[meteorite-list] Re: Crackpot Theory Redux

From: Sterling K. Webb <kelly_at_meteoritecentral.com>
Date: Sat Oct 29 21:05:50 2005
Message-ID: <43641C44.2DC255B4_at_bhil.com>

Hi, Axel,

    The dynamics of the situation are such
that increasing the speed of an incoming object
in an attempt to penetrate the atmosphere
without losing all its mass to frictional
ablation just never happens for small objects.

    Now, a big object, like a 1000 meter
asteroid will ALWAYS penetrate the atmosphere
and reach the surface of the Earth; and a small
object, like a 1 mm grain, will NEVER reach the
Earth's surface at speed (it might float down;
see below). In both cases, this is regardless
of initial speed.

    The division between objects that can reach
the surface and those that can't is this: if the
mass of atmosphere in the path of the object is
greater than the object's mass, it won't make it;
and if it's less, it will. Speed doesn't enter
the equation (much).

    Imagine a 1 mm grain; then imagine a 1 mm
"tube" of atmosphere extending from the top of
the atmosphere to the surface. If that "tube"
contains more mass of atmosphere than the mass
of the grain, the grain won't be able to reach
the surface.

    Such small grains, at "normal" entry
velocities, will be stopped without frictional
heating and just float down to the surface.
This is how most interplanetary and interstellar
dust arrives at the surface and becomes incor-
porated in sediments, many 1000's of tons per
year. At high entry velocities, small grains
burn up completely.

    Firestone's belief that because iron grains
are formed in the heart of a supernova, they could
survive re-entry is completely mistaken. The
individual iron atoms are created in the supernova
and accelerated to immense velocities in nano-
seconds. That does not matter; you can't destroy
an individual atom. They assemble as grains when
the atoms are crowded together under high pressures
and temperatures in their first few milliseconds.
But assemblages of trillions of atoms, like tiny
grains, can be dis-assembled. When that happens,
the individual atoms are not destroyed (they float
down), but they're not particles any more...

    The heating depends on the ratio of particle
surface to particle mass, which is high for small
particles and low for large particles. So, for
a very large object (100's of meters), it just
can't be vaporized fast enough to be stopped in
the 1.5 to 2.0 seconds of atmospheric passage!
The kind of objects that produce meteorites (10's
of meters) lose 90% or more of their mass before
fragmenting and depositing the pieces as meteorites.

    An obvious demonstration of the fact that speed
alone will not get you through the atmosphere is
the example of very energetic "cosmic rays," like
an iron nucleus travelling at 99.999999999% of the
speed of light: very small particle, very high
speed, but such cosmic rays are nicely stopped by
the atoms of the Earth's atmosphere. (To be
completely accurate here, 1 such particle in
10^24th particles will pass right through the
atmosphere and the Earth itself and be detected
as a vertically rising "cosmic ray" on the other
side of the Earth! But, that's because of its
small nuclear dimension, and as you can see,
it's rare...)


Sterling K. Webb
------------------------------------------------
Axel Emmermann wrote:

> Hello list,
>
> I usually lurk from behind the Atlantic but his thing has captured my
> imagination.
>
> Most of you are likely to have more background in astronomy and physics than
> I have, so I'll put it to you as a question:
>
> What would happen if little drops of iron smash into the atmosphere at such
> a velocity that the time they need to reach the surface is smaller than the
> time to heat them up through and through?
>
> Heat has to travel to the inside of such a pellet in order to evaporate it,
> doesn't it?
> Conducting heat to the core of a meteorite must be function of its
> composition, so iron will be hot fast but iron mixed with dust will take a
> lot longer. But still, evaporating a meteorite would still be a process
> which needs a finite amount of time, right?
> Now, if the meteorite's journey through the atmosphere is shorter than the
> time needed to heat it to evaporation from say -150? it would hit the
> earth's surface, or not?
>
> Another thing perhaps: isn't it possible that at VERY high speeds an
> impacting object just compresses the air in front of it and is actually
> protected by this cushion of supercompressed gases?
>
> Axel
>
> -----Oorspronkelijk bericht-----
> Van: meteorite-list-bounces_at_meteoritecentral.com
> [mailto:meteorite-list-bounces_at_meteoritecentral.com]Namens Sterling K.
> Webb
> Verzonden: zaterdag 29 oktober 2005 8:20
> Aan: Darren Garrison; Meteorite List; Marco Langbroek; MarkF; Paul H
> Onderwerp: [meteorite-list] Re: Crackpot Theory Redux
>
> Hi, Darren, Marco, Mark, List
>
> Being really bored recently, I emailed
> Richard B. Firestone at Berkeley, Lawrence's
> Radiation Lab, #1 Cyclotron Road (yeah, that's
> his real address!) the following email.
>
> > To: Richard B. Firestone
> > Re: Disputed Cometary Hypothesis
> >
> > Reading this press release:
> <http://newswire.ascribe.org/cgi-bin/behold.pl?ascribeid=20050923.103123&tim
> e=11%2050%20PDT&year=2005&public=0>
> > about your disputed cometary hypothesis, and having fine
> > arguments with folks who use words much stronger than
> > "disputed" for it, it occurs to me that, if you have a
> > plethora of micro-samples from the dated deposits you discuss,
> > it would be definitive proof of their origin in a supernova if
> > any of their iron content were to be of the isotope Fe60.
> > It also occurs to me that you appear to be located where a
> > shortage of mass spectrometers would not be a problem. Have
> > you attempted to determine if Fe60 is present? Since the
> > discovery, a few years ago, of a sub-handful of Fe60 atoms in
> > oceanic sediments was a major piece of news, such a trial
> > would seem an obvious step, given what you propose.
> >
> > Sterling K. Webb
>
> I mean, what's the point of our talking ABOUT
> somebody on this List when you could just ask them
> what you want to know? They say the information
> universe is global now; let's test that hypothesis,
> I said to myself.
>
> When the original press release was posted to this
> List, there was a certain amount of "Who is this guy?"
> Take a look at:
> <http://isotopes.lbl.gov/rbfcv.html>
>
> For those too lazy to click through, Richard Firestone
> has been a staff scientist at the Lawrence Berkeley National
> Laboratory since 1979. He's the author of 130 books and papers
> in the field of nuclear isotopes and geochronology, and is the
> editor of the "Table of Isotopes," now in its eighth edition,
> a volume that is to isotopes what the "Catalogue of
> Meteorites" is to meteorites.
>
> A few days later, I got the following reply from Dr.
> Firestone to my email (which I got too busy with other
> things to post right away, but here it is):
>
> < Subject:
> < Re: Disputed Comet Hypothesis
> < Date:
> < Sun, 25 Sep 2005 08:18:36 -0700
> < From:
> < Richard B Firestone <RBFirestone_at_lbl.gov>
> < To:
> < "Sterling K. Webb" <kelly_at_bhil.com>
> <
> < Sterling:
> <
> < There are many things to look for and 60Fe
> < is a good one. I don't think that this is
> < easy and nobody has come forward to do
> < it. So far we have found anomalous 40-K
> < abundances and strong evidence that the
> < impacting body was composed of KREEP-like
> < material identified on the Moon. We are
> < looking for fullerenes and diamonds in the
> < particle layer.
> <
> < It is interesting that people are critical
> < of something they haven't seen. The
> < archaeologists I showed this to are very
> < receptive. The particles that bombarded
> < mammoths probably are comparable to well
> < known "pre-solar grains" that are forged
> < in the supernova explosion itself. If
> < they can survive that environment, they
> < can likely penetrate the atmosphere.
> < Of course, this is a hypothesis and people
> < are welcome to provide other explanations,
> < but not to simply dismiss the data.
> <
> < Regards,
> <
> < Rick Firestone
>
> The key point is to be found in the last
> sentence, if course. We have here a case of
> someone with perfectly good data and a perfectly
> lousy hypothesis to explain it.
>
> The original hypothesis about super fast
> particles surviving the atmosphere is silly
> because as we all know the faster you goes the
> more thoroughly you burn up!
>
> The new hypothesis about super slow particles
> is equally silly because nothing can "fall" to
> Earth without achieving escape velocity in the
> process -- just ask old Isaac; he explains it
> better than I do.
>
> Dr. Firestone is an expert on ONE thing
> (isotopes) and I'm sure his data is correct,
> but NO ONE IS INTERESTED IN DATA ALONE, without
> a successful and compelling hypothesis to keep
> it company, so he gets called a "crackpot." So
> now he's put together another hypothesis,
> equally poor, to replace the first one.
>
> The case is a complete parallel to another
> well-known scientific "flurry": The Small Comets
> of Louis Frank. There is nothing wrong with Frank's
> data; it his explanation of it that is seriously
> flawed. Frank is a great experimental physicist,
> and as all theoreticians know you never let an
> experiemntalist propose a hypothesis, just as
> they never let a theoretician near an experiment.
> It's always disastrous!
>
> The irony is that, oddly enough, in BOTH
> cases, everyone seems to be perfectly to toss
> the data our with the hypothesis, and that shows
> insufficient reverence for simple facts, which are
> all the Universe gives us to work with -- explaining
> them is our job; the Universe doesn't do that part!
>
> So this time around, instead of a flurry of
> "this is dumb..." comments, how about some sound
> suggestions of how you would explain the data?
>
> As for my suggestion of looking for 60-Fe
> (which would be absolute proof of supernova origin
> since that isotope is only formed in the deadly
> heart of the biggest explosion in the Universe
> and nowhere else), you will note that Dr.
> Firestone says that "nobody has come forward
> to do it."
>
> I looked into the work done to find that
> handful of probably 5 million year old 60-Fe
> atoms in oceanic sediments a few years ago,
> and it was a monumental task, involving the
> processing of a huge amount of material to find
> a few atoms among the trillions of trillions of
> atoms processed, like Madame Curie going through
> tons of pitchblende to find some radium... It
> took years, in both cases, really hard work.
> This may be why there is no line of volunteers
> going around the block to do this work on
> Firestone's samples... The total number of
> atoms found by the German team? 23.
>
> However, those 60-Fe atoms prove that we
> were exposed to a major supernova explosion
> that recently, a controversial suggestion now
> nailed down, like, rock solid. Science is
> hard work.
>
> Here's the poop on the 60-Fe atoms:
> "An interdisciplinary team of German
> scientists from the Technical University
> of Munich (Gunther Korschinek, 011-49-89-
> 289-14257,korschin_at_physik.tu-muenchen.de),
> the Max-Planck Institute (Garching), and
> the University of Kiel have identified
> radioactive iron-60 atoms in an ocean
> sediment layer from a seafloor site in
> the South Pacific. First, several sediment
> layers were dated, and only then were
> samples scrutinized with accelerator mass
> spectroscopy, needed to spot the faintly-
> present iron. The half-life of Fe-60
> (only 1.5 million years), the levels
> detected in the sample, and the lack
> of terrestrial sources point to a
> relatively nearby and recent supernova
> as the origin. How recent? Five million
> years. How close? Close. An estimated 90
> light years. If the supernova had been
> any closer than this, it might have had
> an impact on Earth's climate. The resear-
> chers believe traces of the Fe-60 layer
> (like the iridium layer that signaled
> the coming of a dinosaur-killing meteor
> 65 million years ago) should be found
> worldwide but have not yet been able
> to search for it.
> (K. Knie, W. Hillebrandt, et al., Physical
> Review Letters, 5 July 1999.)"
>
> Or see this reference:
> <http://www.sciencenews.org/pages/sn_arc99/7_10_99/fob3.htm>
>
> The discovery has been variously haled
> as "major, astonishing, compelling," and so
> forth.
>
> Since then the same team has repeated their
> results with greater precision:
> "Back then they analyzed three layers
> of South Pacific sediment, each over 2
> million years thick in geologic time. The
> new measurements, acquired at a site some
> 3000 km away, are much more robust: 28 layers
> (rather than 3), from deeper depths (4830 m
> rather than 1300 m), with a better dating
> method (beryllium-10 dating) and a more
> accurate estimate of the layers' age (in
> some cases to within a few 100,000 years).
> On the basis of their measurement, the
> researchers deduce that the samples
> represent the remains of a star that
> exploded 2.8 million years ago (with
> an uncertainty of 0.3 million years)
> at a distance from Earth of some tens
> of parsecs."
>
> It's important to point out that these
> atoms had to be physically transported to
> Earth as particles or grains, probably adhered
> to larger particles or grains, from the site
> of the supernova explosion:
> "The German researchers say that after
> the stellar explosion, gaseous iron-60
> condensed on dust particles, probably
> from inside the star. Hitching a ride
> on these particles, the iron-60 had enough
> velocity to pierce the solar wind and
> reach Earth. From the amount of iron-60
> in the samples, the supernova must have
> been within about 90 light-years, they
> calculate."
>
> It's worth pointing out for those of
> you that don't follow this sport, that this
> supernova explosion is MUCH CLOSER and MUCH
> MORE RECENT than what astronomers thought
> was likely or even possible, but the
> evidence is apparently very solid.
>
> The (mistaken) notion that you have to
> collect all these particles into a big body,
> like a comet, and have it make the trip to
> Earth, is ridiculous, of course, and quite
> unnecessary. The high-speed particles from
> a supernova explosion form an expanding
> thin shell of gas and dust as you can see
> in countless Hubble photographs of gaseous
> nebulae. They're everywhere. The velocity of
> such particles are sufficient to pierce the
> heliopause and they will just race through
> the solar system undeterred unless intercepted
> by a planet. Whether the material is "burned
> up" is irrelevant; the atoms do not "go away;"
> they reach the Earth's surface in one form or
> another and are incorporated in sediments, etc.
>
> Firestone's poor ad hoc theorizing only
> damages what could be valuable evidence. Given
> the unique isotopic composition of the soil
> layers he has analyzed, he has very strong
> evidence that the material in them contains
> a fraction that is of extraterrestrial origin,
> but explaining how that material got there
> will require A LOT MORE WORK and a much better
> hypothesis than these recent suggestions.
>
> Anybody got one?
>
> Sterling K. Webb
> ----------------------------------------------
> Darren Garrison wrote:
>
> A short while back I posted what I called
> a crackpot theory on a comet striking the Earth
> at interstellar speeds around 13,000 years ago.
> Well, the "theory" is in the news again, but
> this time, instead of the comet being impossibly
> fast (I calculated the speed, based on the
> supposed time ago and distance away of the
> supernova at close to 1 percent of c) it is
> now being reported as impossilby slow-- 1,000
> kilometers an hour, or about 277 meters per
> second. And what about these "lunar meteorites
> that fell to the Earth about 10,000 years ago"?
>
> <http://abcnews.go.com/Technology/wireStory?id=1261061>
>
> Scientist: Comets blasted early Americans
> Scientist says Supernova, comets may have impacted early
> Americans
>
> COLUMBIA, S.C. Oct 28, 2005 ??? A supernova could be the
> "quick and dirty"
> explanation for what may
> have happened to an early North American culture, a nuclear
> scientist here said
> Thursday.
>
> Richard Firestone said at the "Clovis in the Southeast"
> conference that he thinks "impact
> regions"
> on mammoth tusks found in Gainey, Mich., were caused by
> magnetic particles rich in
> elements like
> titanium and uranium. This composition, the Lawrence
> Berkeley National Laboratory
> scientist said,
> resembles rocks that were discovered on the moon and have
> also been found in lunar
> meteorites that
> fell to Earth about 10,000 years ago.
>
> Firestone said that, based on his discovery of similar
> material at Clovis sites, he estimates
> that
> comets struck the solar system during the Clovis period,
> which was roughly 13,000 years
> ago. These
> comets would have hit the Earth at 1,000 kilometers an hour,
> he said, obliterating many
> life forms
> and causing mutations in others.
>
> "I'm not going to tell you that there's Clovis people on the
> moon, or that they had a space
> program," Firestone said. But these particles look "very
> much like the material that comes
> from the
> moon, which is the only place we've found with this same
> high titanium concentration."
>
> Amateur archaeologist Richard Callaway said he was surprised
> by Firestone's theory.
>
> "I've always considered myself a pretty open-minded person,"
> Callaway said, while
> browsing some of
> the artifacts on display at the conference. "And it's kind
> of shocking to hear that
> something from
> the solar system could have done something like this."
>
> Callaway, an Episcopal priest from Atlanta, said that he and
> his wife have volunteered at
> the Topper
> site in Allendale County for the past two summers.
>
> "To be a part of this ??? and find something no human being
> has touched in 15,000 years
> that's
> something," Callaway said. "That's what I like about what we
> do. You don't find the next
> answer. You
> find the next question."
>
> Earlier Thursday, University of South Carolina archaeologist
> Al Goodyear lectured on his
> discoveries
> at Topper, where he says he has found evidence that man
> existed in North America much
> earlier than
> previously thought. Goodyear showed slides of the many tools
> he has recovered from
> Topper, as well
> as a charcoal strip he discovered in soil two meters beneath
> a 16,000-year-old level of
> the site.
>
> "Topper's like a box of chocolates," Goodyear said. "Every
> time we dig a hole,
> something new comes
> up."
>
> As the final event of the four-day conference, partially
> sponsored by USC, Goodyear will
> lead
> attendees on a visit to Topper on Saturday.
>
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Received on Sat 29 Oct 2005 09:05:09 PM PDT