Previously, I introduced a bizarre pseudoscience website that claimed to revolutionize modern astrophysics. It doesn’t actually do that. I thought I would show exactly why, and teach some cool astrophysics at the same time. This is part 3 of the series. You can follow along with what I’m debunking here.
So before I get started, I should mention that Dr. Scott hasn’t developed his crazy pseudoscience all on his own. The ‘electric universe’ theory is a fairly common pseudoscience in modern astrophysics. Basically, the proponents of the theory (and I use that term in the colloquial, not the scientific, sense) claim that electromagnetic forces are far more powerful on the interstellar scale than most astrophysicists are willing to grant. These people believe that electromagnetic forces can explain nearly every open astronomical question, and that most of modern astrophysics is wrong.
In short, they’re the creationists of the astrophysics community, with electromagnetism as their bible.
If you have some sort of morbid curiosity about this movement, you can check out these sites for more information. Just make sure to take everything written there with a grain of salt. If you’re looking for a more rational discussion of the Electric Universe theory, you can start here.
Anywho, on to Dr. Scott’s wacky theory of the day. Today he’s looking at dark matter!
What Was Missing
Dutch astronomer Jan Oort first discovered the ‘missing matter’ problem in the 1930’s. By observing the Doppler red-shift values of stars moving near the plane of our galaxy, Oort assumed he could calculate how fast the stars were moving. Since the galaxy was not flying apart, he reasoned that there must be enough matter inside the galaxy such that the central gravitational force was strong enough to keep the stars from escaping, much as the Sun’s gravitational pull keeps a planet in its orbit. But when the calculation was made, it turned out that there was not enough mass in the galaxy. And the discrepancy was not small; the galaxy had to be at least twice as massive as the sum of the mass of all its visible components combined. Where was all this missing matter?
In addition, in the 1960’s the radial profile of the tangential velocity of stars in their orbits around the galactic center as a function of their distance from that center was measured. It was found that typically, once we get away from the galactic center all the stars travel with the same velocity independent of their distance out from the galactic center…. Usually, as is the case with our solar system, the farther out an object is, the slower it travels in its orbit.
To visualize the seriousness of the problem cosmologists face, we need to consider just a bit of Newtonian dynamics:
- To change a body’s velocity vector – either in direction or magnitude or both, a force must be applied to the mass of the body. The resulting acceleration is equal to the ratio of the applied force divided by the mass of the object; i.e., f = m a, where f is the force applied to the body, m is the mass of the body, and a is the resulting acceleration (change in velocity). Both f and a are vectors; the change in direction of the velocity will be in the direction of the applied force.
- When an Olympic athlete, starting to do the hammer throw, swings the hammer around himself in a circle, the force he feels stretching his arms (the force he is applying to the hammer) is the ‘centripetal force’. That force is equal to the product of the hammer’s mass, m1, times the centripetal acceleration (which in this case is the acceleration that continually changes only thedirection, not the magnitude, of the velocity vector of the hammer – inward – so as to keep it in a circular orbit around the athlete). This acceleration is equal to the square of the hammer’s tangential velocity, v, divided by the radius of the circle. So, the inward force the athlete needs to exert to keep the hammer in its circular path is: f = m1 v^2/R.
- Newton’s law of gravitational force says that the force between two masses is equal to G (the gravitational ‘constant’) times the product of the two masses divided by the square of the distance between them. f = G(m1 x m2)/R^2.
Consider the case of a star on the outskirts of a galaxy. Its radius from the galactic center is R. Its mass is m1, and m2 is the total mass of everything else (all the other stars and matter) inside a circle whose radius is R, the distance of the star from the galaxy’s center. Newtonian dynamics assumes all that combined mass, m2, acts as if it were located at a single point at the galaxy’s center. For the star to remain in a fixed orbit, the necessary inward (centripetal) force, m1 V^2/R, must be exactly equal to the available (gravitational) force, G(m1 x m2)/R^2. Setting these two expressions equal to each other results in the expression:
m2 = (V^2) R /G
This says that for the tangential velocity, V, to remain constant as R increases – as it does in figure 1 (as we look at stars farther and farther out from the galaxy’s center) the included mass, m2, must increase proportionally to that radius, R. But we realize that, if we move far out from the center, to the last few stars in any galaxy, included mass will not increase proportionally to the radius. So there seems to be no way the velocity can remain the same for the outermost stars as for the inner stars. Therefore, astrophysicists have concluded that, either some mass is ‘missing’ in the outer regions of galaxies, or the outer stars rotating around galaxy cores do not obey Newton’s law of gravity.
There were problems, too, at a larger scale. In 1933 astronomer Fritz Zwicky announced that when he measured the individual velocities of a large group of galaxies known as the Coma cluster, he found that all of the galaxies that he measured were moving so rapidly relative to one another that the cluster should have come apart long ago. The visible mass of the galaxies making up the cluster was far too little to produce enough gravitational force to hold the cluster together. So not only was our own galaxy lacking mass, but so was the whole Coma cluster of galaxies.
Okay, let’s take a breath. Everything that Dr. Scott has said so far is true. To summarize: In order for the galaxy to hold together, it needs to have a certain amount of mass. However, when astronomers calculated the mass of the galaxy from the number of visible stars, they came up short. By a lot. So either there’s a bunch of matter that we can’t see, or our equations are wrong.
The most widely accepted explanation is that our galaxy contains a bunch of matter that we can’t see. This is actually not a very controversial position. We can only see objects that emit or reflect light, so any matter that doesn’t do either of those things is invisible to us.
Scientists have called the matter that we can’t see ‘dark matter.’ It turns out that dark matter makes up the vast majority of all matter in the universe. The trick now is to determine what exactly dark matter is.
MACHOs, WIMPs & MOND
At first, cosmologists decided to leave Newton’s laws inviolate and to postulate the existence of some invisible dark entities to make up the missing mass. Apparently it never ocurred to anyone to go back and examine the basic assumption that only gravity was at work in these cases. It was easier to patch up the theory with invisible entities. (Remember the invisible gnomes in my garden?)
So the garden gnomes are a reference to Chapter 1 where Dr. Scott used the claim ‘there are invisible gnomes in my garden’ as an example of an unfalsifiable claim.
What Dr. Scott is saying here is that dark matter can’t be observed, so the theory is unfalsifiable. Of course, this is completely wrong. Dark matter can’t be seen, but that doesn’t mean it can’t be observed. We can measure the gravitational effect of dark matter on stars and galaxies, and get an fairly accurate picture of what it looks like. For instance, here’s a picture of what the dark matter distribution in our own galaxy looks like.
To quote Astronomy magazine (Aug. 2001 p 26):
“What’s more, astronomers have gone to great lengths to affectionately name, define, and categorize this zoo of invisible stuff called dark matter. There are the MAssive Compact Halo Objects (MACHOs) – things like … black holes, and neutron stars that purportedly populate the outer reaches of galaxies like the Milky Way. Then there are the Weakly Interacting Massive Particles (WIMPs), which possess mass, yet don’t interact with ordinary matter – baryons such as protons and neutrons – because they are composed of something entirely foreign and unknown. Dark matter even comes in two flavors, hot (HDM) and cold (CDM)…..”
1. Cold dark matter – supposedly in dead stars, planets, brown dwarfs (“failed stars”) etc.
2. Hot dark matter – postulated to be fast moving particles floating throughout the universe, neutrinos, tachions [sic] etc.
“And all the while astronomers and physicists have refined their dark matter theories without ever getting their hands on a single piece of it. But where is all of this dark matter? The truth is that after more than 30 years of looking for it, there’s still no definitive proof that WIMPs exist or that MACHOs will ever make up more than five percent of the total reserve of missing dark stuff.”
First, what are WIMPs? As Dr. Scott has so helpfully summarized, WIMP stands for Weakly Interacting Massive Particle. There are four main forces that particles can ‘interact’ with: the elctromagnetic force, the strong nuclear force, the weak nuclear force, and gravity. WIMPs ignore half of these, and only interact with gravity and the weak nuclear force.
You may be asking what these forces are. You’re already familiar with gravity, and probably familiar with electromagnetism as well. The strong nuclear force is the force that holds atoms together. It’s the force that binds protons and neutrons together in an atom, and it’s also the force that holds quarks together to form those protons and neutrons in the first place. The weak nuclear force is responsible for radioactive decay. It’s what allows one element to decay into another.
The thing about the nuclear forces is that they’re really powerful at short distances. The strong nuclear force is about ten times as powerful as electromagnetism, which we’ve already established is really powerful. The weak nuclear force is much, um, weaker, but still more powerful than gravity. However, they’re only strong at short distances, that is, within the nucleus. Outside of that, they’re very weak.
What this means is that WIMPs, which only really interact with the weak nuclear force, can only be detected if they actually collide with a nucleus. Of course, nuclei are really small, so more often than not, WIMPs don’t collide with anything at all. This means that WIMPs are really hard to detect. They’re ‘weakly interacting,’ after all, and they usually pass through materials without ever hitting a single nucleus. It’s very hard to detect something that refuses to interact with your detector.
Many scientists have spent years trying to detect a WIMP. So far, all we have to show is a few isolated observations that have yet to be confirmed. That said, we’re really close to a positive detection, and there are several experiments around the world working on this. At this point, we’ll probably have a positive identification in a few years, if not sooner.
Science is an ongoing process. Good results take time, and saying ‘we haven’t found proof yet’ is not even close to ‘there is no proof.’ In this case, WIMPs are predicted by current particle physics, and there’s nothing to suggest that they don’t exist. Dr. Scott’s attitude here is surprisingly reminiscent of, “Scientists haven’t found that one transitional fossil, so evolution can’t be true.”
Of course, the second possibility mentioned above (that the outer stars rotating around galaxy cores do not obey Newton’s Law of Gravity) was thought to be impossible. But the first alternative – the fanciful notion that 99% of the matter in the universe was invisible – began to be worrisome too. It was stated that WIMPs and MACHOs were in the category of particle known as “Fabricated Ad hoc Inventions Repeatedly Invoked in Efforts to Defend Untenable Scientific Theories” (FAIRIE DUST). Even such an august authority as Princeton University cosmologist Jim Peebles has been quoted as saying,
“It’s an embarrassment that the dominant forms of matter in the universe are hypothetical…”
The snark in this paragraph is overwhelming. Moving on.
So the second alternative, radical as it is, was chosen by some astrophysicists and called “MOdify Newton’s Dynamics” [sic] (MOND) This paradigm shaking proposal to alter Newton’s Law of Gravity – because it does not seem to give correct answers in the low density regions of galaxies – was first put forward in 1983 by astrophysicist Mordehai Milgrom at the Weizman Institute of Science in Israel. It has recently been given more publicity by University of Maryland astronomer Stacy McGaugh. Milgrom, himself, has recently (“Does Dark Matter Really Exist?”,Scientific American, Aug. 2002, p. 42-52) said, “Although people are right to be skeptical about MOND, until definitive evidence arrives for dark matter or for one of its alternatives, we should keep our minds open.” One wonders what alternatives was he referring to?
Well, he was probably not referring to crazy pseudoscience. In fact, Modified Newtonian Dynamics (MoND) is just one possible theory that revises Newton’s law of gravity. There are also several others, which is probably what Milgrom was referring to. Unfortunately, they’re all a bit above my pay grade in terms of the physics involved, so I’m unable to explain them. I will say that all of these theories are less widely accepted than WIMPs as an explanation for the missing matter in our galaxy.
Some other astrophysicists have grasped at the announcement that neutrinos, that permeate the cosmos, have mass. This, they say, must be the previously “missing matter”. But the “missing mass” is not missing homogeneously throughout the universe – just in specific places (like the outer reaches of galaxies). The neutrinos are homogeneously distributed. So this last ditch explanation fails as well.
Neutrinos are similar to WIMPs, in that they only interact through gravity and the weak nuclear force. However, neutrinos are far less massive. There’s no way that neutrinos could possibly account for all the dark matter, which is why it’s strange that Dr. Scott says that there are ‘other astrophysicists’ who think it can. Who are these ‘other astrophysicists?’ Because I don’t know of anyone who seriously considers neutrinos to be a valid explanation of dark matter. Ooh, strawmanning!
The dilemma presented by the fact that Newton’s Law of Gravity does not give the correct (observed) results in most cases involving galaxy rotation can only be resolved by realizing that Newton’s Law of Gravity is simply not applicable in these situations. Galaxies are not held together by gravity. They are formed, driven, and stabilized by dynamic electromagnetic effects.
Haha no they aren’t.
The Real Explanation:
Dynamic Electromagnetic Forces in Cosmic Plasmas
Ninety nine percent of the universe is made up of tenuous clouds of ions and electrons called electric plasma. Plasmas respond to the electrical physical laws codified by James Clerk Maxwell and Oliver Heaviside in the late 1800’s. An additional single law due to Hendrick Lorentz explains the mysterious stellar velocities described above.
d/dt(mv) = q(E + v x B)
Simply stated, this law says that a moving charged particle’s momentum (direction) can be changed by application of either an electric field, E, or a magnetic field, B, or both. Consider the mass and charge of a proton for example. The electrostatic force between two protons is 36 orders of magnitude greater than the gravitational force (given by Newton’s equation). It’s not that Newton’s Law is wrong. It is just that in deep space it is totally overpowered by the Maxwell-Lorentz forces of electromagnetic dynamics.
As I showed last time, electromagnetic forces are not relevant on an interstellar scale. While electromagnetic forces are much more powerful than gravitational forces, most stellar objects are electrically neutral, so they don’t create a net electric force. This inconvenient fact undermines Dr. Scott’s entire argument.
I’ll post the rest of this section without comment.
Notice, in the equation in the previous paragraph, that the change in a charged particle’s momentum (left hand side of the equation) is directly proportional to the strength of the magnetic field, B, the particle is moving through. The strength of the magnetic field produced by an electric current (e.g., a cosmic sized Birkeland current) falls off inversely as the first power of the distance from the current. Both electrostatic and gravitational forces fall off inversely as the square of the distance. This inherent difference in the spatial distribution of electromagnetic forces as compared to gravitational forces may indeed be the root cause of the inexplicable velocity profiles exhibited by galaxies.
Electrical engineer Dr. Anthony L. Peratt, using Maxwell’s and Lorentz’s equations, has shown that charged particles, such as those that form the intergalactic plasma, will evolve into very familiar galactic shapes under the influence of electrodynamic forces. The results of these simulations fit perfectly with the observed values of the velocity contours in galaxies. No missing matter is needed – and Newton can rest easy in his grave. The electromagnetic force is many orders of magnitude stronger than the force due to gravity and it distributes itself more widely throughout space. But present day astronomy refuses to recognize the existence of any cosmic force other than gravity. That error is the cause of their mystification.
A farmer and his young daughter are driving along a dusty road. They are almost home when the car breaks down. The farmer walks to the barn and gets his horse, Dobbin. He harnesses Dobbin to the front bumper of the car and begins to drag it along the road toward home. The young daughter takes a piece of string and attaches it to the bumper and says, “I’ll help drag the car, Daddy.”
Anyone who cannot see horses will think the daughter must possess “missing muscle”.
Or, as in Moti Milgrom’s MOND proposal, they might suggest that Newton’s Laws of motion needed “modification” in this case.
In 1986, Nobel laureate Hannes Alfven postulated both an electrical galactic model and an electric solar model. Recently physicist Wal Thornhill has pointed out that Alfven’s circuits are really scaled up versions of the familiar homopolar motor that serves as the watt-hour meter on each of our homes. The simple application of the Lorentz force equation (“crossing” the direction, v, of the current into the direction, B, of the magnetic field) yields a rotational force. Not only does this effect explain the mysterious tangential velocities of the outer stars in galaxies, but also (in scaled down version) the observed fact that our Sun rotates faster at its equator than at higher (solar) latitudes.
Up to now astronomers and cosmologists have not given serious consideration to any sort of electrical explanation for any of the above observations. This is puzzling because all these electrical principles have now been known for decades. They have long been applied in the solution of problems in plasma laboratories here on Earth and have been used successfully in the invention of many practical devices – such as industrial electrical arc machining, particle accelerators, etc. The correct, simple, solution to the “mysteries” of galaxy rotation lies in Plasma Electro-Dynamics – not in the invention of imaginary, fanciful entities such as WIMPs and MACHOs or in the trashing of a perfectly valid law of physics as is proposed in MOND.
Present day astronomy/cosmology seems to be on the horns of a very painful dilemma. This dilemma is caused by the fact that Newton’s Law of Gravity does not give the correct (observed) results in most cases involving galaxy rotation. The “missing matter” proposal attempts to balance the equation by increasing one of the variables (one of the mass terms). The second proposal (MOND) is to change Newton’s equation itself. (If you are losing the game, change the rules.)
But, the ultimate resolution of the dilemma lies in realizing that Newton’s Law of Gravity is simply not applicable in these situations. Maxwell’s equations are! Why do astrophysicists grope wildly for solutions in every possible direction except the right one?
Change the rules? I wasn’t aware that modifying an existing theory to fit observed data counted as cheating. No, cheating would be modifying the data to fit the theory, as Dr. Scott is doing.
As scientists, it is our job to consider all possible explanations for a phenomenon. What Dr. Scott calls “grop[ing] wildly” is really “methodically testing every possible explanation,” or, as it’s more commonly known, “science.” Both dark matter theory and MoND are valid attempts to explain a specific phenomenon. Dr. Scott’s theory was also considered, and rejected decades ago. At this point, it’s no longer science, it’s pseudoscience.
That’s all for this time! If you have any questions, be sure to leave them in the comments. Join us next time when we talk about the Sun!