Magnetic PerseusA galaxy

Dancing David

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Dancing David
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http://www.sciencedaily.com/releases/2008/08/080820162958.htm
It is an active galaxy, hosting a supermassive black hole at its core, which blows bubbles of radio-wave emitting material into the surrounding cluster gas. Its most spectacular feature is the lacy filigree of gaseous filaments reaching out beyond the galaxy into the multi-million degree X-ray emitting gas that fills the cluster.

These filaments are the only visible-light manifestation of the intricate relationship between the central black hole and the surrounding cluster gas. They provide important clues about how giant black holes affect their surrounding environment.
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http://hubblesite.org/newscenter/archive/releases/2008/28/
 
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Since the word 'magnetic' is in the title, I'm guessing that this somehow shows that Big Bang theory is a bunch of crap.
 
A good 'old news, new news' story.

'AGN blows bubbles in a cluster' could be the heading of this 2005 Chandra PR, marking a milestone in a story that's at least a decade older; note that this is the same Perseus A galaxy at the heart of the Perseus cluster.

It does take decades, but slowly the details of the various processes in play are uncovered and understood.
 
Third Eye Open said:
Since the word 'magnetic' is in the title, I'm guessing that this somehow shows that Big Bang theory is a bunch of crap.
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So rather than follow a link to read an eight-paragraph story that has nothing to do with Big Bang theory, you would rather engage in speculation based on a single word in a thread title.
 
Very interesting pictures by Chandra and HST.
The HST image is newish BVr and the Chandra x-ray image is older.
If you scale and superimpose the 2 images, well , draw your own conclusions.
 
Ladewig said:
So rather than follow a link to read an eight-paragraph story that has nothing to do with Big Bang theory, you would rather engage in speculation based on a single word in a thread title.
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Just trying to beat Zeuzzz and BeAChooser to the punch.
 
Its nice to see the usual fallacy of attributing the plasma filaments to being merely gas, or rather magic "gaseous filaments". Some editors will never learn :rolleyes:

Weird this, theres a couple of people on this forum that persist in claimng that "no galactic sized filaments exist in the universe". And some people also persist in claiming that magnetic fields can not have any effect on large scale structure. The Journal of Nature now seems to disagree with you. And they nearly get the terminology right at nature, calling it an "ionized gas", which is getting closer to just saying plasma. I suppose it depends whether you are referring to the constituents of the plasma on an individual basis, which individually are still considered by most 'gas molecules', or whether your referring to the larger structure the molecules take on, which indicates plasma.

Just out today:

http://www.nature.com/nature/journal/v454/n7207/edsumm/e080821-06.html
Editor's Summary

21 August 2008
Galactic filaments: survival in a hostile environment

Images from the Hubble Space Telescope reveal remarkable detail in the bright filaments of ionized gas that stream out from the giant elliptical galaxy NGC 1275 at the centre of the Perseus galaxy cluster. How these filaments have remained stable — they are thought to be at least 108 years old — despite the disruptive effects of tidal shear forces and extremely hot (4times107 K) surrounding gases has been unclear. The Hubble images now resolve thread-like structures within the filaments. These may indicate the presence of magnetic fields in pressure balance with the surrounding gas, capable of stabilizing the filaments and allowing the accumulation of a large mass of cold gas that could have delayed star formation.
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I'm pretty sure he means 10^8, not 108 :)



Associated papers for this story: (need subsciption :( )

Giant galaxy's filamentous structure is held stable by magnetic fields.

Bright streams of gas fan out from NGC 1275 — the giant elliptical galaxy at the centre of the Perseus constellation — making it look a bit like a supersized space jellyfish. These filaments are thought to be around 100 million years old, and although they appear static, they are buffeted by the extreme pressure and heat of the gases that surround them.
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Letter: Magnetic support of the optical emission line filaments in NGC 1275

The giant elliptical galaxy NGC 1275, at the centre of the Perseus cluster, is surrounded by a well-known giant nebulosity of emission-line filaments1, 2, which are plausibly in excess of 108 years old. The filaments are dragged out from the centre of the galaxy by radio-emitting 'bubbles' rising buoyantly in the hot intracluster gas, before later falling back. They act as markers of the feedback process by which energy is transferred from the central massive black hole to the surrounding gas. The mechanism by which the filaments are stabilized against tidal shear and dissipation into the surrounding extremely hot (4 times 107 K) gas has been unclear. Here we report observations that resolve thread-like structures in the filaments. Some threads extend over 6 kpc, yet are only 70 pc wide. We conclude that magnetic fields in the threads, in pressure balance with the surrounding gas, stabilize the filaments, so allowing a large mass of cold gas to accumulate and delay star formation.
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"Magnetic support" of filaments on that big a scale??? Someone get Sol, nature is publishing woo :D

And can anyone explain to me what the physics of plasma 'bubbles' are? I see this term used a lot, but have never been quite sure what it physically means.

Large scale filaments are hard (if not impossible) to explain with gravity alone anyway. And this observation has forced them to abandon the usual dark matter explanation for filamentary structures in the universe, and use EM forces in plasma. Lets hope this continues.



I had seen the other observations of similar enigmas to this around alleged SMBH candidates, but not with filaments this big. Ah, here it is:

http://hubblesite.org/newscenter/archive/releases/2005/26/full/
Astronomers using NASA's Hubble Space Telescope have identified the source of a mysterious blue light surrounding a supermassive black hole in our neighboring Andromeda Galaxy (M31). Though the light has puzzled astronomers for more than a decade, the new discovery makes the story even more mysterious.

The blue light is coming from a disk of hot, young stars. These stars are whipping around the black hole in much the same way as planets in our solar system are revolving around the Sun. Astronomers are perplexed about how the pancake-shaped disk of stars could form so close to a giant black hole. In such a hostile environment, the black hole's tidal forces should tear matter apart, making it difficult for gas and dust to collapse and form stars.[...]
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(sorry, cant find the associated science paper for that one)
 
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Third Eye Open said:
Just trying to beat Zeuzzz and BeAChooser to the punch.
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By six minutes. Close call. :)

(This story would have nothing to do with the Big Bang. Funnily enough, only observations that contradict the Big Bang serve as evidence aganst the Big Bang)
 
Another very detailed page about NGC 1275 put up today by the Institute of Astronomy X-Ray Group . Loads of pictures and stuff, and links to all the stories about this on other websites.

Magnetic mystery of NGC 1275 revealed

figure_1_thumb.jpg


"Images of the filaments where the smooth light from the galaxy has been subtracted away. The centre of the galaxy hosts a giant supermassive black hole, which blows bubbles of hot gas, dragging the filaments out behind them. "
 
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Zeuzzz said:
And some people also persist in claiming that magnetic fields can not have any effect on large scale structure.
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Really? On galaxy-scale filaments? Who?

And they nearly get the terminology right at nature, calling it an "ionized gas", which is getting closer to just saying plasma.
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Your obsession with terminology is bizarre. "Ionized gas" is a specific and perfectly accurate description of what the observations show. "Plasma" is more specific and might or might not be correct in this case.

Someone get Sol, nature is publishing woo
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Really?!? Where?
 
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There seems to be dispute over the methods by which the filaments become ionized. It is either from Photoionization by the ICM (The hot ICM surrounding NGC 1275 can be the ionization source of the filaments if its energy is channeled efficiently into the nebulosity) electron conduction by the ICM, Ionization by an AGN, ionization from shocks, Magnetic Reconnection, Diffuse Extreme Ultraviolet Radiation, Attenuated Cluster Radiation, and more. Seems like the problem is not that there are no mechanisms that can cuase the ionization, but too many to choose from.

this paper http://arxiv.org/abs/astro-ph?papernum=0007359 looks at all the possibilites. And comes to the conclusion that: None of these models is entirely satisfactory in accounting for the energetic and/or emission-line properties of the filaments. Radio studies of Faraday rotation for cooling-flow galaxies provide tantalizing suggestions that magnetic reconnection plays a significant role in the filament energetics.

And since magnetic reconnection can not happen, I think this adds strong evidence that a double layer is formed due to current disruptions (the approximate equivalent to MR in Ej plasma approach) in the AGN, which is what's causing the ionisation as the ions are accelerated.

also relevant:

http://arxiv.org/PS_cache/astro-ph/pdf/0007/0007359v1.pdf
Early studies of the large-scale nebular morphology of NGC 1275 interpreted this object and its system of radial filaments as the result of a large-scale outflow; indeed, it was called an “exploding galaxy” (Burbidge & Burbidge 1965). [....] Stars may nonetheless play a role in powering the filaments if they generate a radiation field that ionizes gas on scales exceeding that of localized H II regions. A similar scenario has recently gained favor for explaining the ionization of the diffuse ionized gas (DIG) commonly seen in spiral galaxies
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sol invictus said:
Really? On galaxy-scale filaments? Who?
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Thats certainly the impression you give, ie, 36 magnitudes of order weaker, "completely negligable", "uttely ridiculous", blah blah. On bodies with tiny charge to mass ratios's, correct, but not everything in the universe has the mass to charge ratio of stars and planets. Especially when considering the initial nebulae they all formed from.


Really?!? Where?
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"The Hubble Space Telescope has found the answer to a long-standing puzzle by resolving giant but delicate filaments shaped by a strong magnetic field around the active galaxy NGC 1275. [....] The amount of gas contained in a typical thread is around one million times the mass of our own Sun. They are only 200 light-years wide, are often surprisingly straight, and extend for up to 20 000 light-years." (link)

Solution:

Giant galaxy's filamentous structure is held stable by magnetic fields.

Magnetic support of the optical emission line filaments in NGC 1275

Here we report observations that resolve thread-like structures in the filaments. Some threads extend over 6 kpc, yet are only 70 pc wide. We conclude that magnetic fields in the threads, in pressure balance with the surrounding gas, stabilize the filaments, so allowing a large mass of cold gas to accumulate and delay star formation.
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Now what do you think your reaction would have been if I had said that EM forces are responsible for the struture of a 20 000 light-year long object? I can guess: 36 magnitudes of order weaker, "completely negligable", "uttely ridiculous", blah blah.

But now I suppose your gonna say that theres nothing wrong with it in this situation :rolleyes:
 
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Hi Zeuzzz: Of course magnetic forces and gravity are responsible for the filaments. You did read the OP and the linked articles?
It is an active galaxy, hosting a supermassive black hole at its core, which blows bubbles of radio-wave emitting material into the surrounding cluster gas. Its most spectacular feature is the lacy filigree of gaseous filaments reaching out beyond the galaxy into the multi-million degree X-ray emitting gas that fills the cluster.

These filaments are the only visible-light manifestation of the intricate relationship between the central black hole and the surrounding cluster gas. They provide important clues about how giant black holes affect their surrounding environment.
Click to expand...
The "gaseous filaments" are created from the interaction of the black hole with the galaxy (gravity) and maintain their shape with their interaction with extragalactic magnetic fields (EM forces).
Astronomers are smart enough to realize there are places where EM forces dominate gravitational forces, e.g. plasmas contained in strong magnetic fields as in NGC 1275. They also know that such large scale domination is relatively rare. Millions of galaxies have been imaged and there are a small percentage with large scale plasma features (jets, filaments, etc.).
 
Zeuzzz said:
Its nice to see the usual fallacy of attributing the plasma filaments to being merely gas, or rather magic "gaseous filaments". Some editors will never learn :rolleyes:
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Neither do some peeps here on the board. As a plasma obays the gas law, only with a slightly different adiabatic constant gamma in the equation (5/3 for "normal gas" and 4/3 for "plasma gas" if I am not mistaken):

P Vgamma = constant

it is perfectly fine to call a plasma a gas. (and don't forget NOT every ionized gas is automatically a plasma, there are 3 characteristics that the ionized gas has to fulfill)

We also have to take into account that plasma does not mean frag to the larger part of the unedumacated masses.

Plasma, that is what you donate at the blood bank, izzend it?
 
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Zeuzzz said:
And since magnetic reconnection can not happen, I think this adds strong evidence that a double layer is formed due to current disruptions (the approximate equivalent to MR in Ej plasma approach) in the AGN, which is what's causing the ionisation as the ions are accelerated.
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Really, reconnection cannot happen? Do you have any proof for that?
And please give us the description of current disruption re-organization of the magnetic field topology.
Don't forget that in the Earth's magnetotail we have a enormous amount of observations of magnetic field and plasma that all totally agree with the model of magnetic reconnection. I would love to see your explanation.

And how do you figure out that last part about the (imfamous) double layer? The DL causes the ionization because it accelerates the ions? But ........ how did the ions become ions before they are accelerated? Ah, the got ionized by .... acceleration by the DL?? but .... a DL can only accelerate ions and not neutrals, so ............

And, did you not start a magnetic reconnection thread?
 
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Zeuzzz said:
Thats certainly the impression you give, ie, 36 magnitudes of order weaker, "completely negligable", "uttely ridiculous", blah blah.
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That's the impression I give? That might be the impression you got, but I can hardly be held responsible for your misunderstandings, can I?

On bodies with tiny charge to mass ratios's, correct, but not everything in the universe has the mass to charge ratio of stars and planets. Especially when considering the initial nebulae they all formed from.
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Actually these gas clouds probably have a similar (i.e. very small) charge/mass ratio as stars. It's not that ratio that makes them susceptible to magnetic field effects. This has been explained to you countless times before; I'm not going to waste my time try again.

"The Hubble Space Telescope...
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So? You're saying you think that's woo? It looks fine to me.

But now I suppose your gonna say that theres nothing wrong with it in this situation :rolleyes:
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I haven't checked the numbers, but it would be easy to do so. If you have the B field strength on the appropriate scale and some numbers describing the ionized gas, you can just check whether or not its reasonable for the field to strongly affect the structure of the filament. Just as we already checked what would be necessary for B fields could affect stars.
 
Zeuzzz said:
[...]

"Magnetic support" of filaments on that big a scale??? Someone get Sol, nature is publishing woo :D

And can anyone explain to me what the physics of plasma 'bubbles' are? I see this term used a lot, but have never been quite sure what it physically means.

Large scale filaments are hard (if not impossible) to explain with gravity alone anyway.

[...]
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Hmm ...

As sol said, this has been explained to you before, more than once - would you be kind enough to tell all readers of this thread why you so persistently and consistently ignore those explanations?

And somewhat OT, what do you think the defining characteristics of an internet troll are?
 
tusenfem said:
Really, reconnection cannot happen? Do you have any proof for that?
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He used to think it violated Gauss's law for magnetic fields. We've tried to pound it into his thick skull at length in past threads, even giving him equations for fields which exhibit reconnection and don't violate Gauss's law, but apparently he still clings to his delusions. Perhaps he's changed his rationalization, but his delusion remains comfortably intact.
 
Ziggurat said:
He used to think it violated Gauss's law for magnetic fields. We've tried to pound it into his thick skull at length in past threads, even giving him equations for fields which exhibit reconnection and don't violate Gauss's law, but apparently he still clings to his delusions. Perhaps he's changed his rationalization, but his delusion remains comfortably intact.
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You misrepresentation of my position is quite startling. And the field you showed didn't show magnetic reconnection. No plasma. No magnetic tension. No MHD terms. It was just a neutral point. I started a thread all about this, so you can stop misrepresenting my position and answer my questions about MR there: http://www.internationalskeptics.com/forums/showthread.php?t=120782
 
Zeuzzz said:
Please continue this converstaion in the appropriate thread http://www.internationalskeptics.com/forums/showthread.php?t=120782, and explain your reasoning. Just saying 'wrong' is not very helpful to anyone.
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There's nothing else to say, zeuzzz. We've been over this again and again and again and again and again and again. You've been told countless times the reasons for what I said above and you still haven't learned, or you've forgotten, or you're lying now. In any of those cases, why should I tell you for an nth time?

Why don't you compute the current for the field configuration Zig and I gave you? If you can do it you will have exhibited some (very basic) level of knowledge of E&M, and you will also have addressed all of your confusions. OK?
 
sol invictus said:
There's nothing else to say, zeuzzz. We've been over this again and again and again and again and again and again. You've been told countless times the reasons for what I said above and you still haven't learned, or you've forgotten, or you're lying now. In any of those cases, why should I tell you for an nth time?

Why don't you compute the current for the field configuration Zig and I gave you? If you can do it you will have exhibited some (very basic) level of knowledge of E&M, and you will also have addressed all of your confusions. OK?
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I cant remember the exact configuration you used to be frank, and if I remember correctly you didn't state any magnitudes of the B-fields involved anyway. So I wouldn't be able to calculate the current from that anyway. Post it again or quote it if you feel the need.
 
Zeuzzz said:
I cant remember the exact configuration you used to be frank, and if I remember correctly you didn't state any magnitudes of the B-fields involved anyway. So I wouldn't be able to calculate the current from that anyway. Post it again or quote it if you feel the need.
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You don't remember it, after all the times it was posted and discussed? And you're too lazy to find it for yourself? You want me to do it for you?

:dl:
 
OK, what the hell - why give you the excuse?

It's [latex]$\vec B = a~x~\hat y + b~y~\hat x$[/latex]. The notation is standard.

For computing the current you can assume a and b are constant or that they depend on time, as you wish.
 
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Zeuzzz said:
I cant remember the exact configuration you used to be frank, and if I remember correctly you didn't state any magnitudes of the B-fields involved anyway. So I wouldn't be able to calculate the current from that anyway. Post it again or quote it if you feel the need.
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I envy you Sol, must be good for someone to hand you their ass on a plate. :D
 
sol invictus said:
You don't remember it, after all the times it was posted and discussed? And you're too lazy to find it for yourself? You want me to do it for you?

:dl:
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It's called stone-walling.

How pathetic. Zeuzzz wants to be taken seriously by the physicists on this board, yet he either cannot or refuses to do simple calculations that clearly show the error of his thinking.

C'mon Zeuzzz, for someone who is so into "plasma physics", a simple set of calculations involving Maxwell's equations shouldn't be too challenging for you. Heck, Sol even got you started (again) :rolleyes:
 
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Zeuzzz said:
By six minutes. Close call. :)

(This story would have nothing to do with the Big Bang. Funnily enough, only observations that contradict the Big Bang serve as evidence aganst the Big Bang)
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Okay, I'll bite. Just what exactly are these supposed "observations" which contradict the Big Bang Cosmology (BBC)?

I should note for the lurkers that this is old hat. Zeuzzz is a classic pseudo-scientist - he doesn't understand the physics of electromagnetism and plasma (as Sol is pointing out) yet he continues to act as if he does; he also is (for some reason) ideologically opposed to the BBC and wishes to promote "Plasma Cosmology" (PC); so he makes statements that there is "evidence against the BBC" which there isn't.

Classic pseudo-scientific tactic - start with the false premise that there is evidence against the BBC, refuse to justify the statement, and assume that by default PC is correct. It's the same tactic employed when creationists attempt to criticize evolution and imply that by default ID/creationism is correct, without justifying their claims either way.

Now wait for Zeuzzz to bleat on and on about how he isn't a creationist, we're being mean and nasty skeptics with closed minds, blah blah blah...

... and he still won't have figured out how to do basic physics with Maxwell's equations.


 
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MattusMaximus said:
Okay, I'll bite. Just what exactly are these supposed "observations" which contradict the Big Bang Cosmology (BBC)?
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There is a mass of evidence against the Big Bang. Current cosmological theory rests on a disturbingly small number of independent observations. People in the field just pass them off as inconsiquential issues to be resolved in the future, until we finally know everything about the universe and we can all go home to bed with our beautiful mathematical theories and live happily ever after. The history of science tells us something quite different, theories rise and fall as time progresses. I personally see these inconsiquential issues as glaring issues, as I prefer a PC approach to cosmology. Its called having an opinion. Live with it.


To name a few:

1) Light Element Abundances predict contradictory densities, the chance that the theory is right is now less than one in one hundred trillion.

2) Large-scale Voids are too old, given the observed velocities these voids must have taken at least 70 billion years to form, five times as long as the theorized time since the Big Bang.

3) Surface brightness has been shown many times now to be constant, the Big Bang expanding universe predicts that surface brightness decreases as (z+1)-3. More distant objects actually should appear bigger. But observations show that in fact the surface brightness of galaxies up to a redshift of 6 are exactly constant, as predicted by a non-expanding universe

4) The Big Bang theory requires THREE hypothetical entities--the inflation field, non-baryonic (dark) matter and the dark energy field to overcome contradictions of theory and observation.

5) The hypothetical dark energy field violates one of the best-tested laws of physics--the conservation of energy and matter, since the field produces energy at a titanic rate out of nothingness. To toss aside this basic conservation law in order to preserve the Big Bang theory is something that would never be acceptable in any other field of physics.

6) The Alignment of CBR with the Local Supercluster. The largest angular scale components of the fluctuations(anisotropy) of the CBR are not random, but have a strong preferred orientation in the sky. The quadrupole and octopole power is concentrated on a ring around the sky and are essentially zero along a preferred axis. The direction of this axis is identical with the direction toward the Virgo cluster and lies exactly along the axis of the Local Supercluster filament of which our Galaxy is a part. This contradicts the Big Bang assumption that the CBR originated far from the local Supercluster and is, on the largest scale, isotropic without a preferred direction in space.

7) It has been shown, by Richard Lieu and others, that the Sunyaev-Zeldovich effect is much less than was expected, implying that the CBR originated between us and the clusters, not beyond them. They found that not only was the SZ effect less than expected, it tended to disappear as the redshift of the clusters studied went from 0.1 to 0.3, implying that most of the CBR come from redshifts less than 0.3.

8) Luca Casagrande et al have shown that old main sequence stars have much less helium than Big Bang nucleosynthesis predicts. Since He-4 is produced by stars, they should have more helium, not less, than the Big Bang predictions.

9) Conventional cosmology hypothesizes that the universe, on a large scale, is isotropic. Yet this year, evidence has shown large-scale anisotropies in measurements other than that of the CBR. Michael J. Longo showed that spiral galaxies tend to spiral more in one direction than another, possibly implying a large scale magnetic field in region some 350 Mpc across.

10) At all points in its history the Big Bang model has had more independent adjustable parameters than observable data points, giving it almost no powers of prediction, the key characteristic of scientific theories. For exmaple, The currently fashionable LCDM model of cosmology has 18 parameters, 17 of which are independent. Thirteen of these parameters are well fitted to the observational data; the other four remain floating. This situation is very far from healthy.

11) The idea of Big Bang just makes no logical sense.

BBC is not one single theory; it is more like 5 separate theories piled ontop of one another. The base is general relativity, used to explain redshifts, ie, expansion, which luckily also accounts for the CMB. The next pillar is Inflation, needed to solve the horizon and 'flatness' problems. The third is the Dark Matter hypothesis requiored to explain galaxies and clusters, which otherwise would never be created from the expanding fireball. The fourth is some kind of description for the 'seeds' from which they all have to grow. The fifth and topmost floor is the mysterious Dark Energy, needed to allow for the acceleration of cosmic expansion. Dark Energy could be falsified, leaving the rest of the building intact. But if for example the expansion floor collapsed, everything else would come down with it. Everything is precariously balanced on top of each other. Some would argue that the foundations have already been removed, and the whole structure is doomed now anyway. But never fret, there will always be some new hypothetical dark construct to hold it up no doubt.


I should note for the lurkers that this is old hat. Zeuzzz is a classic pseudo-scientist - he doesn't understand the physics of electromagnetism and plasma (as Sol is pointing out) yet he continues to act as if he does; he also is (for some reason) ideologically opposed to the BBC and wishes to promote "Plasma Cosmology" (PC); so he makes statements that there is "evidence against the BBC" which there isn't.
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See above. And I suggest taking your head out of your *** long enough to read just one single plasma cosmology publication that compares the predictions PC has made and compares them with the predictions of the Big Bang, in the areas of element abundances, the CMB, Large Scale Structure of the universe and other aspects. In its proper context you can see it here at the peer reviewed IEEE Transactions on Plasma Science: http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1265349 or if you dont have access rights to IEEE documents like I do you can see it at this link: http://www.bigbangneverhappened.org/p27.htm


... and he still won't have figured out how to do basic physics with Maxwell's equations.
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Sols question makes absolutely no sense (come on, I thought you at least would have pointed this out by now?) Current is flux through some given surface. You could use [latex]\nabla \times \mathbf{B}[/latex] to give you the current density, but unless the surface is specified, that's all you can ever get from the magnetic configuration he supplied. You certainy cant work out the current like he asked me to do. Its a trick question, and shows very poor form.


Classic pseudo-scientific tactic - start with the false premise that there is evidence against the BBC, refuse to justify the statement, and assume that by default PC is correct. It's the same tactic employed when creationists attempt to criticize evolution and imply that by default ID/creationism is correct, without justifying their claims either way.
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I justified it above. All this talk of the Big Bang theory being unquestionably correct I find rather amuzing. Given statements emanating from some cosmologists today one could be forgiven for assuming that the solution to some of the great problems of the subject, even 'the origin of the Universe' lie just around the corner. See the following conclusion from Hu et al. to a preview of the results they expect from spacecraft such as MAP and PLANCK designed to map the CMB: "we will establish the cosmological model as securely as the Standard Model of elementary particles. We will then know as much, or even more, about the early Universe and its contents as we do about the fundamental constituents of matter"

Such statements are naive in the extreme and betray a complete lack of understanding of history, of the huge difference between an observational and an experimental science, and of the peculiar limitations of cosmology as a scientific discipline.

Shouldn’t instead scientists be saying something like this to the general public:

“It is not likely that we primates gazing through bits of glass for a century or two will dissemble the architecture and history of infinity. But if we don’t try we won’t get anywhere. Therefore we professionals do the best we can to fit the odd clues we have into some kind of plausible story. That is how science works, and that is the spirit in which our cosmological speculations should be treated. Don’t be impressed by our complex machines or our arcane mathematics. They have been used to build plausible cosmic stories before - which we had to discard afterwards in the face of improving evidence. The likelihood must be that such revisions will have to occur again and again and again.”
 
Zeuzzz said:
Sols question makes absolutely no sense (come on, I thought you at least would have pointed this out by now?) Current is flux through some given surface. You could use [latex]\nabla \times \mathbf{B}[/latex] to give you the current density, but unless the surface is specified, that's all you can ever get from the magnetic configuration he supplied. You certainy cant work out the current like he asked me to do. Its a trick question, and shows very poor form.
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Well, this clearly shows you have no knowledge whatsoever about electrodynamics and plasma physics. Total current is basically NEVER important (unless you want to pay your electricity bill). Current density, however, is fraggin' basic to electrodynamics and plasma physics.

Git yousself a eddumacation, Zeuzzz

And by the way peeps, keep this thread to the OP and not BBC again (although they do produce Dr. Who and Torchwood).
 
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Nice of you to copy someone else's work wholesale and not reference it Zeuzzz. How many times have you been told what bad form this is?
 
tusenfem said:
Well, this clearly shows you have no knowledge whatsoever about electrodynamics and plasma physics. Total current is basically NEVER important (unless you want to pay your electricity bill). Current density, however, is fraggin' basic to electrodynamics and plasma physics.

Git yousself a eddumacation, Zeuzzz

And by the way peeps, keep this thread to the OP and not BBC again (although they do produce Dr. Who and Torchwood).
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If any person with the slightest knowledge of physics was asked the question that sol did above they wouldn't have a clue what he's on about. Sol didn't mention any plasma physics. If someone is asking for current density, they should say this. I'm not a mind reader. By doing [latex]\vec{\nabla} x \vec{B}[/latex] you can get the current density (and it's a pretty simple answer) but you have to have a defined loop to get the current. The current density can tell you some important things about the current itself, but Sol did not ask for the current density. So its a misleading question.

And someone else brought up the Big Bang, in the second post and in latter posts. I merely responded.

Edit: What the hell is up with latex on this forum? I type in " \vec{\nabla}x\vec{B} " and it just comes up as [latex]{\vec{\nabla}}x{\vec{B}}[/latex] :confused:
 
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Zeuzzz said:
If any person with the slightest knowledge of physics was asked the question that sol did above they wouldn't have a clue what he's on about. Sol didn't mention any plasma physics. If someone is asking for current density, they should say this. I'm not a mind reader. By doing [latex]\vec{\nabla} x \vec{B}[/latex] you can get the current density (and it's a pretty simple answer) but you have to have a defined loop to get the current. The current density can tell you some important things about the current itself, but Sol did not ask for the current density. So its a misleading question.
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Whatever! If you have the current density you also have the current, so you are just pulling your heels here and confusing stuff. curl of B will give you the current density and therefore give the currents that are flowing. How the currents close in this system is another question, and you have to give the whole picture, which is not in the animation that you have shown. You have to show the current(density, for simplicity current) in the neutral sheet, you have to show the Hall currents and the field aligned currents that close the Hall currents etc. But the whole circuit (e.g. that the field aligned currents, in the Earth's tail, close through the ionosphere etc.) is secondary.

Zeuzzz said:
And someone else brought up the Big Bang, in the second post and in latter posts. I merely responded.
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Peeps is plural I did not specifically target you.

Then, I still have an open question from my second post

tusenfem said:
Really, reconnection cannot happen? Do you have any proof for that?
And please give us the description of current disruption re-organization of the magnetic field topology.
Don't forget that in the Earth's magnetotail we have a enormous amount of observations of magnetic field and plasma that all totally agree with the model of magnetic reconnection. I would love to see your explanation.

And how do you figure out that last part about the (imfamous) double layer? The DL causes the ionization because it accelerates the ions? But ........ how did the ions become ions before they are accelerated? Ah, the got ionized by .... acceleration by the DL?? but .... a DL can only accelerate ions and not neutrals, so ............
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And what I forgot here is that current disruption IS NOT the Ej equivalent of reconnection in the Bv paradigm, they are very separate processes.
 
Zeuzzz said:
If any person with the slightest knowledge of physics was asked the question that sol did above they wouldn't have a clue what he's on about.
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Actually there are at least four posting in this thread, and they all knew exactly what the question meant.

Sol didn't mention any plasma physics.
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Dear me...

Zeuzzz said:
And the field you showed didn't show magnetic reconnection. No plasma.
sol invictus said:
Wrong
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You managed to forget what we were talking about in the space between those two posts? Impressive...

The current density can tell you some important things about the current itself, but Sol did not ask for the current density. So its a misleading question.
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Nonsense. The current density tells you everything - you can use it to compute the current through any surface. Moreover, we were discussing your claims about this field!!

Now - compute the current density (or the current through any surface you choose) if you can. It's completely trivial - I can do it in my head in seconds (I'm not exaggerating - it's really trivial).
 
Zeuzzz said:
By doing [latex]$\vec{\nabla} \times \vec{B}$[/latex] you can get the current density (and it's a pretty simple answer) but you have to have a defined loop to get the current.
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No. You get the current by defining a surface, not a loop. And given how simple the answer for the current density is (have you managed to actually calculate it yet?), I think it should have been pretty obvious that this was what Sol was after. Hell, you could even give the answer for the current as a function of any arbitrary surface in a VERY compact form, that's how simple the answer is.

Edit: What the hell is up with latex on this forum? I type in " \vec{\nabla}x\vec{B} " and it just comes up as [latex]{\vec{\nabla}}x{\vec{B}}[/latex] :confused:
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You need to include '$' before and after your math expressions. And using 'x' just gives you the letter, not the cross product symbol. I fixed it above, using '$\vec{\nabla} \times \vec{B}$'
 
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