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Can anybody tell me why crystalline powders become more white when the
particle size is reduced.
A collegue of mine claims that all crystalline powders become perfectly
white when their particle size is reduced, is this true ?

In article <32DC2CE6.5B58@cisco.com>, John Jordano  wrote:
> Given the condition that an excess of positively charged particles were
> to fall into a black hole, would the black whole exhibit a positive
> charge?
Yes.
> My intuition says "Yes," but if so, how does the "information" about the
> charge inside of the event horizon get communicated outside of the
> horizon?  It's my understanding that the effect of a charge is carried
> by the electromagnetic force, and that the force carrying particle for
> the EM force are photons.  If photons can't escape from a black hole,
> then how can the black hole exhibit the positive charge?
The sci.physics.relativity FAQ talks about this in detail. You can
access it via the sci.physics FAQ at
http://www.public.iastate.edu/~physics/sci.physics/faq/faq.html 
http://www.phys.unsw.edu.au/physoc/physics_faq/faq.html
http://math.ucr.edu/home/baez/physics/faq.html 
Look in the section of the sci.physics.relativity FAQ on black holes,
and specifically at the question "How does the gravity get out of
the black hole?" Like your post, the essay uses electromagnetism as
a starting point, since the quantum theory of electromagnetism is
much better understood than the quantum theory of gravity.
-- 
Matt McIrvin   

In article <5bg5vi$kv0@geraldo.cc.utexas.edu> candy@mildred.ph.utexas.edu
(Jeff Candy) writes:
> After a relatively low threshold (say, well below 
> 100,000 US per year) more money has only 
> a weak influence on happiness.  I'm sure lots
> of traders would pay a fortune to have a nice
> physique, or to be as happy as the surfer they
> see on rare occasion at the beach.
Jeff's right on the first point. Actually no one really knows the treshold
and a recent survey showed, that Multi-Millionaires are not the least
happier than the average people. Happiness (and/or contendedness) seems to
be inherited from the parents rather than anything else. So we are talking
of money, and maybe safety, not of happiness or to be satisfied with the
life you lead.
But that goes for the surfer just the same. All extreme sportsmen agree,
that they climb the highest mountains or jump the loop in the surf to get
"the ultimate kick". Joggers tell you the same (endorphines after half an
hour hard run) and it seems to me, that in daily life they must be
unhappier than me, who is happy to glide downhill on skies once every few
years and else to be able to drink a bottle of wine once in a while (ahem,
rather regularly I should admit). Would anyone change his life with pickle
face Bill Gates? Or with mystery man Michael Jackson? Thank you very much.
How about the trader Leesson? Anyone thinks he was happy????
The most dangerous untruths are truths slightly deformed.
Lichtenberg, Sudelbuecher
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Per the FCA: this eMail adress is not to 
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Uncalled for eMail maybe treated as public.

buckleyda@main.put.com (Dan Buckley) writes:
> On 6 Jan 1997 07:04:00 GMT, sealion2@ix.netcom.com(Stephen L. Johnson)
> wrote:
> 
> >Would someone kindly convince me that the alleged Mars rock actually
> >came from Mars.  From what I read in the newspapers and such, the logic
> >goes like this:  Once upon a time (note the fairy tale beginning) some
> >large object must have smashed into Mars, dislodging some rocks which
> >eventually landed in Antarctica.
> >
> >Seems to me this line requires a lot to swallow.  If an object got
> >caught in the Mars gravity web and spiralled in to impact, it means in
> >the first place that the object did not have enough velocity to escape
> >the Mars gravity.  To think that it could impart such velocity to a
> >rock, or to several, is stretching it, or so it seems to me.  After
> >all, the object would have lost some energy due to friction, making it
> >even more unlikely to have retained the energy required.
> >
> >Maybe I'm missing a few rocks in my head, too, but truly you might be
> >doing the public a service by explaining how such an event could
> >happen.
> >
> >Regards,
> >
> >stephen
> OK, let's assume the object that smashed into Mars was a comet, or
> something similar.  The object will have had a high velocity of its
> own before hitting Mars.  It didn't have to just fall onto the Martian
> surface, it could have been travelling at a high rate of speed and
> just run into Mars.  This type of object could easily have passed
> nearby to Mars without spiralling into Mars' gravity field.
> 
> Also, the object will transfer a great deal of energy to Mars.  This
> energy may not be able to free the entire object from Mars' gravity,
> but it can transfer enough energy to a small Martian rock to allow the
> rock to leave Mars' gravity.
> 
> I'm not sure how the scientists decide that a rock found on earth is
> actually from Mars, perhaps someone familiar with this process can
> provide more detail.
> 
> Dan
> "Your superior intellect is no match for our puny weapons!" Kang

On 16 Jan 1997 robert.koss@mail.snet.net wrote:
>    >So, if you go away from me, I will see your clock going slower at each
>    >point of your journey, except when you turn around and come back.
>    >Therefore you will have aged less than I have.
> 
>    That is one big illogical 'therefore'.
> 
>    When he turns around and comes back, you see his clock speed up again
>    don't you? In the end your clocks sync back up (all other things being
>    equal) ...
> 
>    This is a different effect than time dialation. It is called the dopler
>    effect.
That is not true.....the clocks appearing slower and faster is not due to 
the doppler effect.
The whole twin paradox is explained clearly in the book 'About Time' by 
Paul Davies.
Rich.
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In article <5b5e6d$qqe@goofy.snet.net>,   wrote:
>
>   >C is an absolute constant. We cannot measure it exactly, but it is
>   >absolute.
>
>   Says who?
>
Says about 6 million experiments, the orbit of Mercury, etc, etc...
>   C _appears_ to be a constant.
C is assumed to be a constant in Einstein's relativity. Based on his
theory, many experiments have been done, included the measurement of
the precession of the orbit of Mercury, all of which confirmed Einstein's
theories.
In view of the accuracy of the predictions, C is confirmed as constant.
At least until another more accurate theory displaces Einstein's theory.
Even then, in the cases where Einstein's theory apply, C is a constant.
>
>   >Similarly to the value of pi, which we know has a particular value,
>   >which we can measure or calulate aproximately,
>
>   Indeed we cannot measure Pi to infinite precision, and indeed we can't
>   measure C to infinite precision - we also can't measure the mass of
>   the earth with inifinite precision
>
>   The last one is certainly not a constant - the first one certainly is
>
Your point? There is no theory that says that the earth has a constant
value. However there are theories that require C and Pi to be constant.

In article <01bc0294$18ba5010$5229b7c7@smpmackiller>, "Guy Nussbaum"
 wrote:
> John  wrote in article
> > I think one of the Popes asked S. Hawking not to look any further back
> > than our Big Bang, so another conspiracy was born.
> > John
> 
> i am not kidding, how should i take this as a joke, or are you being
> serious? 
> and if you are being serious.. where did you hear it?
>  from what i understand hawkings is claiming it's hard (nearly impossible)
> to go any further then 10^ -43 second 
> (or something like that) back into the big bang
It wasn't a conspiracy, since Hawking didn't follow instructions.
The Vatican, which has been fairly enlightened about cosmology and science
in modern times, sponsored a conference on cosmology which Hawking
attended. In _A Brief History of Time_, he describes the Pope giving an
address to the conferees in which he urged them not to attempt to study the
*precise moment of creation* scientifically, since that was God's
department. (I don't think he was so much declaring an injunction as
insisting that any attempts were doomed to failure, because of the
miraculous nature of the event.)
Hawking remembered thinking it fortunate that the Pope didn't know that he
was working on that subject. Established theory doesn't cover the epoch
prior to 10^-43 second or so (actually, it doesn't even go back that far in
much detail), but Hawking was trying to do so with some speculative
quantum gravity ideas. He's still working at it.
I think it's interesting that the Pope specifically warned them away from
the first moment of the universe. That is at variance with the theological
ideas of, for instance, St. Augustine, who described God as being outside
of time and creating the whole history of the universe. The first moment
wouldn't be any more privileged or miraculous than any other moment.
Describing it in terms of physical laws might still not explain why the
laws are there or why anything exists at all. I don't think that this
mystery necessarily cries out for a religious explanation, but I also don't
think that anyone has much hope of figuring it out scientifically, at least
not with any of the tools we know.
-- 
Matt McIrvin   

In article <5bev6g$1ld6@r02n01.cac.psu.edu> ale2@psu.edu (ale2) writes:
>
>Microsoft Bill Gates didn't have a degree did he?
 Nope, but he did drop out of one of the finest universities in the US. 
 His partner, however, did have a degree. 
 The reason he dropped out was that timing was more important that a 
 degree at that time, since it was more important to have a product 
 than to have a high quality product when there were no products on 
 the market. 
-- 
 James A. Carr        |  "The half of knowledge is knowing
    http://www.scri.fsu.edu/~jac/       |  where to find knowledge" - Anon. 
 Supercomputer Computations Res. Inst.  |  Motto over the entrance to Dodd 
 Florida State, Tallahassee FL 32306    |  Hall, former library at FSCW.