In my previous post, I showed direct statistical evidence that the Arp notion of non-cosmological redshifts for quasars is wrong. That was just the tip of the iceberg, though. Non-cosmological redshifts are a crank theory in astronomy that a scary fringe element keeps whinging on about. However, there's this other crank theory that no actual respectable astronomer subscribes to, yet that seems to keep sucking in interested members of the public. That is so-called plasma cosmology (which also has an even more extreme (!!) version known as the "electric universe"). The non-cosmological redshifts for quasars model may have been a respectable alternate model in the first years or first decade after Maarten Schmidt's identification of the then-amazingly high redshift of quasar 3C273 (that paper was in Nature, so you won't actually get to see it, sigh). In contrast, the whole plasma cosmology paradigm was never reasonable, and is certainly not reasonable now.
The basic idea of plasma cosmology is that electromagnetic forces in the bulk motions of astronomical objects are far more important than mainstream astronomy admits. Now, to be sure, mainstream astronomy places tremendous importance on electromagnetic forces. There's all kind of crazy stuff going on on the Earth's magnetosphere, as a result of the plasma from the Sun interacting with the magnetic fields of the Earth. Magnetic fields are responsible for initially collimating jets in active galactic nuclei that are observed shooting out over hundreds of thousands of light-years. So, the assertion you sometimes see that astronomers don't train their grad students about electromagnetic forces and that astronomers don't take into account those forces is an assertion that's wildly wrong. However, plasma cosmology also asserts that electromagnetic forces between plasma flowing through the solar system and through the Universe and the magnetic fields of objects (or even the objects themselves, as they'll often decide, for instance, that comets must have a substantial electric charge) make significant contributions to the motion of objects that mainstream astronomy is able to explain entirely through gravity.
Unfortunately, rhetoric being what it is, it's very easy to find sites on the web (and books) that promote the notion of plasma cosmology, and after reading them it's easy for the interested but uninformed layman to be convinced. It helps that it feeds into the whole "few brave pioneers fighting the oppression of the mainstream dogma" story that seems to be so popular in (at least) American culture. How do you know whether to believe my assertion in the first paragraph above that plasma cosmology is all bunk, or a much more elegant assertion that people like me are just part of the entrenched mainstream refusing to listen to somebody with a new idea that challenges the underpinning of our whole careers? The problem is that when actual real astronomers such as myself are confronted with plasma cosmology, we have a hard time doing anything other than shaking our heads sadly, because it's so amazingly wrong, so patently silly if you know anything, that it's difficult even to know how to begin saying that it's wrong.
I'm going to try to take down plasma cosmology on two points. The first is a general point, the second is a specific point. As far as I can tell, plasma cosmology is motivated by people who just want to be different, or by people who have aesthetic or conceptual problems with things such as dark matter and cosmological distances. However, let's go ahead and give it the benefit of the doubt (way too much benefit, but bear with me) of saying that it's an idea inspired by trying to explain something that may not be satisfactorily explained by mainstream science. An example of something like this is MOND, or "MOdified Newtonian Dynamics". Standard Newtonian gravity can't explain the observed rotation speeds of galaxies. The right answer is that there is dark matter in those galaxies; we know this is the right answer because there is a whole lot of other evidence for dark matter. However, MOND was introduced as a way of modifying Newtonian gravity, rather than by introducing a new component to galaxies, to explain the flaw.
Here's the thing, though. Even if the "standard" explanation has a flaw, when you introduce an alternate explanation to address that flaw, your alternate explanation must explain everything the standard explanation already explains. (Strictly speaking, it doesn't have to initially explain everything. For instance, Copernicus' model of the heliocentric Solar System initially didn't produce as accurate predictions for planet positions as the old Ptolemaic geocentric model did. However, your new model must at least get close, and there must be ways to improve your model to explain what the old model explained.) Given the wide range of observations that standard gravity-based expanding-Universe cosmology explains, there's really no need for a gigantic rethink of all of it such as plasma cosmology offers. If we are to do that gigantic rethink, there has got to be a compelling observational reason beyond somebody's aesthetic sensibilities. (For instance, Quantum Mechanics was a gigantic rethink of our understanding of the fundamental nature of reality. However, not only did it explain some troubling problems about the light emitted by hot objects, it went on to propose a whole bunch of other experiments that couldn't have been explained without it. That's how successful paradigm-changing theories work.)
Given that we're able to explain all the orbits in the solar system with a straightforward application of gravity, where's the problem that plasma cosmology is supposed to solve? Likewise, with the whole Universe, we explain a wide range of observations with Big Bang cosmology. If we are to even bother spending ten minutes thinking about plasma cosmology, we must first know: does it even show promise to explain everything, and what does it offer that the Big Bang does not?
In other words, plasma cosmology is a waste of time.
However, let me also take down one of the specific pieces of the model that underpins plasma cosmology. That's actually very difficult to do— not because the model is robust, but because it's so ill-defined! If you go to plasmacosmology.net and follow the "technical" links, you get a bunch of text about various different "core concepts". If you don't know a lot about physics and astronomy, I can see where it looks like they've put together a well thought-out framework here, and that it's criminal for mainstream astronomers not to address this. The problem is, if you're a mainstream astronomer like me, and you try to figure out exactly what it is that their model here is doing, often you can't. What you've got, really, is a lot of nice sounding technical jargon that ultimately doesn't make clear what it is that they're really saying. In short, where's the math? If you're going to make quantitative predictions about where things are going, we need to know the equations that go along with your nice words.
Here's one of the things they say about the Solar System that's at odds with what mainstream science knows:
Because the sun is seen to emit roughly equal quantities of ions and electrons, the solar wind is considered electrically neutral in mainstream circles. This is wrong. In reality it is a huge bipolar electric current, and the terms solar wind and solar radiation result from the fact that the mainstream refuses to acknowledge electricity in space.
OK.... First of all, the mainstream does acknowledge electricity in space. But, never mind that. The term "solar radiation" results from the fact that the Sun is radiating. We see light coming off of the Sun. We also, via satellites, observe a stream of charged particles (of both signs, mixed together) coming off of the Sun. It seems exceedingly bizarre to assert that the term "solar radiation" comes out of some sort of global willful blindness, when it's just a very straightforward identification of the fact that the Sun is not completely dark, and is thus, er, radiating.
But, OK, what I really wanted to object to was "a huge bipolar electric current". What exactly does this mean? To me, if it's bipolar, it would mean that on the North pole (say) the particles flowing off of the Sun are mostly positive, and on the South pole they're mostly negative. This would, indeed, be a bipolar current. The problem is, if it's really bipolar like this, then the particles flowing along the equator— you know, the plane where most of the planets and comets are all orbiting, so where you'd need things happening to have an effect— would be neutral in bulk. (That is, there is an even mix of positive and negative particles.) Thus, you're not going to get any net interactions of that current with the magnetic fields of planets or anything else that will produce bulk motions. (You will get all the fun stuff like the Van Allen belts and aurora... but, of course, mainstream astronomy already describes all of that!)
So what are you guys really trying to say here?
I do have one guess, based on something written further down:
This behaviour derives from Ampére's Law or the Biot-Savart force law which states that currents in the same direction attract while currents in the opposite direction repel. They do so inversely in relation to the distance between them. This results in a far larger ranging force of interaction than the gravitational force between two masses. Gravitational force is only attractive and varies inversely with the square of the distance.
Except for one crucial omission, this statement is correct. It is true that if you calculate the attractive force between two long parallel currents, it only goes as 1/r, whereas gravity goes as 1/r2. This means that the strength of gravity drops off faster with distance than the magnetic attraction of the two currents, so even if gravity dominates, eventually you will reach a point where the strength of gravity drops below the magnetic strength. So, it seems, you really ought to be taking all this current stuff seriously.
Here's the problem though. The result that the magnetic attraction between two parallel currents drops off as 1/r only applies to infinitely long parallel currents. Practically speaking, that means that the length of each current (the length of the wire carrying the current, for example) must be a substantially bigger than the distance between the two currents. In other words, for this 1/r law to be relevant in the Solar System, there would have to be some current associated with (say) the Earth, perpendicular to the plane of the Solar System, whose length is at least several times the distance between the Earth and the Sun. The Sun would likewise have to have a current that long associated with it.
And that's just batty.
The mistake here is a common mistake, actually. It involves taking a legitimate result from legitimate equations, and applying it where it does not apply. This is why, in physics, you shouldn't just do algebra blindly. You should understand what you're doing. Even if you understand the vector algebra that leads to the derivation of the 1/r force law, you need to understand why you used the equations you did, and why you made the simplifying assumptions that you did, in deriving that law. And, in understanding that you need to understand the limitations on when you can apply your result.
If you (somehow) manage to have two short parallel lengths of current all going in one direction, then the strength of the force between them drops off as 1/r2, just like gravity, once the distance between the two currents is large compared to their length. But, you can't have this, as all the charge from that current has to go somewhere. So, in practice, if you have a small bit of current, you have to have a loop. The force between two loops of current drops off faster than 1/r2. In other words, even if it's significant at smallish distances, eventually it will become insignificant compared to gravity.
That's why you can trivially make an electromagnet and pick up paper clips with it, easily overcoming Earth's gravity. However, once you move that electromagnet (say) a meter away from the paperclip (unless you've really gone nuts with your current), the Earth's gravity overcomes it and you no longer pick up the paperclip.
As far as I can tell, the plasma cosmology people are basing all of their objections on a (probably unconscious) desire to be the Justified Iconoclast, latching on with their friends to a Truth that the mainstream refuses to see. And, indeed, this is a very attractive notion, and I think this is part of why intelligent and interested members of the public get sucked in by it. The problem is, their justifications fall apart under even a little bit of scrutiny. Please, please, pay no attention to plasma cosmology. It's a persistent but extremely off-base crackpottery that plagues astronomy.