[meteorite-list] re: meteorite lands near Mt. Fuji Japan

From: Chris Peterson <clp_at_meteoritecentral.com>
Date: Sat Aug 20 01:12:22 2005
Message-ID: <05c001c5a545$b7fc2a10$f551040a_at_bellatrix>

Incandescence requires speed- about Mach 5 and above. In order to maintain
such speeds below about 10 miles height requires a high mass. For a meteor
to persist at 5 miles, it would need to have an initial mass of at least 500
tons, or a size of 3-7 meters diameter, depending on composition. Such an
object would produce a brilliant fireball of the sort seen by thousands,
even in broad daylight, and impressive sonic booms. I expect that the
fireball seen by Dirk was in fact 100km or more beyond Mt Fuji with respect
to his position. Such fireballs frequently appear to be much closer, and
often appear to drop in front of nearby mountains, clouds, or other objects.
In order for a much smaller object to persist to low height would require a
very unusual combination of conditions.

Can you describe the artillery observer methods that you used to estimate
the low height for the fireball you saw?

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message -----
From: "E. L. Jones" <jonee_at_epix.net>
To: "Meteorite List" <meteorite-list_at_meteoritecentral.com>
Cc: <marco.langbroek_at_wanadoo.nl>
Sent: Friday, August 19, 2005 9:29 PM
Subject: Re: [meteorite-list] re: meteorite lands near Mt. Fuji Japan


> Dirk can add to this as he wishes, however Mt Fuji is around 12,400ft?--(I
> walked up part of it and am still out of breath 2 years later) Any trail
> falling below the near crest would indicate incandescence below 12,000.
> (2miles?) and would be sufficient for estimating 10k ft.
>
> Somewhere, I read that active incandescence can't exist below 5 miles as
> the air is too dense for your typical meteoroid to maintain incandescence
> generating velocity I however, observed a bolide that may have exploded
> at certainlky less than 4 and possibly around 3 miles using artillery
> observer methods and from which a 2kg meteorite was recovered. So I am
> not sure how valid the 5 mile barrier is. I hope we get some more data.
> Does anyone have a reference to altitudes where incandescence is
> extinguished?
>
> Recovering a meteorite from that vicinity is problematic owing that it is
> a series of lava flows and part of it is a US Marine tank gunnery range.
>
> Elton
Received on Sat 20 Aug 2005 01:12:10 AM PDT