arXiv subjects

Alasdair Macleod

Publications and source records attributed to Alasdair Macleod.

11 recordsLinked to original sources

arXiv2023

Determining Molecular Complexity using Assembly Theory and Spectroscopy

Determining the complexity of molecules has important applications from molecular design to understanding the history of the process that led to the formation of the molecule. Currently, it is not possible to experimentally determine, without full structure elucidation, how complex a molecule is. Assembly Theory has been developed to quantify the complexity of a molecule by finding the shortest path to construct the molecule from building blocks, revealing its molecular assembly index (MA). In this study, we present an approach to rapidly and exhaustively calculate the MA of molecules from the spectroscopic measurements. We demonstrate that molecular complexity (MA) can be experimentally estimated using three independent techniques: nuclear magnetic resonance (NMR), tandem mass spectrometry (MS/MS), and infrared spectroscopy (IR), and these give consistent results with good correlations with the theoretically determined values from assembly theory. By identifying and analysing the number of absorbances in IR spectra, carbon resonances in NMR, or molecular fragments in tandem MS, the molecular assembly of an unknown molecule can be reliably estimated from experimental data. This represents the first experimentally quantifiable approach to defining molecular assembly, a reliable metric for complexity, as an intrinsic property of molecules and can also be performed on complex mixtures. This paves the way to use spectroscopic and spectrometric techniques to unambiguously detect alien life in the solar system, and beyond on exoplanets.

q-bio.QM↗

arXiv2007

A physical basis for MOND

MOND is a phenomenological theory with no apparent physical justification which seems to undermine some of the basic principles that underpin established theoretical physics. It is nevertheless remarkably successful over its sphere of application and this suggests MOND may have some physical basis. It is shown here that two simple axioms pertaining to fundamental principles will reproduce the characteristic behaviour of MOND, though the axioms are in conflict with general relativistic cosmology.

physics.gen-ph↗

arXiv2006

Physics at the Transition between Bounded and Unbounded Trajectories

The electromagnetic interaction is characterised by discrete states for bound systems in contrast to continuous states for unbound systems. The difference merely arises because the characteristic equations do not exhibit the same behaviour for negative and positive energy parameter values, thus the apparent distinction between bound and unbound states can be considered purely descriptive and completely superficial - there is no indication that bounded and unbounded systems are subject to differing physical laws. However, the remarkable suggestion has been made that there exists a behavioural distinction between bound and unbound states of systems under gravitational influence. This notion is critically evaluated here. At the very basic level, a severe problem is found in defining a local concept of boundedness consistent with the current understanding of the gravitational interaction. Nevertheless it is difficult to exclude the possibility that bound and unbound systems are dynamically distinct, a distinction that may be relevant to existing cosmological and astronomical anomalies.

physics.gen-ph↗

arXiv2006

Solar Eclipse Anomalies and Wave Refraction

There is some inconclusive evidence that measurement devices sensitive to local gravitation exhibit anomalous behaviour during solar eclipses. We investigate if these findings can be incorporated into the standard general relativistic model of gravitation. The General Theory of Relativity (GTR) describes gravitation as the response of an object to local spacetime curvature. Gravitational waves travelling at the speed of light are then a necessary mechanism to maintain the required consistency between local curvature and distant gravitating mass. Gravitational waves will certainly be subject to refraction by bodies such as the moon and we explore if such an effect can result in an error in the apparent position of the sources and thereby give rise to the characteristic pattern of response associated with the eclipse anomaly. It is found there are phenomenological similarities, but only if gravitational waves are considered not merely to respond to spacetime curvature but are also significantly affected by the presence of mass, perhaps in a manner analogous to electromagnetic waves propagating through matter.

physics.gen-ph↗

arXiv2005

Do redshifted cosmological photons really violate the principle of energy conservation?

Although the Universe is far from understood, we are fairly confident about some key features: Special Relativity (SR) describes the kinematics of inertial frames; General Relativity (GR) explains gravitation; the Universe had a beginning in time and has been expanding since. Nevertheless it is quite difficult to see the 'big picture', although the idea of applying GR to the entire Universe has been very successful with a model emerging that is consistent with observation. One unpleasant feature of the model is that cosmological photons appear not to conserve energy, and the only explanation forthcoming is the claim that GR is exempt from the principle of energy conservation. It is demonstrated here that cosmological observations may legitimately be projected onto flat spacetime and can then be treated Special Relativistically, whereupon energy conservation is restored. This is not to say that the concordance General Relativistic cosmological model is incorrect, just that in observational terms there is no energy conservation anomaly.

physics.gen-ph↗

arXiv2005

An Interpretation of Milne Cosmology

The cosmological concordance model is consistent with all available observational data, including the apparent distance and redshift relationship for distant supernovae, but it is curious how the Milne cosmological model is able to make predictions that are similar to this preferred General Relativistic model. Milne's cosmological model is based solely on Special Relativity and presumes a completely incompatible redshift mechanism; how then can the predictions be even remotely close to observational data? The puzzle is usually resolved by subsuming the Milne Cosmological model into General Relativistic cosmology as the special case of an empty Universe. This explanation may have to be reassessed with the finding that spacetime is approximately flat because of inflation, whereupon the projection of cosmological events onto the observer's Minkowski spacetime must always be kinematically consistent with Special Relativity, although the specific dynamics of the underlying General Relativistic model can give rise to virtual forces in order to maintain consistency between the observation and model frames.

physics.gen-ph↗

arXiv2005

Coexisting Spacetimes in the Solar Neighborhood

We consider the proposition that multiple universes exist by reviewing the various manifestations. In recent years, this idea has been elevated from science fiction and introduced in separate guises as an explanation for coincidence problems in cosmology, the prediction of dark energy, gravitational anomalies, a consequence of string theory, an extension of inflation, and conceptual issues in quantum mechanics. However, there appears to be no single consistent formalism that addresses all the issues - it is not even clear if the multiple universes interact or are accessible. Because of the absence of clear evidence, it is easy to dismiss claims for multiple Universes, but it is not that simple: Space-time geometries in a variety of forms are an established aspect of physics, and history has shown that things which are not expressly forbidden often appear at a later date. With this in mind, a new example of possible multiple geometries is introduced to explain a difficult problem in cosmology: Why are distant galaxies subject to the Hubble expansion but rulers within our galaxy (and presumably, by the Cosmological Principle, all other galaxies) do not appear to expand? There has actually been much debate in recent years about whether local systems really are subject to the cosmological expansion; we adopt the established view that local systems are not expanding and investigate the transition condition where a mass may be part of the static galactic system or participate in the expansion. We show that a remarkably simple model based on coexisting spacetimes clarifies the situation and makes quantative, testable cosmological predictions. The model is also testable through Earth-based experiments.

physics.gen-ph↗

arXiv2004

Redshift and Energy Conservation

It has always been considered a serious error to treat the cosmological redshift as a Doppler velocity effect rather than the result of space expansion. It is demonstrated here that in practical terms this is not the case, and that the apparent distance - redshift relation derived from a Doppler interpretation is reasonably consistent with supernova data (though not as good as the standard model with dark energy). The normal Doppler effect is examined in detail and shown to conserve energy as expected. Because of the equivalence between the general relativistic space expansion paradigm and the Doppler effect (as demonstrated) the long-standing problem of energy loss associated with the expansion of the Universe is treated in a similar manner to the normal well-behaved Doppler effect. The mechanism by which energy is conserved with the normal Doppler shift is applied to the cosmological redshift and the energy violation disappears. However, an additional luminosity-dependent recession factor is introduced. The effect on astronomical objects is examined and it is found to add only a small additional redshift to a body generating power by nuclear means but can be very large for objects powered by gravity. A possible connection to the claimed anomalous redshift of quasars is considered.

physics.gen-ph↗

arXiv2004

Evidence for a Universe expanding at the speed of light

Although big bang cosmology effectively models even the most puzzling observational data, it offers no insight into why the cosmological expansion should occur at all. In this paper it is suggested that a finite Universe poses particular problems at the boundary point when time begins. An alternative model is proposed where the expansion arises from a need to incorporate the boundary effects into observation in a consistent way that avoids discontinuities and singularities. The theory predicts that the Universe is expanding at a constant rate, the speed of light, and is a reasonable match for apparent magnitude - redshift data for both supernovae and 3CR radio sources using only one adjustable parameter, the absolute visual magnitude. Values of -21.8 for the 3CR galaxies and -25.2 for the 3CR quasars give the best fit. The new model is mapped to standard cosmology and predicts a deceleration parameter with a time dependence of the form q(t)=1-2t/T, where T is the current age of the Universe. The model of expanding space-time with expansion retarded by gravity is usually associated with Friedmann's equation(s) but here is considered erroneous, giving rise to spurious concepts such as dark energy - in this new model mass and gravity have no effect on expansion.

physics.gen-ph↗

arXiv2004

The Causal Event Set

To clarify some aspects of the application of Special Relativity, spacetime is sliced into null geodesic hypersurfaces as an alternative to the hypersurfaces of simultaneity normally adopted. Events at particle locations on the hypersurface are identified as the causal event set. It is demonstrated that a Lorentz boost applied to the causal event set maintains the property of connectedness and with this formalism it is simple to derive the redshift equation. The twin paradox is naturally explained as an instantaneous reconfiguration of particle position 4-vectors in the frame of the accelerated object. The metaphysical implications are examined with the tentative conclusion that a relationist view of spacetime is more consistent with this treatment than the substantivalist viewpoint.

physics.gen-ph↗

arXiv2004

Hubble Energy

Light received from a cosmological source is redshifted with an apparent loss of energy, a problem first pointed out by Edwin Hubble in 1936. A new type of energy called Hubble Energy is introduced to restore the principle of energy conservation. The energy has no inertial or gravitational effect but retards radial motion in a manner consistent with the anomalous acceleration experienced by the Pioneer probes leaving the solar system. The energy is predicted to have important effects on the scale of galaxies, and some of these effects are qualitatively examined: for example, with Hubble Energy, flat rotation curves are found to be an inevitable consequence of spiral galaxy formation. The Hubble Energy is incorporated into the Friedmann Equation and shown to add a term similar to the cosmological term, with a magnitude of order 10^-35 s^-2.

physics.gen-ph↗