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Re: (meteorobs) hypothesis



Title: Re: (meteorobs) hypothesis
Tom, there are likely two mechanisms at work. First is the one you mention, with meteroids breaking up well after ejection from the comet, remaining close together, and entering the earth's atmosphere within one second of each other. These pairings are undeniably real; I have seen quite a few. I don't know of any formal studies of the phenomenon, as it appears to be something of a dead-end. Yes, we'd expect pairings, but there are so few that we probably couldn't extract a lot of useful information from a statistical study of the phenomenon. However, someday some clever scientist will likely figure out something useful to extract from such data.

The other mechanism is the common release of a number of meteoroids. It's likely that a goodly portion of the meteroids are released in the form of chunks of ice that break loose and drift away, with the ices subsequently sublimating. In such an event, you'd expect to see the meteoroids grouped in some fashion. That grouping would spread out along the orbital path, resulting in the filaments that first began looking for in the late 60s. We'd expect to see the elongation of the filament to increase concomitantly with the number of orbital revolutions. The big question in my mind is, just how big should these filaments be? My experimental design would have given us a spatial resolution of about 10**4 meters, but with the failure of my equipment, I will have to use data from other observers, which will have a resolution of only about 10**5 or 10**6 meters. Maybe we'll get lucky; if the filaments are big enough, we might still see some in the data.

By the way, you are not alone in your gut feeling that they are clumped. Just about everybody who observes meteors has that gut feeling. But when you look hard at the data statistically, you just can't prove it. Until now, we've never had enough data, but perhaps this mountain of data we just collected might prove sufficient.

Chris



on 11/22/01 7:09 PM, Tom Fleming at enders_gt1@prodigydot net wrote:

The dirty iceball description combined with the dynamic spewing of material as a comet approaches the sun conjurs in my mind an image (supported by some formal education in astronomy and physics but lacking the advanced knowledge required to pursue it with certainty or confidence).
The size of the particles ejected from the comet should cover a wide range with small particles being most numerous. Larger chunks  may hold together for some time  and subsequently break apart under tidal stresses (or collision)  as the entire comet mass reaches perihelion. These non-random bursts that we see could then be particles that had been part of one mass that is gradually drifting apart as separate particles.
Can anyone discuss the dynamics that would drive the behavior of the particles once they separated?

One response had discussed clumping as a random process, to this I agree (it cant be refuted) . But I believe (emotionally and unscientifically :-)   that the frequency of tight clumping exceeds the likelihood of random clumping. Shelby's discussion of some of the history reveals a dynamic (scientific) process where a long trend of observational data forces the Scientists to dismiss their kneejerk reaction to the comments of the amateurs and begin to develop a theory which fits the behavior. I am guessing this process is underway. I see the clumping as highly analagous to the stream behavior developed by Asher & McNaught and others.

On another topic. . . the discussion regarding micrometeorites suprised me a bit as I tended to think of cometary derbis as pretty lacking in metallic particles. Does the 'dirty' part of dirty snowball connote stony iron composition?

Tom



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