(meteorobs) Meteorites on The Ground! (Was: To Dirk)

[Meteorites USA]

Wayne, List, With all due respect.

Bad science and hype...? Determining if there are or aren't meteorites 
on the ground from any given firbeball event isn't possible (yet) based 
on current data and studies.

Interestingly enough there is insufficient evidence to conclude that 
there are no meteorites on the ground from any given fireball 
fragmentation event, nor is there proof there is, because a lack of 
evidence is not evidence, therefore an accurate conclusion cannot be 
determined.

There is insufficient evidence to suggests any fragmenting 
bolide/fireball/meteoroid ablates up to 90% of it's mass upon entry AND 
that the remaining mass does not impact the ground, simply because most 
(99.9%?) of past fragmenting fireball events ever witnessed are never 
hunted, and have only been observed, much less have meteorite specimens 
been found from those past events. Hence I find it hard to believe 
anyone could determine empirically based on that clear lack of 
observational, recorded, and experimental data that meteorites are NOT 
on the ground from any given event.

Simply viewing the fireball, and calculating how much of that body 
ablates, and then determining that meteorites are NOT on the ground is 
patently impossible without knowing all variables. Yes speed can be 
determined, yes angle of decent can be determined, yes ablation physics 
and equations can be produced, and many other factors are thrown into 
that calculation, but the most important is usually ignored in most 
circumstances. Determining composition.

Most (99% or more) of the fireballs recorded/witnessed are not analyzed 
for composition via spectrographic analysis or other means by scientific 
equipment. Therefore how can one determine that one fireball or another 
ablates 90% of it's meteoroid mass or more, or if there are meteorites 
on the ground? You can't, at least not accurately.

Further, there are no recorded/experimental data to support the 
conclusion that 90% of any meteoroid is ablated during atmospheric 
entry. It's an ablation physics equation. Has anyone ever taken a large 
meteorite back into space and shot it at the Earth and recorded that 
ablation data? Not that I know of, because it's probably too darn 
expensive.

Even the size and type of a meteoroid body able to reach and impact the 
surface of the planet is debatable within the scientific community. Look 
at the Carancas Crater event.

 From the Lunar & Planetary Institute: THE CARANCAS CRATER AND METEORITE 
FALL: THE FIRST RECORDED IMPACT ON EARTH
http://www.lpi.usra.edu/meetings/acm2008/pdf/8260.pdf

Quote: "Unlike what it is generally expected, a few tons stony meteorite 
did not disintegrate in its pas-sage thorugh the atmosphere, but rather 
it reached the ground with a velocity high enough to produce an im-pact 
crater. This event challenge our present view of the fate of meteoroids 
striking the Earth."

It was thought before this event happened (due to calculations and 
equations) that a stone meteoroid body could not create a crater because 
it would ablate away or disintegrate completely. Yet, here we have 
observed evidence of that happening which proved many hypotheses wrong.

Look at the Whetstone meteorite fall. This event changed our 
understanding somewhat (not as dramatically as the Carancas Crater 
event) but it gave some insight into how a very small fragmenting event 
could produce a locatable amount of meteorite specimens on the ground.

If one comes to a conclusion that 99% of all fragmenting bodies ablate 
90% of their mass, and that the surviving masses do in fact drop 
meteorites, that number is no more accurate, nor does it have evidence 
enough to determine that conclusion any more than saying a God exists. 
You can't prove one does, and atheists can't prove one doesn't exist.

All I'm saying is that there is insufficient observed and recorded 
evidence to make this conclusion. Especially when that conclusion is 
based on a lack of evidence. (lack of meteorites recovered). We're 
simply looking at a pretty light in the sky, seeing a fragmentation 
event, *sometimes* analyzing that data, making calculations, and 
determining that there are no meteorites on the ground. No one know 
this, because so many of these event don't ever get searched. It's 
considered pointless based on insufficient evidence.

In other words. The statement, "This puts rocks on the ground" is just 
as valid from a hunters perspective, as the "It burned up completely" 
statement is on the opposite side of the fence.

Sorry to be argumentative, but if someone can show me a paper or 
scientific study that proves the ablation rate of ALL meteoroid bodies 
empirically with recorded (not calculated) data, I'll be happy to admit 
I'm wrong.

In short: You can't find them if you don't look for them.

Regards,
Eric



On 3/25/2011 3:28 AM, Wayne Hally wrote:
> Dirk,
>
>
>
> First, let me offer my support for all of you in Japan; I know it has been a
> horrible time for you all, and unlike others, I do not think you are fiends
> J I prefer the term friends.
>
>
>
> My issue was strictly with the definitive statement that you made "This put
> rocks on the ground!"
>
>
>
> That to me was a statement of fact.and I found no evidence in the comments
> that it was supported. All I was asking for was such evidence. If it did not
> exist at the time, than your declaration of it as a fact was bad
> science/hype.
>
>
>
> I have nothing personally against you, or green fireballs. I do have a
> vendetta against bad science. And FWIW, I have done fireball investigations,
> so understand the difficulties and challenges.
>
>
>
> Personally, I hope you turn out to be right and meteorites will be
> recovered. Any meteorite recovery adds to the science of our field.  But for
> you to make that statement, in the absence of anything suggesting a fall
> (And I went to your website to check, so you got the hits that you appear to
> want) just sticks in my craw.
>
>
>
> So please, just stick to the facts, and we will all be happy.
>
>
>
> This is my last post on the subject.
>
>
>
> Wayne
>
>
>
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