sol invictus
Philosopher
- Joined
- Oct 21, 2007
- Messages
- 8,613
Here's a well-written little anecdote our local crackpots might benefit from reading:
http://www.edge.org/q2008/q08_9.html#carroll
http://www.edge.org/q2008/q08_9.html#carroll
.If you believe that, you don't believe in general relativity. The inevitability of the formation of black holes when the total energy within a region reaches a certain cutoff (and it doesn't matter what form the energy takes - adding magnetic fields makes it worse) can be proven rigorously.
Do you believe in GR?
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I don't believe that Carlqvist and Alfvén's model of plasma cloud collapse has anything to do with black holes, and certainly has no relationship to whether I believe in general relativity or not.
I've not said black holes are necessarily a fiction (although has anyone actually seen one?) ... just their ubiquitous use to explain away every little unexplainable observation Big Bang encounters. Especially when other physics is already available that would seem to explain those observations. Plus the fact that they now seem to number as many as stars in the heaven.![]()
Actually, general relativity did not "predict" dark energy. Lambda was actually added to the equation by Einstein in order to make the universe static. And for no other reason.
And far as it "predicting" black holes is concerned, Einstein actually said that a theory that incorporates the existance of singularities should be avoided.
One month after the black hole concept was first introduced in 1939 by Oppenheimer and a graduate student, Einstein wrote a paper ("On a stationary system with spherical symmetry consisting of many gravitating masses", Annals of Mathematics, Oct. 1939, vol 40, No 4, pp 922-936) wherein he stated (calling black holes "Schwartzschild singularities") that "The essential result of this investigation is a clear understanding as to why the ‘Schwartzschild singularities’ do not exist in physical reality."
And here is what Einstein wrote in 1945 (Albert Einstein, The Meaning of Relativity) regarding the big-bang singularity: "Theoretical doubts [concerning the creation of the universe] are based on the fact that [at the] beginning of the expansion, the metric becomes singular and the density becomes infinite. . . In reality, space will probably be of a uniform character, and the present [relativity] theory will be valid only as a limiting case. . . One may not therefore assume the validity of the equations for very high density of field and of matter, and one may not conclude that the 'beginning of the expansion' must mean a singularity in the mathematical sense. All we have to realize is that the equations may not be continued over such regions."
So it's probably inaccurate to claim GR predicted black holes or BBC.![]()
No, you need only adopt either Narlikar's QSSC or SCC cosmology. Both still adhere to GR but both do not require a BB or ubiquitous BHs.![]()
Here's a well-written little anecdote our local crackpots might benefit from reading:
http://www.edge.org/q2008/q08_9.html#carroll
One month after the black hole concept was first introduced in 1939 by Oppenheimer and a graduate student, Einstein wrote a paper ("On a stationary system with spherical symmetry consisting of many gravitating masses", Annals of Mathematics, Oct. 1939, vol 40, No 4, pp 922-936) wherein he stated (calling black holes "Schwartzschild singularities") that "The essential result of this investigation is a clear understanding as to why the ‘Schwartzschild singularities’ do not exist in physical reality."
As MattusMaximus has already pointed out, black holes were predicted well before you seem to think they were. However, I should also point out that this quote is technically correct. Schwartzschild singularities do not exist in physical reality. The reason for this is very simple - conservation of angular momentum. A Schwartzschild black hole does not rotate. Since it is essentially impossible to have any collection of matter with zero angular momentum, and even if such a thing happened, the first interaction with anything else would spoil it. Schwartzschild black holes are theoretically possible under general relativity, but can't actually happen in the real world.
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I think you're not far wrong. The magnetic field in a plasma cloud may stop gravitational collapse. This was investigated by Per Carlqvist in 1988, resulting in the eponymous Carlqvist Relation, peer reviewed in (ref, full text). As Carlqvist and Hannes Alfvén mention in another paper, the magnetic field may either counteract, or aid the contraction of cloud resulting in a pinch.
is what the abstract for the linked paper says.It is shown that magnetic fields, which have generally been regarded as obstructing the condensation of interstellar clouds, will promote the contraction of such clouds under certain conditions and may even constitute the main mechanism for contraction.
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I don't believe that Carlqvist and Alfvén's model of plasma cloud collapse has anything to do with black holes, and certainly has no relationship to whether I believe in general relativity or not.
It does look like their paper is based on known laboratory physics of plasmas, and they have made their case quite rigorously.
.You claimed magnetic fields can stop gravitational collapse.
Sorry Ian, but how does that allow the plasmoid to overcome gravity and where does the energy come from to maintain against gravity.
The issue is that the mass of the plasmoid will still cause it to contract, and at some point it has to get more energy to sustain against the pull of gravity.
Now, it may be that while magnetic fields counteract gravitational collapse, they may not be able to prevent it; once grain sizes increase, gravity certainly plays the dominant role. But magnetic plasmas whose particle size is less than grains, electromagnetic forces dominate. Period. (See Gravitoelectrodynamics)
Uh, the abstract talks about magnetic fields causing a collapse, not maintaining a plasmoid against gravitational collapse.
You can't escape the black hole, light has been demonstrated to be bent by gravity, if you bend it enough you have a black hole.
.Actually it's not like that. Gravity acts on all forms of energy. There is no way to add energy to prevent gravitational collapse - once you are close to the bound, adding energy (of any form) makes the problem worse, not better.
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I stand corrected. It just occurred to me that you are referring to "Gravitational Collapse" of a massive body, whereas I was discussing the collapse, gravitationally, of a plasma cloud (a non-massive body).
Actually it's not like that. Gravity acts on all forms of energy. There is no way to add energy to prevent gravitational collapse - once you are close to the bound, adding energy (of any form) makes the problem worse, not better.
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Originally Posted by iantresman
Now, it may be that while magnetic fields counteract gravitational collapse, they may not be able to prevent it; once grain sizes increase, gravity certainly plays the dominant role. But magnetic plasmas whose particle size is less than grains, electromagnetic forces dominate. Period.
OK, that is a concrete claim for once. It's also totally wrong (as usual with plasma cosmology) - and it's wrong at a level that anybody who has studied even a little general relativity will recognize immediately.
Improvements in our knowledge of the absolute value of the Newtonian gravitational constant, G, have come very slowly over the years. Most other constants of nature are known (and some even predictable) to parts per billion, or parts per million at worst. However, G stands mysteriously alone, its history being that of a quantity which is extremely difficult to measure and which remains virtually isolated from the theoretical structure of the rest of physics. Several attempts aimed at changing this situation are now underway, but the most recent experimental results have once again produced conflicting values of G and, in spite of some progress and much interest, there remains to date no universally accepted way of predicting its absolute value.
It violates singularity theorems which have been proven rigorously (by Stephen Hawking and others).
The conditions for gravitational collapse have nothing to do with particle or "grain" sizes, or any other local characteristic of the fluid or matter in question. They are extremely simple, and depend only on the total mass in some region and the size of that region.
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I stand corrected. It just occurred to me that you are referring to "Gravitational Collapse" of a massive body, whereas I was discussing the collapse, gravitationally, of a plasma cloud (a non-massive body).
Well i have studied it (although briefly), and I see nothing wrong with that statement.
This the whole probem with gravity, it barely has any effect at a particle level at all, only on large scales, and so is very hard to test. Gravity at atom/molecule level is negligable, and only comes into play significantly when you get above dust size, so I see nothing wrong with the statement that small particles are more effected by EM forces.
Millikan made an oil drop hover by applying an electric field to it in his original experiment, making the electric force surpass the force of gravity on something as large as a oil drop. When it comes to dust size and below (until you reach the weak and strong force), EM forces really do reign supreme.
How does the fact that EM forces far dominate gravity at small scales violate singularity theorem?
Yes, those gravitational collapse equations are very simple, and dont take into account many variables. I totally agree.
I have a question that has been bugging me for a while, maybe you could answer it Sol, or anyone else.
Take a large, Isolated, nebula that is collapsing in on itself, and contains an overall charge of any value spread out across its length (lets say 20 C overall). Since it is isolated, there is no surrounding conducting medium to discharge the cloud.
Now the only thing I can see resulting from this situation is a star with a charge on it.
Now the only thing I can see resulting from this situation is a star with a charge on it. If the gravitational force is compressing the plasma to a certain size, as this happens the repulsive force of the similar charges inside the plasma will increase with time, until the compressive force of gravity equals the repulsive force of the ions, leading to a state of equilibrium where the collapsing force equals the repulsive force. I think this may be why some people think that gravity itself plays a part in 'charging' stars. Would this work? i can't think of a reason why this would not happen, given the original conditions.
How does the fact that EM forces far dominate gravity at small scales violate singularity theorem?
This is a point that I have made repeatedly about Zeuzzz's referencing of this paper - he does so quite dishonestly. I originally posted about this way back in post #18.
He presents this as some kind of "evidence" for his plasma/electric/crack-pipe universe claims, but he intentionally leaves out a critical observation by the authors.
While the paper does argue for the existence of a net charge on the Sun, in the middle of the second page of that paper, the authors state:
"We can also demonstrate that the electrostatic interaction between two idealized stars charged with the electrostatic charges, derived here, is extremely weak compared to gravity. The magnitude of electrostatic force represents only about 10−36 of the magnitude of gravity. However, if we study the dynamics of an electrically charged elementary particle or ion, with mass mx and charge qx, then the electrostatic force acting between this particle and charge Qr is −qx(mp−me)=(2qmx) multiple of gravitational force. Thus, the magnitude of the force represents about 50% of the magnitude of gravity, if the star acts on proton, and it is about 918 times more intensive than gravity, if the star acts on electron."
See that?! The effect is only large if acting on individual charges (protons, electrons, and ions). The authors of the very paper Zeuzzz keeps citing for "evidence" of the electric universe say that over large distance scales (interstellar) the electrical effects they are discussing are weaker than gravity by 36 orders of magnitude!
So, Zeuzzz is claiming that this paper supports his EU claims by inferring that if such an effect exists on the Pioneer probe then just imagine the effects elsewhere, which supposedly explain large-scale structures in the universe over million and billions of light-years. Yet the paper clearly doesn't support these claims, so why does he keep referencing it?
Originally posted by Zeuzzz
it is a good paper as it indicates that the sun can ehibit a net charge and an electric field, a fact widely denied by conventional astronomy
I have done no such thing, i fact, i have continually stated the exact context in which i cite that paper, and its not to use their (very theoretical) value of the charge on the sun. As i said (about three seperate times) it is an interesting paper as it demonstrates that the sun can exhibit a net charge, a proposition that was widely thought not possible by most astronomers, who view the universe and entireley neutral.
And if you actually read the paper, you will find a whole host of assumptions that could throw off their value of 77C by a very considerable amount. For example their model can only be applied to a an ideally quiet, perfectly spherical, non-rotating star in the first place, and so obviously falls short of being accurate in this respect.
When you factor in things like the different forces acting on protons and electrons due to centripetal force (due to mass differences) when the star is spinning, the actual value of separation between charges could be far in excess of this.
As i said previously, To find the charge on the sun you would have to take varying measurements of the strength of the E-field at separate radii
It's completely false, that's what's wrong with it.
It is true that gravity is a much weaker force than EM when it's acting only on two charged particles. But the fundamental fact about physics that you guys seem not to be able to comprehend is that it's a much, much stronger force than EM when it's acting on lots of particles.
Had Millikan tried to do an experiment with an oil drop the size of the galaxy, the answer would have been rather different.
Or to make a better analogy, if you had a trillion Millikan oil drop experiments distributed in some region, their mutual gravitational attraction would cause them to form a black hole and get crunched at the singularity, thus rather strongly affecting the results of each.
The claim was that we can ignore gravitational forces. That is false and violates the theorem if the cloud of plasma is large enough, regardless of what precisely it's composed of.
Hmmm, i can't see that claim, and i certainly dont agree with it.
Well, duh. I know how gravity works,
i also know that it is incredibly weak (even negligable) in comparison to EM forces at the atom / molecule level. Of course for large size structures gravity is the dominant force in the universe, but not at smaller levels.
http://www.aanda.org/index.php?opti...articles/aa/full/2001/24/aah2649/aah2649.html
Can anyone find me another paper that works out what the charge on the sun is? possibly not one so theoretical, more based on observations? That one seems to be the only one, which i find odd.
If this is the only publication that looks at the suns total charge, why is that so? are they to be trusted? why have no other astronomers worked on this?
False. Gauss's law says measurements at one radius will suffice. Assuming symmetry, one position is good enough. I've already pointed this out.
http://www.aanda.org/index.php?opti...articles/aa/full/2001/24/aah2649/aah2649.html
Can anyone find me another paper that works out what the charge on the sun is? possibly not one so theoretical, more based on observations? That one seems to be the only one, which i find odd.
If this is the only publication that looks at the suns total charge, why is that so? are they to be trusted? why have no other astronomers worked on this?
There's a textbook: according to your article, Glendenning, N. K. 1997, Compact Stars (Springer-Verlag, New York), page 71, derives a bound on the maximum possible charge in a star.
Sol, you are a better man (I assume a man - gender is tough to determine online) than I... I lost patience with Zeuzzz and the other EU-PU woos long ago. Could you tell?![]()
I should take a page from you on attempting to be a wee bit calmer in my arguments, though I find it very difficult when contronted with such maddeningly self-imposed delusion.
There's a textbook: according to your article, Glendenning, N. K. 1997, Compact Stars (Springer-Verlag, New York), page 71, derives a bound on the maximum possible charge in a star.
Using your line of thinking, I suppose that you will maintain that ultra-violet & infra-red radiation as well as the wind are all not "observable" because they aren't visible.
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Actually, general relativity did not "predict" dark energy. Lambda was actually added to the equation by Einstein in order to make the universe static. And for no other reason.
I concede this point concerning Einstein - that term was inserted by Einstein as a "correction."
However, it should be noted that another physicist, Alexander Friedman, did use GR to predict such a cosmological constant (what we now call "dark energy") in 1922...
There is more to general relativity than just Einstein, pal...
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And far as it "predicting" black holes is concerned, Einstein actually said that a theory that incorporates the existance of singularities should be avoided.
And Einstein was wrong.
The concept of infinite gravitational collapse (what we now call "black holes") into a singularity was first proposed in 1915 by Karl Schwartzchild, you moron.
See?! Einstein's equations did predict the existence of black holes, though they weren't called "black holes" until later. Duh...
And Einstein was wrong. His theory was right, but he just didn't want to accept its conclusions concerning an expanding spacetime.
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So it's probably inaccurate to claim GR predicted black holes or BBC.
You're an idiot. Learn some history in addition to physics.
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No, you need only adopt either Narlikar's QSSC or SCC cosmology. Both still adhere to GR but both do not require a BB or ubiquitous BHs.
More Big Gnomes?
BeAChooser: Try to guess what a plasmoid with a mass of 2.6 million solar masses and a radius of no more than 1 AU is?
Sorry Ian, but how does that allow the plasmoid to overcome gravity and where does the energy come from to maintain against gravity.
BAC, for example, is a classic internet troll - (s)he isn't interested in the subject, only the arguments and reactions. There's no point in carrying on a conversation with someone like that unless it entertains you.
The two here seem marginally more reasonable, at least at the moment (although I remain unconvinced that neither of them is a BAC-puppet).
For the record, I post only under the BeAChooser screenname. Period.
But given how often Sol shows up to say "me too" to something Ziggurat wrote, maybe a case could be made he's a ZIG-puppet.![]()
No, because they are DIRECTLY visible to sensors. Nothing has to be inferred.
A correction whose sole purpose at the time was to make the universe static.
That's not accurate (Wikipedia is often not the best source to rely on). Friedmann's overall solution may have allowed for a cosmological constant but in fact the specific solution he sought and used as the basis for an expanding universe assumed a ZERO cosmological constant.
http://books.google.com/books?id=Om...g=GCb_kvZIFQMv90fMyw3lH5K8oq0&hl=en#PPA105,M1 "101 Things You Didn't Know About Einstein: Sex, Science, And the Secrets of the Universe, Cynthia Phillips and Shana Priwer, 2005 ... snip ... By 1922, a Russian mathematician named Alexander Friedmann was working on creating a model of the universe that didn't]/b] require the cosmological constant, and he met with success. ... snip ... The Friedmann equation works within the larger framework of general relativity, but excludes the cosmological constant in an effort to represent the universe as dynamic."
http://books.google.com/books?id=v_...g=dTByPko0t4aMc5gwkoJlegN6bpY&hl=en#PPA367,M1 "The physical universe: an introduction to astronomy By Frank H. Shu ... snip ... "In 1922, Friedmann discovered two classes of nonempty cosmological models which did not require the cosmological constant; and they were also discovered independently by Lamaitre."
http://scienceweek.com/2005/sw051230-2.htm From PhysicsToday ... "Only then was much attention given to the expanding-universe models introduced in 1922 by Alexander Friedmann (1888-1925), in which no cosmological constant is needed."
Really? Oh how the mighty have fallen. One moment he's almost a God to you folks. The next ... dirt.![]()
But in any case, I haven't seen any true proof that black holes exist. Just a claim inferred from observations that might very well be explained by much more ordinary and well tested physics.
To be more precise, Schwartzchild's paper described a structure that he called a point mass ... later dubbed a singularity.
But lot's of equations produce singularities that aren't real entities.
So now you think yourself brighter than Einstein?![]()
Hardly. I suggest you use Wikipedia like you always do.![]()
I believe you about that. Not that it makes much difference, you're still dishonest and clueless.
That's ridiculous. Sol pointed out an error I made once. I'm far too arrogant to be willing to do that to myself. Really, don't you know anything about me yet?
.Can anyone find me another paper that works out what the charge on the sun is? possibly not one so theoretical, more based on observations? That one seems to be the only one, which i find odd.