[meteorite-list] Meteoroid/Asteroid Electro-Magnetic Disruption and Charge Properties?

From: Jim Wooddell <jimwooddell_at_meteoritecentral.com>
Date: Wed, 27 Feb 2013 18:00:59 -0700
Message-ID: <CAH_zgwHOE=nG6t2huAaoiyd8Th4cH9Z3=mkar=rXiP+MyH9RQw_at_mail.gmail.com>

Hi Dirk and all!

There were so many different pressures placed on this object, not sure
you could point to a single one conclusively to answer your question
about resonance. You would have to define the causes to consider
resonance.

I suppose if we knew the air density we could SWAG the ram pressure
(which I'd guess may be the single largest contributor) as the mass
has already been determined. I have not heard anyone give those
details yet. Was the mass determined upon entry or when it burst? It
did have some time to ablate.

I think the physicists have their work cut out and I look forward to
reading about it!

In regards to the strewn field. I think it's going to take a lot of
time to determine it. They have a great opportunity to record a
spectacular strewn field. The frenzy probably hosed that hope up
already. With other known strewn fields, such as JaH 073 at ~19.6km
long and Franconia at ~17km long, it may take a while to find large
fragments. We know in both of these fields, thousands of small 0-20
gram fragments were recovered on the beginning end and middle of the
fields and much much larger fragments down field many kilometers away.
  I am hoping to hear some 40kg + frags are found!

Cheers!

Jim Wooddell




On Wed, Feb 27, 2013 at 11:36 AM, drtanuki <drtanuki at yahoo.com> wrote:
> Chris and all,
> I will refine my questions a bit regarding the Russian asteroid (meteoroid) body:
>
> Could resonance (differential-harmonics) within the body cause disintegration?
>
> Can we expect to see an Earth-ground electrical discharge towards the meteoroid? Is it possible?
>
> And could differential electrical charges on the leading and trailing part of the body cause internal disruption leading to disintegration?
>
> Thank you. Forgive me if my questions are poorly based or asked.
>
> Dirk Ross...Tokyo
>
> --- On Thu, 2/28/13, Chris Peterson <clp at alumni.caltech.edu> wrote:
>
>> From: Chris Peterson <clp at alumni.caltech.edu>
>> Subject: Re: [meteorite-list] Meteoroid/Asteroid Electro-Magnetic Disruption and Charge Properties?
>> To: meteorite-list at meteoritecentral.com
>> Date: Thursday, February 28, 2013, 1:21 AM
>> A body larger than about a centimeter
>> transfers its kinetic energy to other forms primarily by
>> compressing the air in front of it as it descends into the
>> atmosphere. The pressure involved is typically very large-
>> tens or hundreds of megapascals for meter-class bodies. Once
>> this ram pressure exceeds the material strength of the body,
>> it breaks apart (presumably along existing fault lines, so
>> the material properties of the body are important- and
>> generally unknown).
>>
>> Before the breakup, the heat created by compressing air is
>> melting the surface of the meteoroid, resulting in ablation.
>> This ablation is responsible for some of the light we see
>> (along with atmospheric ionization from the same heat
>> source), but is not particularly disruptive to the
>> meteoroid. Only the outer surface is affected. Ablation is a
>> very efficient way of removing energy (which is why
>> spacecraft heat shields prior to the shuttles were
>> ablative). When the meteoroid fragments at hypersonic
>> speeds, however, additional surface area is instantly
>> exposed, resulting in a rapid heating of the surrounding air
>> (which is just a fancy way of saying "explosion"). If a body
>> breaks into just a few pieces, as is common, we may see a
>> central or terminal brightening. If it completely shatters
>> into thousands of pieces (as seems likely with Chelyabinsk)
>> the energy from the suddenly heated air is immense- an
>> efficient conversion of kinetic energy to thermal energy.
>> The expanding hot air can produce an impressive sonic wave,
>> and probably further disrupts the meteoroid itself.
>>
>> I don't that there are any electrical forces of a
>> significant size to affect the structure or motion of the
>> meteoroid, although atmospheric electrical effects probably
>> occur (e.g. electrophonics).
>>
>> Chris
>>
>> *******************************
>> Chris L Peterson
>> Cloudbait Observatory
>> http://www.cloudbait.com
>>
>> On 2/26/2013 11:59 PM, drtanuki wrote:
>> > Dear List,
>> > If there is anyone willing to discuss the how and why
>> meteoroids/asteroids "detonate" please explain for the list
>> and myself. I am interested learning more about the
>> electrical/mechanical/physical forces that these bodies
>> undergo as they reach the earth such as in the latest
>> Russian event. Thank you.
>> > Dirk Ross...Tokyo
>>
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-- 
Jim Wooddell
jimwooddell at gmail.com
928-247-2675

Received on Wed 27 Feb 2013 08:00:59 PM PST