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arXiv2022

Diffraction Patterns of Apertures Shaped as National Borders

How aesthetically pleasing is your country's diffraction pattern? This work summarizes the calculated and experimental Fraunhofer diffraction patterns obtained from using apertures lithographically formed into shapes of national borders. Calculations are made based on the fast Fourier transform of the aperture images. The entropy of each of the 113 nations' diffraction patterns was also computed based on its two-dimensional gradient. Results suggest that most nations' diffraction patterns fall under one of two prominent trends forming as a function of geographical area, with one trend being less entropic than the other.

physics.pop-ph↗

arXiv2022

Soap bubbles on the surface of a liquid: a playful universe in 3+1 dimensions, a real universe in 4+1 dimensions

Very simple experiments based on an analogy between two theories (gravitation and capillarity) allowed us to construct a two dimension space toy-universe composed of the surface of a three-dimensional water tank with floating soap bubbles and bubble clusters.This very simple approach leads to a surprising description of our universe with, in particular, the existence of a fourth dimension inaccessible to us. Such a 4th macroscopic dimension suggests the existence of a huge 4 D tank of heavy fluid (analogous to our 3 D water tank) sitting below our three dimensional universe (which is the surface of the main 4 dimensions universe). Among other consequences:an original interpretation of the event horizon of black holes or a simple answer to the problem of missing dark matter.

physics.pop-ph↗

arXiv2022

La Antimateria

Antimatter is one of the most fascinating aspects of Particle Physics and one of the most unknown ones too. In this article we concisely explain what is antimatter and its distinction between primordial and secondary, how it is produced, where it can be found, the experiments carried out at CERN to create and analyze antiatoms, the problem of the matter-antimatter asymmetry, and the medical and technological applications of antimatter in our society. -- La antimateria es uno de los aspectos más fascinantes de la Física de Partículas, y también uno de los más desconocidos. En este artículo explicamos concisamente qué es la antimateria y su diferenciación entre primordial y secundaria, cómo se produce, donde se encuentra, los experimentos que se realizan en el CERN para crear y analizar antiátomos, el problema de la asimetría materia-antimateria, y las aplicaciones médicas y tecnológicas de la antimateria en nuestra sociedad.

physics.pop-ph↗

arXiv2022

In der Unruhe liegt die Kraft

Fluctuations are ubiquitous in nature. They are one of the fundamental building blocks of quantum mechanics and are responsible for a wide variety of phenomena in many areas of physics, ranging from biology to cosmology. Far from any classical intuition, quantum fluctuations are for instance responsible for the appearance of forces between non-magnetic and electrically neutral objects in vacuum, which seem to arise out of nothing. Ever since, quantum fluctuations have fascinated basic research providing new insights into physics and their understanding is becoming increasingly important for various future technologies. -- Fluktuationen sind allgegenwärtig. Sie bilden einen fundamentalen Baustein der Quantenmechanik und sind verantwortlich für die unterschiedlichsten Phänomene, angefangen in der Biologie bis hin zur Kosmologie. Fern jeder klassischen Intuition findet man zum Beispiel Kräfte zwischen nichtmagnetischen und elektrisch neutralen Objekten. Einzig bedingt durch Quantenfluktuationen entstehen diese Kräfte wie aus dem Nichts. Seit jeher begeistern sie die Grundlagenforschung mit neuen Einsichten und gewinnen immer mehr an Bedeutung für verschiedene Zukunftstechnologien.

physics.pop-ph↗

arXiv2022

Estimating the prevalence of malicious extraterrestrial civilizations

This paper attempts to provide an estimation of the prevalence of hostile extraterrestrial civilizations through an extrapolation of the probability that we, as the human civilization, would attack or invade an inhabited exoplanet once we become a Type-1 civilization in the Kardashev Scale capable of nearby interstellar travel. The estimation is based on the world's history of invasions in the last century, the military capabilities of the countries involved, and the global growth rate of energy consumption. Upper limits of standard deviations are used in order to obtain the estimated probability of extraterrestrial invasion by a civilization whose planet we send a message to. Results show that such probability is two orders of magnitude lower than the impact probability of a planet-killer asteroid. These findings could serve as a starting point for an international debate about sending the first serious interstellar radio messages to nearby potentially habitable planets.

physics.soc-ph↗

arXiv2024

Social network heterogeneity benefits individuals at the expense of groups in the creation of innovation

Innovation is fundamental for development and provides a competitive advantage for societies. It is the process of creating more complex technologies, ideas, or protocols from existing ones. While innovation may be created by single agents (i.e. individuals or organisations), it is often a result of social interactions between agents exchanging and combining complementary expertise and perspectives. The structure of social networks impacts this knowledge exchange process. To study the role of social network structures on the creation of new technologies, we design an evolutionary mechanistic model combining self-creation and social learning. We find that social heterogeneity allows agents to leverage the benefits of diversity and to develop technologies of higher complexity. Social heterogeneity, however, reduces the group ability to innovate. Not only the social structure but also the openness of agents to collaborate affect innovation. We find that interdisciplinary interactions lead to more complex technologies benefiting the entire group but also increase the inequality in the innovation output. Lower openness to interdisciplinary collaborations may be compensated by a higher ability to collaborate with multiple peers, but low openness also neutralises the intrinsic benefits of network heterogeneity. Our findings indicate that social network heterogeneity has contrasting effects on microscopic (local) and macroscopic (group) levels, suggesting that the emergence of innovation leaders may suppress the overall group performance.

physics.soc-ph↗

arXiv2022

Magnitudes, distance moduli, bolometric corrections, and so much more

This pedagogical document about stellar photometry - aimed at those for whom astronomical arcana seem arcane - endeavours to explain the concepts of magnitudes, color indices, absolute magnitudes, distance moduli, extinctions, attenuations, color excesses, K corrections, and bolometric corrections. I include some discussion of observational technique, and some discussion of epistemology, but the primary focus here is on the theoretical or interpretive connections between the observational astronomical quantities and the physical properties of the observational targets.

astro-ph.IM↗

arXiv2022

Falling non-harmonic Slinkys

Slinkys that start from a stretched equilibrium position supported at the top and then released to fall under the influence of gravity exhibit the interesting behavior that the bottom of the slinky does not move until the collapsing top of the Slinky reaches the bottom. In this paper, we examine this problem using numerical methods to investigate whether this property holds for generalizations of the slinky physics such as changing the restoring force from the traditional Hookes law or considering random and non-uniform distributions of masses.

physics.pop-ph↗

arXiv2022

Higgs in a box: investigating the nature of a scientific discovery

The discovery of the Higgs boson by the ATLAS and CMS collaborations in 2012 concluded the longest search for a particle in the history of particle physics and was based on the largest and most complex physics experiments ever conducted, involving thousands of scientists and engineers from around the world. It provided crucial evidence for a theory developed in the 1960s that describes the existence of the invisible Brout-Englert-Higgs field and the effects of this field on the mass of elementary particles. After the discovery, the work on the theoretical prediction was awarded the Nobel Prize in Physics 2013. This discovery provides a prime example of modern science in the making and a fantastic opportunity to discuss important aspects of Nature of Science (NoS) in the classroom. In this article, we draw connections between a) milestones in the discovery of the Higgs boson, b) important aspects of NoS, and c) hands-on activities with mystery boxes, which are an effective tool to enable students to experience elements of scientific discovery and explicitly reflect on NoS. We hope that this supports educators in bringing lively discussions about modern physics research into their classrooms.

physics.ed-ph↗

arXiv2022

Polaris: The Mathematics of Navigation and the Shape of the Earth

For millenia, sailors have used the empirical rule that the elevation angle of Polaris, the North Star, as measured by sextant, quadrant or astrolabe, is approximately equal to latitude. Here, we show using elementary trigonometry that Empirical Law 1 can be converted from a heuristic to a theorem. A second ancient empirical law is that the distance in kilometers from the observer to the North Pole, the geodesic distance measured along the spherical surface of the planet, is the number of degrees of colatitude multiplied by 111.1 kilometers. Can Empirical Law 2 be similarly rendered rigorous? No; whereas as the shape of the planet is controlled by trigonometry, the size of our world is an accident of cosmological history. However, Empirical Law 2, can be rigorously verified by measurements. The association of 111 km of north-south distance to one degree of latitude trivially yields the circumference of the globe as 40,000 km. We also extend these ideas and the parallel ray approximation to three different ways of modeling a Flat Earth. We show that photographs from orbit, taken by a very expensive satellite, are unnecessary to render the Flat Earth untenable; simple mathematics proves Earth a sphere just as well.

physics.pop-ph↗

arXiv2022

The 1908 Tunguska Event And The 2013 Chelyabinsk Meteoritic Event: Comparison Of Reported Seismic Phenomena

Till now there is no solid scientific proof for any of the numerous hypotheses proposed for the Tunguska 1908 event. Regarding the most popular "spacebody infall" interpretation it is reasonable to compare the Tunguska event with the 2013 Chelyabinsk meteoritic event which energy deposition was about a half megaton TNT. In this paper seismic manifestations are compared. The comparison demonstrates that while a "seismic image" of the 2013 Chelyabinsk meteoritic event is an agreement with the "spacebody infall" theory, the 1908 Tunguska event one strongly differs. There are evidences of a swarm of earthquakes on June 30, 1908 in the region of the Tunguska event manifestation.

physics.pop-ph↗

arXiv2022

False positives and the challenge of testing the alien hypothesis

The origin of life and the detection of alien life have historically been treated as separate scientific research problems. However, they are not strictly independent. Here, we discuss the need for a better integration of the sciences of life detection and origins of life. Framing these dual problems within the formalism of Bayesian hypothesis testing, we show via simple examples how high confidence in life detection claims require either (1) a strong prior hypothesis about the existence of life in a particular alien environment, or conversely, (2) signatures of life that are not susceptible to false positives. As a case study, we discuss the role of priors and hypothesis testing in recent results reporting potential detection of life in the Venusian atmosphere and in the icy plumes of Enceladus. While many current leading biosignature candidates are subject to false positives because they are not definitive of life, our analyses demonstrate why it is necessary to shift focus to candidate signatures that are definitive. This indicates a necessity to develop methods that lack false positives, by using observables for life that rely on prior hypotheses with strong theoretical and empirical support in identifying defining features of life. Abstract theories developed in pursuit of understanding universal features of life are more likely to be definitive and to apply to life-as-we-don't-know-it. In the absence of alien examples these are best validated in origin of life experiments, substantiating the need for better integration between origins of life and biosignature science research communities.

astro-ph.EP↗

arXiv2022

Milestones of research activity in quantum computing: EPS grand challenges

We argue that quantum computing underwent an inflection point circa 2017. Long promised funding materialised which prompted public and private investments around the world. Techniques from machine learning suddenly influenced central aspects of the field. On one hand, machine learning was used to emulate quantum systems. On the other hand, quantum algorithms became viewed as a new type of machine learning model (creating the new model of {\it variational} quantum computation). Here we sketch some milestones which have lead to this inflection point. We argue that the next inflection point would occur around when practical problems will be first solved by quantum computers. We anticipate that by 2050 this would have become commonplace, were the world would still be adjusting to the possibilities brought by quantum computers.

physics.hist-ph↗

arXiv2023

The reconstruction of the Antikythera Mechanism Instruction Manual after a diligent study and analysis of the Back cover inscription (Part-1 and Part-2)

The Inscriptions which were on the Back Cover of the Antikythera Mechanism were the Users Manual of the Antikythera Mechanism. In the Back Cover Inscription Part 1 text, the Presentation, Position, and Operation of the outer parts of the Mechanism Front face was engraved by the ancient manufacturer. Although this technical text is partially or poorly preserved, useful information, results and conclusions were retracted by studying the words and the sentences adapted on their original geometrical positions, concerning the image of the Mechanism front face. After the study and the analysis of the preserved text and its characteristics, the missing text completion is presented. A significant part of the reconstructed text was reproduced using the preserved words and phrases. In many cases the reconstructed text can be considered as definite. The use of the authors Antikythera Mechanism functional model was critical for the analysis and understanding the preserved text, contributing to the design and reconstruction of the Mechanism Front Face parts, which are not preserved nowadays.

physics.hist-ph↗

arXiv2022

On technical considerations of UCI-regulated velodrome track design

A novel approach to velodrome design for UCI-regulated tracks is presented. The mathematical model uses differential geometry to form a three-dimensional ruled surface. The surface accounts for the safety zone, blue band, and track region, the latter of which is comprised of three types of segments: straight lines, the arcs of circles, and connecting transition curves. Following a first-principles approach, the general expressions are derived from the Frenet-Serret relations, as a function of the banking and curvature profiles, lengths of curve segments, and turn radii of the bends. Given the underdetermined nature of the design problem, particular solutions are obtained using a least-squares minimization of an objective function, within the framework of numerical optimization. Computer renderings of two designs, a symmetric assembly of quadrants as well as an asymmetric one, are presented to demonstrate the versatility of the approach, which may be used to design velodrome tracks of any UCI Category and track geometry specification.

physics.pop-ph↗

arXiv2022

Cutting and Sewing Riemann Surfaces in Mathematics, Physics and Clay

A series of ceramic artworks are presented, inspired by the author's research connecting theoretical physics to the beautiful theory of Riemann surfaces. More specifically the research is related to the classification of curves on the surfaces based on a description of them as built from basic building blocks known as "pairs of pants". The relevant background on this mathematics of these two dimensional spaces is outlined, some of the artistic process is explained: Both the conceptual ideas and their implementation. Many photos of the ceramics are included to illustrate this and the connected physics problem is briefly mentioned.

physics.pop-ph↗

arXiv2022

Physical description and modelling of paper strip flights

Paper strips, e.g. confetti, descending to the floor begin to rotate around the horizontal axis after a short time. This slows down the vertical velocity compared to free fall and adds a horizontal velocity component. The frequency of rotation, the angle of fall and the speed of fall seem to depend on the dimensions and mass of the paper strips. The physics of this flight can be described, i.e. the movement, the translation of the centroid (energy analysis, force analysis, formula for fall speed v(b,h,m), formula for angle of fall α(b,h,m)), the rotation around centroid (formula for frequency f(b,h,m), rotation speed), the flight path with the results from translation and rotation, the visualization of air turbulence and the loss of energy.

physics.pop-ph↗

arXiv2022

Recollections of Kip Thorne

Brief recollections by the author about how his work with Kip Thorne influenced his career in physics.

physics.pop-ph↗