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Cosmology's Missing Mass Problems - Part 2

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New Force Laws

MOND (MOdified Newtonian Dynamics) Mordehai Milgrom, 1983. (MS1)

MOND is a modification of the usual Newtonian force law, hypothesized in 1983 by Moti Milgrom of the Weizmann Institute, as an alternative to Dark Matter. It explains the flat rotation curves of some* spiral galaxies without resorting to the use of dark matter. It applies to Dwarf and Low Surface Brightness galaxies only. (MS2)
*(Acceleration is critical factor - Low acceleration disk galaxies needed.)

MOND can be interpreted as either a modification of gravity through a change to the Poisson equation, or as a modification of inertia through a breaking of the equivalence of inertial and gravitational mass. (It's basically a mathematical exercise.) The modification occurs at very small accelerations.

Stacy McGaugh, a proponent of MOND, says "MOND is difficult to test, and does not constitute a falsifiable theory." (MS1) With that in mind, we move on to new territory.

Chandra observations of the hot gas halo of NGC 720 (a flattened gas distribution) is not consistent with the MOND predictions.
(NNR02) - Was http://www1.msfc.nasa.gov/NEWSROOM/news/releases/2002/02-264.html

Soap-Box Statement

In the writer's opinion, the first missing mass problem (not enough visible mass to account for observed spiral nebulae motions) is inextricably tied to the scale of the universe problem, which is intertwined with the controversy spawned by the idea that Hubble's increasing redshifts should be interpreted as evidence of actual radial velocity increases, or of an expansion of space. [Re-phrased on 01 Aug 2003, and again on 18 Mar 2006.]

* * *

Einstein's equations of GTR did not permit a static universe. The Universe must either be expanding or contracting. The de Sitter solution to the GTR equations predicted an expanding universe.* De Sitter is also the mathematician who almost buried the ideas of Einstein's biggest competitor on relativity theory, Swiss Physicist Walter Ritz. See: (SV87) The author happens to be a fan of Ritz's Newtonian-like electrodynamics, some of which can be seen at (RW08).
*(This statement may need some modifications. Checking! - 17 July 2003)

The Friedman-Lemaitre Standard Cosmological Model (which came to be accepted as a fix to GTR) also predicts an expanding universe. Hubble's increasing redshifts for galaxies at greater and greater distances came to be interpreted as being evidence of the required expansion of the universe, and thus the Big Bang came to be the paradigm.

The author contends that cosmological redshift, as a velocity/distance indicator, has led to a universe whose size is grossly overestimated, and that the inflated "scale of the universe" has contributed to the first of the missing mass problems. Such a view demands a re-interpretation of cosmological redshift. The author's re-interpretation will be respectfully offered for consideration. [Modified 18 Mar 2006.]

The second ... missing mass problem (the flat rotation velocity curves of galaxies/spiral nebulae) is hypothesized to be related to our failure to take into account the electrodynamic interactions of moving interstellar plasma as it affects the group transport of visible galactic matter (stars and gases). This paper will not dwell on the electrodynamic interactions just mentioned, but astrometric evidence consistent with flat galactic velocity curves was copiously published in the early part of the twentieth century. That evidence came to be rejected by mainstream cosmologists. The author maintains that the real reason for the rejection (of the astrometric evidence) was because the evidence was ... contrary to the growing consensus regarding the idea of a large expanding universe. This article calls for renewed attention to the rejected evidence. [Paragraph was "tweaked" on 1 August 2003.}

The Shapley-Curtis Debate (SC21)

Words inserted into these quotes, to clarify matters, are enclosed in [square brackets].
This procedure will be used in other quotations below.

By 1920, the nature of spiral nebulae had become one of the major questions in astronomy. The National Academy of Sciences organized a Scale of the Universe debate on the topic between Harlow Shapley and Heber Curtis.

Shapley defended the "conventional" view that spiral nebulae were objects associated with the galaxy, rather than large, independent stellar systems. (He did want a bigger Milky Way; 300,000 light-years in diameter.)

At that time the estimates for the diameter of "our" galaxy ranged from 7,000 to 60,000 light years. (SC21)

Curtis wanted to restrict the diameter of the Milky Way to about 30,000 light-years, and championed the hypothesis of a large universe in which spiral nebulae were independent stellar systems, e.g., other island universes.

Among Shapley's arguments:

    "Another consequence of the conclusion that the galactic system is of the order of
    300,000 light-years in greatest diameter, is the previously mentioned difficulty it gives
    to the 'comparable-galaxy' theory of spiral nebulae. I shall not undertake a description and
    discussion of this debatable problem. Since the theory probably stands or falls with the
    hypothesis of a small galactic system, there is little point in discussing other material on
    the subject, especially in view of the recently measured rotations of spiral nebulae which
    appear fatal to such an interpretation."

Curtis had difficulty dealing with Shapley's proposed 300,000 light-year diameter galaxy. In his words:

    "If the spirals are island universes it would seem reasonable and most probable to assign
    to them dimensions of the same order as our galaxy. If, however, their dimensions are
    as great as 300,000 light-years, the [other] island universes must be placed at such enormous
    distances that it would be necessary to assign what seem impossibly great absolute magnitudes
    to the novae which have appeared in these objects." (SC21)

Currently, the galaxy is thought to be about 110,000 light-years in diameter, [roughly four times larger than Curtis wanted but about one third the diameter estimated by Shapley.] with the solar system being about 30,000 light-years from the center. (DT71 p. 290)

Here are some further thought provoking remarks that Curtis made with respect to spirals.
(From SC21)

    Many edge-on spirals show a dark, obscuring belt in the middle of the disk. A similar belt
    in the Galaxy would explain why spiral nebulae aren't seen near the plane [of our galaxy].

    Most spiral nebulae have large radial velocities, [based on their redshifts] so they would
    probably escape from the Galaxy's gravity. [This is what lead Zwicky and later researchers
    to postulate missing mass.]

    "The spirals are found in greatest numbers just where the stars are fewest (at the galactic
    poles), and not at all where stars are most numerous (in the galactic plane).... No spiral
    has yet been found actually within the structure [within the confines of the disk] of the
    Milky Way."

    "Their abhorrence of the regions of greatest star density can only be explained on
    the hypothesis that they are, in some unknown manner, repelled by the stars [in our galaxy]."

    "Why should this repulsion have invariably acted essentially at right angles to our galactic plane?"

    "Why have not some been repelled in the direction of our galactic plane?"

    "Should the results of the next quarter-century show close agreement among different
    observers to the effect that the annual motions of translation or rotation of the spirals
    equal or exceed 0.01 arc-seconds in average value, it would seem that the island
    universe theory must be definitely abandoned."

This last remark seems to be in reference to van Maanen's work, who had been regularly reporting annual spiral rotations on the order of 0.02 arcseconds, and in one case as high as 0.038. (Curtis didn't mention van Maanen by name.)

    "It is improbable that our galaxy should, by mere chance, be placed about half way
    between the two great groups of island universes."

Here, he was getting close to admitting a Copernican problem, i.e., a special position for us in the universe.

    "Their space velocity [based on redshifts?] is one hundred times that of the galactic
    diffuse nebulosities, about thirty times the average velocity of the stars, ten times that
    of the planetary nebulae, and five times that of the clusters."

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