Dark Matter
Re: dark matter
Well, if it passes through walls, it has to pass through balance plates just as well.Michael Mozina wrote:If it's five times more abundant than the dirt in backyard, why can't you folks manage to provide us with a gram of the stuff, or a single controlled experiment that shows it has some effect on matter?
There are quite a few dark matter particle detectors around the world - XENON, for example.
The problem facing all those who would try to detect such particles is guessing what (interaction, collision) cross-sections are likely to be sufficiently large to enable detectors to have a reasonable chance of finding any DM particles (oh, and filtering out the non-DM background).
At least one astronomical DM particle search has been done, by one of the INTEGRAL teams. They looked for gamma ray signatures of some possible SUSY (super-symmetry) particle decays in the MW bulge, but didn't find anything unambiguous.
It's both a frustrating and fascinating challenge for particle physicists - we know the Standard Model (SM) is incomplete, there are many proposed extensions (all of the useful ones of which are consistent with the SM), there is a vast unexplored territory (in terms of particle masses)*, and so on, but the parameter space for experimentalists and observers to explore is huge.
Why? One reason is that astronomers cannot place any significant constraints on the nature of any DM particles ... other than that they are 'cold', and that decays and collisions are either rare, or produce only other dark particles (such as neutrinos), or both.
*One snapshot: the highest energy cosmic rays detected to date have energies nine orders of magnitude higher than the best we can do with our puny particle accelerators here on Earth ... yes, that's a billion times more energetic. In this regard it's worth remembering that there are only ~3 OOM between the electron and proton.
The problem facing all those who would try to detect such particles is guessing what (interaction, collision) cross-sections are likely to be sufficiently large to enable detectors to have a reasonable chance of finding any DM particles (oh, and filtering out the non-DM background).
At least one astronomical DM particle search has been done, by one of the INTEGRAL teams. They looked for gamma ray signatures of some possible SUSY (super-symmetry) particle decays in the MW bulge, but didn't find anything unambiguous.
It's both a frustrating and fascinating challenge for particle physicists - we know the Standard Model (SM) is incomplete, there are many proposed extensions (all of the useful ones of which are consistent with the SM), there is a vast unexplored territory (in terms of particle masses)*, and so on, but the parameter space for experimentalists and observers to explore is huge.
Why? One reason is that astronomers cannot place any significant constraints on the nature of any DM particles ... other than that they are 'cold', and that decays and collisions are either rare, or produce only other dark particles (such as neutrinos), or both.
*One snapshot: the highest energy cosmic rays detected to date have energies nine orders of magnitude higher than the best we can do with our puny particle accelerators here on Earth ... yes, that's a billion times more energetic. In this regard it's worth remembering that there are only ~3 OOM between the electron and proton.
Perhaps you could read the technical literature on this subject?Michael Mozina wrote:Nereid wrote:There are quite a few dark matter particle detectors around the world - XENON, for example.XENON plans to probe the lowest SUSY parameter space, with a sensitivity of 1 event/100 kg/year.So if I'm understanding this plan, a single event in a year is all we can expect to observe from this 'detector' when it's built? How do they actually rule out any false hits?The experience gained through this development effort, and the prior years of R&D on noble liquid detectors, give us the confidence that a 100 kg TPC optimized for dark matter detection can be built successfully.
It takes us a rather long way from astonomy (these searches are of great interest to astronomers, but are designed, built, and results analysed, by particle physicists).
You might find it fruitful to spend some time learning a bit more about the Standard Model, Michael; there's a great deal more to it than just the Higgs ... neutrino oscillations, for one.If nothing is found at this particular energy state, will that falsify dark matter, or is this an endless cat and mouse thing?
I don't see how you intend to filter out the non-dark matter background from a single hit per year.The problem facing all those who would try to detect such particles is guessing what (interaction, collision) cross-sections are likely to be sufficiently large to enable detectors to have a reasonable chance of finding any DM particles (oh, and filtering out the non-DM background).
So since there is no defined energy state to look at (unlike neutrinos) there is no way to falsify the theory, correct?At least one astronomical DM particle search has been done, by one of the INTEGRAL teams. They looked for gamma ray signatures of some possible SUSY (super-symmetry) particle decays in the MW bulge, but didn't find anything unambiguous.
Particularly since you can't identify the energy state we should expect to find them at. It's more or less any impossible problem.It's both a frustrating and fascinating challenge for particle physicists
Technically it's only incomplete as it relates to the Higgs Boson, and compared to your experiment, they are light years ahead of where dark matter detection seems to be today.- we know the Standard Model (SM) is incomplete,
The experimental hint that I, personally, am most excited about is the ~2 (or was it 3?) sigma difference between the latest and best g-2 experimental result and the theoretical prediction ... there may be a way to probe energies impossibly large (in terms of anything we'll ever do with earthly accelerators) this way ...
Hmm, more grist for the 'mis-understanding of modern science' mill.This is all too convenient from my perspective. Since you cannot identify it's energy state, there is no way to falsify anything. If nothing is found at one energy state, you are then justified in trying another energy state, and another and another and so on. There is no way to actually falsify a Gumby theory, and this is certainly a Gumby theory. It can be stretched and twisted into any lepton description and any energy state description as well. There is no way to kill it.there are many proposed extensions (all of the useful ones of which are consistent with the SM), there is a vast unexplored territory (in terms of particle masses)*, and so on, but the parameter space for experimentalists and observers to explore is huge.
There is absolutely no way to falsify such a concept then and it therefore does not qualify as 'science" anymore. Since you refuse to be pinned down to a single energy state, or a specific lepton configuration, there isn't any way to know that we've looked at every energy state and therefore there is no way to falsify this theory in any conceivable way.Why? One reason is that astronomers cannot place any significant constraints on the nature of any DM particles ... other than that they are 'cold', and that decays and collisions are either rare, or produce only other dark particles (such as neutrinos), or both.
If by 'falsify' you are referring to Popper's naive falsificationism, then:
a) you are definitely in the wrong forum - astronomy obviously doesn't work like that (and never has)
b) even Popper only used it for illustrative purposes.
If you mean something else, then please take it up in a separate thread, where we may discuss it for a short while. Also, you'd be much better off exploring the nature of modern science, and the extent to which Popper's views on falsificationism provide an adequate - or even useful - framework for judging scientific theories, elsewhere (I can suggest some philosophy of science fora for you, if you'd like).
Something to add: each negative detection, in a particular region of parameter space, helps constrain the nature of DM particles*.
The role of 'negative detections' can be difficult to appreciate, especially as they are almost never reported in the popular press.
Take a very significant, early, discovery from the Hubble Space Telescope (HST): the non-detection of red dwarfs in a small region of parameter space (it's one of John Bahcall's papers; I'll dig it up if anyone is interested; it's classic Bahcall).
Prior to the first HST observations, a century or so's work, by several generations of astronomers, had characterised the nature of the 'dark matter halo' of our Milky Way galaxy (the quote marks are a 'tipping of the hat' to folk like Michael, and also to Milgrom, and many others). A very much open question at the time was whether much, or most, of this DM could be in the form of red dwarf stars**.
The HST's negative result (no stars were found within the small window of parameter space; what was found turned out to be extremely interesting!) was but one more piece of solid evidence that baryonic matter cannot account for more than a trivial fraction of the halo mass of spiral galaxies (our MW galaxy, in this case).
I have a sneaking suspicion that folk who tilt at mainstream astronomy windmills are quite unaware of most, perhaps nearly all, of these negative detections. That's a pity; if any alternative idea is ever developed to the point of being quantitative, these rather obscure negative detection papers will surely be dusted off, and rather pointed questions indeed asked about consistency with good observational (and experimental) results.
*If they exist. If 'DM' turns out to be a phenomenological aspect of a non-GR theory of gravity (for example), then there would have been no such particles anyway.
**Subsequently, research programmes such as OGLE and MACHO, esp MACHO, corroborated - and extended - the HST result, but that was, then, in the future ...
The role of 'negative detections' can be difficult to appreciate, especially as they are almost never reported in the popular press.
Take a very significant, early, discovery from the Hubble Space Telescope (HST): the non-detection of red dwarfs in a small region of parameter space (it's one of John Bahcall's papers; I'll dig it up if anyone is interested; it's classic Bahcall).
Prior to the first HST observations, a century or so's work, by several generations of astronomers, had characterised the nature of the 'dark matter halo' of our Milky Way galaxy (the quote marks are a 'tipping of the hat' to folk like Michael, and also to Milgrom, and many others). A very much open question at the time was whether much, or most, of this DM could be in the form of red dwarf stars**.
The HST's negative result (no stars were found within the small window of parameter space; what was found turned out to be extremely interesting!) was but one more piece of solid evidence that baryonic matter cannot account for more than a trivial fraction of the halo mass of spiral galaxies (our MW galaxy, in this case).
I have a sneaking suspicion that folk who tilt at mainstream astronomy windmills are quite unaware of most, perhaps nearly all, of these negative detections. That's a pity; if any alternative idea is ever developed to the point of being quantitative, these rather obscure negative detection papers will surely be dusted off, and rather pointed questions indeed asked about consistency with good observational (and experimental) results.
*If they exist. If 'DM' turns out to be a phenomenological aspect of a non-GR theory of gravity (for example), then there would have been no such particles anyway.
**Subsequently, research programmes such as OGLE and MACHO, esp MACHO, corroborated - and extended - the HST result, but that was, then, in the future ...
*Sigh!*
Modern scientific theories, of relevance to us here in this astronomy discussion forum, begin with postulates (a.k.a. premises).
These have, in and of themselves, no intrinsic scientific value, or even meaning.
From these postulates, anyone can derive logical conclusions.
Some of these conclusions are predictions, in that they should match what you can observe, with a telescope, etc.
That's the logical structure of modern astronomical (as a science) theories.
To the extent that the observations match the predictions (conclusions), the theory is validated.
However, all theories are provisional ... unlike the days of old, modern physics is both more tentative (no theory is absolute) and more certain (the match between theory and experiment and observation is far greater).
So it is with dark matter.
Wrt "heavy solar systems": where are the papers describing the postulates? displaying the logic that leads to observational predictions? that shows the quantitative match between these logically derived predictions and the relevant good observational results (in this case, rich cluster gravitational lensing, x-ray observations of rich clusters, and line of sight velocity dispersions of component galaxies in those rich clusters)?
If you can write such papers, then this idea of yours may get serious airtime; until then ...
One more time ...Michael Mozina wrote:I love that disclaimer! You aren't even sure if we're looking for particles, or some phenomenological aspect of something else altogether! This kind of completely undefined "could-be-this-or-that" sort of item could never hope to be falsified in any of our lifetimes. We could have a hundred failed detections, and there would always be something else to consider, except of course heavy solar systems which you have personally ruled out, and we cannot even discuss any further. Mind you, it's perfectly acceptable for you to handwave in a "non-GR theory" as a possible option, but somehow you've ruled out heavy solar systems.Nereid wrote:*If they exist. If 'DM' turns out to be a phenomenological aspect of a non-GR theory of gravity (for example), then there would have been no such particles anyway.
Go figure.
Modern scientific theories, of relevance to us here in this astronomy discussion forum, begin with postulates (a.k.a. premises).
These have, in and of themselves, no intrinsic scientific value, or even meaning.
From these postulates, anyone can derive logical conclusions.
Some of these conclusions are predictions, in that they should match what you can observe, with a telescope, etc.
That's the logical structure of modern astronomical (as a science) theories.
To the extent that the observations match the predictions (conclusions), the theory is validated.
However, all theories are provisional ... unlike the days of old, modern physics is both more tentative (no theory is absolute) and more certain (the match between theory and experiment and observation is far greater).
So it is with dark matter.
Wrt "heavy solar systems": where are the papers describing the postulates? displaying the logic that leads to observational predictions? that shows the quantitative match between these logically derived predictions and the relevant good observational results (in this case, rich cluster gravitational lensing, x-ray observations of rich clusters, and line of sight velocity dispersions of component galaxies in those rich clusters)?
If you can write such papers, then this idea of yours may get serious airtime; until then ...
It is obvious that you, personally, don't like the way modern science, as used in astronomy, works.Michael Mozina wrote:[snip]
You are welcome to look into your telescope and make predictions about any known forces of nature. You are not welcome to look into that telescope and imagine new forces of nature that no one on earth has ever observed and no one on earth could ever hope to falsify.Some of these conclusions are predictions, in that they should match what you can observe, with a telescope, etc.
So be it.
I guess one hope I had was that you would at least acquire an understanding of what constitutes science, in modern astronomy, even though it very much grates with your personal feelings.
This last part of your post that I have quoted suggests that my hope has not been realised.
Let's work this example through ...Imagine for a moment that Birkeland had looked that aurora, and claimed "dark energy did it". Would that actually have had any scientific value at all, and if dark energy in that instance can be replaced with "electrical flow", then how do you know your "dark energy" of astronomy isn't an EM effect too?That's the logical structure of modern astronomical (as a science) theories.
First, "dark energy did it" is useless ... by itself, just as "electrical flow", by itself, would also be useless ...
What (I imagine) Birkeland did was develop, logically, a hypothesis or three, and show that they lead to conclusions which match the observations. He would, I imagine, also have carefully checked his logic (for consistency) and checked his ideas against the well-established theories of his day (Maxwell's equations, for example), and showed consistency.
That, greatly oversimplified, is a summary of the structure of a theory paper.
An 'observation' paper starts at the other end: here are the observations, and here's how well they match with (previously published) predictions/derivations from {some theory}.
Of course, the actual process by which Birkeland came to write his papers was almost certainly unlike the above ... the historical development of an idea (before it gets written up as a paper) and the logical structure of a well-developed theory do not necessarily line up.
As to "how do you know your "dark energy" of astronomy isn't an EM effect too?": the parts of my post you didn't quote point the way ...
a) because no one (yet) has put together an internally consistent, consistent with relevant well-established theories where domains of applicability overlap, and (above all) consistent with the totality of good observational results case for "an EM effect"
b) if someone does actually do that, then a "dark energy is an EM effect" theory will be taken quite seriously.
No ... your 'invisible potato theory' would, indeed, be validated ...By your logic if I slap you math related to dark matter to my invisible potato theory, my invisible potato theory is validated by the same observations as your dark matter. See the problem?To the extent that the observations match the predictions (conclusions), the theory is validated.
Of course, I suspect that you would encounter quite a few tricky problems betwixt postulate and conclusion ... don't forget there's more than one criterion.
If that is, truly, how you feel - or what your personal belief system informs you - then:Michael Mozina wrote:I'm fine with modern sciences Nereid. I'm not as fine with the way astronomers of today actually practice "science". Astronomers today seem to think it's just fine to invent metaphysically undefined forces that have never been empirically demonstrated and that cannot ever be falsified.Nereid wrote:It is obvious that you, personally, don't like the way modern science, as used in astronomy, works.
a) I guess you won't be posting here much longer; and
b) any astronomical papers you, alone, write may well make for fascinating case studies by philosophers of science.
We've pretty much covered this, in the other Cafe thread; I'll not comment further here (as it relates to a much broader topic than just DM).You don't personally get to define "science" Nereid, and astronomers as a whole group don't get to define science. You seem to want to skip the whole "testing" process of science altogether, and you have your own concept of a "test" that has no control mechanism of any sort!I guess one hope I had was that you would at least acquire an understanding of what constitutes science, in modern astronomy, even though it very much grates with your personal feelings.
Not. You've only so identified if you state the extent to which "electrical flow" is consistent with, for example, Maxwell's equations.That's not a test of invisible potatoes or dark matter Nereid, that's an observation that you interpret to be invisible potatoes, er "dark matter".
We agree so far.First, "dark energy did it" is useless ...
It would have been equally useless with a bucketful of math too.by itself,
That is a false statement. I have *identified a known force of nature as the possible culprit*.just as "electrical flow", by itself, would also be useless ...
The postulate, in and of itself, does not establish any connection with any other theory, "known force of nature", and so on.
It may seem that this is pedantic; however, as the example I wrote about - in the other thread ('GR vs Newtonian gravity') should make clear, it is a logical fallacy to impute to the postulates themselves quite separate physical theories.
You do?!?!?!?!?!?I have created a theory that can be tested and falsified. I have a concept I can test in my lab.
In which lab, on Earth, have you reproduced the aurorae?
Specifically, which lab contains a plasma of {density exactly the same as that in aurorae} and {physical size exactly the same as that of aurorae}?
So you say.I may no know how the math works, but I may still be able to build experiments to simulate an aurora, or a coronal loop. Birkeland did exactly that based on the fact he identified the *known force of nature* that was involved in the aurora.
When you tell me which labs, here on Earth, reproduce aurorae and coronal loops, in terms of all physical parameters, then I might start to take your claims seriously (within the framework of science as you yourself have defined it).
He did?The moment he understood the actual cause of the phenomenon, he could design equipment to test his theory, with or without any understanding of the math involved in these processes.
Yes, and he *checked* his logic by building controlled experiments and by changing the variables individually to see their effects on his experiments. He *controlled* the variables.What (I imagine) Birkeland did was develop, logically, a hypothesis or three, and show that they lead to conclusions which match the observations. He would, I imagine, also have carefully checked his logic (for consistency) and checked his ideas against the well-established theories of his day (Maxwell's equations, for example), and showed consistency.
How big was the stage within which he performed these "controlled experiments"?
Indeed.[snip]There you go insisting you have to be right, and my explanations must jive with yours to be right. That is purely an assumption on your part, and an arbitrary need on your part. It's also not scientific in that you cannot *assume* that the correct answer must jive with well established theory. In essence you're requirement *insists* that the well-established theories are true, and must be proven true, when in fact they may be proven false.a) because no one (yet) has put together an internally consistent, consistent with relevant well-established theories
It may well be that this statement can serve as the most succinct summary of your misunderstanding of modern astronomy, as a science.
When you write a paper on accounting for the many sets of independent, good observational results re rich clusters (that are consistent with papers accounting for these observations in terms of DM), and have it up on the arXiv preprint server, please let us know.
I thought we were discussing, in this thread, dark matter?Let's start with the million degree corona. There's a very obvious and noticeable effect of EM fields in our solar system. Care to explain how you get million degree temps on top of a 6K photosphere without EM fields?where domains of applicability overlap, and (above all) consistent with the totality of good observational results case for "an EM effect"
AFAIK, there is no relationship, in any published astronomy (astrophysics, cosmology) papers, between the coronal temperatures of the Sun and DM.
Indeed.There is no such thing as DE, so I can't take DE seriously until a real force of nature is identified.b) if someone does actually do that, then a "dark energy is an EM effect" theory will be taken quite seriously.
So you have stated, a great many times.
However, even a casual reading of the published papers, in astronomy (etc) may lead one to the conclusion that your personal feelings are not shared by astronomers, cosmologists, ...
(and what does DE have to do with DM anyway?)
OK ... make my day ...Why would that matter? I can pull things out of my back pocket just as easily as you can, especially if I never have to empirically demonstrate any of it.No ... your 'invisible potato theory' would, indeed, be validated ...By your logic if I slap you(r) math related to dark matter to my invisible potato theory, my invisible potato theory is validated by the same observations as your dark matter. See the problem?
Of course, I suspect that you would encounter quite a few tricky problems betwixt postulate and conclusion ... don't forget there's more than one criterion.
Please present even an order of magnitude case showing the consistency between an 'invisible potato' idea and the relevant sets (three of them) of independent observations. Be sure to include in your case a) demonstration of internal consistency, and b) demonstration of consistency with the relevant, well-establish theories whose domains of applicability overlap with your 'invisible potato' idea.
DARK MATTER
The above was quoted from the New Scientist Website.
We know they are heavy, but how exactly do you weigh a black hole? The usual way to estimate the mass of black holes orbiting stars is to look at how the star wobbles under the influence of the black hole's motion. But this method is imprecise, says Nikolai Shaposhnikov, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Instead, Shaposhnikov and Lev Titarchuk, at George Mason University in Fairfax, Virginia, thought about the disc of material ripped from the companion star that forms around such black holes. As more matter falls in, the inner part of the disc becomes congested, "like when five lines of traffic have to merge into one", Shaposhnikov says. This clogged material oscillates, producing X-ray pulses at a rate that is related to the black hole's mass, he says.
The pair measured such pulses using NASA's Rossi X-ray Timing Explorer (RXTE) satellite and found the black hole Cygnus X-1 has 8.7 times the mass of our sun - reducing the estimated error of previous measurements tenfold. The work will appear in The Astrophysical Journal.
The point being that if the error(size not given) is reduced tenfold, how many other measurements of the distant items in the universe have similar errors, and are all calculations assuming the same degree of accuracy. The above article does not state how much the figure they got differs from accepted figures but:
http://www.astro.uiuc.edu/~kaler/sow/cygx1.html
does state that Cygnus X-1 has a mass of 40 stellars plus or minus 10.
This is a massive change in mass, so one must wonder about the accuracy of both the former and the latter. Before anyone goes to any great expense to discover Dark Matter I think that some recalculating has to be done. This includes starting right here on earth, for there are changes still happening in the figures derived for the mass of the earth.
But if the figure for the mass of Cynus X-1 as recently measured is accurate and ONE star is found to be out by almost 500% then the whole subject of Dark Matter is akin to the child's tale of the king and his new clothes.
It's been bugging me for quite some time, but I think I've found a vital clue!
That his view of science has only a passing resemblence to modern science (as used in astronomy, today) is clear; what I've been wondering, for quite a while, is where these views come from ...
Here's the key, and under my nose all the time!
Let's get some dates:
Kristian Birkeland (December 13, 1867 - June 15, 1917)
Birkeland's The Norwegian Aurora Polaris Expedition: 1902-03
The Thompson atom: 1897
The Rutherford atom: 1911
Plank's quantum theory: 1901 (but highly theoretical; I doubt that Birkeland read it then)
Einstein's key quantum theory paper: 1905
Fleshing out of quantum mechanism, resolution of the dilemmas in classical electromagnetism (i.e. where Maxwell's equations fail, and how to fully address this): ~1920s.
Problem solved: Michael Mozina's science seems to have its roots in the classical physics of the 19th century ... while some gloss from the quantum (and, earlier, relativity) revolution seems to have been absorbed, the basics have not been updated ...
No wonder communication has been so difficult!
At the time Birkeland was working on his terrella and observing aurorae, Thompson's 'plum pudding' atom was shown, by Rutherford, to be wrong. That in turn created a deep crisis: classical electromagnetism required that atoms comprised of electrons orbiting positively charged nuclei decay in a burst of radiation in tiny fractions of a second. A 'new force of nature' was required, one that was not properly worked out until after Birkeland's death.
And what is this 'new force of nature' - quantum mechanics - if not 'metaphysical'? And if not 'metaphysical', surely it is quintessentially mathematical?
This is, of course, the kind of thing Michael Mozina has been saying for quite some time.Michael Mozina wrote:I'm fine with modern sciences Nereid. I'm not as fine with the way astronomers of today actually practice "science". Astronomers today seem to think it's just fine to invent metaphysically undefined forces that have never been empirically demonstrated and that cannot ever be falsified.Nereid wrote:It is obvious that you, personally, don't like the way modern science, as used in astronomy, works.
That his view of science has only a passing resemblence to modern science (as used in astronomy, today) is clear; what I've been wondering, for quite a while, is where these views come from ...
You don't personally get to define "science" Nereid, and astronomers as a whole group don't get to define science. You seem to want to skip the whole "testing" process of science altogether, and you have your own concept of a "test" that has no control mechanism of any sort!I guess one hope I had was that you would at least acquire an understanding of what constitutes science, in modern astronomy, even though it very much grates with your personal feelings.
[snip]
That is a false statement. I have *identified a known force of nature as the possible culprit*. I have created a theory that can be tested and falsified. I have a concept I can test in my lab. I may no know how the math works, but I may still be able to build experiments to simulate an aurora, or a coronal loop. Birkeland did exactly that based on the fact he identified the *known force of nature* that was involved in the aurora.
The moment he understood the actual cause of the phenomenon, he could design equipment to test his theory, with or without any understanding of the math involved in these processes.
Here's the key, and under my nose all the time!
![Shocked :shock:](./images/smilies/icon_eek.gif)
![Surprised :o](./images/smilies/icon_surprised.gif)
Let's get some dates:
Kristian Birkeland (December 13, 1867 - June 15, 1917)
Birkeland's The Norwegian Aurora Polaris Expedition: 1902-03
The Thompson atom: 1897
The Rutherford atom: 1911
Plank's quantum theory: 1901 (but highly theoretical; I doubt that Birkeland read it then)
Einstein's key quantum theory paper: 1905
Fleshing out of quantum mechanism, resolution of the dilemmas in classical electromagnetism (i.e. where Maxwell's equations fail, and how to fully address this): ~1920s.
Problem solved: Michael Mozina's science seems to have its roots in the classical physics of the 19th century ... while some gloss from the quantum (and, earlier, relativity) revolution seems to have been absorbed, the basics have not been updated ...
No wonder communication has been so difficult!
In light of the relevant historical dates, the irony in this part of Michael's post is rich indeed![snip]
Ya, it starts at the other end alright. It *assumes* the validity of the idea, and does the math to support the assumption. Never once has anyone bothered to experiment in any lab with any quantity of [snip]Birkeland didn't propose new forces of nature to explain nature. He proposed a known force of nature to explain nature. You are using metaphysics to explain nature, so of course there is no real comparison between these two approaches.Of course, the actual process by which Birkeland came to write his papers was almost certainly unlike the above ... the historical development of an idea (before it gets written up as a paper) and the logical structure of a well-developed theory do not necessarily line up.
[snip]
At the time Birkeland was working on his terrella and observing aurorae, Thompson's 'plum pudding' atom was shown, by Rutherford, to be wrong. That in turn created a deep crisis: classical electromagnetism required that atoms comprised of electrons orbiting positively charged nuclei decay in a burst of radiation in tiny fractions of a second. A 'new force of nature' was required, one that was not properly worked out until after Birkeland's death.
And what is this 'new force of nature' - quantum mechanics - if not 'metaphysical'? And if not 'metaphysical', surely it is quintessentially mathematical?
Re: DARK MATTER
rodly wrote:The above was quoted from the New Scientist Website.
We know they are heavy, but how exactly do you weigh a black hole? The usual way to estimate the mass of black holes orbiting stars is to look at how the star wobbles under the influence of the black hole's motion. But this method is imprecise, says Nikolai Shaposhnikov, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Instead, Shaposhnikov and Lev Titarchuk, at George Mason University in Fairfax, Virginia, thought about the disc of material ripped from the companion star that forms around such black holes. As more matter falls in, the inner part of the disc becomes congested, "like when five lines of traffic have to merge into one", Shaposhnikov says. This clogged material oscillates, producing X-ray pulses at a rate that is related to the black hole's mass, he says.
The pair measured such pulses using NASA's Rossi X-ray Timing Explorer (RXTE) satellite and found the black hole Cygnus X-1 has 8.7 times the mass of our sun - reducing the estimated error of previous measurements tenfold. The work will appear in The Astrophysical Journal.
The point being that if the error(size not given) is reduced tenfold,
About 5 minutes of work on the internet is sufficient to get some hard numbers ...
First, the Shaposhnikov and Lev Titarchuk preprint includes the following:
Second, the estimate for the Cyg X-1 BH depends upon the estimated mass of a different BH in another x-ray binary (GRO J1655).For the mass of the BH in Cyg X-1 we have:
MCygX-1 = [...] (8.7 +/-0.8)Msol
[...] This inferred value of Cyg X-1 BH mass is slightly lower than 10 Msol given by Herrero et al. (1995) (with no error bars quoted) and it is within the mass range found by Gies & Bolton (1986).
Actually, if you read that page a little more carefully, you'll see that this estimate refers to the bright O supergiant in the Cyg X-1 binary, not the (invisible) BH.how many other measurements of the distant items in the universe have similar errors, and are all calculations assuming the same degree of accuracy. The above article does not state how much the figure they got differs from accepted figures but:
http://www.astro.uiuc.edu/~kaler/sow/cygx1.html
does state that Cygnus X-1 has a mass of 40 stellars plus or minus 10.
So, if instead of relying on press releases, you turn to the actual papers (and note that the Shaposhnikov and Titarchuk one is still only a preprint), you could find the answers to your own questions ... and learn that what you wrote in the post I am quoting contains a number of, shall we say, errors.
So, now that it's clear there is no such "massive change in mass", what leg has your assertion got left to stand on?This is a massive change in mass, so one must wonder about the accuracy of both the former and the latter. Before anyone goes to any great expense to discover Dark Matter I think that some recalculating has to be done.
Here's a suggestion: check out the calculations of the estimated mass of DM, in rich clusters, from the three, independent methods I have mentioned. Run the numbers through your own calculator or spreadsheet. Pore over the published methods. Poke into the nooks and crannies of the physics behind the estimates.
And so on.
In short, don't just leap to conclusions that may be comforting to whatever beliefs you may (or may not) have; go outside, open a horse's mouth, and actually count the teeth!
Can you provide some references please?This includes starting right here on earth, for there are changes still happening in the figures derived for the mass of the earth.
I'd like to look into this some more.
And "if the figure for the mass of Cynus X-1 as recently measured is accurate and ONE star is found to be out by almost 500%" NOT then what child's tale follows, logically?But if the figure for the mass of Cynus X-1 as recently measured is accurate and ONE star is found to be out by almost 500% then the whole subject of Dark Matter is akin to the child's tale of the king and his new clothes.
We've been over this, and over it, and over it, and over it, and ...Michael Mozina wrote:http://www.cosmologystatement.org/Nereid wrote:If that is, truly, how you feel - or what your personal belief system informs you - then:Michael Mozina wrote: I'm fine with modern sciences Nereid. I'm not as fine with the way astronomers of today actually practice "science". Astronomers today seem to think it's just fine to invent metaphysically undefined forces that have never been empirically demonstrated and that cannot ever be falsified.
a) I guess you won't be posting here much longer;
Does that statement mean that you intend to ban me soon because I refuse to agree with you personally about the existence of dark energy, dark matter and inflation?
You can believe whatever you wish ... no one, least of all me, denies you your beliefs.
However, as this is a scientific forum, and as it is now very clear that your ideas of what science is, and what modern astronomers actually do, are incongruent, I don't see why you'd even want to keep posting here.
Specifically, wrt this thread on dark matter, you have nothing to offer in terms of an alternative, scientific, explanation of the relevant astronomical observations.
Of course. Any number of those whose papers are, directly or indirectly, cited in APODs may be among those who have a tough time with these ideas.You do realize that a lot of "scientists' also have a tough time with these ideas don't you?
[snip]
But what does that have to do with your inability (or, if you prefer, continued failure) to present an alternative, scientific explanation of the relevant astronomical observations?
We have been over this before too, and over it, and over, and over, and ...I don't believe that I am asking for anything I wouldn't ask of any branch of science. All I am requesting of you is that you provide empirical evidence to support your positions on these specific topics. Is the fact that you can't provide any such support in a controlled scientific test somehow my fault personally?
[snip]
First, this is a forum about (modern) astronomy, as a science.
Second, even within your own, freely expressed, views on astronomy, you concede the impossibility of what you are asking for (take me to an earthly lab where controlled experiments are being done on systems of ~1 billion masses, each of mass ~10^(30+/-2) kg, to use just one example).
(there's more, but it would be needless repetition).
Once more, this is a scientific forum, devoted to astronomy.The one thing I have always appreciated about this forum is that it has followed a freedom of speech policy to the letter. It would be a pity to see it become something less tolerant of skeptical viewpoints only because of it's discomfort over public dissent. In no way would that serve anyones interest over the long haul IMO.
The way astronomy, as a science, is done today is pretty easy to describe (the role of theories, the criteria for testing the validity of theories; the primacy of good observations; papers published in the relevant, peer-reviewed literature as the vehicle; etc).
Questions are always welcome; answers are expected to be from within the mainstream of modern astronomy*. If you think you have a viable alternative (to some accepted, modern astronomical work), then please make sure you can cite relevant papers published in relevant peer-reviewed journals to back up your ideas ... before you present them.
*This is merely a shorthand summary; there is a separate thread devoted to this topic.
So, in two weeks' time, when you're back, how about we have you present a viable alternative explanation for the millions of relevant, high quality astronomical observations?harry wrote:Hello All
I'm still moving office and home,,,,,,,,,,and project.
Be back in 2 weeks
I see Neried still unable to understand the status of today and science.
I would advice Neried to research more and and understand the readings.
The ones that are consistent with the modern astronomical 'dark matter'.
To be sure, your presentation will be a quantitative, scientific one, backed by references to papers published in relevant, peer-reviewed journals.
What to you say harry (oops, I mean hrary)?
Nereid,
Do these aforementioned "Relavent, peer reviewed Journals" publish papers which present views tangent to modern accepted theories WRT BBT, Dark Matter, etc.? Or does the peer review process "weed out" the alternate viewpoint papers?
It would seem to me that you might be asking the impossible of Michael and others to reference theory papers that peer review Journals will not publish.
In your view, to which peer reviewed journals should they turn to find the data needed to qualify as acceptable references?
Sorry about the laymens questions but I am curious.
Do these aforementioned "Relavent, peer reviewed Journals" publish papers which present views tangent to modern accepted theories WRT BBT, Dark Matter, etc.? Or does the peer review process "weed out" the alternate viewpoint papers?
It would seem to me that you might be asking the impossible of Michael and others to reference theory papers that peer review Journals will not publish.
In your view, to which peer reviewed journals should they turn to find the data needed to qualify as acceptable references?
Sorry about the laymens questions but I am curious.
BMAONE23 wrote:Nereid,
Do these aforementioned "Relavent, peer reviewed Journals" publish papers which present views tangent to modern accepted theories WRT BBT, Dark Matter, etc.? Or does the peer review process "weed out" the alternate viewpoint papers?
One search on ADS, using "MOND" as a keyword, shows 25 papers with "2007" as the year.
Of these, 14 apparently have already been published, in ApJ, AJ, MNRAS, PhRvL (Physics Review Letters, cosmo_uk should have included those in his list; there are several under the heading "Physics Review"), Ap&SS (ditto?), and A&A. The rest are preprints, on arXiv*.
Halton Arp has 405 entries in ADS; from 2000 on, he has, apparently, 13 papers in the journals cosmo_uk lists, plus several conference proceedings, and journals such as PASP. Of course, he was not the sole author of all these papers!
I chose these two examples because a) they are most certainly 'alternative', and b) insofaras they relate to dark matter, they would fail Michael's 'metaphysics' or 'new force of nature' or 'controlled lab experiments' test far more dramatically than the current consensus on CDM!
Re "weeding out": if anything, I think the editors of certain journals are too permissive. For example, reading some of Arp's published papers, you have to wonder whether the reviewers were sleeping, or that the editors were being deliberately lenient. More generally, journals' editorial and submission policies are clearly stated. Further, as nothing (AFAIK) is ever removed from arXiv (the link takes you to the astro-ph section), it should be straight-forward, if somewhat tedious, to check the extent to which journals are 'weeding out'. I'm not aware of any serious claims that any such 'weeding out' takes place, in astronomy.
There are, indeed, thousands of 'theory papers' that ApJ, MNRAS, A&A, AJ, PhRv, etc will not publish.It would seem to me that you might be asking the impossible of Michael and others to reference theory papers that peer review Journals will not publish.
However, surely the only serious question is whether the decisions to not publish have anything whatsoever to do with the 'alternative' nature of the theories being presented?
In this regard, you can do your own research (see above); my personal view is that 'alternative theory' papers which meet certain minimum standards can, and do, get published. What standards? In addition to the consistency criteria I might have mentioned once or twice, they include things like having references that are accurate and relevant, not leaving out highly pertinent material that's already published, and (of course) adhering to the publication's layout, language, etc templates and guidelines.
Please don't apologise!In your view, to which peer reviewed journals should they turn to find the data needed to qualify as acceptable references?
Sorry about the laymens questions but I am curious.
Questions are always welcome.
*One has already been accepted, and all but 6 have been submitted to the likes of MNRAS, ApJ, and PhRv; 2 are conference proceedings, leaving just 4 not yet submitted. The time from appearing on arXiv to publication varies considerably, from mere weeks (or even days) to months or even years.