Parent Bodies of Meteorites H class of meteorites: Asteroid Hebe L Classes L4: Asteroid Eros L6: Asteroid Bozemcova 3628 LL Class: Asteroid SF36 (1998) Carbonaceous Group CM2: Asteroid Ceres, Asteroid: Fortuna19 CR2: Asteroid Pallas 2 CO3: Asteroids Eos Family C2 Tagish Lake may be linked to D Asteroid 368 Haidea Achondrite Classes Aubrites: Asteroid Nysa 44, Asteroid Eger 3103 Brachinites: Asteroid Benetta 289 Howardites: Eucrites: Asteroid Vesta (4) Diogenites: Olivine Diogenites: Stony Iron Classes Pallasites: A Type Asteroids, Asteroid Asporina (46), Asteroid Eleonora (354) (there are three or four known parent bodies for pallasites) Iron Classes M-Type Asteroids: Asteroid Psyche, Asteroid 1986 DA Mars Meteorites (SNC 's) From The Planet Mars Shergotties: Nakhlaites: Chassigniates: Allan Hills: Lunar Meteorites (LUN) LUN A: Anorthositic Highland Rocks (four combinations of this group) LUN B: Mare Basalts LUN G:Mare Gabbros LUN N: Lunar Norites This list is derived from Harry McSween's book Meteorite and their Parent Planets and from other sources on the internet that have posted pairings. --AL Mitterling ensoramanda wrote: Hi Al, All, Nice shots for first attemptI hav'nt had a go for ages...you've inspired me to give it a try whilst there is something special about. You also made me wonder about parent bodies when considering if there might be bits of Holmes about. I am not sure if this has been discussed on the list before much...but wondered if there was any more recent research that indicated more about where all our collections have come from? I have read about various possibilities, matching various classifications of meteorite with various asteroids and suggestions that certain ones might be cometary material...but is there an up to date simple summary or list that matches them up as far as current thinking can? Anyone know? Regards, Graham Ensor __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes/Parent bodies?
Hi Al, All, Nice shots for first attemptI hav'nt had a go for ages...you've inspired me to give it a try whilst there is something special about. What equipment are you using? You also made me wonder about parent bodies when considering if there might be bits of Holmes about. I am not sure if this has been discussed on the list before much...but wondered if there was any more recent research that indicated more about where all our collections have come from? I have read about various possibilities, matching various classifications of meteorite with various asteroids and suggestions that certain ones might be cometary material...but is there an up to date simple summary or list that matches them up as far as current thinking can? Anyone know? Regards, Graham Ensor AL Mitterling wrote: Greetings, Here are some photos I took November 1st, 2007 of Comet Holmes. If you haven't been out looking at this comet, it is a very unique once in a lifetime event. For those who might want to view them. This is my first attempt at digital astrophotography (other than the moon). Not perfect but fair. Perhaps there is material from this comet in our collections somewhere. There are also photos of the August 28th Total Lunar Eclipse from out west. http://s239.photobucket.com/albums/ff244/AlMitt/ --AL Mitterling __ 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] Comet Holmes
Finaly I saw the comet tonight, thanks to clear skies here in southern Austria. I think that little animation I found on YouTube shows best what happend to the comet: http://www.youtube.com/watch?v=TJBHm2f-4zo Stefan __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Comet Holmes
Greetings, Here are some photos I took November 1st, 2007 of Comet Holmes. If you haven't been out looking at this comet, it is a very unique once in a lifetime event. For those who might want to view them. This is my first attempt at digital astrophotography (other than the moon). Not perfect but fair. Perhaps there is material from this comet in our collections somewhere. There are also photos of the August 28th Total Lunar Eclipse from out west. http://s239.photobucket.com/albums/ff244/AlMitt/ --AL Mitterling __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes
Hello List: We are finally back to clear skies. Once the Moon went away (rose later) we have had enough clouds to make observing comet Holmes frustrating. We saw something interesting tonight: There was a star clearly visible through the comet coma! Using Starry Night, it appears that the comet is 3 arc minutes (1/10 of the lunar diameter) from a 7th magnitude star (HIP17476). It really gives you a feel for how thin the material in the coma of Holmes really is! Larry and Nancy Lebofsky __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes
Hi Sterling, only a side aspect, which is always disturbing me in general. We're talking about the asteroid belt, families, streams, herds. Whenever in an animation on TV the asteroid belt is shown, a fleet of chunks is valving by like a flock of sheeps (often making silly noise). A common misrepresentation. In books, if the inner solar system printed on a page of a few inches across and the distances of the single asteroids are plottes, the belt is totally mottled... but if one reads the estimation of the total mass of all asteroids together is only one thousandth of the mass of Earth (and already the fifth part packed into Ceres), I'd say it's still relatively empty out there.. Best! Martin -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Sterling K. Webb Gesendet: Dienstag, 30. Oktober 2007 02:35 An: [EMAIL PROTECTED]; Chris Peterson Cc: meteorite-list@meteoritecentral.com Betreff: Re: [meteorite-list] Comet Holmes Larry, Chris, List It crosses the plane... at 4.8 AU. Here's a list of 2278 objects which orbit in the plane of the ecliptic, almost all of which have their perihelion at or around a median figure of 4.8 AU http://cfa-www.harvard.edu/iau/lists/JupiterTrojans.html You're right; I didn't go and look at the ecliptical crossing points, but this is even better! The Jupiter Trojans are clustered at Jupiter's L4 and L5 points in elongated bananas. Additionally, there are no doubt even more of them than these 2278 objects presently catalogued (being discovered by Listmembers, even). Thousands more. They make a fine dangerous crossing for a 3.4 km comet with no working brakes, them dawdling around that intersection without ever really getting out of the way, like a crowd of teenagers. And poor 17P's orbit goes through them once every 81.834 years. That's for both the Greek camp and the Trojan camp, so 17P runs the gaunlet every 40 years. Of course, the Trojans are not AT perihelion all at the same time; their aphelia are an AU or so further out. But Trojans are the only numerous class of bodies that stay herded into one general area all the time (one area in Jupiter's rotating frame of reference). Larry, I realize that you only wanted to get the Asteroids off the hook, but I think you pointed a finger at the ones who did it. Sterling K. Webb --- - Original Message - From: [EMAIL PROTECTED] To: Chris Peterson [EMAIL PROTECTED] Cc: meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 7:49 PM Subject: Re: [meteorite-list] Comet Holmes Hi All: Another thing against an asteroid impact. If you go to the comet orbit site at JPL for Holmes, because of its inclination relative to the ecliptic, it crosses near Mars and Near Jupiter, not in the middle of the asteroid belt. It passed through the plane of the Solar System back in February (before closest approach to the Sun in May) and is now well above the plane of the Solar System. It crosses the plane at 2.1 AU (near the inner edge of the asteroid belt) and at 4.8 AU well beyond the asteroid belt. Granted, there are lots of asteroids with inclinations that put them well above the plane of the solar system, but I would not say that Holmes goes through the center of the belt. On another note, it has been years since I have done any thermal modeling of asteroids, but, even with rocky material, it takes some time for the interior to notice that the asteroid has been near the Sun (thanks to thermal inertia). It should take even longer for the thermal wave to penetrate into the surface of a fluffy comet. Also, when it will be warmest will also depend on the direction of it polar axis. I do not remember the numbers, but even 10 or 15 years after Pluto's closest approach to the Sun, it is still getting warmer and its atmosphere getting thicker (at least as of 3 or 4 years ago). Larry On Mon, October 29, 2007 4:08 pm, Chris Peterson wrote: I don't disregard the possibility of collisions with co-orbiting material. But the probability of colliding with something while passing through the asteroid belt is still exceedingly small. That zone is still basically empty space- very little material spread out in a massive volume. 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 Sent: Monday, October 29, 2007 4:07 PM Subject: Re: [meteorite-list] Comet Holmes Hi, Chris, List The best argument against a collision is the absurd improbability of TWO collisions in the last century, since this comet has a history of outbursts. The problem with probability is the probability of the assumptions that are applied. If 17P is an isolated object and any impactor must come from another
Re: [meteorite-list] Comet Holmes
Hi, Larry, List Sitting up late at night and being too rusty to do things the hard way, I used the simulator at http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=17porb=1 and am doing just what they say NOT to do, namely, run it for decades and decades... If you tilt the view all the way over to a completely flat, looking-down-from-above view of the solar system, it's much easier to visualize the state of the 17P orbit. You can see that Holmes 17P can only go through the Jupiter Trojan points at its own (17P's) descending node. (Just in case there's anybody else following this, here's a really nice map of the gravitational potentials around the Lagrange Points, using the Earth for illustration: http://en.wikipedia.org/wiki/Image:Lagrange_points.jpg) Round and round we go... Yes, Holmes did go through the trailing (L5, Trojan Camp) Trojans around January, 1989 and during the summer of 1906, roughly 81.6 years apart. Holmsie went through the leading (L4, Greek Camp) Trojans about January, 1934 and in July, 1851, roughly 81.5 years apart. All of this assumes that driving the simulator 'way beyond its warranty mileage isn't making it crazy. (As soon as I wrote that, I went and checked known perihelion dates and, yeah, it wanders off at distant dates, but let's just assume it's a progressive error that affects dates only, OK? But the dates I derived could be off by many months.) Then, there's the possibility of Lagrangian Clouds. The Earth has'em. They've been photographed, but they seem to come and go. They were discovered in the 1950's: http://en.wikipedia.org/wiki/Kordylewski_cloud by Kordylewski. Given Jupiter's massive GravPotential, do you suppose dust and small debris accumulate at its Lagrange points? I mean, if it can accumulate thousands of masses the size of Jupiter Trojans... Another Google Chase: the 1200 brightest Jupiter Trojans are between 85 and 105 km in diameter. Big guys. My guess is that there's a lot of little junk in the Trojan Clouds. The Jupiter Trojans are arranged in families like Zone asteroids, and there are double or binary Trojans. The smallest Trojans being detected by big fat 'scopes are down to 700 meters in diameter, and their distribution is normal (with a power coefficient of 2), meaning that there are lots of little ones and little stuff awaiting detection. More stuff to bonk into. Fascinating to observe a plot of the Jupiter Trojans' positions; they are scattered along, inside, and outside Jupiter's orbit, but they never leave... There's a plot in: http://www.dtm.ciw.edu/sheppard/pub/Sheppard04JupChapter.pdf (As one who gripes about knowledge being locked up by academic publishers, Kudo's to Scott S. Sheppard of the Carnegie Institution, who has all his papers online.) The Trojans extend along the orbit for many, many degrees, so the timing of Holmes 17P's passage is not very critical. In fact, I'd say the comet goes through Trojan territory on about 25% of its descending node passages. It's still mostly empty space. All of space is mostly empty space. But time is long. There's a lot of it, too. And Larry is right about the heat pulse from perihelion taking a long time to warm down through the object and reach some touchy volatile which then goes crazy and explodes into a coma. Or, it could be a graze by a co-orbiter, or, a bonk from Trojan debris that exposes it. Or, maybe it has a natural ice-moderated 235U breeder reactor at its core... I would be glad to be proven wrong by finding out what's actually going on; that's why we speculate. What's happened to that comet? Hey! That's all we want to know. Monkey sitting in the tree, staring at that big white shining disc in the sky... Sterling K. Webb - Original Message - From: [EMAIL PROTECTED] To: Sterling K. Webb [EMAIL PROTECTED] Cc: [EMAIL PROTECTED]; Chris Peterson [EMAIL PROTECTED]; meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 8:49 PM Subject: Re: [meteorite-list] Comet Holmes Hi Again Sterling: Next plane crossing (at 4.8 AU or so) is in 2 years. At that time Jupiter is on the other side of the Sun, so the Trojans, which ar, on average, 60 degrees fore and aft of Jupiter not not even close this time around. So, my bias is a thermal burp (belch). I have seen what an expanding gas can do. From a solid to a gas, things like carbon dioxide can expand 500-fold or more. Can cause quite a bang. Larry On Mon, October 29, 2007 6:35 pm, Sterling K. Webb wrote: Larry, Chris, List It crosses the plane... at 4.8 AU. Here's a list of 2278 objects which orbit in the plane of the ecliptic, almost all of which have their perihelion at or around a median figure of 4.8 AU http://cfa-www.harvard.edu/iau/lists/JupiterTrojans.html You're right; I didn't go and look at the ecliptical crossing points, but this is even better! The Jupiter Trojans are clustered at Jupiter's L4 and L5 points in elongated bananas
Re: [meteorite-list] Comet Holmes
Sterling Webb wrote: (Has anybody done spectra for Holmes?! A little IR would be nice.) Sterling, that reminded me that I have a large book with a large title - Atlas of Representative Cometary Spectra. I checked and although it had data for lots of comets (including Encke), it didn't have Holmes. Sorry. Chauncey __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes
Some preliminary spectrometry is reported on here: http://menkescientific.com/Comet17P-Holmes.pdf Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message - From: Sterling K. Webb [EMAIL PROTECTED] To: Chauncey Walden [EMAIL PROTECTED]; meteorite-list@meteoritecentral.com Sent: Tuesday, October 30, 2007 11:12 PM Subject: Re: [meteorite-list] Comet Holmes Hi, Thanks for the try, but I was hoping some observatory would do spectra on this outburst. Since the last outburst was in 1893, there would be no spectroscopy since! This would explain why it wasn't in even the most complete references. Holmes has been coma-free until now. I just hope somebody somewhere in a professional facility finds a hole in their schedule (big telescopes being scheduled to the minute months ahead) and does one. The gases of the coma of Holmes may be a perfectly conventional mixture -- or not. Never know unless you do some measurements. Generally the head of the coma (being dust) is just reflected sunlight anyway; you need a nice tail to identify the gases, and Holmes has not yet grown a tail, poor puppy. And even if it does, we may not be well-positioned to view it. Would be nice to know, though... Sterling K. Webb -list __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes
Hi, Thanks for the try, but I was hoping some observatory would do spectra on this outburst. Since the last outburst was in 1893, there would be no spectroscopy since! This would explain why it wasn't in even the most complete references. Holmes has been coma-free until now. I just hope somebody somewhere in a professional facility finds a hole in their schedule (big telescopes being scheduled to the minute months ahead) and does one. The gases of the coma of Holmes may be a perfectly conventional mixture -- or not. Never know unless you do some measurements. Generally the head of the coma (being dust) is just reflected sunlight anyway; you need a nice tail to identify the gases, and Holmes has not yet grown a tail, poor puppy. And even if it does, we may not be well-positioned to view it. Would be nice to know, though... Sterling K. Webb -- - Original Message - From: Chauncey Walden [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Tuesday, October 30, 2007 10:15 PM Subject: Re: [meteorite-list] Comet Holmes Sterling Webb wrote: (Has anybody done spectra for Holmes?! A little IR would be nice.) Sterling, that reminded me that I have a large book with a large title - Atlas of Representative Cometary Spectra. I checked and although it had data for lots of comets (including Encke), it didn't have Holmes. Sorry. Chauncey __ 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] Comet Holmes
Dear List, Yes, the clouds finnnallly cleared in the Ohio Valley. After a week of hearing the pitter patter of rain on the observatory roof, it cleared and I screamed aloud: Now I can see Comet Homes!!! I eagerly and excitedly rolled off the roof to the roll-off-roof observatory and paced the floor, waiting for darkness. 11:15 AM... 11:20 AM...11:25 AM...Noon...12:05 PMit seemed like an eternity. Finally, the terminator swept across me as if it were a great liberation from the oppressive rule of some garish solar dictator. I long already had the telescope circles set, locked, and tracking. Wowwweee Zoweee! I was not disappointed. What a beautiful totally symmetric outburst! What a wonderful comet! Sterling Webb's post is food for thought. Old periodic comets evaporate and their crusts get covered with a silicate carbonaceous crust, like melting ice on a roadside in spring. When pressure builds up and vapor-dust eruptions occur, it should fountain, like the wonderful beautiful megafountains of Hale-Bopp. But Comet Holmes?!? Noo. Something very bizarre is at work. There was no specific locality, the coma was symmetric.Is it an impact? Even a Carnacas-sized whallop on a small crusty periodic comet nucleus would do for a brightening; I suspect this (if an impact) was a bit larger. Which, renders it improbable. It's like a meteor hitting an area the size of Washington DC. But maybe that's what it is. After all, the fictional detective Charlie Chan once said, Strange events often permit themselves the luxury of having occurred. Which sums up this outburst to a T. I toyed with the idea of the intervening Earth-Moon system acting as a gravitational focuser, from 1 AU to 1.3 AU, from sun-directed meteors, but the flux would not be much higher than the sporadic background. Francis Graham __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes
In fact, the coma is not entirely symmetric. There is clearly a denser region which is offset from the nucleus. This may be a product of whatever caused the outburst, or it may be tail structure seen through the coma- that remains to be seen. Our imagination is perhaps contaminated by visions of Armageddon (the movie) like geysers bursting from the surface, but in reality the escape of gas may be much less violent. It isn't unreasonable to expect it to obey the rules of diffusion, and produce a substantially spherical zone of expanding material. It is likely that the nucleus is spinning. The best argument against a collision is the absurd improbability of TWO collisions in the last century, since this comet has a history of outbursts. Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message - From: Francis Graham [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 12:34 PM Subject: [meteorite-list] Comet Holmes Dear List, Yes, the clouds finnnallly cleared in the Ohio Valley. After a week of hearing the pitter patter of rain on the observatory roof, it cleared and I screamed aloud: Now I can see Comet Homes!!! I eagerly and excitedly rolled off the roof to the roll-off-roof observatory and paced the floor, waiting for darkness. 11:15 AM... 11:20 AM...11:25 AM...Noon...12:05 PMit seemed like an eternity. Finally, the terminator swept across me as if it were a great liberation from the oppressive rule of some garish solar dictator. I long already had the telescope circles set, locked, and tracking. Wowwweee Zoweee! I was not disappointed. What a beautiful totally symmetric outburst! What a wonderful comet! Sterling Webb's post is food for thought. Old periodic comets evaporate and their crusts get covered with a silicate carbonaceous crust, like melting ice on a roadside in spring. When pressure builds up and vapor-dust eruptions occur, it should fountain, like the wonderful beautiful megafountains of Hale-Bopp. But Comet Holmes?!? Noo. Something very bizarre is at work. There was no specific locality, the coma was symmetric.Is it an impact? Even a Carnacas-sized whallop on a small crusty periodic comet nucleus would do for a brightening; I suspect this (if an impact) was a bit larger. Which, renders it improbable. It's like a meteor hitting an area the size of Washington DC. But maybe that's what it is. After all, the fictional detective Charlie Chan once said, Strange events often permit themselves the luxury of having occurred. Which sums up this outburst to a T. I toyed with the idea of the intervening Earth-Moon system acting as a gravitational focuser, from 1 AU to 1.3 AU, from sun-directed meteors, but the flux would not be much higher than the sporadic background. Francis Graham __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes
Hi, Chris, List The best argument against a collision is the absurd improbability of TWO collisions in the last century, since this comet has a history of outbursts. The problem with probability is the probability of the assumptions that are applied. If 17P is an isolated object and any impactor must come from another unrelated orbit, the likelihood of any collision, ever, is very, very low. Like all short period periodic comets, it is assumed that 17P was perturbed into its present orbit, probably by Jupiter. Since its orbit ranges from Jupiter to Mars and is inclined to the solar system plane, 17P must transit the Asteroid Zone twice every orbit (i.e., every 3.5 years). One might pass harmlessly through the Zone at many locations; at other places, you might not be so lucky. If 17P is undergoing an on-going disintegration (from a past major impact, perhaps very long ago), it may well share its orbit with many smaller, darker (harder) fragments, millennia-worth of its own space-junk, a debris stream, possibly arising from this ancient impact or partial breakup. This would raise the probability of future trouble from near zero to near 1.0. There may be more than one debris stream accompanying it, braided around the principal orbit, with objects distributed along the stream. Such streams would be quite invisible to us. In the case of Holmes, the odds of an outburst per orbit seem to be 12 to 1 against. Collisions with co-orbiting objects occur at very small velocity differentials (from the speed of a man walking briskly up to that of a fast runner). Such collisions are not catastrophic but damaging: gouging, ripping, crushing, crust-breaking, volatile churning affairs. Once a century is not that unlikely for such glancing impacts if there enough co-orbiting fragments (especially the more silicate ones). On the other hand, there may be no external impact event responsible; it may be the result of some endogenous process we do not understand. Whipple began the creation of models that explain comet behavior and self-modification of their orbits, the effects of thermal exposure, and so forth, and these models have been greatly elaborated over the years, yet we cannot explain much of comet behavior. Whipple suggested that Holmes had been a double comet in which the pairs collided. Holmes is a prime example of this. We think that it never gets close enough to the Sun to explain the outbursts, but both the discovery outburst and the present one occured after perihelion passage with some delay. In both the discovery brightening and the present one, the delay was five months! (June 16, 1892 to November 6, 1892 -- 143 days; with a second outburst of equal brilliance 60 days later. May 4, 2007 to October 24, 2007 -- 173 days. A 60-day second outburst would make Holmes a Christmas Comet.) Does perihelion warming trigger some internal mechanism that takes about five months to boil up? Or does Holmes catch up with a stream of significant debris (a collisional association) about five months after perihelion and sometimes interact collisionally with it? Sterling K. Webb -- - Original Message - From: Chris Peterson [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 1:49 PM Subject: Re: [meteorite-list] Comet Holmes In fact, the coma is not entirely symmetric. There is clearly a denser region which is offset from the nucleus. This may be a product of whatever caused the outburst, or it may be tail structure seen through the coma- that remains to be seen. Our imagination is perhaps contaminated by visions of Armageddon (the movie) like geysers bursting from the surface, but in reality the escape of gas may be much less violent. It isn't unreasonable to expect it to obey the rules of diffusion, and produce a substantially spherical zone of expanding material. It is likely that the nucleus is spinning. The best argument against a collision is the absurd improbability of TWO collisions in the last century, since this comet has a history of outbursts. Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message - From: Francis Graham [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 12:34 PM Subject: [meteorite-list] Comet Holmes Dear List, Yes, the clouds finnnallly cleared in the Ohio Valley. After a week of hearing the pitter patter of rain on the observatory roof, it cleared and I screamed aloud: Now I can see Comet Homes!!! I eagerly and excitedly rolled off the roof to the roll-off-roof observatory and paced the floor, waiting for darkness. 11:15 AM... 11:20 AM...11:25 AM...Noon...12:05 PMit seemed like an eternity. Finally, the terminator swept across me as if it were a great liberation from the oppressive rule
Re: [meteorite-list] Comet Holmes
I don't disregard the possibility of collisions with co-orbiting material. But the probability of colliding with something while passing through the asteroid belt is still exceedingly small. That zone is still basically empty space- very little material spread out in a massive volume. 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 Sent: Monday, October 29, 2007 4:07 PM Subject: Re: [meteorite-list] Comet Holmes Hi, Chris, List The best argument against a collision is the absurd improbability of TWO collisions in the last century, since this comet has a history of outbursts. The problem with probability is the probability of the assumptions that are applied. If 17P is an isolated object and any impactor must come from another unrelated orbit, the likelihood of any collision, ever, is very, very low. Like all short period periodic comets, it is assumed that 17P was perturbed into its present orbit, probably by Jupiter. Since its orbit ranges from Jupiter to Mars and is inclined to the solar system plane, 17P must transit the Asteroid Zone twice every orbit (i.e., every 3.5 years). One might pass harmlessly through the Zone at many locations; at other places, you might not be so lucky. If 17P is undergoing an on-going disintegration (from a past major impact, perhaps very long ago), it may well share its orbit with many smaller, darker (harder) fragments, millennia-worth of its own space-junk, a debris stream, possibly arising from this ancient impact or partial breakup. This would raise the probability of future trouble from near zero to near 1.0. There may be more than one debris stream accompanying it, braided around the principal orbit, with objects distributed along the stream. Such streams would be quite invisible to us. In the case of Holmes, the odds of an outburst per orbit seem to be 12 to 1 against. Collisions with co-orbiting objects occur at very small velocity differentials (from the speed of a man walking briskly up to that of a fast runner). Such collisions are not catastrophic but damaging: gouging, ripping, crushing, crust-breaking, volatile churning affairs. Once a century is not that unlikely for such glancing impacts if there enough co-orbiting fragments (especially the more silicate ones). On the other hand, there may be no external impact event responsible; it may be the result of some endogenous process we do not understand. Whipple began the creation of models that explain comet behavior and self-modification of their orbits, the effects of thermal exposure, and so forth, and these models have been greatly elaborated over the years, yet we cannot explain much of comet behavior. Whipple suggested that Holmes had been a double comet in which the pairs collided. Holmes is a prime example of this. We think that it never gets close enough to the Sun to explain the outbursts, but both the discovery outburst and the present one occured after perihelion passage with some delay. In both the discovery brightening and the present one, the delay was five months! (June 16, 1892 to November 6, 1892 -- 143 days; with a second outburst of equal brilliance 60 days later. May 4, 2007 to October 24, 2007 -- 173 days. A 60-day second outburst would make Holmes a Christmas Comet.) Does perihelion warming trigger some internal mechanism that takes about five months to boil up? Or does Holmes catch up with a stream of significant debris (a collisional association) about five months after perihelion and sometimes interact collisionally with it? __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes
Offering arguments to account for reality, i.e.. observed phenomenon, where logic is fully implemented, when other KNOWN probabilities, i.e. solar excitation [at least in the present (12 min.)] are eliminated or at the very least, less likely than alternatives, NO MATTER THE MATHEMATICAL ODDS, would lend itself to collision. I suggested this the first night this Comet entered the List discussion. Sterling's accompanying fragments does nicely provide a credible suggestion to explain the repetitious nature of the event, BUT passage through SPACE, as EMPTY as it is does not preclude the possibility of getting wacked twice in 100+ years. Jerry Flaherty - Original Message - From: Chris Peterson [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 7:08 PM Subject: Re: [meteorite-list] Comet Holmes I don't disregard the possibility of collisions with co-orbiting material. But the probability of colliding with something while passing through the asteroid belt is still exceedingly small. That zone is still basically empty space- very little material spread out in a massive volume. 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 Sent: Monday, October 29, 2007 4:07 PM Subject: Re: [meteorite-list] Comet Holmes Hi, Chris, List The best argument against a collision is the absurd improbability of TWO collisions in the last century, since this comet has a history of outbursts. The problem with probability is the probability of the assumptions that are applied. If 17P is an isolated object and any impactor must come from another unrelated orbit, the likelihood of any collision, ever, is very, very low. Like all short period periodic comets, it is assumed that 17P was perturbed into its present orbit, probably by Jupiter. Since its orbit ranges from Jupiter to Mars and is inclined to the solar system plane, 17P must transit the Asteroid Zone twice every orbit (i.e., every 3.5 years). One might pass harmlessly through the Zone at many locations; at other places, you might not be so lucky. If 17P is undergoing an on-going disintegration (from a past major impact, perhaps very long ago), it may well share its orbit with many smaller, darker (harder) fragments, millennia-worth of its own space-junk, a debris stream, possibly arising from this ancient impact or partial breakup. This would raise the probability of future trouble from near zero to near 1.0. There may be more than one debris stream accompanying it, braided around the principal orbit, with objects distributed along the stream. Such streams would be quite invisible to us. In the case of Holmes, the odds of an outburst per orbit seem to be 12 to 1 against. Collisions with co-orbiting objects occur at very small velocity differentials (from the speed of a man walking briskly up to that of a fast runner). Such collisions are not catastrophic but damaging: gouging, ripping, crushing, crust-breaking, volatile churning affairs. Once a century is not that unlikely for such glancing impacts if there enough co-orbiting fragments (especially the more silicate ones). On the other hand, there may be no external impact event responsible; it may be the result of some endogenous process we do not understand. Whipple began the creation of models that explain comet behavior and self-modification of their orbits, the effects of thermal exposure, and so forth, and these models have been greatly elaborated over the years, yet we cannot explain much of comet behavior. Whipple suggested that Holmes had been a double comet in which the pairs collided. Holmes is a prime example of this. We think that it never gets close enough to the Sun to explain the outbursts, but both the discovery outburst and the present one occured after perihelion passage with some delay. In both the discovery brightening and the present one, the delay was five months! (June 16, 1892 to November 6, 1892 -- 143 days; with a second outburst of equal brilliance 60 days later. May 4, 2007 to October 24, 2007 -- 173 days. A 60-day second outburst would make Holmes a Christmas Comet.) Does perihelion warming trigger some internal mechanism that takes about five months to boil up? Or does Holmes catch up with a stream of significant debris (a collisional association) about five months after perihelion and sometimes interact collisionally with it? __ 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] Comet Holmes
Unfortunately, prophetically true. Jerry Flaherty - Original Message - From: Sterling K. Webb [EMAIL PROTECTED] To: Jerry [EMAIL PROTECTED]; Chris Peterson [EMAIL PROTECTED]; meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 8:56 PM Subject: Re: [meteorite-list] Comet Holmes Hi, does not preclude the possibility of getting wacked twice in 100+ years Are you saying that some of us are just unlucky? Sterling K. Webb Holmes is a prime example of this. We think that it never gets close enough to the Sun to explain the outbursts, but both the discovery outburst and the present one occured after perihelion passage with some delay. In both the discovery brightening and the present one, the delay was five months! (June 16, 1892 to November 6, 1892 -- 143 days; with a second outburst of equal brilliance 60 days later. May 4, 2007 to October 24, 2007 -- 173 days. A 60-day second outburst would make Holmes a Christmas Comet.) Does perihelion warming trigger some internal mechanism that takes about five months to boil up? Or does Holmes catch up with a stream of significant debris (a collisional association) about five months after perihelion and sometimes interact collisionally with it? __ 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] Comet Holmes
Hi, does not preclude the possibility of getting wacked twice in 100+ years Are you saying that some of us are just unlucky? Sterling K. Webb - - Original Message - From: Jerry [EMAIL PROTECTED] To: Chris Peterson [EMAIL PROTECTED]; meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 7:00 PM Subject: Re: [meteorite-list] Comet Holmes Offering arguments to account for reality, i.e.. observed phenomenon, where logic is fully implemented, when other KNOWN probabilities, i.e. solar excitation [at least in the present (12 min.)] are eliminated or at the very least, less likely than alternatives, NO MATTER THE MATHEMATICAL ODDS, would lend itself to collision. I suggested this the first night this Comet entered the List discussion. Sterling's accompanying fragments does nicely provide a credible suggestion to explain the repetitious nature of the event, BUT passage through SPACE, as EMPTY as it is does not preclude the possibility of getting wacked twice in 100+ years. Jerry Flaherty - Original Message - From: Chris Peterson [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 7:08 PM Subject: Re: [meteorite-list] Comet Holmes I don't disregard the possibility of collisions with co-orbiting material. But the probability of colliding with something while passing through the asteroid belt is still exceedingly small. That zone is still basically empty space- very little material spread out in a massive volume. 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 Sent: Monday, October 29, 2007 4:07 PM Subject: Re: [meteorite-list] Comet Holmes Hi, Chris, List The best argument against a collision is the absurd improbability of TWO collisions in the last century, since this comet has a history of outbursts. The problem with probability is the probability of the assumptions that are applied. If 17P is an isolated object and any impactor must come from another unrelated orbit, the likelihood of any collision, ever, is very, very low. Like all short period periodic comets, it is assumed that 17P was perturbed into its present orbit, probably by Jupiter. Since its orbit ranges from Jupiter to Mars and is inclined to the solar system plane, 17P must transit the Asteroid Zone twice every orbit (i.e., every 3.5 years). One might pass harmlessly through the Zone at many locations; at other places, you might not be so lucky. If 17P is undergoing an on-going disintegration (from a past major impact, perhaps very long ago), it may well share its orbit with many smaller, darker (harder) fragments, millennia-worth of its own space-junk, a debris stream, possibly arising from this ancient impact or partial breakup. This would raise the probability of future trouble from near zero to near 1.0. There may be more than one debris stream accompanying it, braided around the principal orbit, with objects distributed along the stream. Such streams would be quite invisible to us. In the case of Holmes, the odds of an outburst per orbit seem to be 12 to 1 against. Collisions with co-orbiting objects occur at very small velocity differentials (from the speed of a man walking briskly up to that of a fast runner). Such collisions are not catastrophic but damaging: gouging, ripping, crushing, crust-breaking, volatile churning affairs. Once a century is not that unlikely for such glancing impacts if there enough co-orbiting fragments (especially the more silicate ones). On the other hand, there may be no external impact event responsible; it may be the result of some endogenous process we do not understand. Whipple began the creation of models that explain comet behavior and self-modification of their orbits, the effects of thermal exposure, and so forth, and these models have been greatly elaborated over the years, yet we cannot explain much of comet behavior. Whipple suggested that Holmes had been a double comet in which the pairs collided. Holmes is a prime example of this. We think that it never gets close enough to the Sun to explain the outbursts, but both the discovery outburst and the present one occured after perihelion passage with some delay. In both the discovery brightening and the present one, the delay was five months! (June 16, 1892 to November 6, 1892 -- 143 days; with a second outburst of equal brilliance 60 days later. May 4, 2007 to October 24, 2007 -- 173 days. A 60-day second outburst would make Holmes a Christmas Comet.) Does perihelion warming trigger some internal mechanism that takes about five months to boil up? Or does Holmes catch up with a stream of significant debris
Re: [meteorite-list] Comet Holmes
Hi, Chris, List We have no way of knowing how long Holmes has been in its present orbit; it could easily be many millions of years (or a few scores of thousands). It would make a million Zone passages every 3.5 million years, which would give a good chance of a million-to-one collision event. I am only suggesting an initial impact with a Zone body (or any other body) just once to create streams of co-orbiting debris, which would then grow by the Kessler process, i.e., rubble makes more rubble. Whatever has caused Holmes' condition MUST have been an unfrequent or unlikely event, as there seem to be no other comets around that behave in this oddball way. This is equally true of some unique compositional feature that may be responsible for these outbursts. (Has anybody done spectra for Holmes?! A little IR would be nice.) Comets, once thought to be compositionally simple and essentially similar, even near-identical, are proving to be far more dissimilar and individual than we thought. Perhaps Holmes, instead of being around for millions of years, is relatively fresh from the outer system and contains vast deposits of a volatile that gets very touchy when it gets exposed within 2 AU of the Sun. (Spectra again come to mind.) There are a lot of possibilities. Sterling K. Webb --- - Original Message - From: Chris Peterson [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 6:08 PM Subject: Re: [meteorite-list] Comet Holmes I don't disregard the possibility of collisions with co-orbiting material. But the probability of colliding with something while passing through the asteroid belt is still exceedingly small. That zone is still basically empty space- very little material spread out in a massive volume. 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 Sent: Monday, October 29, 2007 4:07 PM Subject: Re: [meteorite-list] Comet Holmes Hi, Chris, List The best argument against a collision is the absurd improbability of TWO collisions in the last century, since this comet has a history of outbursts. The problem with probability is the probability of the assumptions that are applied. If 17P is an isolated object and any impactor must come from another unrelated orbit, the likelihood of any collision, ever, is very, very low. Like all short period periodic comets, it is assumed that 17P was perturbed into its present orbit, probably by Jupiter. Since its orbit ranges from Jupiter to Mars and is inclined to the solar system plane, 17P must transit the Asteroid Zone twice every orbit (i.e., every 3.5 years). One might pass harmlessly through the Zone at many locations; at other places, you might not be so lucky. If 17P is undergoing an on-going disintegration (from a past major impact, perhaps very long ago), it may well share its orbit with many smaller, darker (harder) fragments, millennia-worth of its own space-junk, a debris stream, possibly arising from this ancient impact or partial breakup. This would raise the probability of future trouble from near zero to near 1.0. There may be more than one debris stream accompanying it, braided around the principal orbit, with objects distributed along the stream. Such streams would be quite invisible to us. In the case of Holmes, the odds of an outburst per orbit seem to be 12 to 1 against. Collisions with co-orbiting objects occur at very small velocity differentials (from the speed of a man walking briskly up to that of a fast runner). Such collisions are not catastrophic but damaging: gouging, ripping, crushing, crust-breaking, volatile churning affairs. Once a century is not that unlikely for such glancing impacts if there enough co-orbiting fragments (especially the more silicate ones). On the other hand, there may be no external impact event responsible; it may be the result of some endogenous process we do not understand. Whipple began the creation of models that explain comet behavior and self-modification of their orbits, the effects of thermal exposure, and so forth, and these models have been greatly elaborated over the years, yet we cannot explain much of comet behavior. Whipple suggested that Holmes had been a double comet in which the pairs collided. Holmes is a prime example of this. We think that it never gets close enough to the Sun to explain the outbursts, but both the discovery outburst and the present one occured after perihelion passage with some delay. In both the discovery brightening and the present one, the delay was five months! (June 16, 1892 to November 6, 1892 -- 143 days; with a second outburst of equal
Re: [meteorite-list] Comet Holmes
Hi All: Another thing against an asteroid impact. If you go to the comet orbit site at JPL for Holmes, because of its inclination relative to the ecliptic, it crosses near Mars and Near Jupiter, not in the middle of the asteroid belt. It passed through the plane of the Solar System back in February (before closest approach to the Sun in May) and is now well above the plane of the Solar System. It crosses the plane at 2.1 AU (near the inner edge of the asteroid belt) and at 4.8 AU well beyond the asteroid belt. Granted, there are lots of asteroids with inclinations that put them well above the plane of the solar system, but I would not say that Holmes goes through the center of the belt. On another note, it has been years since I have done any thermal modeling of asteroids, but, even with rocky material, it takes some time for the interior to notice that the asteroid has been near the Sun (thanks to thermal inertia). It should take even longer for the thermal wave to penetrate into the surface of a fluffy comet. Also, when it will be warmest will also depend on the direction of it polar axis. I do not remember the numbers, but even 10 or 15 years after Pluto's closest approach to the Sun, it is still getting warmer and its atmosphere getting thicker (at least as of 3 or 4 years ago). Larry On Mon, October 29, 2007 4:08 pm, Chris Peterson wrote: I don't disregard the possibility of collisions with co-orbiting material. But the probability of colliding with something while passing through the asteroid belt is still exceedingly small. That zone is still basically empty space- very little material spread out in a massive volume. 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 Sent: Monday, October 29, 2007 4:07 PM Subject: Re: [meteorite-list] Comet Holmes Hi, Chris, List The best argument against a collision is the absurd improbability of TWO collisions in the last century, since this comet has a history of outbursts. The problem with probability is the probability of the assumptions that are applied. If 17P is an isolated object and any impactor must come from another unrelated orbit, the likelihood of any collision, ever, is very, very low. Like all short period periodic comets, it is assumed that 17P was perturbed into its present orbit, probably by Jupiter. Since its orbit ranges from Jupiter to Mars and is inclined to the solar system plane, 17P must transit the Asteroid Zone twice every orbit (i.e., every 3.5 years). One might pass harmlessly through the Zone at many locations; at other places, you might not be so lucky. If 17P is undergoing an on-going disintegration (from a past major impact, perhaps very long ago), it may well share its orbit with many smaller, darker (harder) fragments, millennia-worth of its own space-junk, a debris stream, possibly arising from this ancient impact or partial breakup. This would raise the probability of future trouble from near zero to near 1.0. There may be more than one debris stream accompanying it, braided around the principal orbit, with objects distributed along the stream. Such streams would be quite invisible to us. In the case of Holmes, the odds of an outburst per orbit seem to be 12 to 1 against. Collisions with co-orbiting objects occur at very small velocity differentials (from the speed of a man walking briskly up to that of a fast runner). Such collisions are not catastrophic but damaging: gouging, ripping, crushing, crust-breaking, volatile churning affairs. Once a century is not that unlikely for such glancing impacts if there enough co-orbiting fragments (especially the more silicate ones). On the other hand, there may be no external impact event responsible; it may be the result of some endogenous process we do not understand. Whipple began the creation of models that explain comet behavior and self-modification of their orbits, the effects of thermal exposure, and so forth, and these models have been greatly elaborated over the years, yet we cannot explain much of comet behavior. Whipple suggested that Holmes had been a double comet in which the pairs collided. Holmes is a prime example of this. We think that it never gets close enough to the Sun to explain the outbursts, but both the discovery outburst and the present one occured after perihelion passage with some delay. In both the discovery brightening and the present one, the delay was five months! (June 16, 1892 to November 6, 1892 -- 143 days; with a second outburst of equal brilliance 60 days later. May 4, 2007 to October 24, 2007 -- 173 days. A 60-day second outburst would make Holmes a Christmas Comet.) Does perihelion warming trigger some internal mechanism that takes about five months
Re: [meteorite-list] Comet Holmes
Hi Again Sterling: Next plane crossing (at 4.8 AU or so) is in 2 years. At that time Jupiter is on the other side of the Sun, so the Trojans, which ar, on average, 60 degrees fore and aft of Jupiter not not even close this time around. So, my bias is a thermal burp (belch). I have seen what an expanding gas can do. From a solid to a gas, things like carbon dioxide can expand 500-fold or more. Can cause quite a bang. Larry On Mon, October 29, 2007 6:35 pm, Sterling K. Webb wrote: Larry, Chris, List It crosses the plane... at 4.8 AU. Here's a list of 2278 objects which orbit in the plane of the ecliptic, almost all of which have their perihelion at or around a median figure of 4.8 AU http://cfa-www.harvard.edu/iau/lists/JupiterTrojans.html You're right; I didn't go and look at the ecliptical crossing points, but this is even better! The Jupiter Trojans are clustered at Jupiter's L4 and L5 points in elongated bananas. Additionally, there are no doubt even more of them than these 2278 objects presently catalogued (being discovered by Listmembers, even). Thousands more. They make a fine dangerous crossing for a 3.4 km comet with no working brakes, them dawdling around that intersection without ever really getting out of the way, like a crowd of teenagers. And poor 17P's orbit goes through them once every 81.834 years. That's for both the Greek camp and the Trojan camp, so 17P runs the gaunlet every 40 years. Of course, the Trojans are not AT perihelion all at the same time; their aphelia are an AU or so further out. But Trojans are the only numerous class of bodies that stay herded into one general area all the time (one area in Jupiter's rotating frame of reference). Larry, I realize that you only wanted to get the Asteroids off the hook, but I think you pointed a finger at the ones who did it. Sterling K. Webb --- - Original Message - From: [EMAIL PROTECTED] To: Chris Peterson [EMAIL PROTECTED] Cc: meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 7:49 PM Subject: Re: [meteorite-list] Comet Holmes Hi All: Another thing against an asteroid impact. If you go to the comet orbit site at JPL for Holmes, because of its inclination relative to the ecliptic, it crosses near Mars and Near Jupiter, not in the middle of the asteroid belt. It passed through the plane of the Solar System back in February (before closest approach to the Sun in May) and is now well above the plane of the Solar System. It crosses the plane at 2.1 AU (near the inner edge of the asteroid belt) and at 4.8 AU well beyond the asteroid belt. Granted, there are lots of asteroids with inclinations that put them well above the plane of the solar system, but I would not say that Holmes goes through the center of the belt. On another note, it has been years since I have done any thermal modeling of asteroids, but, even with rocky material, it takes some time for the interior to notice that the asteroid has been near the Sun (thanks to thermal inertia). It should take even longer for the thermal wave to penetrate into the surface of a fluffy comet. Also, when it will be warmest will also depend on the direction of it polar axis. I do not remember the numbers, but even 10 or 15 years after Pluto's closest approach to the Sun, it is still getting warmer and its atmosphere getting thicker (at least as of 3 or 4 years ago). Larry On Mon, October 29, 2007 4:08 pm, Chris Peterson wrote: I don't disregard the possibility of collisions with co-orbiting material. But the probability of colliding with something while passing through the asteroid belt is still exceedingly small. That zone is still basically empty space- very little material spread out in a massive volume. 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 Sent: Monday, October 29, 2007 4:07 PM Subject: Re: [meteorite-list] Comet Holmes Hi, Chris, List The best argument against a collision is the absurd improbability of TWO collisions in the last century, since this comet has a history of outbursts. The problem with probability is the probability of the assumptions that are applied. If 17P is an isolated object and any impactor must come from another unrelated orbit, the likelihood of any collision, ever, is very, very low. Like all short period periodic comets, it is assumed that 17P was perturbed into its present orbit, probably by Jupiter. Since its orbit ranges from Jupiter to Mars and is inclined to the solar system plane, 17P must transit the Asteroid Zone twice every orbit (i.e., every 3.5 years). One might pass harmlessly through the Zone at many locations; at other places
Re: [meteorite-list] Comet Holmes
Larry, Chris, List It crosses the plane... at 4.8 AU. Here's a list of 2278 objects which orbit in the plane of the ecliptic, almost all of which have their perihelion at or around a median figure of 4.8 AU http://cfa-www.harvard.edu/iau/lists/JupiterTrojans.html You're right; I didn't go and look at the ecliptical crossing points, but this is even better! The Jupiter Trojans are clustered at Jupiter's L4 and L5 points in elongated bananas. Additionally, there are no doubt even more of them than these 2278 objects presently catalogued (being discovered by Listmembers, even). Thousands more. They make a fine dangerous crossing for a 3.4 km comet with no working brakes, them dawdling around that intersection without ever really getting out of the way, like a crowd of teenagers. And poor 17P's orbit goes through them once every 81.834 years. That's for both the Greek camp and the Trojan camp, so 17P runs the gaunlet every 40 years. Of course, the Trojans are not AT perihelion all at the same time; their aphelia are an AU or so further out. But Trojans are the only numerous class of bodies that stay herded into one general area all the time (one area in Jupiter's rotating frame of reference). Larry, I realize that you only wanted to get the Asteroids off the hook, but I think you pointed a finger at the ones who did it. Sterling K. Webb --- - Original Message - From: [EMAIL PROTECTED] To: Chris Peterson [EMAIL PROTECTED] Cc: meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 7:49 PM Subject: Re: [meteorite-list] Comet Holmes Hi All: Another thing against an asteroid impact. If you go to the comet orbit site at JPL for Holmes, because of its inclination relative to the ecliptic, it crosses near Mars and Near Jupiter, not in the middle of the asteroid belt. It passed through the plane of the Solar System back in February (before closest approach to the Sun in May) and is now well above the plane of the Solar System. It crosses the plane at 2.1 AU (near the inner edge of the asteroid belt) and at 4.8 AU well beyond the asteroid belt. Granted, there are lots of asteroids with inclinations that put them well above the plane of the solar system, but I would not say that Holmes goes through the center of the belt. On another note, it has been years since I have done any thermal modeling of asteroids, but, even with rocky material, it takes some time for the interior to notice that the asteroid has been near the Sun (thanks to thermal inertia). It should take even longer for the thermal wave to penetrate into the surface of a fluffy comet. Also, when it will be warmest will also depend on the direction of it polar axis. I do not remember the numbers, but even 10 or 15 years after Pluto's closest approach to the Sun, it is still getting warmer and its atmosphere getting thicker (at least as of 3 or 4 years ago). Larry On Mon, October 29, 2007 4:08 pm, Chris Peterson wrote: I don't disregard the possibility of collisions with co-orbiting material. But the probability of colliding with something while passing through the asteroid belt is still exceedingly small. That zone is still basically empty space- very little material spread out in a massive volume. 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 Sent: Monday, October 29, 2007 4:07 PM Subject: Re: [meteorite-list] Comet Holmes Hi, Chris, List The best argument against a collision is the absurd improbability of TWO collisions in the last century, since this comet has a history of outbursts. The problem with probability is the probability of the assumptions that are applied. If 17P is an isolated object and any impactor must come from another unrelated orbit, the likelihood of any collision, ever, is very, very low. Like all short period periodic comets, it is assumed that 17P was perturbed into its present orbit, probably by Jupiter. Since its orbit ranges from Jupiter to Mars and is inclined to the solar system plane, 17P must transit the Asteroid Zone twice every orbit (i.e., every 3.5 years). One might pass harmlessly through the Zone at many locations; at other places, you might not be so lucky. If 17P is undergoing an on-going disintegration (from a past major impact, perhaps very long ago), it may well share its orbit with many smaller, darker (harder) fragments, millennia-worth of its own space-junk, a debris stream, possibly arising from this ancient impact or partial breakup. This would raise the probability of future trouble from near zero to near 1.0. There may be more than one debris stream accompanying it, braided around the principal orbit, with objects distributed along
Re: [meteorite-list] Comet Holmes
Larry, Every 81.787865 years (the product of the two periods of 6.882994 years and 11.8626 years) is the magic number. For any given crossing point relative to Jupiter's orbit, the same configuration will repeat every 81.787865 years. Or, to put it another way, the position of the Jupiter Trojans advances on the 17P crossing point 208.8787 deg with every revolution of 17P. As for when 17P last went through the heart of Trojan country, if I had a big Spirograph with wheels of 688 teeth and 1186 teeth, I could solve the rest of the problem like an ancient Greek cranking the Antikythera Machine! And the creation of a debris stream only requires ONE impact in the last few or ten thousand years. The problem with the thermal theory is: why was there no thermal eruption in all its 15 intervening perihelion passages from the original 1892 outburst until now? Life can always get more complicated. Perhaps the volatile that boils out at 2 AU needs to be excavated by a minor impact to allow the Sun to get at it, so it may be that the Unified Bump and Burp Theory is required! For 2 AU Burps, we need a substance that just goes crazy at ~200 degrees K (if it's white) or ~250 K if it's black. At least that what my bolometer says... Looking at lists of gas boiling points I see one candidate we can absolutely eliminate -- the noble gas ununoctium boils at 250 K. Sterling K. Webb The position of the Jupiter Trojans advances on the 17P crossing point 208.8787 deg every revolution of 17P - Original Message - From: [EMAIL PROTECTED] To: Sterling K. Webb [EMAIL PROTECTED] Cc: [EMAIL PROTECTED]; Chris Peterson [EMAIL PROTECTED]; meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 8:49 PM Subject: Re: [meteorite-list] Comet Holmes Hi Again Sterling: Next plane crossing (at 4.8 AU or so) is in 2 years. At that time Jupiter is on the other side of the Sun, so the Trojans, which ar, on average, 60 degrees fore and aft of Jupiter not not even close this time around. So, my bias is a thermal burp (belch). I have seen what an expanding gas can do. From a solid to a gas, things like carbon dioxide can expand 500-fold or more. Can cause quite a bang. Larry On Mon, October 29, 2007 6:35 pm, Sterling K. Webb wrote: Larry, Chris, List It crosses the plane... at 4.8 AU. Here's a list of 2278 objects which orbit in the plane of the ecliptic, almost all of which have their perihelion at or around a median figure of 4.8 AU http://cfa-www.harvard.edu/iau/lists/JupiterTrojans.html You're right; I didn't go and look at the ecliptical crossing points, but this is even better! The Jupiter Trojans are clustered at Jupiter's L4 and L5 points in elongated bananas. Additionally, there are no doubt even more of them than these 2278 objects presently catalogued (being discovered by Listmembers, even). Thousands more. They make a fine dangerous crossing for a 3.4 km comet with no working brakes, them dawdling around that intersection without ever really getting out of the way, like a crowd of teenagers. And poor 17P's orbit goes through them once every 81.834 years. That's for both the Greek camp and the Trojan camp, so 17P runs the gaunlet every 40 years. Of course, the Trojans are not AT perihelion all at the same time; their aphelia are an AU or so further out. But Trojans are the only numerous class of bodies that stay herded into one general area all the time (one area in Jupiter's rotating frame of reference). Larry, I realize that you only wanted to get the Asteroids off the hook, but I think you pointed a finger at the ones who did it. Sterling K. Webb --- - Original Message - From: [EMAIL PROTECTED] To: Chris Peterson [EMAIL PROTECTED] Cc: meteorite-list@meteoritecentral.com Sent: Monday, October 29, 2007 7:49 PM Subject: Re: [meteorite-list] Comet Holmes Hi All: Another thing against an asteroid impact. If you go to the comet orbit site at JPL for Holmes, because of its inclination relative to the ecliptic, it crosses near Mars and Near Jupiter, not in the middle of the asteroid belt. It passed through the plane of the Solar System back in February (before closest approach to the Sun in May) and is now well above the plane of the Solar System. It crosses the plane at 2.1 AU (near the inner edge of the asteroid belt) and at 4.8 AU well beyond the asteroid belt. Granted, there are lots of asteroids with inclinations that put them well above the plane of the solar system, but I would not say that Holmes goes through the center of the belt. On another note, it has been years since I have done any thermal modeling of asteroids, but, even with rocky material, it takes some time for the interior to notice that the asteroid has been near the Sun (thanks to thermal inertia
[meteorite-list] comet Holmes 17P
Hi list, I was able to observe the comet last night. The southern hemisphere is disfavoured, we have clear skies though... It is a bright star for the unaided eye, in a 10x50 it appears as a small bright circular disk. The 4 Newtonian reveals a circular disk with a bright center, just outside the center of the disk. I made some fotos. I used a Canon EOS 350D digital camera and a 300m lens, took 30 exposures of 1 each and stacked. Then I used a Larson-Sekanina algorithm to reveal a shell structure, yet no eruptions or jets. Look here for the pics: (the german words are the same what I described here, basically): (scoll down) http://www.meteoros.de/php/viewtopic.php?p=23601#23601 Clear skies, Jan __ Jetzt neu! Im riesigen WEB.DE Club SmartDrive Dateien freigeben und mit Freunden teilen! http://www.freemail.web.de/club/smartdrive_ttc.htm/?mc=021134 __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] COMET HOLMES LONG LIVED?
http://www.space.com/spacewatch/071026-comet-holmes-update.html Dramatic Comet Outburst Could Last Weeks By Robert Roy Britt Senior Science Writer posted: 26 October 2007 02:09 pm ET A comet that suddenly brightened earlier this week has astronomers around the globe fascinated. And the show could go on for some time. Comet Holmes, discovered in 1892, had in recent years been visible only through telescopes until a dramatic outburst made it visible to the naked eye. In fewer than 24 hours, it brightened by a factor of nearly 400,000. It has now brightened by a factor of a million times what it was before the outburst, a change absolutely unprecedented in the annals of cometary astronomy, said Joe Rao, SPACE.com's Skywatching Columnist. The comet is now rivaling some of the brighter stars in the sky. Anyone with a map should be able to spot it now. But Comet Holmes lacks a tail, so it's more like a fuzzy, yellow star, observers report. The view is improved with a small telescope. This is a terrific outburst, said Brian Marsden, director emeritus of the Minor Planet Center, which tracks known comets and asteroids. And since it doesn't have a tail right now, some observers have confused it with a nova. We've had at least two reports of a new star. The comet could fade in a matter of days or weeks, according to a statement from the Harvard-Smithsonian Center for Astrophysics. Comet expert John Bortle expects the comet to continue as a naked-eye object for the next few weeks as it dims gradually. Bortle said the coma, or fuzzy head of the comet, could expand as weeks go by. The coma could reach the apparent size of the moon in the sky, he said. The comet is located among the stars of the constellation Perseus, which is about halfway up in the northeast sky in the evening. Perseus is almost directly overhead by around 2 a.m. local daylight time and remains well up in the northwest at dawn. The comet was plainly visible, disturbing the normal pattern of stars that make up Perseus, Rao said after observiing it last night. The comet orbits the Sun once every seven years at a distance of about 200 million miles (compared to Earth's 93-million-mile orbit). It was re-observed in 1899 and 1906 before being lost for nearly six decades. Based on a prediction by Marsden, the comet was found again in 1964. Since then, it's been behaving well-until now, Marsden said. Astronomers don't know why the outburst occurred. __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] comet holmes
Jerry, In a century or two, the lightminute will become a common measure of distance. Say you're working on Titan, at the Hydrocarbon Pipeline Base at the foot of the skyhook that pumps it up to static orbit, and you realize that next month you'll have to budget for a long phone call to your wife's parents because it's their 100th wedding anniversary. It's not cheap to call The Old Folks At Home (back on The Moon, as they still call it) and your wife is going to blab endlessly, you know that. The charge rate of the call will contain lightspeed connection times, a surcharge per lightminute. You recall vaguely that Saturn and Earth are both on the same side of the Sun right now; that helps. You get online and check the current surcharge on a call to The Moon. At least it's nowhere as bad as the surcharge to Mars. The lightminute is the most comfortable unit to use inside the solar system, whether you're communicating or not. Just as today anyone who moves around a lot knows that a mile is 5280 feet (and a kilometer is 3280* feet; isn't that handy?), in 200 years all traveled persons will know a lightminute is 18,000,000 kilometers. Only pedants will object that it's really 17,987,547.5 kilometers. Hey! Close enough! For everything but the landing, anyway. It's a lot more convenient to think of the Earth's distance from the Sun as 8.5 lightminutes, or Mars' close approach is just over 3 lightminutes (and Venus' closest just under 3 lightminutes or Jupiter at 39 lightminutes). AU's are too big. Miles and kilometers are too small. The lightminute is just right. And if you're IN a spacecraft making a routine trip in the solar system and covering 2,500,000+ kilometers a day for days on end, you're covering a lightminute every week and wishing you had the price of a high-boost ticket on a hyperbolic orbit liner knocking off a lightminute or more every day. Oh, yeah, those big numbers we use today look very impressive in print (and that's why we use them), but in constant everyday conversation? I don't think so. The lightminute has a future! It's either that, or a new common-use unit like the kilometer: the gigameter. So, a lightminute is 18 gigameters. But because the gigameter doesn't tie to time (and communication) like the lightminute, I think the lightminute will be the winner. Sterling K. Webb - * 3280.8399 feet, you pedants. - - Original Message - From: [EMAIL PROTECTED] To: Jerry [EMAIL PROTECTED] Cc: meteorite-list@meteoritecentral.com Sent: Wednesday, October 24, 2007 11:32 PM Subject: Re: [meteorite-list] comet holmes Hello Jerry: Based on Starry Night, the Shuttle was about 360km away at closest and ISS about 390km away. At 300,000 km/sec (speed of light), we are talking about 1/1000 of a second for light to get from there to here. Not sure how far apart they were, but do not think that it was very much different than that. Larry On Wed, October 24, 2007 8:50 pm, Jerry wrote: What's the time interval for light transmission from this distance to earth? Jerry Flaherty __ 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] comet holmes
Thank you Sterling. That's why I asked, honestly. Skies are clearing overhead. I'll be interested in observing tonight. Last night's moon was of little consequence in seeing the comet. Time to set up tripods for the binocs and a scope as well. I'll get back to you. Jerry Flaherty - Original Message - From: Sterling K. Webb [EMAIL PROTECTED] To: Meteorite List meteorite-list@meteoritecentral.com Cc: Larry Lebofsky [EMAIL PROTECTED]; Jerry [EMAIL PROTECTED] Sent: Thursday, October 25, 2007 3:15 PM Subject: Re: [meteorite-list] comet holmes Jerry, In a century or two, the lightminute will become a common measure of distance. Say you're working on Titan, at the Hydrocarbon Pipeline Base at the foot of the skyhook that pumps it up to static orbit, and you realize that next month you'll have to budget for a long phone call to your wife's parents because it's their 100th wedding anniversary. It's not cheap to call The Old Folks At Home (back on The Moon, as they still call it) and your wife is going to blab endlessly, you know that. The charge rate of the call will contain lightspeed connection times, a surcharge per lightminute. You recall vaguely that Saturn and Earth are both on the same side of the Sun right now; that helps. You get online and check the current surcharge on a call to The Moon. At least it's nowhere as bad as the surcharge to Mars. The lightminute is the most comfortable unit to use inside the solar system, whether you're communicating or not. Just as today anyone who moves around a lot knows that a mile is 5280 feet (and a kilometer is 3280* feet; isn't that handy?), in 200 years all traveled persons will know a lightminute is 18,000,000 kilometers. Only pedants will object that it's really 17,987,547.5 kilometers. Hey! Close enough! For everything but the landing, anyway. It's a lot more convenient to think of the Earth's distance from the Sun as 8.5 lightminutes, or Mars' close approach is just over 3 lightminutes (and Venus' closest just under 3 lightminutes or Jupiter at 39 lightminutes). AU's are too big. Miles and kilometers are too small. The lightminute is just right. And if you're IN a spacecraft making a routine trip in the solar system and covering 2,500,000+ kilometers a day for days on end, you're covering a lightminute every week and wishing you had the price of a high-boost ticket on a hyperbolic orbit liner knocking off a lightminute or more every day. Oh, yeah, those big numbers we use today look very impressive in print (and that's why we use them), but in constant everyday conversation? I don't think so. The lightminute has a future! It's either that, or a new common-use unit like the kilometer: the gigameter. So, a lightminute is 18 gigameters. But because the gigameter doesn't tie to time (and communication) like the lightminute, I think the lightminute will be the winner. Sterling K. Webb - * 3280.8399 feet, you pedants. - - Original Message - From: [EMAIL PROTECTED] To: Jerry [EMAIL PROTECTED] Cc: meteorite-list@meteoritecentral.com Sent: Wednesday, October 24, 2007 11:32 PM Subject: Re: [meteorite-list] comet holmes Hello Jerry: Based on Starry Night, the Shuttle was about 360km away at closest and ISS about 390km away. At 300,000 km/sec (speed of light), we are talking about 1/1000 of a second for light to get from there to here. Not sure how far apart they were, but do not think that it was very much different than that. Larry On Wed, October 24, 2007 8:50 pm, Jerry wrote: What's the time interval for light transmission from this distance to earth? Jerry Flaherty __ 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] comet holmes
Hi Sterling, Jerry and Listees, Entertaining treatise Sterling! Though I think your idea of time won't fly because you are very over-sexagesimal. In a perfect future, we would have disposed of the inefficient measure of time every applied to a decimal world. And hopefully trash all these confusing angular measurements from the same obsolete 5000 year old Sumerian system that we are stuck with which re-enfore the seconds, minutes and hours(degrees) system! Just try using a GPS without getting CTS with all these useless conversions. How many people have been turned off from math, and absolutely gone wacky with trig conversions and needlessly complex coordinate systems, not to mention poor, poor, poor astronomers that have to deal with all of these needlessly nasty formulas of time seconds minutes hours and all kinds of years that always cause typos, incredibly clunky measuring systems and mistakes in decimalization? 24 hours in a day? 7 days in a week? 12 months in a year but months vary in length? Better yet, 365.242... something days in a year? 360 degrees in a circle? 60 arcminutes in a degree? And the Sun measures how many arcseconds means what? The Cesium 133 atom at what location? Hopefully, we, the forefathers can take an idea from ancient enlightened France (no doubt Ben Franklin and Thomas Jefferson would have preferred it too, but just assumed we'd clean up the mess for them by now). The new unit is the decimal second and everything is base 10's. For example, when someone says the Sun measures 0.15 chi (32 arcminutes), you'll know it is 0.15% of a full circle which has 100 degrees all around. And the telephone company can surcharge us for light-tick (600 microdays, chis, etc.) if you want, when a call to Venus at three light-ticks (1800 microdays, or chis, etc.) will mean to you delay of 2.59 light minutes. And all this will fit perfectly into the metric system, and make Poincaré and Lagrange proud. A good example of a new year http://www.angelfire.com/hi/funline/digitime.html Of course, your light-minute spirit can still fly, as long as we fix the time. The future is just a tick away...by then we hopefully can figure out how to get rid of that Cesium isotope, too. Best wishes, Doug PS Things that scientists mascarade about explaining suddenly will be so obvious, everyone will know what is going on and scientists will have to keep busy doing real science. As for distance, there is no problem with giga and mega, just ask any kid. Not a good idea introducing yet another arbitrary thing into the mix. The distance light travels in whatever time period is useful when dealing with interplanetary communication and imaging, but these distances are always changing above absolute zero, so I don't see much a point except when making observations or explaining delays in communicating. There won't be any linear scale for charging for distance any more than cell phone providers currently surcharge us by our distance from the nearest cell phone transmission tower. $$$ just depends on who's network you go roaming to Titan on... some things will never change. - Original Message - From: Jerry [EMAIL PROTECTED] To: Sterling K. Webb [EMAIL PROTECTED]; Meteorite List meteorite-list@meteoritecentral.com Sent: Thursday, October 25, 2007 3:57 PM Subject: Re: [meteorite-list] comet holmes Thank you Sterling. That's why I asked, honestly. Skies are clearing overhead. I'll be interested in observing tonight. Last night's moon was of little consequence in seeing the comet. Time to set up tripods for the binocs and a scope as well. I'll get back to you. Jerry Flaherty - Original Message - From: Sterling K. Webb [EMAIL PROTECTED] To: Meteorite List meteorite-list@meteoritecentral.com Cc: Larry Lebofsky [EMAIL PROTECTED]; Jerry [EMAIL PROTECTED] Sent: Thursday, October 25, 2007 3:15 PM Subject: Re: [meteorite-list] comet holmes Jerry, In a century or two, the lightminute will become a common measure of distance. Say you're working on Titan, at the Hydrocarbon Pipeline Base at the foot of the skyhook that pumps it up to static orbit, and you realize that next month you'll have to budget for a long phone call to your wife's parents because it's their 100th wedding anniversary. It's not cheap to call The Old Folks At Home (back on The Moon, as they still call it) and your wife is going to blab endlessly, you know that. The charge rate of the call will contain lightspeed connection times, a surcharge per lightminute. You recall vaguely that Saturn and Earth are both on the same side of the Sun right now; that helps. You get online and check the current surcharge on a call to The Moon. At least it's nowhere as bad as the surcharge to Mars. The lightminute is the most comfortable unit to use inside the solar system, whether you're communicating or not. Just as today anyone who moves around a lot knows that a mile
[meteorite-list] Comet Holmes
Hi List just went outside a few minutes ago. Tell me if I saw the comet. I looked down from Marfak (brightest star in perseus) to the next star called Delta Persei. Then I looked 2° to the left (which would be west at this time now) and BAM! This thing is bright!! Too bad no tail but my guess is something cataclysmic occurred internally and made it's way to the surface. So for those experts out there who have seen the comet does it seem as if I was looking in the right area and saw it? Just looking for some verification is all. Thanks Don M __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Comet Holmes
Hello Don: Sounds good to me! We could see all three in the same field of the binocs and then could see it even with the naked eye. Not bad for a nearly full moon! It looked a little reddish and the three of us (Nancy, me, and one of my students) all could convince ourselves that it did not quite look starlike (just a tad fuzzy). On top of that, saw ISS at -27 magnitude and the shuttle 90 degrees behind at -1.5 or a little brighter. Not a bad evening! Larry On Wed, October 24, 2007 7:33 pm, Don Merchant wrote: Hi List just went outside a few minutes ago. Tell me if I saw the comet. I looked down from Marfak (brightest star in perseus) to the next star called Delta Persei. Then I looked 2° to the left (which would be west at this time now) and BAM! This thing is bright!! Too bad no tail but my guess is something cataclysmic occurred internally and made it's way to the surface. So for those experts out there who have seen the comet does it seem as if I was looking in the right area and saw it? Just looking for some verification is all. Thanks Don M __ 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] Comet Holmes
Hi, Don, That is the correct location. There can't be two of them. In some locations (like mine), that is the sky coordinates of the Great Cloudy Nebula, as Walter called it. And, of course, the sky to the southwest is clear, where it doesn't matter. Sterling K. Webb - - Original Message - From: Don Merchant [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Cc: [EMAIL PROTECTED] Sent: Wednesday, October 24, 2007 9:33 PM Subject: [meteorite-list] Comet Holmes Hi List just went outside a few minutes ago. Tell me if I saw the comet. I looked down from Marfak (brightest star in perseus) to the next star called Delta Persei. Then I looked 2° to the left (which would be west at this time now) and BAM! This thing is bright!! Too bad no tail but my guess is something cataclysmic occurred internally and made it's way to the surface. So for those experts out there who have seen the comet does it seem as if I was looking in the right area and saw it? Just looking for some verification is all. Thanks Don M __ 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] Comet Holmes
Good fortune shines on comet observers in Plymouth, Massachusetts. A break of 15 minutes in the cloud cover allowed us an easy view of Comet Holmes. Quite unstarlike but not the ordinary hazy comet. A sharp object more planetlike than any comet I've seen. Probably due to its unusual brightening at such an extrodinary distance from Earth. Easy naked eye object even drenched in moonlight, but binoculars are amazing. Good luck on this one to all dwellers in light polluted areas. It should be observable but its time of continued brightening may be limited if the event that caused it is NOT the usual solar excitation. Consider our comet crasher last year. The interval of brightening was short lived. Cool! Jerry Flaherty __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] comet holmes
What's the time interval for light transmission from this distance to earth? Jerry Flaherty __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] comet holmes
Hi, Jerry, I don't know the exact distance to 17P (starts Googling). Light speed is 18 million kilometers a minute. If I did it right (don't hold me to it) Mars is 121,422,000 kilometers away right now (give or take), or a light travel time of 6 minutes, 44.67 seconds -- that's why all those phone calls you've been making to Mars are so expensive. Doug says: Comet 17P (Holmes) estimated at under 3.5 Km in diameter, and being twice as far from the Earth as the planet Mars I don't know if he means at the moment or that its perihelion distance is 2.1655 AU (and aphelion at 5.2 AU). Holmes has passed perihelion (May 4) and is heading out, so a long way. The Space.com article says it's 243,000,000 km away (twice as far as Mars, like Doug said) and assuming they mean actual Earth-Comet distance, the light travel time is 13 minutes, 30 seconds. Long distance call... Sterling K. Webb --- - Original Message - From: Jerry [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Wednesday, October 24, 2007 10:50 PM Subject: [meteorite-list] comet holmes What's the time interval for light transmission from this distance to earth? Jerry Flaherty __ 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] comet holmes
Hello Jerry: Based on Starry Night, the Shuttle was about 360km away at closest and ISS about 390km away. At 300,000 km/sec (speed of light), we are talking about 1/1000 of a second for light to get from there to here. Not sure how far apart they were, but do not think that it was very much different than that. Larry On Wed, October 24, 2007 8:50 pm, Jerry wrote: What's the time interval for light transmission from this distance to earth? Jerry Flaherty __ 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] comet holmes, Oops
Too mnay objects running around. 1 AU = 149,600,000 km Comet Holmes = 1.6345 AU from earth this evening (in two days it will be down to 1.630 AU, better duck) This gives a distance of 244,500,000 km Speed of light is 299,800 km/sec So Light Distance = 816 seconds (give or take) Larry On Wed, October 24, 2007 9:29 pm, Sterling K. Webb wrote: Hi, Jerry, I don't know the exact distance to 17P (starts Googling). Light speed is 18 million kilometers a minute. If I did it right (don't hold me to it) Mars is 121,422,000 kilometers away right now (give or take), or a light travel time of 6 minutes, 44.67 seconds -- that's why all those phone calls you've been making to Mars are so expensive. Doug says: Comet 17P (Holmes) estimated at under 3.5 Km in diameter, and being twice as far from the Earth as the planet Mars I don't know if he means at the moment or that its perihelion distance is 2.1655 AU (and aphelion at 5.2 AU). Holmes has passed perihelion (May 4) and is heading out, so a long way. The Space.com article says it's 243,000,000 km away (twice as far as Mars, like Doug said) and assuming they mean actual Earth-Comet distance, the light travel time is 13 minutes, 30 seconds. Long distance call... Sterling K. Webb -- - - Original Message - From: Jerry [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Wednesday, October 24, 2007 10:50 PM Subject: [meteorite-list] comet holmes What's the time interval for light transmission from this distance to earth? Jerry Flaherty __ 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
