Jihad needs scientists
in [Design]
|
From: fkasner on 26 Oct 2006 17:32 lucasea(a)sbcglobal.net wrote: > <mmeron(a)cars3.uchicago.edu> wrote in message > news:Dg80h.5$e06.363(a)news.uchicago.edu... >> In article <ehqa97$8qk_008(a)s783.apx1.sbo.ma.dialup.rcn.com>, >> jmfbahciv(a)aol.com writes: >> >>> I get real annoyed when people say that Newtonian physics doesnt' >>> work. It does work with crude measurements of certain things. >> Crude? For nearly all macroscopic situations we encounter Newtonian >> physics is good to 7-8 decimal places or better, far more accurate >> than the input parameters typically are. Not so crude:-) > > This is just a demonstration of the depth of her misunderstanding of how > exactly GR relates to Newtonian gravity. GR is only needed to describe the > situation for things that are very, very, very massive, or moving very, very > very fast....and as such, it explains why light bends around stars, when it > shouldn't in Newtonian gravity, since weightless photons should be > completely unaffected by a star's gravity. > > One application of relativistic effects that has always fascinated me is in > computational studies of very heavy atoms like Hg. As I understand it, > incorporation of relativistic effects is needed to understand certain > phenomena...like, for example, the low unusually low melting point of Hg > compared to related elements, and the stability of Hg(I) compounds. > > >>> I know what the scientists mean; but it's a bad form to use >>> because the cranks and the newbies do not know what they mean. >> It is even worse than bad form, under most circumstances it is pompous >> twittery. You know, you've the kind of people who enjoy saying "all >> you know is wrong, I know better, nah nah nananah...". You would >> think they should grow out of this by the end of adolescence but some >> people never do. >> >> Sure, Newtonian physics is not exact. It is an approximation, and a >> damn good one over a broad range of physical parameters. Calling it >> "wrong" is stupid. > > And it is something I've never heard any serious scientist do. > > Eric Lucas > > Even Newton was aware that something was strange about his physics. The fact that his pendulum equation could not distinguish between gravitational mass and inertial mass (they seemed to cancel one another) and he designed an experiment that could distinguish a variation of one part per million if those masses differed. But the experiment led him to determine that they had to be the same. Quite a fine experimental test. Hardly a basis for calling Newtonian physics wrong. It is merely limited in what it can explain. James Franck told me one day that Einstein had postulated that Newtonian physics explained 99.9% of all physical phenomena. Quantum mechanics explained 99.9% of the 0.1% that remained. And relativistic mechanics explained 99.9% of what previously was unexplained. FK
From: John Larkin on 26 Oct 2006 18:03 On Thu, 26 Oct 2006 19:44:21 +0100, "T Wake" <usenet.es7at(a)gishpuppy.com> wrote: >You must have misread my post. Can you read over it again and see where I >said Newtonian gravity doesn't work, I don't think I said it and I hope I >didn't imply it. I think you said that it works when it works. No argument. > >I am talking about the possibility that a future theory of gravity _may_ >overhaul the Newtonian mechanics for low mass objects and slow speeds. There >is nothing in the scientific method which precludes a future generation >discovering a better experimental test and finding a flaw in the Newtonian >theory because of something we have no knowledge of at this time. Someone is currently experimenting to see if the forces change at small, mm, sorts of distances. Some theory suggests this, higher dimensions wrapped into smallish circles or something. > >It remains the case, that until such a time, scientists _believe_ Newtonian >theory is the best theory for describing gravity in the circumstances in >which it is used. It is not possible to know that this is the only theory. >The same applies to GR. It is scientist's belief that GR is the best theory >for describing gravity on a cosmic scale. > >Belief is a word. Giving it mystical meaning is pandering to religious >extremists. > So all spiritual concepts are religious extremism. Not much wiggle room there! John
From: John Larkin on 26 Oct 2006 18:05 On Thu, 26 Oct 2006 20:41:02 +0100, "T Wake" <usenet.es7at(a)gishpuppy.com> wrote: > >"Jonathan Kirwan" <jkirwan(a)easystreet.com> wrote in message >news:dj02k2d23ajq2bp4rr92nif0l6n5g3imle(a)4ax.com... >> On Thu, 26 Oct 2006 19:45:15 +0100, "T Wake" >> <usenet.es7at(a)gishpuppy.com> wrote: >> >>>> Cool, it's perfect when it's perfect; otherwise, it's not. >>>> >>>> Got it. >>> >>>Yep :-) That pretty much sums it up. >> >> Hehe. That sums up anything and everything and nothing, too. > >Great isn't it. :) > Yeah, something we can all agree on. John
From: T Wake on 26 Oct 2006 18:22 "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:0sb2k29hdbpv2963m3p6a193gdea0tjb0h(a)4ax.com... > On Thu, 26 Oct 2006 19:44:21 +0100, "T Wake" > <usenet.es7at(a)gishpuppy.com> wrote: > > >>You must have misread my post. Can you read over it again and see where I >>said Newtonian gravity doesn't work, I don't think I said it and I hope I >>didn't imply it. > > I think you said that it works when it works. No argument. > >> >>I am talking about the possibility that a future theory of gravity _may_ >>overhaul the Newtonian mechanics for low mass objects and slow speeds. >>There >>is nothing in the scientific method which precludes a future generation >>discovering a better experimental test and finding a flaw in the Newtonian >>theory because of something we have no knowledge of at this time. > > Someone is currently experimenting to see if the forces change at > small, mm, sorts of distances. Some theory suggests this, higher > dimensions wrapped into smallish circles or something. Well, string theory and its offshoots are borderline science (IMHO of course), but at least they make _some_ predictions. >>It remains the case, that until such a time, scientists _believe_ >>Newtonian >>theory is the best theory for describing gravity in the circumstances in >>which it is used. It is not possible to know that this is the only theory. >>The same applies to GR. It is scientist's belief that GR is the best >>theory >>for describing gravity on a cosmic scale. >> >>Belief is a word. Giving it mystical meaning is pandering to religious >>extremists. >> > > So all spiritual concepts are religious extremism. Not much wiggle > room there! That isn't what I said, nor was it in the context of the current discussion.
From: Jonathan Kirwan on 26 Oct 2006 18:49
On Thu, 26 Oct 2006 23:22:04 +0100, "T Wake" <usenet.es7at(a)gishpuppy.com> wrote: > >"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >news:0sb2k29hdbpv2963m3p6a193gdea0tjb0h(a)4ax.com... >> On Thu, 26 Oct 2006 19:44:21 +0100, "T Wake" >> <usenet.es7at(a)gishpuppy.com> wrote: >> >> >>>You must have misread my post. Can you read over it again and see where I >>>said Newtonian gravity doesn't work, I don't think I said it and I hope I >>>didn't imply it. >> >> I think you said that it works when it works. No argument. >> >>> >>>I am talking about the possibility that a future theory of gravity _may_ >>>overhaul the Newtonian mechanics for low mass objects and slow speeds. >>>There >>>is nothing in the scientific method which precludes a future generation >>>discovering a better experimental test and finding a flaw in the Newtonian >>>theory because of something we have no knowledge of at this time. >> >> Someone is currently experimenting to see if the forces change at >> small, mm, sorts of distances. Some theory suggests this, higher >> dimensions wrapped into smallish circles or something. > >Well, string theory and its offshoots are borderline science (IMHO of >course), but at least they make _some_ predictions. ><snip> I'm still struggling with Lie Algebras and reflection spaces, right now, so I'm kind of working towards but generally ignorant of string theory. But I'm also about at the same place regarding string theory's borderline status. And as you say, at least it does make _some_ predictions. I suppose it probably will be a few years before some new experimental results will test the low-energy domain where some differences may show up from m-theory, though. For all that, string theory has provided at least one answer in an area where other theories, as I understand them, have fallen short. It's not much, but there it is. It deals with the problem of Bekenstein-Hawking entropy of black holes. Bekenstein, in 1970 or so, as a grad student of Wheeler (Princeton), suggested the idea that black holes might have entropy - a lot of entropy, in fact. He was motivated by the idea that the entropy of a closed system always increases. He reasoned that if you drop a bunch of disorganized matter into a black hole, it just 'disappears' leaving a highly ordered vacuum, so to speak. The entropy of the black hole would certainly have to increase to account for the lost entropy elsewhere. He then drew on Hawking's demonstration that the area of the event horizon of a black hole always increases in any physical interaction. Bekenstein felt this suggested a link in that the greater the total area of the event horizon of a black hole should be directly proportional to the entropy of that black hole -- in other words, that the area would be a precise measure of its entropy. Most physicists didn't much like this idea, at the time. Black holes were thought to be among the most ordered objects in the universe. With only mass, charge, and spin to account for, a black hole just didn't seem to have enough defining characteristics to account for a lot of entropy (or much of any, at all.) More, Hawking felt that Bekenstein's proposal was nothing more than coincidence -- Hawking pointed out that if one takes the law of thermodynamics seriously in this case, that assigning entropy to the area of the event horizon would require a temperature to be assigned, as well. Which would require that black holes radiate! Hawking felt simply that when matter carrying entropy fell into a black hole, the entropy was simply lost. So much for the 2nd law of thermodynamics. But Hawking was okay with that.. for a time. But in 1974 I think, Hawking considered the idea of the frantic mess of virtual particles in empty space, with particles and their antiparticles errupting and annihilating one another. Near the black hole, it's possible that one of these pairs falls into the event horizon, never to be seen again. The other actually gets a boost of energy from the gravitational energy of the black hole and gets shot outward. Black holes actually radiate! Hawking calculated the temperature that a far-off observer would associate with the emitted radiation, thus produced, and discovered that it is given simply by the strength of the graviational field at the event horizon and in exactly the amount that prosaic thermodynamics would suggest from Berkenstein's entropy proposal. A black hole has entropy... and temperature. And the gravitational laws of black holes are little other that just another way of rewriting the law of thermodynamics, even if in a highly exotic gravitational context. Just another of those confirming arches one finds in physics, linking strongly different domains. Anyway, there was still the problem of what disorder?? Black holes appear to be very simple objects. So what's the source of the disorder they must have? On this, Hawking was silent. Hawking was able to finesse a partial union of quantum mechanics and general relativity to yield his limited results, that black holes *do* radiate. But he wasn't able to go further. This lack of a microscopic insight became the Berkenstein-Hawking entropy problem of black holes. String theory, by way of Strominger and Vafa in 1996, and building on Susskind and Sen, put out a paper called 'Microscopic Origin of the Beckenstein-Hawking Entropy.' They were able to use string theory to precisely calculate the associated entropy of certain kinds of black holes. They meticulously wove a precise combination of branes into these black holes and were able to exactly predict the characteristics from that process. They could sum and thus demonstrate the various observable properties, from the ground up so to speak. And they could compare these with the entropy predicted by Bekenstein and Hawking. Perfect agreement! So there's one modest success. An insight _may be_ that black holes and elementary particles are just different phases of fundamental vibrational string patterns, configured only by their initial Calabi-Yau shape. Of course, string theory seems to have a lot of these _may be_ situations. So as you say, "borderline science." The next decade will tell a lot, I think. Jon |