Split Thread Hannes Alfven's cosmology

W.D.Clinger

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W.D.Clinger
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schrodingasdawg said:
I included more of the quote than you did since I think the complete sentence is relevant. Minkowski was indeed the one who introduced the concept of space-time to special relativity, but it can be reasonably argued that the geometric viewpoint is just a mathematical trick in the theory. (As far as I can infer---from a cursory reading of this thread---that was Alfven's argument.) General relativity, though, seems to require the geometrical viewpoint more strongly: in it, space-time really is a manifold, and so time really is the fourth dimension. I suppose this is what W.D.Clinger meant.
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Yes, thank you.

To be fair, however, Alfvén had quoted someone else who attributed the fourth dimension to Einstein, was merely accepting that attribution for the sake of argument, and was discussing it in section II "E. Special Relativity".

The explicitly religious character of Alfvén's argument is relevant to this thread, and Alfvén is certainly one of the more accomplished scientists whose publications support this thread's title, so I hope the moderators will allow me to trace his argument from this minor detail through his conclusions. All quotations are from Hannes Alfvén, "Cosmology: Myth or Science", IEEE Transactions on Plasma Science 20(6), December 1992, 590-600, and all italics are in the original.

From section II E, "Special Relativity":
Alfvén said:
It was claimed that "Einstein has discovered that space is four-dimensional," a statement which is incorrect....

However, the fourth coordinate which Einstein introduced was not time, but time multiplied by √-1 ....

Many people probably felt relieved by being told that the true nature of the physical world could not be understood except by Einstein and a few other geniuses who were able to think in four dimensions. They had tried hard to understand science, but now it was evident that science was something to believe in, not something which should be understood....Contrary to Bertrand Russell, science became increasingly presented as the negation of common sense. One of the consequences was that the limit between science and pseudo science tended to be erased....
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From section III A, "Revival of Pythagorean Philosophy":
Alfvén said:
On the other hand, in the general theory of relativity the four-dimensional formulation is more important. The theory is also more dangerous, because it came into the hands of mathematicians and cosmologists, who had very little contact with empirical reality....

....The cosmological discussion became monopolized by Big Bang believers who had studied general relativity for years. No one else is allowed to have any views about cosmology....
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Alfvén, of course, was not one of those who had studied general relativity for years. His resentment is evident.

So are several of his misunderstandings of GR. For example, he thinks Friedmann found only one solution of Einstein's field equations, and that Big Bang cosmology is based on this supposedly unique solution. In reality, Friedmann found an entire family of solutions. Several of those solutions have no singularities at all. Some solutions have a Big Crunch singularity but no Big Bang singularity. The solutions with Big Bang singularity were mostly ignored at first, for reasons that really were essentially philosophical or religious. It was empirical evidence, for Hubble expansion and later for cosmic microwave background radiation, that has brought those Big Bang solutions to the fore.

Alfvén has this backwards. From section III C, "Big Bang Hypothesis":
Alfvén said:
....Big Bang cosmology...is based on Friedman's solution of Einstein's equations. This solution has a singular point. To a mathematician a singular point is nothing very remarkable, but to a physicist it had earlier meant that something had gone wrong, a warning that the theory could not be applied to a real problem. However, without any serious discussion, this old tradition in physics was suddently neglected. Instead, it was generally accepted that the singular point represented reality, and meant that at a certain time the whole universe consisted of one single point only.
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Alfvén's interpretation of that singular point must have come from the popularized accounts he deplores. Mathematicians understand that the so-called singular point is not and cannot be a point of the spacetime manifold. Cosmologists, astronomers, and physicists understand that the laws of physics break down at the singularity; we simply don't know what happens there, or if indeed there is any "there" there.

Alfvén goes on in this vein, drawing a caricature of Big Bang cosmology based upon his own misunderstandings. The purpose of his misrepresentations is to create the false impression that Big Bang cosmology has no support beyond the philosophical or religious imagination of its high priests. From sections III D and III F:
Alfvén said:
The Big Bang is indeed a cosmology of the same character as the Ptolemaic: absolutely sterile.
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Alfvén said:
A very important conclusion from the Big Bang cosmology, which is seldom drawn explicitly, is that the state at the singular point necessarily presupposes a divine creation....Peratt [13] suggests that the creationism extra muros is inspired by the Big Bang creationism intra muros.
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Need I point out that the Scopes trial of 1925 predates Lemaître's 1927 paper that first proposed the idea of a Big Bang?

More importantly, there is nothing inherently divine about spacetime singularities. Black holes involve singularities also, but Alfvén doesn't even try to argue that black holes imply divine creation. He mentions them only in passing. From section IV C, "Mundane and Celestial Mechanics":
Alfvén said:
Even if it is admitted that in principle general relativity is valid, the difference between this and Newtonian mechanics is negligible except in a few special cases....Exceptions are special cases like neutron stars and black holes (if there are any!).
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Alfvén's doubts about the existence of black holes have not aged well, nor has his belief that the discovery of quasars counts as evidence against the Big Bang or spacetime singularities.

As this thread has demonstrated, however, some still hold to Alfvén's beliefs. From section V, "The Cosmological Pendulum":
Alfvén said:
Three or four millennia of cosmological speculation have resulted in essentially three different types of approaches to cosmology.

1) The Scientific Approach: As science is basically empirical, this means that cosmology should be based on observations with experimental results (from laboratory or nowadays also spaced experiments) as a background....

2) The Agnostic Attitude: This is the Rigvedic and Buddhist approach: How can we know about or why should we care about problems so distant?

3) The Mythological Approach: ....This approach is closely related to the mathematical myths: It is possible to explore the structure and evolutionary history of the universe by pure theoretical thinking without very much contact with observations. Typical examples are the Pythagoras-Plato-Ptolemaic cosmology or, in our day, the Eddington cosmology, but also the Big Bang.
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Sounds familiar, doesn't it?
 
W.D.Clinger said:
Yes, thank you.

To be fair, however, Alfvén had quoted someone else who attributed the fourth dimension to Einstein, was merely accepting that attribution for the sake of argument, and was discussing it in section II "E. Special Relativity".

The explicitly religious character of Alfvén's argument is relevant to this thread, and Alfvén is certainly one of the more accomplished scientists whose publications support this thread's title, so I hope the moderators will allow me to trace his argument from this minor detail through his conclusions. All quotations are from Hannes Alfvén, "Cosmology: Myth or Science", IEEE Transactions on Plasma Science 20(6), December 1992, 590-600, and all italics are in the original.

From section II E, "Special Relativity":


From section III A, "Revival of Pythagorean Philosophy":

Alfvén, of course, was not one of those who had studied general relativity for years. His resentment is evident.

So are several of his misunderstandings of GR. For example, he thinks Friedmann found only one solution of Einstein's field equations, and that Big Bang cosmology is based on this supposedly unique solution. In reality, Friedmann found an entire family of solutions. Several of those solutions have no singularities at all. Some solutions have a Big Crunch singularity but no Big Bang singularity. The solutions with Big Bang singularity were mostly ignored at first, for reasons that really were essentially philosophical or religious. It was empirical evidence, for Hubble expansion and later for cosmic microwave background radiation, that has brought those Big Bang solutions to the fore.

Alfvén has this backwards. From section III C, "Big Bang Hypothesis":

Alfvén's interpretation of that singular point must have come from the popularized accounts he deplores. Mathematicians understand that the so-called singular point is not and cannot be a point of the spacetime manifold. Cosmologists, astronomers, and physicists understand that the laws of physics break down at the singularity; we simply don't know what happens there, or if indeed there is any "there" there.

Alfvén goes on in this vein, drawing a caricature of Big Bang cosmology based upon his own misunderstandings. The purpose of his misrepresentations is to create the false impression that Big Bang cosmology has no support beyond the philosophical or religious imagination of its high priests. From sections III D and III F:


Need I point out that the Scopes trial of 1925 predates Lemaître's 1927 paper that first proposed the idea of a Big Bang?

More importantly, there is nothing inherently divine about spacetime singularities. Black holes involve singularities also, but Alfvén doesn't even try to argue that black holes imply divine creation. He mentions them only in passing. From section IV C, "Mundane and Celestial Mechanics":

Alfvén's doubts about the existence of black holes have not aged well, nor has his belief that the discovery of quasars counts as evidence against the Big Bang or spacetime singularities.

As this thread has demonstrated, however, some still hold to Alfvén's beliefs. From section V, "The Cosmological Pendulum":

Sounds familiar, doesn't it?
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Wow. I knew Alfven was by no means a cosmologist and was totally out of his depth when talking about the Big Bang. I hadn't realised he probably knows less about it than me.
 
W.D.Clinger said:
Alfvén's interpretation of that singular point must have come from the popularized accounts he deplores. Mathematicians understand that the so-called singular point is not and cannot be a point of the spacetime manifold.
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Then what is it a "point" of exactly since it certainly has mass?

Your criticisms of Alfven's views on GR could be correct, but having read many dozens of his papers and a couple of his books, it seems as through he primary rails against the systematic herding of cosmology theory into "prophetic" forms of science, or "creation" theories that contain a "creation date".

In his mind, a "bang" (expansion) is certainly a logical possibility (I think he preferred it actually), but the notion of infinite density at a singular "point" was never an option in his mind and he resented the concept. I think even those of use that accept that "black holes" do exist (heavy objects with an event horizon) still have a difficult time accepting the concept of infinite density at a "point". That seems to be the crux of his beef with the whole singularity concept, not so much the idea of a heavy massive (very dense) object.
 
Michael Mozina said:
Then what is it a "point" of exactly since it certainly has mass?

Your criticisms of Alfven's views on GR could be correct, but having read many dozens of his papers and a couple of his books, it seems as through he primary rails against the systematic herding of cosmology theory into "prophetic" forms of science, or "creation" theories that contain a "creation date".

In his mind, a "bang" (expansion) is certainly a logical possibility (I think he preferred it actually), but the notion of infinite density at a singular "point" was never an option in his mind and he resented the concept. I think even those of use that accept that "black holes" do exist (heavy objects with an event horizon) still have a difficult time accepting the concept of infinite density at a "point". That seems to be the crux of his beef with the whole singularity concept, not so much the idea of a heavy massive (very dense) object.
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the 'point' breaks the models and in most likely not a point.
 
Michael Mozina said:
If mainstream theory wasn't depending upon 96% metaphysics, your argument wouldn't ring so hollow from my perspective. Many branches of 'science" produce real tangible goods. I don't have to have a lot of 'faith' in electrical engineers. They produce real goods that come to market. They produce useful tangible goods that have a positive effect on my life. That's true of the field of chemistry too, and particle physics as well. Some branches of science are less productive than others.
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Now why does that argument sound familiar... Oh yes.
 
Tubbythin said:
Now why does that argument sound familiar... Oh yes.
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The problem with your argument is that GR theory is not now and never has been dependent upon any of your newly created invisible friends. :) Without them, I'm fine with GR theory. It's when you start stuffing make believe invisible buddies into those formulas that I cry foul.
 
Michael Mozina said:
The problem with your argument is that GR theory is not now and never has been dependent upon any of your newly created invisible friends. :)
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Newly created? Ignoring the petty name calling: the idea of dark matter predates most (all?) of the precision tests of GR.

Without them, I'm fine with GR theory. It's when you start stuffing make believe invisible buddies into those formulas that I cry foul.
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How is dark matter make believe? We know it exists and is made, every day, on Earth. We can make beams of it and send it from one side of the Earth to the other.
 
Dancing David said:
the 'point' breaks the models and in most likely not a point.
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And that is essentially the "point" that Alfven was talking about when he says that physicists of the past recognized that when formulas reached that stage it was recognized as a significant "problem" that was likely to be an incorrect answer. Today however it is essentially taken for granted.

The basic problem is pretty simple to demonstrate. Let's begin with a massively heavy object with a presumed event horizon with a given mass, a given spin and a given charge. There is no way for us to probe inside that event horizon, and no way to be certain that the mass contained inside that event horizon actually achieves an "infinite" density. It might get very close, but the mass may never actually achieve it. In that case, the mass inside the event horizon will take up a specific volume of spacetime, and be larger than a "point". It will have finite density and volume. How can you be sure anything ever achieves infinite density, or falls outside the manifold?
 
Michael Mozina said:
Then what is it a "point" of exactly since it certainly has mass?
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Dancing David said:
the 'point' breaks the models and in most likely not a point.
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What Dancing David said. Whether the singularity is a point of the spacetime manifold depends upon highly technical details of what it means to be a spacetime manifold. With the usual definitions, a singularity is not a point.

Hawking and Ellis, The Large-Scale Structure of Space-Time, §8.1, "The definition of singularities":
Hawking & Ellis said:
....Indeed, it would seem inappropriate to regard such singular points as being part of space-time, for the normal equations of physics would not hold at them and it would be impossible to make any measurements. We therefore defined space-time in §3.1 as a pair (M, g) where the metric g is Lorentzian and suitably differentiable...
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That's enough to prevent the singularities from being points of the spacetime manifold. I omitted the last part of their definition, which provides technical machinery for distinguishing between holes/boundaries that correspond to singularities from holes/boundaries that don't.

Wald, General Relativity, §9.1, "What is a Singularity?":
Wald said:
Thus, the "big bang" singularity of the Robertson-Walker solution is not considered to be part of the spacetime manifold; it is not a "place" or a "time." Similarly, only the region r > 0 is incorporated into the Schwarzschild spacetime; unlike the Coulomb solution in special relativity, the singularity at r = 0 is not a "place."
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Michael Mozina said:
In his (Alfvén's) mind, a "bang" (expansion) is certainly a logical possibility (I think he preferred it actually), but the notion of infinite density at a singular "point" was never an option in his mind and he resented the concept. I think even those of use that accept that "black holes" do exist (heavy objects with an event horizon) still have a difficult time accepting the concept of infinite density at a "point". That seems to be the crux of his beef with the whole singularity concept, not so much the idea of a heavy massive (very dense) object.
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If so, then both* of you guys can relax. In most modern formalizations of general relativity, there is no notion of infinite density at a singular point. That concept comes from popular accounts.

While we're at it, the mathematical notion of a manifold already assumes spacetime is infinitely divisible, which may be incompatible with quantum theory. According to Kip Thorne, "most physicists" expect the singularities to be "tamed" by a better theory of quantum gravity.

*Alfvén has already relaxed.
 
Tubbythin said:
Newly created?
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When did Guth dream up inflation? When was "dark energy" discovered? :)

Ignoring the petty name calling: the idea of dark matter predates most (all?) of the precision tests of GR.;
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The exotic non baryonic brands of dark matter are fairly new, or more accurately the exclusion of "normal" matter is relatively new. I hear that among it's other attributes, non baryonic matter is particularly tasty in the Spring. :)
 
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W.D.Clinger said:
What Dancing David said. Whether the singularity is a point of the spacetime manifold depends upon highly technical details of what it means to be a spacetime manifold. With the usual definitions, a singularity is not a point.
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It seems to be a question of whether or not all that mass achieves infinite density doesn't it? Yes? No?
 
Michael Mozina said:
It seems to be a question of whether or not all that mass achieves infinite density doesn't it? Yes? No?
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No.

In a previous post, which may no longer reside within the public portion of this forum, you said you were reviewing your calculus. The following calculus questions may help you to understand how and why modern definitions of spacetime eliminate exclude singularities from the spacetime manifold itself.

Suppose f(x)=1/x. Does 0 lie within the domain of f? If so, is f differentiable at 0? If so, then what is the derivative of f at 0?
 
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W.D.Clinger said:
No.

In a previous post, which may no longer reside within the public portion of this forum, you said you were reviewing your calculus. The following calculus questions may help you to understand how and why modern definitions of spacetime eliminate exclude singularities from the spacetime manifold itself.

Suppose f(x)=1/x. Does 0 lie within the domain of f? If so, is f differentiable at 0? If so, then what is the derivative of f at 0?
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What makes you think x actually reaches zero (metaphorically speaking)? In this case the limit could only reach a zero volume by achieving an infinite density.
 
W.D.Clinger said:
The following calculus questions may help you to understand how and why modern definitions of spacetime eliminate exclude singularities from the spacetime manifold itself.

Suppose f(x)=1/x. Does 0 lie within the domain of f? If so, is f differentiable at 0? If so, then what is the derivative of f at 0?
Click to expand...

Michael Mozina said:
What makes you think x actually reaches zero (metaphorically speaking)? In this case the limit could only reach a zero volume by achieving an infinite density.
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Had you answered my calculus questions, you'd have answered your own questions.

By avoiding my calculus questions, you have convinced me that you cannot answer them, from which I conclude that you are incapable of understanding the answers to your questions---which, by the way, I had answered previously within this very thread.
 
For r to ever reach zero, the mass must necessarily achieve infinite density. How do you know that's ever going to happen?
 
Michael Mozina,

In mathematics, a function is thought of associating every member of some set D with a member of another set C. D is called the domain of the function and C the codomain, and we often denote this fact by saying we have a function f: D -> C. If x is a member of D and y is the member of C that f associates with x, we denote this fact y=f(x). (This latter notation is probably what you're more familiar with.) If there is some superset of D, call it perhaps E, and s is a member of E and not D, then your function f: D -> C does not map s to anything since s is not in its domain.

The example W.D.Clinger gave you, f(x) = 1/x, was being presented as a function from the set of all non-zero real numbers to the set real numbers. i.e. the domain of this function is R\{0}.

The reason he gave for presenting the example is that some authors define a space-time manifold as the domain of the metric tensor. A space-time singularity is not in the metric tensor's domain, so would be excluded from the space-time manifold in this case.

Anyway, W.D.Clinger:

I'm an amateur when it comes to understanding GR, so I share Michael Mozina's ignorance when it comes to black holes' singularities. I know any matter that's beyond the event horizon but not at the singularity falls towards the singularity in a finite amount of time (at least from that matter's perspective: the time and radial coordinates getting their meanings mixed up has always confused me a bit). So I would be inclined to think that all the matter in a black hole is present at its singularity, which would thus have infinite density. What am I missing?
 
schrodingasdawg said:
The reason he gave for presenting the example is that some authors define a space-time manifold as the domain of the metric tensor. A space-time singularity is not in the metric tensor's domain, so would be excluded from the space-time manifold in this case.
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Yes. (I'd speak of the metric tensor field, but physicists often say "tensor" when they mean tensor field.)

schrodingasdawg said:
Anyway, W.D.Clinger:

I'm an amateur when it comes to understanding GR, so I share Michael Mozina's ignorance when it comes to black holes' singularities.
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I too am an amateur at GR. Although I come to it with professional training in the relevant mathematics, I'm kinda rusty. Several of the regulars here are real pros, however, and I'm confident someone will correct me if I get an important point too badly wrong.

schrodingasdawg said:
I know any matter that's beyond the event horizon but not at the singularity falls towards the singularity in a finite amount of time (at least from that matter's perspective: the time and radial coordinates getting their meanings mixed up has always confused me a bit). So I would be inclined to think that all the matter in a black hole is present at its singularity, which would thus have infinite density. What am I missing?
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You're free to think the black hole has infinite density at the singularity, but the theory of relativity doesn't actually say that. As formalized by professionals, general relativity says the singularity isn't part of the spacetime manifold. You're right about matter falling into the black hole taking only finite proper time to "reach" the singularity and leave the spacetime manifold. (That can't affect anything outside the event horizon, however, which led to the cosmic censorship hypothesisWP mentioned below.) General relativity says matter can go off the reservation.

That's a mathematical expression of humility, a highly technical admission of ignorance about what happens at the singularity. General relativity doesn't say what happens at the singularity because no one knows what happens at the singularity. What happens there, if indeed there is a "there" there, is beyond the scope of general relativity. For all we know, what happens at the singularity is also beyond the scope of all other established laws of physics.

That's important.

Some people, including Hannes Alfvén and Michael Mozina, have attacked general relativity by complaining about the non-sensicality of infinite density at the singularity. That's a bit of projection on their part, abetted by the popular accounts from which they learned about the singularities. They may think the density is infinite at the singularity, but that conclusion is theirs, not general relativity's.

What's more, some people get general relativity mixed up with big bang theory. Michael Mozina, for example, has stated on several occasions that he has no problem with general relativity (absent the cosmological constant, which he endorses when his personal heroes use it but dismisses as an invisible friend when anyone else refers to it). In this thread, however, he is clearly attacking general relativity. He may think he's attacking only the big bang, but the singularities appear to be an inescapable feature of general relativity as presently formulated, and it looks like there are more black holes in this universe than big bangs.

Are the singularities a problem for general relativity, and for physics in general? You betcha. The singularities are the kind of problem true scientists welcome: Here is something we do not understand, something that definitely lies beyond the reach of established theory.

I am not a physicist, so you shouldn't just take my word for that. Here are the words of Kip ThorneWP, from the epilogue to Black Holes & Time Warps: Einstein's Outrageous Legacy, Norton and Company, 1994:
  • We have met, in this book, Eddington's, Wheeler's, and even Einstein's vigorous skepticism about black holes; Eddington and Einstein died before they were firmly proved wrong, but Wheeler became a convert and black-hole advocate....
  • It was a horrendous shock to most physicists, and still is to many, to discover that the singularities are an inevitable consequence of Einstein's general relativistic laws. Some physicists derive comfort from faith in Penrose's cosmic censorship conjecture (that all singularities are clothed; naked singularities are forbidden). But whether cosmic censorship is wrong or right, most physicists have accomodated to singularities and, like Wheeler, expect the ill-understood laws of quantum gravity to tame them....
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These sentiments may be relevant to the thread on "Science is not a religion, but some scientists ARE religous about their science", but the moderators evidently believed this aspect of scientific belief was important enough to justify its own thread.
 
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W.D.Clinger said:
Are the singularities a problem for general relativity, and for physics in general? You betcha. The singularities are the kind of problem true scientists welcome: Here is something we do not understand, something that definitely lies beyond the reach of established theory.

I am not a physicist, so you shouldn't just take my word for that. Here are the words of Kip ThorneWP, from the epilogue to Black Holes & Time Warps: Einstein's Outrageous Legacy, Norton and Company, 1994:

These sentiments may be relevant to the thread on "Science is not a religion, but some scientists ARE religous about their science", but the moderators evidently believed this aspect of scientific belief was important enough to justify its own thread.
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Arent singularities a math theory problem, not a science problem?

The observations of radiation from a highly luminous object are "science" except you cant do an experiment to confirm your hypothesis.
There arent too many astronomers that go into the lab to perform experiments.

The laws of physics dont break down at a singularity, the mathematical description breaks down, assuming it really is a place where there is "alot of gravity" made by ultra dense matter.

Nature doesnt have a problem with existing.

Math has a problem describing the universe.
 
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Alfvén's Cosmology

brantc said:
Aren't singularities a math theory problem, not a science problem?
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No, singularities are both a math theory problem and a science problem. Mathematics expands & strengthens science by providing a logical & explanatory foundation that connects seemingly unconnected observations. Science expands & strengthens mathematics by providing a physical or empirical interpretation of mathematical equations. In this context, nothing meaningful is either purely mathematics or purely science, but rather everything is to some extent both mathematical & scientific.

The singularity is a math theory problem because the equations are literally undefined at the singularities. But they are also a science problem because there is nothing for science to interpret. So, either you need to find new equations that have no singularities and can thus be interpreted by science, or you need a scientific observation that proves the mathematical equations are wrong. In the absence of either of these, then you simply don't know what's happening, either mathematically or scientifically.

With that in mind, consider ...

brantc said:
Nature doesn't have a problem with existing. Math has a problem describing the universe.
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As a general rule, the 2nd sentence is absurd. Math has no problem describing the universe. In fact, quite the opposite is true. Mathematics is too successful at describing the universe for the point to be taken lightly; see, for instance, Max Tegmark's The Mathematical Universe & citations thereto, or Eugene Wigner's 1960 essay "The Unreasonable Effectiveness of Mathematics in the Natural Sciences" (Communications in Pure and Applied Mathematics 13(1): 1-14 (1960).

brantc said:
The observations of radiation from a highly luminous object are "science" except you cant do an experiment to confirm your hypothesis. There arent too many astronomers that go into the lab to perform experiments.
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This is quite misleading, and for the most part wrong. What is an "astronomer"? if by that you mean somebody who only looks through telescopes & etc., you are right. They don't personally do experiments in a laboratory because that's not the manner of science they do. But so what? Maybe you think that laboratory scientists and astronomers never talk to each other, never interact at any level? Astronomers use the Zeeman effect to derive magnetic fields from spectral line measurements. But the Zeeman effect is calibrated for them, in real laboratories by real physicists. Who cares that the astronomers themselves did not actually do the experiments? Astronomers look at highly luminous things like really bright stars and use those observations to derive physical properties (temperature, composition, mass & etc.). But they make use of extensive laboratory studies of nuclear astrophysics. So when astronomers tell you that stars are powered by nuclear reactions rather than electric currents, they have an extensive laboratory experience to support them. Does it really matter that nuclear physicists did the experiments, rather than the astronomers themselves? And so it goes down the line ... plasma physics, thermodynamics, radiative transfer physics, all subject to extensive laboratory experience, and all that experience is exported by the laboratory physicists and imported by the astronomers. Your suggestion that astronomy lacks laboratory support & confirmation is absurd.

brantc said:
The laws of physics don't break down at a singularity, the mathematical description breaks down, assuming it really is a place where there is "alot of gravity" made by ultra dense matter.
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This much is correct. We assume that the laws of physics exist independent of us, and therefore do not break down anywhere. But our understanding of the laws of physics most certainly does break down completely at the singularity. That's because, without being able to observe inside the event horizon of a black hole, we rely on the mathematics to provide us with something to physically interpret. With neither mathematics nor observation to interpret, we are left with nothing. The physical interpretation of the mathematical singularity as literally a point of infinite mass density is unreasonable, and exists only in popular level discussions to avoid complications. But if you look at the real science, nobody says that. Rather, everybody says the obvious, that we simply have no idea what physically happens at the singularity because it is a mathematical entity, not a physical entity. A quantum physical theory of gravity (string theory, loop quantum gravity & etc.) will allegedly provide equations which do not have singularities where the general relativistic equations do. That will in turn mean that we will have something mathematical for which we can then provide a physical interpretation, eliminating the physical (i.e., scientific) problem of the singularity.

Now with all that in mind, ...
W.D.Clinger said:
You're free to think the black hole has infinite density at the singularity, but the theory of relativity doesn't actually say that. ... Some people, including Hannes Alfvén and Michael Mozina, have attacked general relativity by complaining about the non-sensicality of infinite density at the singularity. That's a bit of projection on their part, abetted by the popular accounts from which they learned about the singularities. They may think the density is infinite at the singularity, but that conclusion is theirs, not general relativity's.
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W.D.Clinger is right on the money. Let me repeat myself ... "The physical interpretation of the mathematical singularity as literally a point of infinite mass density is unreasonable, and exists only in popular level discussions to avoid complications. But if you look at the real science, nobody says that. Rather, everybody says the obvious, that we simply have no idea what physically happens at the singularity because it is a mathematical entity, not a physical entity."
 
W.D.Clinger said:
You're free to think the black hole has infinite density at the singularity, but the theory of relativity doesn't actually say that. As formalized by professionals, general relativity says the singularity isn't part of the spacetime manifold.
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I have heard it argued that the Primordial Singularity probably did not violate the laws of physics (as we know them), because the laws of physics probably didn't even exist yet.

Not sure how correct this would be.
 
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smartcooky said:
I have heard it argued that the Primordial Singularity probably did not violate the laws of physics (as we know them), because the laws of physics probably didn't even exist yet.

Not sure how correct this would be.
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You can't be sure because that is pretty much a statement, arguably not even an argument, from ignorance. There simply is no basis for that conclusion at the moment.
 
smartcooky said:
Yeah, this was accidental... I was referencing this part of the quoted post in another thread...

http://www.internationalskeptics.com/forums/showthread.php?p=13776797&highlight=Alfven#post13776797

...and got my tabs confused. I didn't catch the mistake until after the edit time had expired.
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Well worth the effort, though, as it alerted me to yet another excellent post by Tim Thompson!

Problem with Alfven's cosmology is that cosmology was not his forte, and he was writing decades ago. In hindsight, it is obvious nonsense. He actually qualified in electrical engineering. However, his influence on plasma physics is undeniable. Hence the Nobel.
When he teamed up with Oscar Klein, and proposed his matter-anti-matter universe, he was cracking on a bit. He had been left behind. Even in plasma physics. His contributions to that subject cannot be denied. They are on the same level as Biermann and Parker. Modern plasma (astro)physicists know more than Alfven could ever have known about the subject. Ask Tusenfem. What he got right is kept. What he got wrong is discarded. He speculated. Sometimes he was right, sometimes he was wrong. Such is science.
 
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