Re: [meteorite-list] Meteorites 101-Bolide
Hi Elton all, It's funny but I've always been under the same impression as Elton in regards to the term bolide. I'm not sure why though! Basically I've always believed the following to be an approximate summary: Meteor - basically a generic term for all meteors and associated light phenomena. Fireball - exceptionally large and bright meteor at least as bright as Venus (i.e. -3 to -4 mag). Disintegrating body / sparks etc is still possible with a fireball. Bolide - basically a Fireball PLUS an audible report. I believe the term bolide originally stems from the Latin term bolis which roughly translates to a very large fiery meteor with some sources also referencing the associated audible phenomena. The earliest published reference I found online for bolis was Webster's Revised Unabridged Dictionary (1913) (n.) A meteor or brilliant shooting star, followed by a train of light or sparks; esp. one which explodes. I guess there are many variations and opinions. For the most part... they're probably all pretty much correct. Cheers, Jeff - Original Message - From: MEM mstrema...@yahoo.com To: Mark Bowling mina...@yahoo.com; metlist meteorite-list@meteoritecentral.com Sent: Monday, January 17, 2011 8:56 AM Subject: Re: [meteorite-list] Meteorites 101-Bolide We differ some Mark, in that a bolide is not just a fireball showing framentation-- such as we saw in the Peekskill fireball. IMO, historically and by traditional use: a bolide is not just a simple fragmentation but an explosive rupture which occurs at the practical end of incandescent flight--Like an upside down bottle rocket. Perhaps, it is somewhat subjective, and while it may occur out of ear shod, the explosive expansion part has a distinct sound/report different from a sonic boom. The term was adapted possibly from a discussion of military rocketry into early descriptions of meteor fireballs which exploded. Perhaps it is just me but I subscribe to these characteristics of a bolide because it describes a specific combination of conditions. The audible report component is most always associated with the early literature accounts describing a fireball as a bolide. In my bolide theory I believe there is an envelope of stress/shear as the meteoroid is undergoing, being dramatically slowed by the atmosphere. If the envelope is not violated the meator may fragment but it does not do so explosively. Around 5 miles above sea level the meteoroid encounters the boundary of that momentum /shear envelope which reflects maximum aerodynamic pressure at which the meteoroid can retain integrity. This transition is so abrupt for the meteoroid, that it literally shears along molecular bonds releasing a fair amount of heat and possibly rapid oxidation of iron particles, etc. Elton - Original Message From: Mark Bowling mina...@yahoo.com To: meteorite-list@meteoritecentral.com Sent: Sun, January 16, 2011 12:11:03 PM Subject: Re: [meteorite-list] Meteorites 101-Bolide Hi all, I have understood from my study that a bolide refers to a meteor that breaks up - not requiring the detection of an audible report because, if observed from a distance, the sound may not be heard. It is not a bright meteor or fireball or large impactor, but simply a meteor that breaks up. Right or wrong, that's the way I've been using the term when I report seeing one on the list. Has anybody else been using it that way? I've been lucky to have seen several dozen over the years (often colorful), but none up close like Elton (yet!). I would agree that the IAU should come up with a definition because the term has come to mean too many things and its use is not going to go away any time soon. In fact with the current explosion of public interest (no pun intended), more people are going to find the term and grab onto it. See you all soon! Mark B. Vail, AZ __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteorites 101-Bolide
Hi Jeff all, Though I'm not entirely clear on the details, I think I heard the term through discussion in the past (just not fresh in my memory the details of those discussion/lectures), but also through reading some old references. A few years ago, I spent some time rechecking my books when I started to hear bolide used more loosely (or better, I heard it used differently than what I understood it to mean). I was beginning to wonder if I had misunderstood and had been using the term incorrectly. I came to the conclusion that I was not mistaken, so continued to use it as before. I have read similar definitions as given by your reference, but I just haven't interpreted (rightly or wrongly) the last part (explodes) as indicating an audible report. But more of a visual indication - sometimes they are quite dramatic, even though you still don't hear them (you can imagine the violence of the occurrence). If you do hear them, that means it's fairly close by (and great to know and experience!). That's just the way I've interpreted very similar definitions - but that's just me. :) Looking forward to a more official definition (and hoping they change their mind about Pluto too ;-P). Clear skies, Mark P.S. Thanks Martin for the interesting history! - Original Message From: Jeff Kuyken i...@meteorites.com.au To: MEM mstrema...@yahoo.com; metlist meteorite-list@meteoritecentral.com Sent: Mon, January 17, 2011 4:26:05 AM Subject: Re: [meteorite-list] Meteorites 101-Bolide Hi Elton all, It's funny but I've always been under the same impression as Elton in regards to the term bolide. I'm not sure why though! Basically I've always believed the following to be an approximate summary: Meteor - basically a generic term for all meteors and associated light phenomena. Fireball - exceptionally large and bright meteor at least as bright as Venus (i.e. -3 to -4 mag). Disintegrating body / sparks etc is still possible with a fireball. Bolide - basically a Fireball PLUS an audible report. I believe the term bolide originally stems from the Latin term bolis which roughly translates to a very large fiery meteor with some sources also referencing the associated audible phenomena. The earliest published reference I found online for bolis was Webster's Revised Unabridged Dictionary (1913) (n.) A meteor or brilliant shooting star, followed by a train of light or sparks; esp. one which explodes. I guess there are many variations and opinions. For the most part... they're probably all pretty much correct. Cheers, Jeff - Original Message - From: MEM mstrema...@yahoo.com To: Mark Bowling mina...@yahoo.com; metlist meteorite-list@meteoritecentral.com Sent: Monday, January 17, 2011 8:56 AM Subject: Re: [meteorite-list] Meteorites 101-Bolide We differ some Mark, in that a bolide is not just a fireball showing framentation-- such as we saw in the Peekskill fireball. IMO, historically and by traditional use: a bolide is not just a simple fragmentation but an explosive rupture which occurs at the practical end of incandescent flight--Like an upside down bottle rocket. Perhaps, it is somewhat subjective, and while it may occur out of ear shod, the explosive expansion part has a distinct sound/report different from a sonic boom. The term was adapted possibly from a discussion of military rocketry into early descriptions of meteor fireballs which exploded. Perhaps it is just me but I subscribe to these characteristics of a bolide because it describes a specific combination of conditions. The audible report component is most always associated with the early literature accounts describing a fireball as a bolide. In my bolide theory I believe there is an envelope of stress/shear as the meteoroid is undergoing, being dramatically slowed by the atmosphere. If the envelope is not violated the meator may fragment but it does not do so explosively. Around 5 miles above sea level the meteoroid encounters the boundary of that momentum /shear envelope which reflects maximum aerodynamic pressure at which the meteoroid can retain integrity. This transition is so abrupt for the meteoroid, that it literally shears along molecular bonds releasing a fair amount of heat and possibly rapid oxidation of iron particles, etc. Elton - Original Message From: Mark Bowling mina...@yahoo.com To: meteorite-list@meteoritecentral.com Sent: Sun, January 16, 2011 12:11:03 PM Subject: Re: [meteorite-list] Meteorites 101-Bolide Hi all, I have understood from my study that a bolide refers to a meteor that breaks up - not requiring the detection of an audible report because, if observed from a distance, the sound may not be heard. It is not a bright meteor or fireball or large impactor, but simply a meteor that breaks up. Right or wrong, that's the way I've been using the term when I report seeing one on the list. Has
Re: [meteorite-list] Meteorites 101-Bolide
One last (?) comment regarding bolide; Yes it comes from the Latin, and is really a French word, used in France in relation to racing cars. And it really should be pronounced just like solid. Anne M. Black _http://www.impactika.com/_ (http://www.impactika.com/) _IMPACTIKA@aol.com_ (mailto:impact...@aol.com) President, I.M.C.A. Inc. _http://www.imca.cc/_ (http://www.imca.cc/) In a message dated 1/17/2011 4:26:23 AM Mountain Standard Time, i...@meteorites.com.au writes: Hi Elton all, It's funny but I've always been under the same impression as Elton in regards to the term bolide. I'm not sure why though! Basically I've always believed the following to be an approximate summary: Meteor - basically a generic term for all meteors and associated light phenomena. Fireball - exceptionally large and bright meteor at least as bright as Venus (i.e. -3 to -4 mag). Disintegrating body / sparks etc is still possible with a fireball. Bolide - basically a Fireball PLUS an audible report. I believe the term bolide originally stems from the Latin term bolis which roughly translates to a very large fiery meteor with some sources also referencing the associated audible phenomena. The earliest published reference I found online for bolis was Webster's Revised Unabridged Dictionary (1913) (n.) A meteor or brilliant shooting star, followed by a train of light or sparks; esp. one which explodes. I guess there are many variations and opinions. For the most part... they're probably all pretty much correct. Cheers, Jeff __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteorites 101-Bolide
Just to reiterate, the term bolide is best avoided when precision is required- not because it is undefined, but because it is overdefined! It means one thing to (most) meteoriticists, something else to geologists, and yet something else to meteorologists. Like planet, it is a word best left without formal definition, and used only with qualification. AFAIK the IAU is not considering a definition for bolide. A couple of years ago they were considering revising the definition of meteor to include the body itself during its atmospheric passage (which most now use meteoroid for). I don't know where things are on that proposal. In any case, I hope they just leave bolide alone, since even with a formal definition applied to meteoritics, we aren't likely to get any less confusion. If you're talking casually, in a known context, use whatever terms seem reasonable. But if you want to make things clear, something like a 30-second fireball with extensive fragmentation and subsequent acoustic events is always going to be a better choice than an impressive bolide. Chris * Chris L Peterson Cloudbait Observatory http://www.cloudbait.com - Original Message - From: MEM mstrema...@yahoo.com To: Chris Peterson c...@alumni.caltech.edu; Meteorite-list@meteoritecentral.com Sent: Sunday, January 16, 2011 2:47 AM Subject: Re: [meteorite-list] Meteorites 101-Bolide I largely agree, Chris, and like the overuse of the term oriented, it seems everything has become a bolide-- minor fireballs and major impactors alike. The author on the work around the Chesapeake impactor adopted the term bolide in his works and I believe that was a bastardized usage-- not based in traditional usage. IMO a crater producing impactor is NOT a bolide unless it produces an explosive terminus at altitude. An asteroid which excavates an 8 mile deep crater likely doesn't bolide upon encountering maximum aerodynamic pressure, and no ground observer is likely to survive to tell us if there was one anyway! Tagish Lake was by all accounts a super bolide having both the magnitude and the report. I remember seeing the term bolide used in 19th century descriptions, of course areolite was also a term used back then but I think bolide --suitably defined has a use in literature, still. I think the IAU should probably adopt a definition for bolide which narrows the distinctions to reflect not just magnitude but disruption and audible report. Traditionally bolide was used to describe a fireball that terminated in a bright flash and /or explosive report. Having seen a traditional bolide up close and personal, I can attest that it is not your regular fireball class event. The explosive event is distinct from a sonic boom. In preparation for this reply, I revisited the wiki page and I have a lot of disagreement regarding the adequacy or magnitude alone being the distinction. If we are to abandon the term bolide then we need a convention to describe a fireball which terminates in an expanding/explosive disintegration with audible report. IMO. Elton __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteorites 101-Bolide
I largely agree, Chris, and like the overuse of the term oriented, it seems everything has become a bolide-- minor fireballs and major impactors alike. The author on the work around the Chesapeake impactor adopted the term bolide in his works and I believe that was a bastardized usage-- not based in traditional usage. IMO a crater producing impactor is NOT a bolide unless it produces an explosive terminus at altitude. An asteroid which excavates an 8 mile deep crater likely doesn't bolide upon encountering maximum aerodynamic pressure, and no ground observer is likely to survive to tell us if there was one anyway! Tagish Lake was by all accounts a super bolide having both the magnitude and the report. I remember seeing the term bolide used in 19th century descriptions, of course areolite was also a term used back then but I think bolide --suitably defined has a use in literature, still. I think the IAU should probably adopt a definition for bolide which narrows the distinctions to reflect not just magnitude but disruption and audible report. Traditionally bolide was used to describe a fireball that terminated in a bright flash and /or explosive report. Having seen a traditional bolide up close and personal, I can attest that it is not your regular fireball class event. The explosive event is distinct from a sonic boom. In preparation for this reply, I revisited the wiki page and I have a lot of disagreement regarding the adequacy or magnitude alone being the distinction. If we are to abandon the term bolide then we need a convention to describe a fireball which terminates in an expanding/explosive disintegration with audible report. IMO. Elton - Original Message From: Chris Peterson c...@alumni.caltech.edu To: Meteorite-list@meteoritecentral.com Sent: Sat, January 15, 2011 7:53:49 PM Subject: Re: [meteorite-list] Meteorites 101 Bolide is a term that it's good to avoid. It doesn't mean anything... or rather, it means too many different things. Fireball unambiguously means a meteor of a specific apparent brightness. Bolide is simply confusing. Chris __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteorites 101-Bolide
Hi all, I have understood from my study that a bolide refers to a meteor that breaks up - not requiring the detection of an audible report because, if observed from a distance, the sound may not be heard. It is not a bright meteor or fireball or large impactor, but simply a meteor that breaks up. Right or wrong, that's the way I've been using the term when I report seeing one on the list. Has anybody else been using it that way? I've been lucky to have seen several dozen over the years (often colorful), but none up close like Elton (yet!). I would agree that the IAU should come up with a definition because the term has come to mean too many things and its use is not going to go away any time soon. In fact with the current explosion of public interest (no pun intended), more people are going to find the term and grab onto it. See you all soon! Mark B. Vail, AZ - Original Message From: MEM mstrema...@yahoo.com To: Chris Peterson c...@alumni.caltech.edu; Meteorite-list@meteoritecentral.com Sent: Sun, January 16, 2011 2:47:29 AM Subject: Re: [meteorite-list] Meteorites 101-Bolide I largely agree, Chris, and like the overuse of the term oriented, it seems everything has become a bolide-- minor fireballs and major impactors alike. The author on the work around the Chesapeake impactor adopted the term bolide in his works and I believe that was a bastardized usage-- not based in traditional usage. IMO a crater producing impactor is NOT a bolide unless it produces an explosive terminus at altitude. An asteroid which excavates an 8 mile deep crater likely doesn't bolide upon encountering maximum aerodynamic pressure, and no ground observer is likely to survive to tell us if there was one anyway! Tagish Lake was by all accounts a super bolide having both the magnitude and the report. I remember seeing the term bolide used in 19th century descriptions, of course areolite was also a term used back then but I think bolide --suitably defined has a use in literature, still. I think the IAU should probably adopt a definition for bolide which narrows the distinctions to reflect not just magnitude but disruption and audible report. Traditionally bolide was used to describe a fireball that terminated in a bright flash and /or explosive report. Having seen a traditional bolide up close and personal, I can attest that it is not your regular fireball class event. The explosive event is distinct from a sonic boom. In preparation for this reply, I revisited the wiki page and I have a lot of disagreement regarding the adequacy or magnitude alone being the distinction. If we are to abandon the term bolide then we need a convention to describe a fireball which terminates in an expanding/explosive disintegration with audible report. IMO. Elton - Original Message From: Chris Peterson c...@alumni.caltech.edu To: Meteorite-list@meteoritecentral.com Sent: Sat, January 15, 2011 7:53:49 PM Subject: Re: [meteorite-list] Meteorites 101 Bolide is a term that it's good to avoid. It doesn't mean anything... or rather, it means too many different things. Fireball unambiguously means a meteor of a specific apparent brightness. Bolide is simply confusing. Chris __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteorites 101-Bolide
We differ some Mark, in that a bolide is not just a fireball showing framentation-- such as we saw in the Peekskill fireball. IMO, historically and by traditional use: a bolide is not just a simple fragmentation but an explosive rupture which occurs at the practical end of incandescent flight--Like an upside down bottle rocket. Perhaps, it is somewhat subjective, and while it may occur out of ear shod, the explosive expansion part has a distinct sound/report different from a sonic boom. The term was adapted possibly from a discussion of military rocketry into early descriptions of meteor fireballs which exploded. Perhaps it is just me but I subscribe to these characteristics of a bolide because it describes a specific combination of conditions. The audible report component is most always associated with the early literature accounts describing a fireball as a bolide. In my bolide theory I believe there is an envelope of stress/shear as the meteoroid is undergoing, being dramatically slowed by the atmosphere. If the envelope is not violated the meator may fragment but it does not do so explosively. Around 5 miles above sea level the meteoroid encounters the boundary of that momentum /shear envelope which reflects maximum aerodynamic pressure at which the meteoroid can retain integrity. This transition is so abrupt for the meteoroid, that it literally shears along molecular bonds releasing a fair amount of heat and possibly rapid oxidation of iron particles, etc. Elton - Original Message From: Mark Bowling mina...@yahoo.com To: meteorite-list@meteoritecentral.com Sent: Sun, January 16, 2011 12:11:03 PM Subject: Re: [meteorite-list] Meteorites 101-Bolide Hi all, I have understood from my study that a bolide refers to a meteor that breaks up - not requiring the detection of an audible report because, if observed from a distance, the sound may not be heard. It is not a bright meteor or fireball or large impactor, but simply a meteor that breaks up. Right or wrong, that's the way I've been using the term when I report seeing one on the list. Has anybody else been using it that way? I've been lucky to have seen several dozen over the years (often colorful), but none up close like Elton (yet!). I would agree that the IAU should come up with a definition because the term has come to mean too many things and its use is not going to go away any time soon. In fact with the current explosion of public interest (no pun intended), more people are going to find the term and grab onto it. See you all soon! Mark B. Vail, AZ __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteorites 101-Bolide
Hi Mark and all, My definition of bolide which I used years before meteorite collecting, was a bright meteor that breaks up during the fall. I agree an offical definition would be good, although I disagree with the downsizing of Pluto and could only hope for an accurate one for bolide. Best to all. --AL Mitterling - Original Message - From: Mark Bowling mina...@yahoo.com To: meteorite-list@meteoritecentral.com Sent: Sunday, January 16, 2011 12:11 PM Subject: Re: [meteorite-list] Meteorites 101-Bolide Hi all, I have understood from my study that a bolide refers to a meteor that breaks up - not requiring the detection of an audible report because, if observed from a distance, the sound may not be heard. It is not a bright meteor or fireball or large impactor, but simply a meteor that breaks up. Right or wrong, that's the way I've been using the term when I report seeing one on the list. Has anybody else been using it that way? I've been lucky to have seen several dozen over the years (often colorful), but none up close like Elton (yet!). I would agree that the IAU should come up with a definition because the term has come to mean too many things and its use is not going to go away any time soon. In fact with the current explosion of public interest (no pun intended), more people are going to find the term and grab onto it. See you all soon! Mark B. Vail, AZ __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteorites 101-Bolide
Hi, I understood bolide sofar always simply as a bright meteor up to a fireball. And can't remember, whether I read it ever in a different use than that (despite racing cars). Meanwhile I was reading Pliny (AD 23-79), and Pliny says he has the term bolide from Hipparchus (190-120 BC). For looking up Aristotle (384-322 BC) I was too lazy, couldn't find a latin translation on web and Greek I can't. Should be some terms in the 1st book of his meteora or meteorologica, where he writes about meteorsthunderbolts. Best! Martin Pliny, Natural History 2.25 (Bostock translation) CHAP. 25.EXAMPLES FROM HISTORY OF CELESTIAL PRODIGIES; FACES, LAMPADES, AND BOLIDES. The faces shine brilliantly, but they are never seen excepting when they are falling one of these darted across the heavens, in the sight of all the people, at noon-day, when Germanicus Cæsar was exhibiting a show of gladiators. There are two kinds of them; those which are called lampades and those which are called BOLIDES, one of which latter was seen during the troubles at Mutina. They differ from each other in this respect, that the faces produce a long train of light, the fore-part only being on fire; while the bolides, being entirely in a state of combustion, leave a still longer track behind them. -Ursprüngliche Nachricht- Von: meteorite-list-boun...@meteoritecentral.com [mailto:meteorite-list-boun...@meteoritecentral.com] Im Auftrag von Mark Bowling Gesendet: Sonntag, 16. Januar 2011 18:11 An: meteorite-list@meteoritecentral.com Betreff: Re: [meteorite-list] Meteorites 101-Bolide Hi all, I have understood from my study that a bolide refers to a meteor that breaks up - not requiring the detection of an audible report because, if observed from a distance, the sound may not be heard. It is not a bright meteor or fireball or large impactor, but simply a meteor that breaks up. Right or wrong, that's the way I've been using the term when I report seeing one on the list. Has anybody else been using it that way? I've been lucky to have seen several dozen over the years (often colorful), but none up close like Elton (yet!). I would agree that the IAU should come up with a definition because the term has come to mean too many things and its use is not going to go away any time soon. In fact with the current explosion of public interest (no pun intended), more people are going to find the term and grab onto it. See you all soon! Mark B. Vail, AZ __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
