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preprint2022arXiv

The Voronoi Diagram in Soccer: a theoretical study to measure dominance space

In this article, I argue that the concept of the standard Voronoi diagram is incorrect for the calculation of dominance area in soccer. The correct region that should replace the polygonal Voronoi region controlled by a player emerges naturally by studying the motion of the players. It turns out that the widely-used standard Voronoi diagram is true only when all 22 players have the same speed (with vanishing speed being a special case) and it should be replaced by other diagrams whose regions have more complicated boundaries. The unfortunate error happened when the mathematical concept of the Voronoi diagram that has an implicit vanishing speed for its points was transferred to soccer without looking at the kinematical issues involved in the game of soccer. For this reason, as a byproduct of this work, I argue for the promotion of "soccerdynamics", model building for soccer by looking at the underlying mechanisms and not just adopting mathematical ideas only for their appeal and beauty.

preprint2024arXiv

Reysa Bernson, the unconventional head of the first French planetarium

The first modern planetarium was presented in 1923 in Jena, Germany. Very soon in the subsequent years, planetariums were installed in other parts of Europe as well as in America. France, however, got its first planetarium only in 1937, for the World Exhibition organized in Paris. The team that took care of that planetarium was headed by a female amateur astronomer named Reysa Bernson. This choice might seem surprising, but it was not made at random, thanks to her never-ending astronomical activities at that time. This paper aims to bring back memories of this very active amateur astronomer of the 1920s and 1930s, and show the many ways in which astronomy was disseminated a century ago.

preprint2025arXiv

Hawksmoor's Ceiling, Mercator's Projection and the Roman Pantheon

The ceiling of the Buttery in All Souls College, Oxford, designed by the English Baroque architect Nicholas Hawksmoor, has a vaulted form on an oval base. It is coffered with an array of approximately square sunken lacunaria, whose sizes and positions vary so as to accommodate the constraints of the curved surface and its boundaries. A similar design appears in the dome of the Roman Pantheon. Using methods of differential geometry, we hypothesise that these cofferings should be the images under conformal mappings of regular square tilings of a rectangle or finite cylinder. This guarantees that the coffer ribs meet exactly at right angles and the coffers are close to being square. These mappings are simply the inverse of Mercator's projection of the curved surface onto a plane. For a ceiling which is a general surface of revolution, we derive formulae for the dimensions and location of each coffer. Our results, taking into account camera distortion, are in excellent agreement with photographs of the Hawksmoor ceiling and the Pantheon dome, as well as with recent direct measurements of the latter. We also describe a protocol by which Hawksmoor's ceiling might have been constructed without advanced mathematics.

preprint2022arXiv

Radio bridges of the future between Solar system and the nearest 50 stars

The Solar Gravitational Lens (SGL) is a gift of nature that Humanity is now ready to exploit. SGL physics started with Einstein's 1936 paper on the gravitational lensing; it was not until 1979 that the idea of a space mission reaching the Sun's nearest focal sphere at 550 Astronomical Units (AU) was put forward by Von Eshleman. By the year 2000, the senior author of this paper (CM) had submitted a relevant formal proposal to ESA about the relevant space mission to 550 AU. He presented his ideas at NASA-JPL for the first time on August 18. In 2020 NASA awarded a $2million grant to JPL to prepare for the first FOCAL space mission. But radio bridges between the Sun and any nearby star may also be conceived. The idea is that, if Humanity will be able to send unmanned space probes to the nearest stars in the future, each of these probes could be placed behind the star of arrival and along the star-Sun line, thus allowing for TWO gravitational lenses to work together. That will result in a permanent communication system with much REDUCED POWERS to keep the radio link between the two stellar systems: a veritable Galactic Internet. In this paper, we study for the first time the 50 radio bridges between the Sun and each of the nearest 100 stars in the Galaxy. Of course, this work is for the centuries to come. But knowing which natural radio bridge between the Sun and each of the nearest 50 stars is MORE CONVENIENT, will open the ROAD MAP for the HUMAN EXPANSION into the Galaxy.

preprint2022arXiv

Can Decoherence Solve the Measurement Problem?

The quantum decoherence program has become more attractive in providing an acceptable solution for the long-standing quantum measurement problem. Decoherence by quantum entanglement happens very quickly to entangle the quantum system with the environment including the detector. But in the final stage of measurement, acquiring the unentangled pointer states poses some problems. Recent experimental observations of the effect of the ubiquitous quantum vacuum fluctuations in destroying quantum entanglement appears to provide a solution.

preprint2023arXiv

Nonprofit Adopt a Star: Lessons from 15 years of Crowdfunding

In the past 15 years, the number of known planets outside of our solar system has grown from about 200 to more than 5000. During that time, we have conducted one of the longest crowdfunding campaigns in history, a nonprofit adopt a star program that supports astronomy research. The program includes the targets of NASA space telescopes that are searching for planets around other stars, and it uses the proceeds to help determine the properties of those stars and their planetary systems. I summarize how this innovative program has evolved over the years and engaged the public worldwide to support an international team of astronomers.

preprint2023arXiv

Resurfaced 1964 VRT video interview of Georges Lemaître

On December 31 2022, the Vlaamse Radio- en Televisieomroeporganisatie (VRT), the national public-service broadcaster for the Flemish Community of Belgium, recovered a video recording of a 1964 interview of Georges Lemaître. Up until now, that footage was thought to have been lost. This footage represents a unique insight into the views of the physicist often coined as the "father of the Big Bang". The interview was conducted in French and is available online with Flemish subtitles. In an effort to make this treasure broadly available, we provide in this paper some brief context, an English translation of the interview as well as the French transcript for reference.

preprint2022arXiv

A causal limit to communication within an expanding cosmological civilization

If a civilization embarks on high-speed intergalactic expansion, growing to a cosmological scale over time, communication between remote galaxies in the civilization will incur an extreme time delay, due to the distance involved. Indeed, if the net expansion speed v is more than .26c, most of the final volume of such a civilization will not be able to signal the home galaxy at all, due to the presence of a causal horizon. We illustrate the regions of such a civilization according to the degree of "conversation" that is possible with the home galaxy, and describe how the geometry depends on expansion speed. We conclude by reflecting on the value of space settlement beyond the horizon, where colonies can never be observed by the initiating home galaxy.

preprint2023arXiv

AI Insights into Theoretical Physics and the Swampland Program: A Journey Through the Cosmos with ChatGPT

In this case study, we explore the capabilities and limitations of ChatGPT, a natural language processing model developed by OpenAI, in the field of string theoretical swampland conjectures. We find that it is effective at paraphrasing and explaining concepts in a variety of styles, but not at genuinely connecting concepts. It will provide false information with full confidence and make up statements when necessary. However, its ingenious use of language can be fruitful for identifying analogies and describing visual representations of abstract concepts.

preprint2023arXiv

A Theory of Theories

We take a tour through the past, present and future of Effective Field Theory, with applications ranging from LHC physics to cosmology.

preprint2023arXiv

Oumuamua Is Not a Probe Sent to our Solar System by an Alien Civilization

Oumuamua, the first known object of extrasolar origin seen to enter our Solar System, has multiple unusual characteristics that, taken together, are very difficult to explain with conventional astronomical entities like asteroids and comets. Consequently, it has been hypothesized that Oumuamua is an interstellar probe that was constructed by an alien civilization. We demonstrate that the accomplishments that can be achieved with large space telescopes and interferometers in the alien's planetary system will completely quench any motivation for construction and launch of an Oumuamua-like probe. The absence of any such motivation attests that Oumuamua is not an alien creation. The existence of large space telescopes has important implications for a range of topics that include interstellar space travel, the zoo hypothesis, METI, and UFOs.

preprint2023arXiv

Wind energy potential of the German Bight

The wind blows stronger and more reliably over the sea than over land. Thus, offshore wind energy is expected to make a major contribution to the energy transition in Germany, especially in the German Bight. But what happens when a growing number of wind farms extract more and more wind energy from the atmosphere?

preprint2022arXiv

Edible Resonators

The development of green, biodegradable electronics that degrade soon after their function is accomplished is a significant contribution to healthcare where edible electronics can be used for diagnosis. An important component of such systems is a resonator. Here we present the design and development of inductor-capacitor (LC) circuits based on a form of sugar called isomalt. Using its low roughness and mechanical properties, we demonstrate resonators that use capacitors, planar inductors, helical inductors and inductors with an edible core, all fabricated from isomalt.

preprint2022arXiv

Why is Parity Restored?

While Left-Right symmetry (space parity) breaking historically appeared as a surprise, we argue that the real wonder is its restoration in long-distance interactions (at least until we find electric dipole moments!).

preprint2022arXiv

Tall Towers on the Moon

The lunar South pole likely contains significant amounts of water in the permanently shadowed craters there. Extracting this water for life support at a lunar base or to make rocket fuel would take large amounts of power, of order Gigawatts. A natural place to obtain this power are the "Peaks of Eternal Light", that lie a few kilometers away on the crater rims and ridges above the permanently shadowed craters. The amount of solar power that could be captured depends on how tall a tower can be built to support the photovoltaic panels. The low gravity, lack of atmosphere, and quiet seismic environment of the Moon suggests that towers could be built much taller than on Earth. Here we look at the limits to building tall concrete towers on the Moon. We choose concrete as the capital cost of transporting large masses of iron or carbon fiber to the Moon is presently so expensive that profitable operation of a power plant is unlikely. Concrete instead can be manufactured in situ from the lunar regolith. We find that, with minimum wall thicknesses (20 cm), towers up to several kilometers tall are stable. The mass of concrete needed, however, grows rapidly with height, from $\sim$ 760 mt at 1 km to $\sim$ 4,100 mt at 2 km to $\sim 10^5$ mt at 7 km and $\sim 10^6$ mt at 17 km.

preprint2021arXiv

The incredibly strange story of Einstein's Nobel prize

It is well-known that Einstein got the 1921 Nobel prize not for his theory of relativity, but for his theory of photoelectricity. It is not that well-known that he did not get the prize in 1921. Why not, and when did he get it?

preprint2022arXiv

Special Relativity, Einstein Velocity Addition, and Gyrogroups: An Introduction

In these notes we give an introductory unified treatment to the topics of special relativity, Lorentz transformations and the Lorentz group, Einstein velocitiy addition, and gyrogroups and gyrovector spaces. An effort has been made to present the material in a manner that is accessible to non-specialists and graduate students, and may even serve as the basis for a graduate course or seminar.

preprint2022arXiv

Gravity-Assist as a Solution to Save Earth from Global Warming

Global warming is one of the problems of human civilization and decarbonization policy is the main solution to this problem. In this work, we propose using the gravity-assist by the asteroids to increase the orbital distance of the Earth from the Sun. We can manipulate the orbit of asteroids in the asteroid belt by solar sailing and propulsion engines to guide them towards the Mars orbit and a gravitational scattering can put asteroids in a favorable direction to provide an energy loss scattering from the Earth. The result would be increasing the orbital distance of the earth and consequently cooling down the Earth's temperature. We calculate the increase in the orbital distance of the earth for each scattering and investigate the feasibility of performing this project.

preprint2022arXiv

The gravitational potential energy of the Great Pyramid

The calculation of the energy required to raise a constituent block of the Khufu pyramid and the knowledge of the mechanical energy that a worker in charge of the lifting of the blocks can produce per working day allows an estimate of the minimum number of workers. necessary for the establishment of a base of the pyramid. It emerges that this number is limited to a maximum of less than 2,000 workers over a working season, ie less than 200 present each day simultaneously on the site. In addition, the calculation of the flow of blocks leads to the ineluctable conclusion that the construction could only be done in a massively parallel working mode, undermining the hypothesis very often put forward of the use of ramps to convey the blocks to their final destination.

preprint2022arXiv

A physics-driven study of dominance space in soccer

In arXiv:2107.05714 the concept of the Voronoi diagram was investigated closely from a theoretical point of view. Then, a physics-driven kinematical method was introduced to produce an improved model for dominance space in soccer. Remaining faithful to the deterministic approach, we extend the original work by the introduction of (a) an asymmetric influence of the players in their surrounding area, (b) the frictional forces to the players' motion, and (c) the simultaneous combination of both effects. The asymmetric influence is fairly intuitive; players have more control in the direction they are running than any other direction. The sharper the turn they must make to reach a point on the pitch, the weaker their control of that point will be. From simple kinematical laws, this effect can be quantified explicitly. For the frictional force, a portion comes from air resistance, and so will be proportional to the square of the player's speed, as is well known from fluid dynamics. There are no other external frictional forces, but, at the suggestion of biokinematics, there is an internal frictional force, relating to the consumption of energy by the muscles, which is proportional to the player's speed. Although these additions are intuitively understood, mathematically they introduce many analytical complexities. We establish exact analytical solutions of the dominance areas of the pitch by introducing a few reasonable simplifying assumptions. Given these solutions the new Voronoi diagrams are drawn for the publicly available data by Metrica Sports. In general, it is not necessary anymore for the dominance regions to be convex, they might contain holes, and may be disconnected. The fastest player may dominate points far away from the rest of the players.

preprint2022arXiv

PLANETAMOS, A Physics Show Musical (Phyusical)

We present a physics show musical with live physics experiments and live performed songs with live orchestral accompaniment. The musical was first put on stage in German at the Physikalische Institut, University of Bonn, on the 24th of March, 2019. Here we present the original German script as well as an English translation, including a translation of the songs. We also give brief descriptions of all the experiments employed, with photos as well as how we present the experiments. The musical tells the story of a couple, Life and Death, nicknamed Vita and Mortis, who want to buy a planet where they can settle down and raise a family. They arrive at the store Planetamos, run by the manager Luna Callisto and the scientist Jupi Mercury. The latter two present to Vita and Mortis what is required for life on a planet, as well as all of the extra features for sale, to make it that very special place for their family. Through Vita and Mortis the audience learns about the physical requirements for life on a planet orbiting a star. The show involves 14 live physics experiments. The four actors sing 7 songs, which are to well-known tunes with new lyrics, in German. During the show the singers are accompanied by a small live orchestra, consisting of a flute, an oboe, a piano, a violin, a cello, a harp and percussion. The show was developed by the University of Bonn physics students, who have all been very active in the University of Bonn Physics Show (Physikshow der Universitaet Bonn) the past few years. To the best of our knowledge this is the first physics show musical with live experiments and live song and orchestra.

preprint2022arXiv

A Roadmap to Interstellar Flight

In the nearly 60 years of spaceflight we have accomplished wonderful feats of exploration that have shown the incredible spirit of the human drive to explore and understand our universe. Yet in those 60 years we have barely left our solar system with the Voyager 1 spacecraft launched in 1977 finally leaving the solar system after 37 years of flight at a speed of 17 km/s or less than 0.006% the speed of light. As remarkable as this is we will never reach even the nearest stars with our current propulsion technology in even 10 millennium. We have to radically rethink our strategy or give up our dreams of reaching the stars, or wait for technology that does not currently exist. While we all dream of human spaceflight to the stars in a way romanticized in books and movies, it is not within our power to do so, nor it is clear that this is the path we should choose. We posit a technological path forward, that while not simple, it is within our technological reach. We propose a roadmap to a program that will lead to sending relativistic probes to the nearest stars and will open up a vast array of possibilities of flight both within our solar system and far beyond. Spacecraft from gram level complete spacecraft on a wafer ("wafersats") that reach more than $1/4c$ and reach the nearest star in 20 years to spacecraft with masses more than $10^5$ kg (100 tons) that can reach speeds of greater than 1000 km/s. These systems can be propelled to speeds currently unimaginable with existing propulsion technologies. To do so requires a fundamental change in our thinking of both propulsion and in many cases what a spacecraft is. In addition to larger spacecraft, some capable of transporting humans, we consider functional spacecraft on a wafer, including integrated optical communications, imaging systems, photon thrusters, power and sensors combined with directed energy propulsion.

preprint2022arXiv

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.