Dark Matter
The current cosmological model only works by postulating the existence of dark matter – a substance that has never been detected, but that is supposed to constitute approximately 25% of all the universe. But a simple test suggests that dark matter does not in fact exist. If it did, we would expect lighter galaxies orbiting heavier ones to be slowed down by dark matter particles, but we detect no such slow-down. A host of other observational tests support the conclusion: dark matter is not there. The implications of this are nothing short of a revision of Einstein’s theory of gravitation. Why the scientific community is in denial about the falsification of the dark matter model is a question that requires both a sociological and philosophical explanation.
The List of Flawed Falsification Claims about MOND [modified theory of Newton that can account for data without dark matter hypothesis].. Modern theories in physics need to be tested and, if they significantly fail a test, discarded...
In this sense, the dark-matter based theories (case A above) have been rigorously and robustly falsified to any high degree of standard in the physical sciences (see previous and next post). What about MOND (theory B above)? It too is a physical theory allowing predictions. It too can be ruled out.
Srikanth Togere Nagesh has put a large effort to track down and document the published falsifications of MOND. It turns out that the claimed falsifications of MOND have all been shown, in the published scientific research literature via rebuttals, to be flawed.
It is astonishing that there is a deep mystery and controversy about something as apparently simple as the dynamics of our galaxy, the Milky Way. This is not a problem with something esoteric like quantum field theory or general relativity, this is a problem at the level of simple high school physics, ie, Newton’s laws and gravity. It is not about disagreements between theory and experiment of fractions of a percent, but, rather, 5-to-10-fold errors.
I am referring to the problem of the rate of the rotational velocity of gases at the outer fringes of spiral galaxies. The steady state rotational velocity is the resultant of the balance between the centrifugal force and the gravitational force from the mass of the rest of the galaxy. The observed velocity is greater by a factor of two or more than is predicted from Newton’s laws and the known experimental mass density of the stars, gases and dust. To account for this using standard Newtonian theory, it is necessary to postulate that there is some extra missing mass, representing about 75% of the total galaxy gravitational mass, that is made of some exotic particle(s) referred to as “cold dark matter” (CDM). Despite enormous experimental efforts to directly detect CDM, representing hundreds of sophisticated searches using everything from the large hadron collider at CERN to exotic underground detectors, all have come up with absolutely nothing..
The alternative, Modified Newtonian Dynamics, MOND theory was first proposed in 1983 by Mordehai Milgrom (2-4). In place of postulating missing mass to account for the rotational gravitational force, Milgrom proposed that, for the extremely small gravitational force (and resulting rotational acceleration) at the outer fringes of galaxies, Newton’s second law (Force = mass x acceleration or F = m a)) does not apply and should be replaced with the modified relation:
$$ F = m s^2 / a_0 $$
where $a_0 \approx 1.2 x 10^{-10} m/sec^2$. Compared to CDM, this modification provides a much simpler (fewer adjustable parameters) and more accurate description of the galaxy rotation..
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