Comet on SOHO images

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Hi MeteorWayne.<br /><br />Thank you very much for your diagram.<br /><br />A common origin is immediately obvious here. <br /><br />In reply to your statement:<br /><br /><font color="black"> " They are thought to have originated from one large <br />(D=~120km) comet with a period of ~1000 years.<br /> <br />Between 10 and 20,000 years ago, this comet was disrupted by violent outgassing <br />and/or tidal disruption. <br />The largest piece lasted until about 371 BC, when it split into 3". </font><br /><br />These time frames would mean these events could have been seen by prehistoric peoples<br />at the end of the Ice Age. & during the Bronze Age.<br /><br />What a sight that would have been.<br /><br />With a nucleus that large, how big was the Coma? How long was the tail?<br /><br />The nucleus would have been about the same size as the Jupiter moon Thebe!!!!<br /><br />This would have been the mother of all comets.<br /><br />On a slightly different topic, do you sporadic meteors are truly sporadic, or could they<br />be part of very minor meteor streams that we have not as yet identified?<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[MeteorWayne]

I'm sure the prehistoric people were impressed! There were probably grunts about 2 suns!!<br /><br />Regarding sporadic meteors, it's a combination of both.<br />The limits for detection of a meteor shower visually, even with plotted meteors and worldwide collection of data is about ZHR ~ />2.<br />This leads to a list of about 10 Major showers (ZHR = />10), 5 variable showers which are detected only in some years, and 17 minor showers with ZHRs 2-9.<br />Also there is a series of minor showers at the Antihelion (opposite the sun)<br />which progress across the sky at about a degree per day.<br />Whatever is left over are visually sporadic meteors.<br />The distribution is not random, and there are a lot of very minor showers buried in there. <br />One virtual source is called the Apex, for the Apex of the earth's way.<br />This is a result of the earth's 30 km/sec motion around the sun, much as driving a car through a snowstorm with no wind, the meteors appear to radiate from a point in your direction of motion.<br />Another concentration is what is called the toroidal meteors. These are meteoroids that are in higly inclined orbits, hence rarely interact with the planets. So they sort of stay there.<br />Then there are a hundred or so very minor showers with rates well below 1 per hour.<br />Most of these have been detected in photographic, radar and recently video surveys.<br />Dr Jenniskens' book has probably the most comprehensive list; in fact I do a search of my plots after each session for any possible members of any of these very minor showers. 4 or 5 might be listed for any given night, but since these ZHRs are so low, it is rare that I find even a suspected one.<br />All the leftovers are "true" sporadics.<br /><br />Now the question arises are 100 meteors spread over a 50 year orbit where one might be seen on earth each decade or century a meteor stream? That's hard to say <img src="/images/icons/smile.gif" /> Is it even identifiable? Probably not.<br /><br />How did they <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

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Thanks MeteorWayne.<br /><br />I did suspect something like this, that many, if not most are not truly 'sporadic'.<br /><br />I am sure that I am not finished yet.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>