[meteorite-list] Seeking some of this lists knowledge

[GeoZay at aol.com]

Hello Mike...I'm not an expert with sonic  noises, but I feel I can utilize 
their appearance or not, along with other  information, to conclude with 
confidence the chances of whether a fireball might  drop meteorites or not. 
First of all, I got some rules of thumbs I refer to.  Such as: 1) No chance of 
hearing any sonic booms from a meteoroid until it  reaches at least 30 
miles above the earths surface. 2) I also recognize  that the crack of a bullet 
going thru the air and that of a bullwhip are  examples of sonic booms. 
Small meteorites about 30 miles up might produce  similar sounding sonic 
booms...which could easily be absorbed in the air before  reaching human ears on 
the ground. This might account for a lot of meteorites  reaching the ground 
without being heard. But these will be for small meteorites.  these kind of 
meteorites slow down very fast higher up compared to the larger  meteorites. 
The larger the meteoroid/meteorite, the faster it will be traveling  lower in 
the atmosphere before it slows down to free fall speeds. Thus  increasing 
the chances of any produced sonic booms to be heard. 3) If a  meteoroid is 
reported to be glowing all the way to the ground without any sonics  reported 
anywhere, this usually tells me that there is an error in what the  witness 
thinks they are seeing. A glowing meteoroid falling all the way to the  
ground means it is huge...somewhere between 10 to 100 tons. Without an obvious  
large impact point, I tend to dismiss this part of a witness statement.  

>>A well know recent event with many reports of a huge  boom
that shook houses and rattled windows. These booms woke many  people
from a sound sleep. My question here is why would the boom be so  loud
and violent? Is it due to the size or speed of the object entering  our
atmosphere?<<

>From this kind of report, I can conclude that  it wasn't small because its 
sonic sounds weren't absorbed. It wasn't a fist  sized object where it's 
wimpy sonic snap gets muffled. Here I would think size  and speed goes hand in 
hand. At the point where sonics are produced, a large  size also means 
faster speed. In my way of thinking, "loud and violent" also  goes along with 
large and fast. 

>>Then we have another recent  event with three separate distinct booms.
Softer and not as violent but we  have three of the them boom, boom,
boom. Does this mean there are three  separate objects?<<

This might mean a few things. Three soft boom,  boom, boom usually means to 
me that it was very distant at this point. There  might be some other 
interpretations, but this is what I lump it as. Sometimes  folks refer to this as 
a "rumbling" sound.  Perhaps if I knew how long  after the meteors 
appearance are these sounds heard, it might mean something  else to me...maybe 
smaller? or maybe the observer is in a location where the  sound doesn't reach 
him loudly for some reason? As for it being 3 separate  objects, I don't know. 
I guess it could be, but I'm usually trying to figure out  if just one 
piece at least might have reached the ground. If more than one, then  its a 
bonus.


>>We also have a very recent event in the  Flagstaff area with reports
of a sonic boom, now in this case witnesses say  that the meteor was
headed for earth at a very steep angle,(perhaps 80  degrees) I am
wondering what affect this has on a sonic boom. Such a steep  angle of
decent does that produce a smaller area where the boom can be  heard?<<

I really don't know, but I'm sure it affects it some how.  I'm usually just 
interested in knowing if a sonic was heard or not. with a  bright meteorite 
dropping fireball, I lump the general reports of many people as  one for 
this bit of info. Chances are if a sonic boom was created, at least one  
person along the meteoroids flight path will hear it. the general public usually  
don't associate a meteorite dropping fireball with sonics, so I look for at 
 least one report of sonics.  I don't really trust an eyewitness report  
when they say it came in at a steep angle or not, unless the report says it  
crossed almost the entire sky...then there's no doubt to me it wasn't a steep 
 angle. I remember once while meteor observing, a fireball appearing what 
seemed  to be directly above my head coming steeply down. By the time it was 
finishing  its flight path, it had the appearance of flying "horizontally" 
in front of me  before reaching the point of retardation.  I recognize that 
it had made no  turns, only that it had that appearance. Perhaps having 
something to do with the  earth's flight path, the meteoroids path and my 
perspective of observation? With  that meteor, the sonics appeared quite loudly 2 
min. and 18 sec. later. (I was  running a timed chart recorder at the time 
for radio forward scattering).  


>>Does the fragmentation event or bolide event  produce
a sonic boom or just the meteor entering our  atmosphere.<<

Possibly both...depending upon how high up it was and  how fast it was 
traveling. I can picture a large meteoroid reaching below 30  miles up produce a 
sonic signature, then afterwards it explodes while below this  altitude 
also producing a sonic. 

Well...I hope this helps. I might not  have all the answers, but perhaps I 
had some. :O)
GeoZay  

**************An Excellent Credit Score is 750. See Yours in Just 2 Easy 
Steps! 
(http://pr.atwola.com/promoclk/100126575x1222377005x1201454319/aol?redir=http://www.freecreditreport.com/pm/default.aspx?sc=668072&hmpgID=62&bcd=May
Excfooter51609NO62)