Errors in Lerner's Criticism of the Big Bang

Eric Lerner starts his book "The Big Bang Never Happened" (hereafter BBNH) with the "errors" that he thinks invalidate the Big Bang. These are

1. The existence of superclusters of galaxies and structures like the "Great Wall" which would take too long to form from the "perfectly homogeneous" Big Bang.
2. The need for dark matter and observations showing no dark matter.
3. The FIRAS CMB spectrum is a "too perfect" blackbody.

Are these criticisms correct? No, and they were known to be incorrect in 1991 when Lerner wrote his book. [Making Eric Lerner another creationist liar, amoral, crazy, monkey brained, one could say - Corinthian]

Let us look at the superclusters first.

Lerner gives the example of filaments or sheets 150 million light years apart in Figure 1.1, and then asserts that material would have to travel 270 million light years to make the structure. Obviously 75 million light years would do the trick. With material traveling at 1000 km/sec, that would take 22.5 billion years, which is about twice as long as the probable age of the Universe. But when the Universe was younger, everything was closer together, so a small motion made early in the history of the Universe counts for much more than a motion made later. Thus it was easier for the material to clump together early in the history of the Universe. Lerner's math here is like ignoring interest when planning for retirement. If you save $1000 per year for 50 years, you don't retire with $50,000. If the interest rate was 7 percent throughout the 50 years, you will have a $460,000 nest egg.

Furthermore, velocities relative to the Hubble flow naturally decrease with time, so the 1000 km/sec velocity was larger in the past. Lerner's discussion of this point uses loaded words and incorrect logic. He quotes unnamed cosmologists as "speculating" that matter moved faster in the past, and calls this an "unknown" process. In fact, it is just Newton's First Law. Consider an object moving at 1000 km/sec relative to the Hubble flow at our location. For H_o = 65 km/sec/Mpc this object will have moved 1.54 Mpc in 1.5 Gyr, the time it takes for the Universe to grow by 10% for this value of H_o. Its velocity will still be 1000 km/sec, but the Hubble flow at a distance of 1.54 Mpc is 1.54*65 = 100 km/sec, so the object's velocity relative to the Hubble flow is now only 900 km/sec. It went down by 10% while the Universe grew by 10%.

For example, the neutrinos in the hot dark matter model are just coasting, or "free streaming". If a free streaming neutrino has 1000 km/sec velocity now, then since recombination it has traveled from a point that is now 2.8 billion light years away. If instead of free streaming the material has been accelerated by gravitational forces, then the relation between velocity relative to the Hubble flow and the distance to the starting point (measured now), is

v = H*D*Omega0.6 

Using Lerner's value of 1000 km/sec, and a distance of 75 million light years, and H_o = 50 km/sec/Mpc, we find perfect agreement as long as Omega is close to 1. So Lerner's "structures that take too long to grow" are just more evidence for a large amount of dark matter.

In fact, Jim Peebles at Princeton had calculated just how much inhomogeneity in the early Universe would have been needed to grow into the large scale structures we see today. The anisotropy can be used to measure the inhomogeneity. This calculation was published in 1982 (ApJ Lett, 263, L1) and showed that an anisotropy of the temperature of the microwave background with an RMS quadrupole amplitude of 6 microKelvin would have been produced by the inhomogeneity necessary to produce the clustering of galaxies, if the Hubble constant was H_o = 100 km/sec/Mpc. For H_o = 50, the RMS quadrupole would be 12 microK. The actual limit at the time was 600 microK, so there wasn't any problem producing the large scale structure. Later results reduced the limit on the RMS quadrupole to 200 microK by the time Lerner published his book. Thus when Lerner wrote the BBNH, models could reproduce the observed large scale structure with initial conditions that were twenty times more uniform than the observed limit on homogeneity.

In 1991 the limit was reduced to 22 microK by the FIRS balloon experiment and then COBE discovered the anisotropy with a level of 17+/- 5 microK and the current best value is 18.4+/-1.6 microK.

So where was the "crisis"? The "crisis" only arises if there is no dark matter. Without dark matter you need 10 times larger initial perturbations and thus a 10 times larger RMS quadrupole, which was finally ruled out in 1991 after Lerner wrote his book.

Lerner quotes George Field saying there was a crisis, but doesn't give a citation in the book. I remember many newspaper articles saying there was a crisis, but those of us building the COBE satellite knew that nobody had made observations with enough sensitivity to test the models calculated by Peebles, and just hoped that COBE would work well enough to do the job.

By 1992, the model Peebles used had been named "Cold Dark Matter" and people were saying it was "dead" (see "The End of Cold Dark Matter?" by Davis et al., 1992, Nature, 356, 489). But this was from trying to get the details just right: you could make the superclusters and then you had too many cluster of galaxies, or you could make the clusters with a smaller RMS quadrupole and then made too few superclusters. The COBE measurement matched the value needed to make the superclusters. Thus the problem with CDM is that it makes too much structure, not too little. There are several ways to modify CDM to make it work:

• Have H_o low: 42 would probably be OK.
• Have a density less than critical.
• Have a neutrino species with a mass of 5 eV or so.
• Have a cosmological constant.

and I don't know which (if any) if these are correct. Lerner refers to these options as "epicycles" but some of them are just taking the observations at face value: most measurement of the density are 2 to 3 times less than the critical density. Non-zero neutrino masses have been measured. Observations of distant supernovae suggest that the cosmological constant is non-zero.

Ironically, while Lerner uses this false argument against the Big Bang to advocate an infinitely old Universe, young Earth creationists use the same argument to bolster their belief that the Universe is only several thousand years old.

Is there dark matter?

There is certainly lots of evidence for dark matter. When one looks at cluster of galaxies, the gravitational effects of the cluster can be measured three ways. One is by the orbital motions of the galaxies in the cluster. This was first done by Zwicky in 1933 (Helv. Phys. Acta, 6, 110)! A second looks at the hot gas trapped in many big clusters of galaxies. The third way looks at the bending of light from galaxies behind the cluster by the mass in the cluster (gravitational lensing). All three methods give masses that appear to be very much larger than the mass of the stars in the galaxies in the cluster. This is usually given as the mass-to-light ratio, and M/L is several hundred solar units for clusters of galaxies and only about 3 for the stars in the Milky Way near the Sun.

The paper that Lerner cites as evidence for a lack of dark matter, Valtonen and Byrd (1986, ApJ, 303, 523), claims that the Coma cluster of galaxies and the other great clusters of galaxies are not bound objects. However, the observed velocities within the cluster would cause them to disperse in much less than the age of the Universe, so this claim is quite strange. Furthermore, the X-ray and gravitational lensing evidence now available show that Valtonen and Byrd were incorrect.

The only way to satisfy these observations without a lot of dark matter is to hypothesize that the force of gravity is much stronger at large distances than Newton (or Einstein) would predict. This model is called MOND, for Modification Of Newtonian Dynamics, and it has some adherents. But no good relativistic version of MOND exists, and the existence of gravitational lensing in cluster of galaxies requires a relativistic theory that makes the same change for light and for slow moving objects like galaxies. Furthermore, if the MACHO results hold up, then the MOND model will fail for the halo of the Milky Way. If we then need dark matter to explain the Milky Way halo, it is most reasonable to use the same explanation in distant clusters of galaxies.

More about dark matter.

Is the CMB spectrum "too perfect"?

Lerner claims that the CMB spectrum presented by Mather in 1990 was "too perfect", and that it made it impossible for large scale structure to be formed. However, the perfect fit to the blackbody only ruled out explosive structure formation scenarios like the Ostriker and Cowie model (1981, ApJL, 243, L127). The limits on distortion of the CMB spectrum away from a blackbody are now about 100 times better, and these tighter limits are easily met by models which form large scale structure by gravitational perturbations acting on dark matter. Models which act via electromagnetic interactions, like the explosive structure formation scenario or the plasma Universe have a much harder time meeting the constraints imposed by the FIRAS observations of the CMB spectrum.

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