A historical perspective on Modified Newtonian Dynamics

I review the history and development of Modified Newtonian Dynamics (MOND) beginning with the phenomenological basis as it existed in the early 1980s. I consider Milgrom's papers of 1983 introducing the idea and its consequences for galaxies and galaxy groups, as well as the initial reactions, both negative and positive. The early criticisms were primarily on matters of principle, such as the absence of conservation laws and perceived cosmological problems; an important step in addressing these issues was the development of the Lagrangian-based non-relativistic theory of Bekenstein and Milgrom. This theory led to the development of a tentative relativistic theory that formed the basis for later multi-field theories of gravity. On an empirical level the predictive success of the idea with respect to the phenomenology of galaxies presents considerable challenges for cold dark matter. For MOND the essential challenge remains the absence of a generally accepted theoretical underpinning of the idea and, thus, cosmological predictions. I briefly review recent progress in this direction. Finally I discuss the role and sociology of unconventional ideas in astronomy in the presence of a strongly entrenched standard paradigm.Comment: 25 pages, 9 figures, previous uploaded file was out of date, Canadian Journal of Physic

NGC 2419 does not challenge MOND, Part 2

I argue that, despite repeated claims of Ibata et al., the globular cluster NGC 2419 does not pose a problem for modified Newtonian dynamics (MOND). I present a new polytropic model with a running polytropic index. This model provides an improved representation of the radial distribution of surface brightness while maintaining a reasonable fit to the velocity dispersion profile. Although it may be argued that the differences with these observations remain large compared to the reported random errors, there are several undetectable systematic effects which render a formal likelihood analysis irrelevant. I comment generally upon these effects and upon the intrinsic limitations of pressure supported objects as tests of gravity.Comment: 3 page, 2 figure

The ecology of the kākerōri (Rarotonga flycatcher) Pomarea dimidiata, with special reference to fledged young : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Ecology at Massey University

The Kakerori (Pomarea dimidiata) is a small flycatcher, endemic to Rarotonga in the Cook Islands. In August 1991 the total world population was estimated at 47 individuals, an increase of 14 birds from the previous year. Kakerori live in the forest canopy of small valleys in the steep, mountainous interior. This study concentrated on the ecology of young birds and factors affecting the breeding success (the number of fledged young produced) of pairs. Young birds remain in the parental territory for up to four months after fledging, where they are commonly found high in the leafy canopy (mean = 25.7m n=36). After parental care has ceased, young birds move to the high, exposed ridges up to 100m from their natal territories (mean = 87m n=14), and remain on average, 2.4m (n=14) from the ground. Successful Kakerori territories (those that have produced fledged young) have a relatively lowered canopy (10.3m) and few ferns (28.3%), with many juvenile trees (38.3%) and shrubs (33.4%) making up the shrub layer. These juvenile trees may ensure a continued closed canopy. Successful territories also have few, large trees (mean total basal area = 7.39m2) and a higher level of moss (16.5%) which may encourage larger populations of insects as well as providing possible nest sites for Kakerori. Unsuccessful territories (those that produced no fledged young) have many, immature trees (mean total basal area = 3.21 m2) and little moss (8.1%). In general, insect numbers varied little between successful and unsuccessful territories, however during February 1991 successful territories had a large percentage of flies (40.4% n=23) compared to unsuccessful (8.3% n=2). During February when adults are feeding newly fledged young, a greater availability of insects may positively affect breeding success. Poison baits for rats have been laid in the study area since 1988 and the number of fledged young found has increased from one in 1987/1988 to 14 in 1990/1991. The most effective method of conserving the Kakerori may be to continue indefinitely the rat-baiting campaign throughout the study area and neighbouring valleys. This would depend entirely on the availability of funds and committed personnel

The prediction of rotation curves in gas-dominated dwarf galaxies with modified dynamics

I consider the observed rotation curves of 12 gas-dominated low-surface-brightness galaxies -- objects in which the mass of gas ranges between 2.2 and 27 times the mass of the stellar disk (mean=9.4). This means that, in the usual decomposition of rotation curves into those resulting from various mass components, the mass-to-light ratio of the luminous stellar disk effectively vanishes as an additional adjustable parameter. It is seen that the observed rotation curves reflect the observed structure in gas surface density distribution often in detail. This fact is difficult to comprehend in the context of the dark matter paradigm where the dark halo completely dominates the gravitational potential in the low surface density systems; however it is expected result in the context of modified Newtonian dynamics (MOND) in which the baryonic matter is the only component. With MOND the calculated rotation curves are effectively parameter-free predictions.Comment: 9 pages, 4 figures, submitte

Feed-through has polyterminal feature

Feed-through connector with individual solder pots in the polyterminal side provides good connections with small amounts of solder and permits visual inspection of bonds. Polyterminal also provides a friction mechanical bond to position conductors prior to soldering

A tensor-vector-scalar framework for modified dynamics and cosmic dark matter

I describe a tensor-vector-scalar theory that reconciles the galaxy scale success of modified Newtonian dynamics (MOND) with the cosmological scale evidence for CDM. The theory provides a cosmological basis for MOND in the sense that the predicted phenomenology only arises in a cosmological background. The theory contains an evolving effective potential, and scalar field oscillations in this potential comprise the cold dark matter; the de Broglie wavelength of these soft bosons, however, is sufficiently large that they cannot accumulate in galaxies. The theory predicts, inevitably, a constant anomalous acceleration in the outer solar system which, depending upon the choice of parameters, can be consistent with that detected by the Pioneer spacecrafts.Comment: minor corrections, numerical error corrected in eq. 37 and subsequent equations, accepted MNRA