Dark matter and Dark energy

[sol invictus]

I sometimes wonder whether or not dark matter and dark energy -- indeed, perhaps the Big Bang itself -- are just artificial constructs we've created to try to explain how the universe works, when in fact the reality (if such a thing exists) is simply too complex for our insufficiently evolved minds to grasp. Just as an ant can't be taught calculus no matter how hard you try, humans may not be able to understand how the universe actually operates, because what we observe will always appear too varied and contradictory to yield itself to something as limited as the human brain. To put it bluntly, I wonder if we're simply too stupid to figure it out.

One thing to remember is that we evolved in this universe, and therefore our brains are relatively well-suited for understanding the rules it operates by (which appear to be formal logic and mathematics). The computer you are using is good evidence we've succeeded pretty well so far, and the methods of science and logic have so far shown no signs of ceasing to be useful.

Still, I'm uneasy whenever we need to invoke the exotic to explain something. I think one of the greatest leaps in human understanding occurred when Hutton stared at a cliff of exposed strata, and understood it wasn't the result of strange, fantastic processes and events that occured long ago and don't happen anymore. Instead, he realized that this was the handiwork of everyday processes that are occurring now -- slow but inexorable.

Dark matter is not necessarily anything exotic. We can only directly see things that glow, like stars. We can infer the existence of other things (like dust clouds) by how they absorb the light from stars, even when we can't see them directly. And we can infer the existence of dark matter, and something about its properties, from the way galaxies orbit and rotate, and independently from several other sets of observations. And as of this last year, we have seen dark matter directly via gravitational lensing around a particular galaxy cluster. That's as direct an observation as noticing there's some water ina glass from the way its surface refracts light, even though the water is transparent. I think the case is closed on the existence of DM - it's there, and it only remains to find out precisely what it is.

As for dark energy, perhaps some history is in order. When Einstein discovered general relativity (GR), he noticed that one of the only ways his theory could be extended was by adding a constant - the so-called "cosmological constant" (CC). It's hard to explain why, but GR is a very tight mathematical structure, and the CC is one of the only things you can add, and it's simply one single number (one parameter). That single parameter suffices to explain dark energy - it's all you need, although its numerical value is mysteriously small.

That's why I'm concerned when we have to devise things like dark matter and dark energy, entities for which we have no tangible proof, that exist somewhere Out There, untouchable and unobservable except theoretically and indirectly. And not only do we postulate that it exists, but that it comprises most of the known universe. Somehow I'm reminded, however faintly, of the days when people attributed the workings of the universe to "vital forces" or even gods, fantastic invisible causes that are beyond our ability to observe.

Your post was well-written and reasonable, but it (and others here) have made it clear to me how badly understood these two concepts are by the public. Everyone seems to think physicists are just giving up and inventing fantastical explanations. Ironically, the situation is precisely the opposite.

Astrophysicists are using precision cosmological data, available in the last decade for the first time in human history, to constrain the possible theories for the universe. They have determined that, if Einstein was correct, there must be a large amount of matter which doesn't emit or absorb light, and some kind of dark energy. Those are the most conservative possibilities - they don't involve anything really new. Of course many, many scientists are working on alternatives - but all of those alternatives are far more speculative and fantastical than simply admitting that we might not be able to easily see all the stuff millions of light years away in our universe.

 

[Stellafane]

One thing to remember is that we evolved in this universe, and therefore our brains are relatively well-suited for understanding the rules it operates by (which appear to be formal logic and mathematics). The computer you are using is good evidence we've succeeded pretty well so far, and the methods of science and logic have so far shown no signs of ceasing to be useful.

Good point, one with which I completely agree. On the other hand, ants and jellyfish also evolved in this universe, and neither seem capable of producing cosmological answers (or computers for that matter) just yet. I think we humans have a tendency to look upon our intellects as the crowning achievement of creation, when in fact intelligence may be little more than a by-product (however wonderful) of large brains that evolved to better control our highly dexterous hands. We may be smart, but I can easily conceive of intellects far smarter and more capable of understanding the mysteries of the universe.

Dark matter is not necessarily anything exotic. We can only directly see things that glow, like stars. We can infer the existence of other things (like dust clouds) by how they absorb the light from stars, even when we can't see them directly. And we can infer the existence of dark matter, and something about its properties, from the way galaxies orbit and rotate, and independently from several other sets of observations. And as of this last year, we have seen dark matter directly via gravitational lensing around a particular galaxy cluster. That's as direct an observation as noticing there's some water ina glass from the way its surface refracts light, even though the water is transparent. I think the case is closed on the existence of DM - it's there, and it only remains to find out precisely what it is.

I'm not sure that comparing dark matter to dust clouds or water is an apt analogy. Neither may be readily observable visually, but they are still tangible and easily detectable via our other senses. Dark matter, on the other hand, we must accept as passing through us every instant in stupendous volumes even as we speak, outweighing all the known "normal" mass in the universe by far -- and yet we cannot directly detect so much as a single particle. And I wouldn't say that the observation of gravitational lensing is by necessity an observation of dark matter. Rather, it's an indication that something massive that we can't see is causing light to bend. Whether this "dark matter" (no caps) is in fact "Dark Matter" (the exotic stuff) or something more mundane, in my view, remains to be proved.

As for dark energy, perhaps some history is in order. When Einstein discovered general relativity (GR), he noticed that one of the only ways his theory could be extended was by adding a constant - the so-called "cosmological constant" (CC). It's hard to explain why, but GR is a very tight mathematical structure, and the CC is one of the only things you can add, and it's simply one single number (one parameter). That single parameter suffices to explain dark energy - it's all you need, although its numerical value is mysteriously small.

Ah, but Einstein invoked the CC because he couldn't bring himself to accept a seemingly weird implication of his theory, that the universe is expanding. When Hubble and others proved it was indeed expanding, he dropped the CC, called it the biggest blunder of his career, and was furious at himself for lacking the intellectual courage to stick with his initial convictions. So I think the latter-day resurrection of a form of the CC may be making the same blunder Einstein concluded he made, and ultimately rejected.

Your post was well-written and reasonable, but it (and others here) have made it clear to me how badly understood these two concepts are by the public. Everyone seems to think physicists are just giving up and inventing fantastical explanations. Ironically, the situation is precisely the opposite.

I think you're being a bit unfair to what I wrote. As I explained, I understand perfectly that dark matter and dark energy aren't the results of ivory-towered hand-waving and fantasizing. Instead, they are theoretical concepts that not only fit many of the observations, but are in fact supported via experimentation and mathematical models. But I adhere to the philosophical stance that our understanding of the universe may be limited to finding certain algorithms and models that best fit what we currently know, but must ultimately be discarded as further observations render them untenable. This is why I sometimes wonder if dark matter and dark energy are the latter-day equivalents of Ptolemy's epicyles -- temporary fixes to a theory that may in fact require a more radical overhaul (or at least significant revision).

Astrophysicists are using precision cosmological data, available in the last decade for the first time in human history, to constrain the possible theories for the universe. They have determined that, if Einstein was correct, there must be a large amount of matter which doesn't emit or absorb light, and some kind of dark energy. Those are the most conservative possibilities - they don't involve anything really new. Of course many, many scientists are working on alternatives - but all of those alternatives are far more speculative and fantastical than simply admitting that we might not be able to easily see all the stuff millions of light years away in our universe.

This is why this is such a wonderful and amazing time to be alive, because it appears that some of the most profound and mysterious questions of which the human mind can conceive may finally be seriously addressed. On the other hand, I am always leary of accepting too completely profound discoveries and theories recently made. It wouldn't be the first time we humans thought we had everything all figured out, only to be subsequently surprised.

 

[sol invictus]

I'm not sure that comparing dark matter to dust clouds or water is an apt analogy. Neither may be readily observable visually, but they are still tangible and easily detectable via our other senses.

I was talking about interstellar/intergalactic dust, not dust on earth. Much of the ordinary matter in the universe we already know about is not in stars, and we can "see" it only because it absorbs light that passes through it in certain specific ways. You have to understand that everything we know about the universe as a whole has been inferred from indirect observations of various kinds. We're talking about incredibly faint light which left the stars in question billions of years ago. It's not like we can just take a stroll around the universe and find this stuff out.

Dark matter, on the other hand, we must accept as passing through us every instant in stupendous volumes even as we speak

No, not really. The density is probably pretty low. And on the other hand the number of neutrinos (particles we know for sure exist) passing through us every second is enormous, so that's not very exotic.

outweighing all the known "normal" mass in the universe by far

By a factor of 6 or so.

and yet we cannot directly detect so much as a single particle.

Neutrinos are extraordinarily difficult to detect - you need a giant tank of water lined with extremely sensitive photodiodes to detect a single one. Again, not surprising. Why should nature make things easy for us?

And I wouldn't say that the observation of gravitational lensing is by necessity an observation of dark matter. Rather, it's an indication that something massive that we can't see is causing light to bend. Whether this "dark matter" (no caps) is in fact "Dark Matter" (the exotic stuff) or something more mundane, in my view, remains to be proved.

This is a perfect example of the kind of misunderstanding I was talking about. There is no difference between "dark matter" and "Dark Matter". All we know from indirect observations is that there is some weakly interacting, non-luminous mass out there, and roughly how much there is. We don't know whether it's "exotic" or "mundane", whatever that means. The lensing observations confirmed its presence directly.

Ah, but Einstein invoked the CC because he couldn't bring himself to accept a seemingly weird implication of his theory, that the universe is expanding. When Hubble and others proved it was indeed expanding, he dropped the CC, called it the biggest blunder of his career, and was furious at himself for lacking the intellectual courage to stick with his initial convictions. So I think the latter-day resurrection of a form of the CC may be making the same blunder Einstein concluded he made, and ultimately rejected.

Regardless of his motivation, the fact remains that the CC is essentially the only thing you can add to GR, and it's a single parameter. That single parameter can explain all the data we have which indicates acceleration (and there is a lot). That's a very good theory - you fix a single free parameter with a few of the observations, and then all the rest are explained. The most conservative view is just to stop there.

This is why I sometimes wonder if dark matter and dark energy are the latter-day equivalents of Ptolemy's epicyles -- temporary fixes to a theory that may in fact require a more radical overhaul (or at least significant revision).

Every physicist I know wonders that as well, and it's often discussed (particularly dark energy). Take a look at papers published in theoretical cosmology, and check how many are trying to address these mysteries. It's a very large fraction.

Sorry if I came off a little strong. There are a some really irritating woos here that keep harping on this, and it's been getting to me a little. Your posts were very reasonable.

 

[Belz...]

dark matter

when you can't make a theory work, make something up!

It's called science, rob. Try it, sometime.

 

[Belz...]

It's more than that. BAC doesn't believe in the Big Bang, and thinks that an "electric universe" model can produce an infinitely old universe. He also thinks that the sun is powered by electricity and not by fusion. In short, he's a believer in nonsense.

Sun ... powered by electricity ???

How the hell does that work if the temperature is so high that there are no electrons in the core ?

And how does it explain neutrinos ?

 

[sol invictus]

Dark matter, on the other hand, we must accept as passing through us every instant in stupendous volumes even as we speak

I decided to do an estimate of this, since I actually wanted to know the answer. Using some reasonable numbers and a WIMP model for DM, I get something of the other of 1,000 WIMPS (those are a kind of DM particle) per cubic meter (which is really very little - remember there are maybe 10^28 protons per cubic meter in your body). The earth is moving at around 300 km/s with respect to the galactic halo. So there are of order 100 million WIMPS per second passing through your body.

Sound like a lot? Well, remember that there are about 500 trillion solar neutrinos passing through your body each second, and probably more photons than that hitting your skin (I'm too lazy to estimate that number too).

 

[Stellafane]

I was talking about interstellar/intergalactic dust, not dust on earth. Much of the ordinary matter in the universe we already know about is not in stars, and we can "see" it only because it absorbs light that passes through it in certain specific ways. You have to understand that everything we know about the universe as a whole has been inferred from indirect observations of various kinds. We're talking about incredibly faint light which left the stars in question billions of years ago. It's not like we can just take a stroll around the universe and find this stuff out.

I understand, but I'm not sure I see the relevance. Dust, be it interstellar or residing under my bed, is relatively mundane stuff. Dark matter is obviously something else again. And I wouldn't say that the existence of stars and galaxies are inferred by indirect observations. We can see stars directly, capture their light, analyze it, and so on. The light can be considered a product (if not part) of the star itself, which can be directly observed via normal means (i.e. human senses).

..Neutrinos are extraordinarily difficult to detect - you need a giant tank of water lined with extremely sensitive photodiodes to detect a single one. Again, not surprising. Why should nature make things easy for us?

I was actually referring to WIMPs, which I understand are both massive and abundant, and have been referred to as a primary component of dark matter. I'm ready to accept our limited ability to detect something as elusive as the ghostly neutrino. But WIMPs require a much greater suspension of what I consider common sense. That's not to say they don't exist of course, because common sense is probably nothing more than the term we use for the handy, everyday understanding of the universe that we've evolved -- and thus far the need to understand stuff like WIMPs probably hasn't been all that key to human survival. But I think we need to go a little further down the path of verification before so esoteric a concept as WIMPs can pass from the theoretical to the realm of accepted reality.

This is a perfect example of the kind of misunderstanding I was talking about. There is no difference between "dark matter" and "Dark Matter".

Then I'm afraid you're using the term in a way that differs from the multiple astrophysists I've seen interviewed on television, as well as every astrophysists I've read (and they are numerous). They certainly do distinguish between the old-school term "dark matter" as used to describe material that's non-luminous, and "dark matter' as used in modern cosmology. In fact, it's ridiculous not to, unless you're ready to say WIMPs and dirt are the same things.

All we know from indirect observations is that there is some weakly interacting, non-luminous mass out there, and roughly how much there is. We don't know whether it's "exotic" or "mundane", whatever that means. The lensing observations confirmed its presence directly.

All we know is that certain objects in the universe behave as if they possess more gravity than can be accounted for by their observable mass. The rest is theory -- extremely sound, well-considered, and supported theory mind you, but theory nontheless. Other theories may yet prove to better fit the evidence, as we continue to make better and better observations.

Regardless of his motivation, the fact remains that the CC is essentially the only thing you can add to GR, and it's a single parameter. That single parameter can explain all the data we have which indicates acceleration (and there is a lot). That's a very good theory - you fix a single free parameter with a few of the observations, and then all the rest are explained. The most conservative view is just to stop there.

I still smell epicycle. And so did Einstein, I think. And I'm not prepared to bet against him quite yet.

Every physicist I know wonders that as well, and it's often discussed (particularly dark energy). Take a look at papers published in theoretical cosmology, and check how many are trying to address these mysteries. It's a very large fraction.

I've noticed.

Sorry if I came off a little strong. There are a some really irritating woos here that keep harping on this, and it's been getting to me a little. Your posts were very reasonable.

No woo here. And if you want the truth, I hesitated in posting, for fear that some woo may take my thoughts (and they are nothing but conjecture at best) and interpret them as denouncing modern cosmology. I'm not. Instead, I'm expressing what I would consider a metaphysical opinion of the nature -- and perhaps limitations -- of human understanding. Dark matter may well be "real" in the sense that it actually exists somewhere, its reality directly observable and predictable. Or it may be a useful model, like Newtonian physics, that works extremely well to explain the currently available evidence but doesn't quite conform with reality itself. Maybe time (or whatever succeeds us as the world's top intellectuals) will tell.

 

[sol invictus]

I understand, but I'm not sure I see the relevance. Dust, be it interstellar or residing under my bed, is realtively mundane stuff.

Some people study intergalactic dust as a career - it's not so mundane.

Dark matter is obviously something else again.

You think that's obvious? Really?

I'm trying to get a point across - we can only infer how much dust there is from indirect measurements. A relatively small error in that analysis could mean there is far more than we thought.

And I wouldn't say that the existence of stars and galaxies are inferred by indirect observations. We can see stars directly, capture their light, analyze it, and so on. The light can be considered a product (if not part) of the star itself, which can be directly observed via normal means (i.e. human senses).

First of all, I was talking about dust and gas (which constitutes a significant fraction of all the ordinary matter in the universe), not stars. Secondly, only very nearby stars (which are not a representative sample, by the way) can be seen with "normal means". The rest are detected with complicated telescopes plus lots of theory to interpret the results. And in the same vein I could mention electrons, which can never be seen with light, or atoms, or neutrinos, or lots of other things we know are there but can't see.

I was actually referring to WIMPs, which I understand are both massive and abundant, and have been referred to as a primary component of dark matter. I'm ready to accept our limited ability to detect something as elusive as the ghostly neutrino. But WIMPs require a much greater suspension of what I consider common sense.

Why? Seriously - why? What in the world is common-sensical about neutrinos? And were you aware that neutrinos were recently discovered to be massive? And if that mass were just a bit higher than it turns out to be - which could easily have happened - they would account for dark matter?

Then I'm afraid you're using the term in a way that differs from the multiple astrophysists I've seen interviewed on television, as well as every astrophysists I've read (and they are numerous). They certainly do distinguish between the old-school term "dark matter" as used to describe material that's non-luminous, and "dark matter' as used in modern cosmology. In fact, it's ridiculous not to, unless you're ready to say WIMPs and dirt are the same things.

Appeal to authority is not going to work, sorry. I'm very well acquainted with this subject.

Again, we don't know for sure DM is composed of new particles (not that it would be surprising if it was). All we know is roughly how much there is, how it's distributed, and from that a little about its properties. It may turn out to be composed of ordinary matter - brown dwarfs, neutrinos, primordial black holes, etc. None of those possibilities are favored by data, but this stuff is changing from year to year - it's cutting-edge and quite uncertain.

I still smell epicycle. And so did Einstein, I think. And I'm not prepared to bet against him quite yet.

Einstein wasn't a fortune teller and didn't know about the data which became available 50 years after his death, so his opinion isn't relevant. And yet he still provided the key ingredient which accounts for every observations we have of the effects of dark energy.

 

[Stellafane]

Some people study intergalactic dust as a career - it's not so mundane.

C'mon...you know what I mean!

First of all, I was talking about dust and gas (which constitutes a significant fraction of all the ordinary matter in the universe), not stars. Secondly, only very nearby stars (which are not a representative sample, by the way) can be seen with "normal means". The rest are detected with complicated telescopes plus lots of theory to interpret the results.

That really isn't accurate, unless your definition of "nearby" extends out to millions (in the case of individual stars) or billions (in the case of galaxies) of light years. The light we capture from them -- via relatively "ordinary" optical means -- can be analyzed and interpreted, revealing a great deal of information about the stars that produced them. Thus their reality is directly observable, not inferred or theoretical.

And in the same vein I could mention electrons, which can never be seen with light, or atoms, or neutrinos, or lots of other things we know are there but can't see.

Good points.

Why? Seriously - why? What in the world is common-sensical about neutrinos? And were you aware that neutrinos were recently discovered to be massive? And if that mass were just a bit higher than it turns out to be - which could easily have happened - they would account for dark matter?

Wasn't aware of massive neutrinos. Interesting, although not all that germane to my main points.

Appeal to authority is not going to work, sorry. I'm very well acquainted with this subject.

I wasn't appealing to authority, and frankly I think you damn well know it. I was just showing that I wasn't totally making stuff up as I went along. Spurious accusations of rhetorical malfeasance won't work either, sorry. (See? Two can play at that game.)

Again, we don't know for sure DM is composed of new particles (not that it would be surprising if it was). All we know is roughly how much there is, how it's distributed, and from that a little about its properties. It may turn out to be composed of ordinary matter - brown dwarfs, neutrinos, primordial black holes, etc. None of those possibilities are favored by data, but this stuff is changing from year to year - it's cutting-edge and quite uncertain.

Which makes it quite cool!

Einstein wasn't a fortune teller and didn't know about the data which became available 50 years after his death, so his opinion isn't relevant. And yet he still provided the key ingredient which accounts for every observations we have of the effects of dark energy.

I'll grant you Einstein wasn't a fortune teller. But I would hardly deem his opinion as irrelevant, and it wouldn't take much of an appeal to authority to find lots of people in the business who would probably agree with me.

 

[Belz...]

And were you aware that neutrinos were recently discovered to be massive?

They are ? Link ?

How do they manage to travel so fast and to avoid almost all interactions if they're massive ?

 

[Ziggurat]

Sun ... powered by electricity ???

How the hell does that work if the temperature is so high that there are no electrons in the core ?

It doesn't work at all. In order to come up with enough energy, proponents have to assume charges so ridiculously large that the excess charge would be accelerated to almost the speed of light within a second, which means the sun would essentially explode. It's a complete absurdity.

But there are electrons in the core, because the core, like the rest of the sun, is close to charge neutral. Electrons in the core aren't bound to nuclei, but they're definitely there.

And how does it explain neutrinos ?

Search me. If the model depends upon physical impossibilities (as an electric-powered sun does), I tend not to bother trying to figure out the subtleties since there's no point.

 

[BeAChooser]

It affects both matter and dark matter. That's how we know it's there.

No, you just think you know it's there because you think dark matter exists (which I think this thread is demonstrating may not be the case) and because you think the redshift/distance relationship claimed by the Big Bang community is correct in every instance (which I've shown on other occasions may not be correct either). If many high redshift quasars and high redshift galaxies turn out to be rather close objects instead of objects at the extreme edges of the universe, then all the calculations that have been done so far with regards to dark energy get tossed out the window. Which perhaps is why the Big Bang community is so desperate to ignore the many and still growing number of observations that suggest the redshift/distance relationship does not hold in many high redshift cases.

Matter is electrically neutral

Wrong. Plasma, which constitutes some 99+ percent of the verified matter in the universe, is only QUASI-neutral. That means it can carry current, produce magnetic fields and be affected by magnetic fields. And that has significant consequences on the universe and its structure that mainstream astrophysicists still haven't come to properly accept.

Dark energy is something much more peculiar than an EM field. Evidently it exists in vacuum even without sources - unlike EM fields

That's quite a gnome. It just exists and has no source. But I thought the Big Bang was supposed to get around that little problem with the universe ... it's origin.

 

[BeAChooser]

Originally Posted by robinson
I'm not sure what thread would lend itself to some of this, but that whole "empty space" thing is interesting. Is it really empty? What is the amount of energy in a given amount of space?

According to observations of dark energy, the amount is roughly (the equivalent of) one proton per cubic meter, which is incredibly tiny

I'm a little puzzled.

If I understand you right, mainstream theorists are claiming that the average density of the universe, including dark matter and dark energy, is the equivalent of one hydrogen atom per cubic meter. Since dark energy is supposed to be about three-fourths the total mass, that leaves a density of about 0.25 hydrogen atoms per cubic meter for everything else (even assuming we could see dark matter in a cubic meter sample of vacuum).

But this source (http://www.ccmr.cornell.edu/education/ask/index.html?quid=1026 ) states that "It is estimated the gaseous density between stars in the Milky Way to be ~0.1 to 1 atom/cm³ ... snip ... . For intergalactic voids, the density drop further to ~0.001 atom/cm³". That's a density of 1000 atoms per cubic meter.

Care to offer an explanation for this huge discrepancy? Or did I just do the math wrong again? Or is that 1000 atoms per cubic meter just the density in nearby intergalactic space? If so, then there must be some huge areas of the universe where there really is next to nothing. Perhaps those giant voids that have been discovered recently (and that are giving mainstream theorists so much trouble) provide the answer to my dilemma. Let's look:

http://www.acceleratingfuture.com/michael/blog/?p=69 "The Bootes Void ... snip ... is the largest known region of empty space in the observable universe. ... The void ... snip ... is about 2% the diameter of the entire observable universe (!) ... snip ... The Boötes void is probably the most perfect vacuum in the universe. Its density is somewhat less than that of the universe’s average, which is about one atom per cubic meter. The void’s density is certainly lower than that of typical intergalactic space, which is already extremely sparse."

But "somewhat less" than the universe's average is not going to solve the problem. Obviously, this region, even to be labeled a void, must have much less matter than most other regions. Which means the other regions must have substantially more than the universes average density. So I'm still left with a dilemma. Another way to look at it is that if intergalactic space has a density a 1000 times greater than the average density, then no more than 1/1000th of the volume of the universe can be that density, even if the rest is a perfect vacuum (which clearly isn't true based on the above). Something just doesn't make sense. You being such an expert on Big Bang cosmology ... perhaps you can clear this matter D) up, sol?

Quote:
You have gravity, every kind of EM, particles, and dark matter and energy, all within the same area. Is there a formula to calculate this?

Yes, there's a formula, and it gives a completely wrong answer. ... snip ... In fact it's off by at least 10^60.

Well perhaps that's a clue ...

 

[robinson]

I've never found anyone who actually knows the answer to my question. I'm not talking about just the energy of matter, but the Gravitational energy + EM energy of a volume of empty space.

Just the energy from one cosmic ray can be quite a lot. What is the energy of all the EM in a cubic meter of space?

 

[BeAChooser]

And I'm perfectly aware that if current cosmological theories offer a dead end, by necessity we most construct and explore new theories, however bizarre and counterintuitive they may first appear.

The problem is that it doesn't look like certain astrophysical theories (such as electromagnetic effects explaining the rotation curves of galaxies) were actually proven to be a dead end. Looks to me like they were just ignored while mainstream astrophysicists went about constructing their model filled with gnomes.

 

[robinson]

BeAChooser, why did you ignore my thread about the electromagnetic sun/earth?

It is the most obvious example of alternative theories predicting what we found recently, in regards to the solar wind and the earth. Did you just not see it?

 

[Ziggurat]

Wrong. Plasma, which constitutes some 99+ percent of the verified matter in the universe, is only QUASI-neutral.

The universe as a whole cannot have a net charge. That was his point. And you missed it completely.

That means it can carry current, produce magnetic fields and be affected by magnetic fields.

Your cluelessness about electromagnetism shines through yet again. Charge neutrality and conductivity have no inherent connection. A charge-neutral piece of metal can carry a current quite well. A balloon you've rubbed on your hair is not charge neutral, but it's a very poor conductor.

 

[robinson]

I'm not sure I understand. Is a magnet charge neutral? Is a moving magnetic field charge neutral?

 

[Ziggurat]

I'm not sure I understand. Is a magnet charge neutral?

It usually is. If it isn't, that generally has nothing to do with its magnetization.

Is a moving magnetic field charge neutral?

A magnetic field cannot have a charge. It can exert a force on moving charges, and it the field is changing it can even exert a force on stationary charges (induced electric fields), but the field itself does not have any charge.

 

[robinson]

So no matter how powerful a magnetic field is, it is considered charge neutral?