[meteorite-list] Fireball question / sonic boom

From: David Norton <renov8hotels_at_meteoritecentral.com>
Date: Wed, 30 Mar 2011 05:26:41 -0700
Message-ID: <000301cbeed5$b9aae2e0$2d00a8a0$_at_net>

Good morning. Sonic booms are formed by shock wave created by the rapid
displacement of air. The change in air pressure required to generate the
shock wave is only a few pounds per SF. There is a wave generated on the
front and at the back of a moving object. The size of the waves are
determined by the size, shape and mass of the object.

The ability to hear sonic booms are influenced by several factors besides
the weight, shape and size of the moving object. Altitude, flight path and
weather will influence the ability to actually hear the sonic boom on the
ground. Altitude influences the distance the shock wave have to travel
before hitting the ground. The wave dissipates with distance. This is
probably the single biggest influence on the ability to hear the sonic boom.
Wind can affect the shock wave as can the terrain on the earth underneath
the flight of an object. Flight path can affect the wave. A straight path
will generate a stronger wave than an irregular path. A meteor breaking up
will have a more irregular path.

The width of the wave for an aircraft is about 1 mile per 1000 feet of
altitude. The wave is strongest directly below the object and weakest on the
perimeter of the wave.

The speed of sound as mentioned is a number that is for sea level.
Differences in atmospheric conditions will allow for variances in the speed
of sound.

-----Original Message-----
From: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] On Behalf Of
GeoZay at aol.com
Sent: Tuesday, March 29, 2011 11:05 PM
To: meteorite-list at meteoritecentral.com
Subject: Re: [meteorite-list] Fireball question / sonic boom

Eric...for some reason, the figure of about 9,000 mph sticks in my head as
the point of retardation. I don't know where to resource that figure to
see if its right or not...but I think its close.
geozay





>>>>George jut brought up a good point and I have a question. The speed
of
sound is about 760 MPH.

What is the speed at which a meteoroid extinguishes and is no longer
incandescent?>>

I believe its in the neighborhood of 7,000 mph. If its a small meteoroid,
it will extinguish way too high for a sonic boom to reach the ground.
GeoZay <<<<

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Received on Wed 30 Mar 2011 08:26:41 AM PDT