SIGHTINGS



Arkansas Mystery - A
Bolide? - Data Says No
From Brenda Livingston
3-17-00

 
Dear Jeff
 
I was not aware that bolides or fireballs or meteors could cause so much explosive and incendiary activity... perhaps on a very rare occasion...(?) Most meteorites (those rocks, etc. that come to the ground) no longer spark... usually ending ablation 20 km above the earth. Most are usually very cold or ambient temp when they reach the ground... difficult for them to ignite a fire... and really hard for them to be the source of a combustion of the soil or chemicals in the soil.
 
Excerpted from the American Meteor Society FAQ:
 
"8. Can a meteorite dropping fireball be observed all the way to impact with the ground?
 
No. At some point, usually between 15 to 20 km (9-12 miles or 48,000-63,000 feet) altitude, the meteoroid remnants will decelerate to the point that the ablation process stops, and visible light is no longer generated. This occurs at a speed of about 2-4 km/sec (4500-9000 mph).
 
From that point onward, the stones will rapidly decelerate further until they are falling at their terminal velocity, which will generally be somewhere between 0.1 and 0.2 km/sec (200 mph to 400 mph). Moving at these rapid speeds, the meteorite(s) will be essentially invisible during this final "dark flight" portion of their fall.
 
9. Are meteorites "glowing" hot when they reach the ground?
 
Probably not. The ablation process, which occurs over the majority of the meteorite's path, is a very efficient heat removal method, and was effectively copied for use during the early manned space flights for re-entry into the atmosphere. During the final free-fall portion of their flight, meteorites undergo very little frictional heating, and probably reach the ground at only slightly above ambient temperature."
 
It appears that people on the scene reported finding no meteorites. Some even reported finding no craters... although it is quite apparent that there were several at the scene (as seen in Al Collier's photos).
 
I think that it was reported that NORAD and others said that there was no space junk or meteors in the area that could account for what people were seeing in the skies or what might have impacted on the ground.
 
The heat necessary to combust soil or chemicals within soil would be tremendously hotter than that emanating from a fallen meteorite(s). The fireperson on the scene in Arkansas reported intense heat on the scene -- so intense that firefighting efforts had to be postponed from the ground.
 
If this was simply a bolide meteor event which started the fire... which no one... including the sheriff thought it was... why would someone find it necessary to work with heavy equipment in the wee hours of early morning covering up craters and the area with soil? It seems that they would want to keep the area intact for further investigation by scientists interested in meteorite phenomena.
 
My understanding is that a bolide explosion likely would happen miles above the earth. Such an explosion would not be a rising mushroom cloud moving upward from the earth.
 
Am I missing something? If someone has information about bolides that is not in the above materials... I would like to learn about it. If a bolide were the cause of these fires -- I believe this would be an extraordinary event...maybe as spectacular as a UFO crash...
 
In my opinion the mystery continues!
 
Brenda Livingston

 

 
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