In Peratt's model, galaxies form at the intersection of large-scale (many megaparsecs long) Birkeland currents. This model had the interesting feature that it formed objects that resembled spiral galaxies and they exhibited rotation profiles similar to those observed for spiral galaxies, without the need for dark matter needed in the standard Big Bang cosmology. These characteristics were observed in both plasma experiments and in particle simulations.
So why isn't the Peratt model the accepted model for galaxy formation? Because galaxies are not defined by rotation curves alone. Peratt's model made a number of other predictions that failed significantly.
The Birkeland currents, by definition, have magnetic fields parallel to their direction of flow. These currents will also will generate their own magnetic field, just like any other current. However, the field along the path of the current needs to be much stronger than the self-generated field or the stream will be unstable. The electrons will trace out circular or helical paths due to the magnetic field as they move along the current stream. But in circular motion, the electrons will accelerate, and therefore radiate. This radiation is called cyclotron (in the non-relativistic case) or more generally, synchrotron radiation.
So these Birkeland currents will be expected to emit synchrotron radiation. Dr. Peratt calculated just how much they would be expected to radiate and obtained values of energy output on the same order of magnitude as the measured flux of the cosmic microwave background radiation.
But there was a problem. Cyclotron emission for electrons of a fixed energy emits energy in discrete spectral lines corresponding to the cyclotron frequency and harmonics (integer multiples). The cosmic microwave background is a broad smooth blackbody curve, very different from the sharp line spectra of cyclotron radiation.
But we don't expect the electrons to be monoenergetic nor the magnetic field their in to be completely uniform. Peratt assumed a 'bithermal' electron velocity distribution, where the mean electron motion would correspond to one temperature along their direction of motion, but another temperature perpendicular to their direction of motion. [Note that the commenter 'Anaconda' in this thread (link) dismisses the use of 'thermal synchrotron' distribution because I could not demonstrate it had been seen under laboratory conditions. I assume he would condemn Peratt for invoking thermal synchrotron radiation as well. Actually, 'thermal synchrotron radiation' relies on the correctness of two concepts: the Poynting vector definition of electromagnetic energy, and Maxwell's equations. It basically says that the radiation flux from a collection of particles, emitting incoherently, is the sum of the fluxes of radiation from individual particles.]
With a distribution of electron energies and magnetic field strengths, the peaks of the synchrotron radiation broaden into 'bumps'. Peratt found that by assuming the CMB was created by the sum of the emission of many of these current streams, the shape of the CMB spectrum could be matched over frequencies up to 100GHz. But he needed many filaments to do this, about 10^31.
Peratt's model clearly requires synchrotron emission from the current streams powering the galaxies and his own calculations show that instruments such as COBE and WMAP have sufficient sensitivity to see them.
Peratt reports that the mean lengths of these current streams must be on the order of 350 MEGAPARSECS. This means that the currents driving the nearer galaxies, such as M31 & M33 should be clearly visible in the raw WMAP data, before the foreground processing is even performed!
So we look up the coordinates of M31 & M33. From the SIMBAD astronomical database, we find
M31 RA: 00 42 44.31 dec:+41 16 09.4 ICRS 2000. Galactic: 121.1743 -21.5728
M33 RA: 01 33 51.02 dec:+30 39 36.7 ICRS 2000. Galactic: 133.6107 -31.3306
Here's a snapshot of the M31 and M33 superimposed on the WMAP CMB map using Google Earth in Sky mode. (click to enlarge)
We can also check out the nearby Virgo cluster of galaxies.
Where are the current streams to power these galaxies!? The streams for these nearer galaxies and clusters should lie over all the other more distant streams. At a distance of 600,000 pc for M31, a 350Mpc long filament should appear to be 2*arctan((350e6 pc/2)/0.6e6 pc) or 180 degrees across. Even if not strictly linear, this structure should show up! Where is it? All we see are random blobs, more consistent with noise (and consistent with the Big Bang interpretation) than current streams.
Why should I , or anyone else, believe these galactic-scale currents exist when Peratt's own predictions for them fail?
Peratt own calculations demonstrated that the flux from these currents was comparable to the intensity of the cosmic microwave background radiation  and he even expected to see a ''”spaghetti” of radiating filaments surrounding the viewer'.
I have heard reports that in addition to the current streams not being visible, the Peratt model had serious difficulty reproducing the fluctuations of the CMB at the level detected (10^-5), though I have yet to find where this result may have actually been published.
Perhaps the synchrotron radiation is being beamed?
This happens in pulsar emission, so it could be happening in the current stream and is not beaming directly towards us? There are several problems with this scenario:
- Synchrotron radiation is beamed in the direction of motion. In the case of electrons moving in circular orbits, the beam sweeps out a full 360 degrees in the plane of motion, much like the headlight of a motorcycle moving around a circular track. The emission could be confined to a plane, but the plane would be aligned with it's normal (perpendicular) vector along a circle around the current stream. The beaming would still sweep over all directions outbound from the current stream.
- To explain the galaxy distribution, these currents must be pointed all over the sky in random directions. This means the plane of the electron motion will be randomly distributed as well. The odds that we are out of the coverage of all these emitting electrons becomes slim.
- Peratt only needs 30keV electrons to generate the galaxies in his models. This makes the electrons non-relativistic, so the beam of light emission is very broad, not narrow as would be the case for relativistic electrons. The emission would be strong in many directions so beaming is not a problem.
In his rebuttal (link, The WMAP Map, page 10) to my previous paper (link), Dr. Scott tries to deflect this criticism of the Peratt model by asking why don't we see the filaments of galaxies reported in the large-scale galaxy surveys such as 2dFRS or SDSS against the CMB maps (see Large-scale Structure of the Cosmos).
In mainstream cosmology, these filaments are NOT due to electric currents. Computer simulations of structure formation are perfectly capable of forming filamentary structures without the need for them to be powered by currents. You can see for yourself the results of some of these simulations at the website for “Simulating the joint evolution of quasars, galaxies and their large-scale distribution”. This group even makes their simulation code, called Gadget, generally available so others may evaluate it.
In dark matter cosmologies, these filaments are NOT expected to be strong sources of emission over a broad range of wavelengths such as synchrotron radiation. In order to be seen by WMAP, these filaments would need to have sufficient emission or absorption in the radio frequencies observed by WMAP. Since these filaments would be largely atomic hydrogen, their major emission and absorption in radio would occur at a frequency of 1.420 GHz (wavelength = 21 cm). This frequency, as well as others frequencies of emission and absorption expected by atomic hydrogen, are well outside the frequency of WMAP observations (23-94 GHz). Atomic hydrogen is largely transparent in the WMAP frequency range.
WMAP CMB is produced by a combination of measurements from FIVE all-sky maps. The raw input data is available as well. Some high-level image products the the input bands (23-94 GHz) are available here. Note that neutral hydrogen, detected in the intergalactic medium due to its absorption in the Lyman alpha line, is transparent in these radio wavelength bands. Other sources of foreground emission can be accounted for as well, as we can see in these foreground datasets. Free electrons, such as needed for Peratt's currents, show up in the synchrotron radiation maps and the free-free (bremsstrahlung radiation) maps.
The WMAP frequency bands were chosen to for a region near the minmum of microwave emission by galaxies. The yellow bands in the figure below (K, Ka, Q, V, W) represent the frequency coverage of WMAP.
Courtesy of WMAP. Used with permission. http://lambda.gsfc.nasa.gov/product/foreground/
Other Questions About the Peratt Galaxy Model
There are a host of additional problems with the Peratt model which I cannot find addressed anywhere.
- What powers these cosmic-scale Birkeland currents? What is the origin of the EMF that drives them? Are there any laboratory or theoretical models that such currents of such size and magnitude could be driven by turbulence?
- With a mean length of ~350 Megaparsecs for Peratt's filaments, the ends of these filaments should be visible in our current galaxy surveys so we should be able to see the source of the EMF and magnetic field which maintain them. Not only do we not see any objects that could fulfill this role, even Don Scott admitted that they did not know the source of these Birkeland current systems. These invisible, physics-defying current sources must be far more complex than single weakly interacting particles proposed as Dark Matter. Because their predicted emission is well within the sensitivity of our present day instruments, these invisible current sources are a far larger problem for EU than Dark Matter is for the standard cosmology.
- With currents driven by 30 keV electrons in Peratt's simulations, this is more than enough energy to ionize intergalactic neutral hydrogen (ionization potential = 13.6 eV). Recombination (electron and proton reforming the hydrogen atom) will emit photons at these energies, in the ultraviolet. Cosmological redshift could move this emission into the visible range for galaxies at high redshift (z>4) values. More distant and sensitive surveys should see these currents in the range of optical emission!
July 12 Update: Added labels
- A. L. Peratt, W. Peter, and C. M. Snell. 3-dimensional particle-in-cell simulations of spiral galaxies. 1990.
- W. Peter and A. L. Peratt. Synchrotron radiation spectrum for galactic-sized plasma filaments. IEEE Transactions on Plasma Science, 18:49–55, February 1990.
- A. L. Peratt. Plasma and the Universe: Large Scale Dynamics, Filamentation, and Radiation. Astrophysics & Space Science, 227:97–107, May 1995.
- W. Peter and A. L. Peratt. Thermalization of synchrotron radiation from field-aligned currents. Laser and Particle Beams, 6:493–501, August 1988.
- A. L. Peratt. Electric space : evolution of the plasma universe. Astrophysics & Space Science, 244:89–103, 1996.
- J.P. Wild. The Radio-Frequency Line Spectrum of Atomic Hydrogen and its Applications in Astronomy. Astrophysical Journal, vol. 115, p.206. 1952.