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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 {\alpha}(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.

As the space industry matures, large space stations will be built. This paper organizes and documents constraints on the size of these space stations. Human frailty, station design, and construction impose these constraints. Human limitations include gravity, radiation, air pressure, rotational stability, population, and psychology. Station design limitations include gravity, population, material, geometry, mass, air pressure, and rotational stability. Limits on space station construction include construction approaches, very large stations, and historic station examples. This paper documents all these constraints for thoroughness and review; however, only a few constraints significantly limit the station size. This paper considers rotating stations with radii greater than 10 kilometers. Such stations may seem absurd today; however, with robotic automation and artificial intelligence, such sizes may become feasible in the future., Comment: 65 Pages, 61 figures, 15 tables

Bicycle Power Meters have become ubiquitous in professional and amateur cycling. These devices claim high levels of accuracy, and this accuracy is indeed essential if they are to serve their purpose as reliable training aids and indicators of improvements in fitness. Power is generally obtained via the independent estimation of torque and angular velocity. Designs vary in the way in which they estimate angular velocity. Some power meters estimate angular velocity many times a second, whereas other power meters compute an average value for each pedal stroke. The aim of this paper is to investigate whether it is necessary to rapidly sample angular velocity in order to obtain accurate power values under conditions of dynamic equilibrium. Countering previous research on the topic, this paper finds that average angular velocity alone is usually sufficient for the purposes of computing power, although there may be certain exceptional circumstances where consideration of harmonics may appreciably improve fidelity.

A popular science article designed to introduce people familiar with basic cosmological nomenclature with models alternative to cosmological inflation. The paper briefly discusses the modern view of the Big Bang model, inflation (both its advantages and potential deficiencies). This is followed by a discussion of historical alternative models and modern approaches such as matter bounce, ekpyrotic Universe, Conformal Cyclic Cosmology, Hartle-Hawking state and loop quantum cosmology. The final aspect of the paper is to present the advantages and potential problems associated with alternative models and to present the conceptual challenges associated with the uniqueness of cosmology as a specific domain of physics., Comment: Popular science article created as part of the COST Action CA21136 ("Addressing observational tensions in cosmology with systematics and fundamental physics") CosmoVerse website: https://cosmoversetensions.eu/learn-cosmology/did-the-big-bang-and-cosmic-inflation-really-happen/

The Milky Way's name and role in ancient Egyptian culture remain unclear. One suggestion is that the Milky Way may have been a celestial depiction of the sky goddess Nut. In this work, I test this association using an interdisciplinary approach. In the first part of this paper, I combine astronomical simulations of the ancient Egyptian night sky with primary Egyptian sources to map the goddess Nut onto the Milky Way. With her head and groin firmly associated by primary texts with the western and eastern horizons, respectively, I argue that the summer and winter orientations of the Milky Way could be construed as figurative markers of Nut's torso (or backbone) and her arms, respectively. In the second part of this paper, I situate Nut within the global, multicultural mythology of the Milky Way. Specifically, I show that Nut's roles in the afterlife and the autumn bird migration are consistent with similar roles attributed to the Milky Way by other cultures. Finally, I show that Nut's identification with the Milky Way may even have echoes in contemporary African conceptions of the Galaxy., Comment: 18 pages, 7 figures, preprint of paper published in Journal of Astronomical History and Heritage

Data are given, commentary is supplied and explanations are provided with regard to the technical, the organizational and, of course, the human history connected to the time of research, which resulted to the paper entitled "Soil sampling and Cs-137 analysis of the Chernobyl fallout in Greece", written by late Professor S.E. Simopoulos. This paper has been provided in Greek translation within an issued honorary volume (ISBN 978-960-254-714-4). Reasonably, the narration starts with the review of the political, the financial and the social situation of Greece around 1986. Subsequently, an analysis is given on the then available means, the persons involved, the methods used, the lessons learned and any other connection with the oral history of the NTUA's Nuclear Engineering Laboratory and other relevant Greek Laboratories. For this history, written proof is now scarce and the persons available to pass it on are growing less and less. N.P. Petropoulos, now Laboratory member and then student of Professor S.E. Simopoulos was in charge of preparation of this text., Comment: 28 pages, in Greek language, 20 figures

In this paper, we explain the conceptual development of the STAGE Lab Quantum Casino (a.k.a. the STAGE Lab Quantum Arcade), one of the Lab's most recent artistic endeavors about quantum physics. This work consists of a series of card and digital games and an interactive experience, exposing the public to quantum physics and minimizing learning barriers. Furthermore, we will also present a case study of the interactive experience, in the form of The Quantum Photo Booth. The STAGE Lab Quantum Casino provides an entertaining and approachable experience for people of all ages to become familiar with quantum physics. By using core concepts of quantum physics as tools and strategies to overcome challenges that arise in gameplay, players gain an intuitive understanding of these concepts. These games provide players with a first-hand experience of the following quantum physics concepts: measurement, superposition, encryption, decoherence, and entanglement. Instead of teaching the concepts through a traditional classroom pedagogy, these games aim to invoke curiosity, spark moments of playfulness, and catalyze play-centric learning modalities. This paper provides a general overview of the development of the STAGE Lab Quantum Casino, focusing on The Quantum Photo Booth experience and how science is integrated into the very nature of the game development process in addition to its outcome.

This paper presents an innovative and cost-effective approach to understanding the Barkhausen effect through the design and implementation of an educational kit. The Barkhausen effect, characterized by Barkhausen noise (BN) during magnetization changes in soft magnetic materials, is explored for its application in probing hysteresis properties and magnetization dynamics. The study investigates scaling properties, categorizing ferromagnetic materials based on scaling exponents. The primary contribution is the introduction of a practical and accessible kit for hands-on Barkhausen Effect demonstrations, revolutionizing the educational experience. This kit enables students to not only comprehend the intricacies of BN but also calculate the scaling constant ($\tau$) for Soft Iron samples. The paper demonstrates the successful construction of the kit, its signal amplification capabilities, and data collection accuracy, showcasing its potential for widespread educational use.

This paper reviews the physics of stars, the type, structure, evolution and stability. Simple thermodynamics and statistical mechanics are used to show the inner working of white dwarf and neutron stars. The major concentration of the paper will be on white dwarf stars although in some places references will also be made to neutron stars where the relations can be extended easily. It can be shown that a maximum mass limit is attached to each type of star which can be derived rigorously. Maximum entropy can be used to show that the gravitational contraction is balanced by the degeneracy pressure created by the electrons in the case of white dwarfs, and neutrons and protons which constitute the matter of the neutron star. Finally the kinetic equations which describe the luminosity of the star and the radiative transfer are introduced., Comment: arXiv admin note: text overlap with arXiv:cond-mat/9909291 by other authors

One of the most popular movie franchises of late is Legendary's Monsterverse as is evidenced by the gross earnings of the series recently surpassing the two and a half billion dollar mark with the release of $\it{Godzilla X Kong}$. As is typical with many movies of this genre, in order to enjoy them one must suspend their disbelief when it comes to the laws of physics. While there are a plethora of examples of violations of basic principles (the square-cube law being the prime example) the idea of a "gravity inversion" occurring inside of the "Hollow Earth" is among the most debated as well as the most relevant to the storylines of the recent movies. The intent of this paper is to show that, while typical scientific arguments refuting the possibility of such an inversion are definitely completely correct, a slight modification of the conditions assumed to exist inside the planet in these arguments may allow for the inversion to actually occur., Comment: 4 pages, 2 figures

Designing for rotational stability can dramatically affect the geometry of a space station. If improperly designed, the rotating station could end up catastrophically tumbling end-over-end. Active stabilization can address this problem; however, designing the station with passive rotation stability provides a lower-cost solution. This paper presents passive rotational stability guidelines for four space station geometries. Station stability is first analyzed with thin-shell and thick-shell models. Stability is also analyzed with models of the station's major constituent parts, including outer shells, spokes, floors, air, and shuttle bays., Comment: 64 pages, 75 figures, 8 tables

The speed-accuracy tradeoffs are prevalent in a wide range of physical systems. In this paper, we demonstrate speed-accuracy tradeoffs in the game of cricket, where 'batters' score runs on the balls bowled by the 'bowlers'. It is shown that the run scoring rate by a batter and the probability of dismissal follow a power-law relation. Due to availability of extensive data, game of cricket is an excellent model for the study of the effect of speed-accuracy tradeoff on the overall performance of the system. It is shown that the exponent of the power-law governs the nature of the adaptability of the player in different conditions and can be used for their assessment. Further, it is demonstrated that the players with extreme values of the power-law exponent are better suited for different playing conditions as compared to the ones with moderate values. These findings can be utilized to identify the potential of the cricket players for different game formats and can further help team management in devising strategies for the best outcomes with a given set of players., Comment: 6 pages, 3 figures

This paper introduces a card game called "Quark Matter Card Games," inspired by the creativity of a high school student, Csaba T\"or\"ok, and developed in collaboration with physicist Tam\'as Cs\"org\H{o}. The game utilizes a deck of 66 cards representing elementary particles and antiparticles, offering an entertaining way to popularize science and introduce players to particle physics concepts. The initial edition includes games exploring topics like baryon formation, mesons, quark colors, and more. The author proposes a new game focusing on the four fundamental forces. Players must strategically place cards on a central card, simulating interactions based on strong, electromagnetic, weak, and gravitational forces. Specific rules for particle placement, including fundamental forces, annihilation and neutrino oscillations are elucidated. Additional rules and conditions add complexity and strategy to the game, ensuring active engagement. The intended audience ranges from individuals familiar with particle physics to those new to the field. The game provides an engaging platform for learning about elementary particle interactions, with varying levels of complexity. The paper discusses the educational potential, offering suggestions for simplified versions. Furthermore, all necessary concepts are briefly explained, and the physical background of the game is provided. The paper concludes with topics for further discussions, linking game experiences to particle physics concepts. Questions cover gravitational interaction interpretations, differentiation between quarks and leptons, explanations of weak and electromagnetic interactions and more. The acknowledgment section expresses gratitude to mentors and pioneers of card games with elementary particles for their inspiration and support., Comment: 28 pages, 13 figures, Contribution to ISMD 2023

The momentum of human spaceflight initiatives continues to build toward Mars, and technological advances may eventually enable the potential for permanent space settlement. Aspirations for sustaining human life in space must be predicated on human factors, rather than technological constraints alone, and advances in models of governance and ethics are necessary as human civilization becomes a spacefaring species. This paper presents an idealistic but feasible model for economic freedom on Mars, which is situated within a framework in which Mars has been designated as a sovereign juridical peer to Earth. Under such conditions, Mars could maintain monetary stability through full reserve banking and a restriction on exchange with any fractional reserve Earth currencies, with a volume of circulating currency that changes based on the total population within fixed capacity infrastructure. Mars could maintain long-term political stability by diffusing the ownership of capital on Mars, which would allow all citizens of Mars to draw sufficient wealth from a combination of capital ownership and labor to live a good life. This model could also support limited tourism on Mars, in which real goods are exchanged for services but currency transactions between planets are prohibited. This model demonstrates the potential for a viable and sustainable economy on Mars that could conceivably be implemented, including on a sovereign Mars but also in other scenarios of space settlement. More broadly, this model illustrates that ideas such as diffuse capital ownership and limited government can enable freedom in space, and numerous models beyond a centralized world space agency should be explored to ensure the optimal governance of the emerging space economy., Comment: Accepted by Space Policy

In this paper, we propose the replication of scientific experiments, with the participation of the general public, as one of the possible strategies to confront science deniers. Using the social media of the Federal University of Lavras (UFLA), the project entitled : The Magic of Physics and the Universe, invited the public to reproduce the experiment carried out by the Greek Eratosthenes over 2,100 years ago, which he proved that the Earth is spherical. We present a report of this experience to suggest that it is possible for citizens to experience scientific knowledge and observe the phenomena in a simple way, in order to develop a critical interpretation of false information that circulates in society. This proposal distinctively geeks to deconstruct the denial of the Earth's curvature through direct and collective participation of citizens in Eratosthenes' experiment, which permit more reflection on how the scientific method used to study this subject works., Comment: This article is written in Portuguese

Extraterrestrial communication signals are hypothesized to be present in an extensive search space. Using principles of communication theory and system design, methods are studied and implemented to reduce the signal search space, while considering intentional transmitter detectability. The design and observational work reported in this paper adds material to previous related reports. (ref. arXiv:2105.03727, arXiv:2106.10168, arXiv:2202.12791, arXiv:2203.10065). In the current work, a two-element radio interferometer telescope and receiver algorithms are utilized to perform differential angle-of-arrival and multi-bandwidth measurements of delta-t delta-f polarized pulse pairs. The system enhances extraterrestrial signal detectability, while reducing signal false positives caused by noise and radio frequency interference. Statistical analysis utilizes a Right Ascension filter spanning celestial coordinate ranges that include the previously determined anomalous celestial direction: 5.25 +- 0.15 hr Right Ascension, -7.6 degrees +- 1 degree Declination. Observations were conducted during a duration of 61 days, comprising 244 hours of interferometer measurements., Comment: 12 pages, 13 figures

The number of planets in the solar system over the last three centuries has, perhaps surprisingly, been less of a fixed value than one would think it should be. In this paper, we look at the specific case of Vulcan, which was both a planet before Pluto was a planet and discarded from being a planet before Pluto was downgraded. We examine the historical context that led to its discovery in the 19th century, the decades of observations that were taken of it, and its eventual fall from glory. By applying a more modern understanding of astrophysics, we provide multiple mechanisms that may have changed the orbit of Vulcan sufficiently that it would have been outside the footprint of early 20th century searches for it. Finally, we discuss how the April 8, 2024 eclipse provides a renewed opportunity to rediscover this lost planet after more than a century of having been overlooked., Comment: 11 pages, submitted to Acta Prima Aprilia

The Arago spot is an intensity maximum at the center of a shadow created by constructive interference of diffracted waves around a spherical object. While the study of diffraction patterns usually concerns visible light, de Broglie's wave nature of matter makes diffraction theory applicable for particles, such as neutrinos, as well. During a solar eclipse, some of the neutrinos emitted by the Sun are diffracted by the Moon, resulting in a diffraction pattern that can be observed on Earth. In this paper we consider the theoretically emerging solar neutrino Arago spot as a means to measure the location of the Moon with high accuracy and consider its implication on the orbit of the Moon given Heisenberg's uncertainty principle. Our results indicate that the Moon is not at immediate risk of orbital decoupling due to the observation of a solar neutrino Arago spot., Comment: Prepared for April Fools' Day. 13 pages

Empirical studies have demonstrated that humans possess the remarkable capacity to distinguish whether a glass of water is hot or cold solely by the sound of pouring it. However, the underlying physical mechanisms governing the disparities in the acoustic signatures of hot versus cold water remain to be deciphered. In this paper, we conducted a series of experiments to extract the intrinsic features of pouring sounds at contrasting temperatures. The results of our spectral analysis revealed that the sound of pouring hot water exhibited more pronounced low-frequency components and diminished high-frequency components relative to cold water. High-speed photographic evidence elucidated that pouring hot water could generate larger air bubbles in greater abundance. We conjecture that the Minnaert resonance arising from these larger entrained bubbles in hot water produces a lower-frequency acoustic signature, thereby constituting the foundational mechanistic explanation for the auditory distinction between pouring hot and cold water.

Over the past several years, the misidentification of SpaceX Starlink satellites as Unidentified Aerial Phenomena (UAP) by pilots and laypersons has generated unnecessary aviation risk and confusion. The many deployment and orbital evolution strategies, coupled with changing sun specular reflection angles, contribute to this gap in space situational awareness. In this paper we present a case analysis of an incident that generated multiple, corroborating reports of a UAP from five pilots on two commercial airline flights over the Pacific Ocean on August 10th, 2022. This incident included two cell phone photos and a video of an unrecognizable and possibly anomalous phenomenon. We then use supplemental two-line elements (TLEs) for the Starlink train of satellites launched that same day and Automatic Dependent Surveillance Broadcast (ADS-B) data from the flight with the photographs to reconstruct a view of these satellites from the cockpit at the time and place of the sighting. The success of this work demonstrates an approach that could, in principle, warn aviators about satellites that could be visible in unusual or novel illumination configurations, thus increasing space situational awareness and supporting aviation safety. We conclude with recommendations for governments and satellite operators to provide better a-priori data that can be used to create advisories to aviators and the public. The automated simulation of known specular reflection off constellations of satellites could also support researchers investigating sightings of unfamiliar aerial or aerospace objects as likely being from normal versus novel space events., Comment: 35 pages, 10 figures, submitted to the 4th IAA Conference on Space Situational Awareness (ICSSA), May 8-10 2024, Daytona Beach, FL, USA; Abstract number AH-92328

Based on technical work and development conducted under the LunA-10 study, I have identified six hypotheses where, if revolutionary improvements in technology can be made, I assess that a direct acceleration to the fielding of a lunar economy is likely to occur. In this short paper, I explain these six hypotheses, and recommend that these topics be focused on for technical development in the near-future by government and commercial stakeholders. These areas are: (1) Centralized thermal rejection and generation as a service, (2) Widespread orbital lunar prospecting and surveying, (3) Creating large silicon wafers for microsystems on the Moon, (4) Biomanufacturing to accelerate lunar construction, (5) New concepts to increase refinement rates in low gravity, (6) New concepts for Lunar Position, Navigation and Timing., Comment: 7 pages

This paper addresses the problem of determining the optimum shape for a beer glass that minimizes the heat transfer while the liquid is consumed, thereby keeping it cold for as long as possible. The proposed solution avoids the use of insulating materials. The glass is modelled as a body of revolution generated by a smooth curve S, constructed from a material with negligible thermal resistance at the revolution surface but insulated at the bottom. The ordinary differential equation describing the problem is derived from the first law of Thermodynamics applied to a control volume encompassing the liquid. This is an inverse optimization problem, aiming to find the shape of the glass (represented by curve S) that minimizes the heat transfer rate. In contrast, the direct problem aims to determine the heat transfer rate for a given geometry. The solution obtained is analytic, and the resulting expression for S is in closed form, providing a family of optimal glass shapes that can be manufactured using conventional methods., Comment: 10 pages, 7 figures

The rapid growth of quantum technologies requires an increasing number of physicists, computer scientists, and engineers who can work on these technologies. For educating these professionals, quantum mechanics should stop being perceived as incomprehensible. In this paper we contribute to this change by presenting a pedagogical model for explaining Grover's search algorithm, a prominent quantum algorithm. This model visualizes the three main steps of Grover's algorithm and, in addition to explaining the algorithm itself, introduces three key principles of quantum mechanics: superposition, interference, and state collapse at measurement. The pedagogical model, visualized by a video, is called the "Ant Colony Maze model". It represents the search problems as finding the exit of a maze, and visualizes Grover's search algorithm as a strategy by which a colony of ants finds that exit., Comment: 18 pages, 4 figures

In this paper, a quantum variant of chess is introduced, which can be played on a traditional board, without using computers or other electronic devices. The rules of the game arise naturally by combining the rules of conventional chess with key quantum-physical effects such as superposition and entanglement. Niel's Chess is recommended for ages 10 and above, to everyone who wishes to play a creative game with historical roots and at the same time gain intuition about the foundational quantum effects that power cutting-edge technologies like quantum computing and quantum communication, which are poised to revolutionize our society in the coming decades. Takeaways from a pilot educational session that was carried out with 10-to-12-year-old children are also presented., Comment: 8 pages, 16 figures, accepted for the Third Annual Quantum Science and Engineering Education Conference (QSEEC24). arXiv admin note: substantial text overlap with arXiv:2306.13669

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., Comment: published in JAHH, see complements on https://hdl.handle.net/2268/310591

In what will likely be a litany of generative-model-themed arXiv submissions celebrating April the 1st, we evaluate the capacity of state-of-the-art transformer models to create a paper detailing the detection of a Pulsar Wind Nebula with a non-existent Imaging Atmospheric Cherenkov Telescope (IACT) Array. We do this to evaluate the ability of such models to interpret astronomical observations and sources based on language information alone, and to assess potential means by which fraudulently generated scientific papers could be identified during peer review (given that reliable generative model watermarking has yet to be deployed for these tools). We conclude that our jobs as astronomers are safe for the time being. From this point on, prompts given to ChatGPT and Stable Diffusion are shown in orange, text generated by ChatGPT is shown in black, whereas analysis by the (human) authors is in blue.

What's in a name, a poet once asked. To which we present this work, where we investigate the importance of a paper title in ensuring its best outcome. We queried astronomy papers using NASA ADS and ranked 6000 of them in terms of cheekiness level. We investigate the correlation between citation counts and (i) the presence of a colon, and (ii) cheekiness ranking. We conclude that colon matters in the anatomy of a paper title. So does trying to be cheeky, but we find that too much cheekiness can lead to cringefests. Striking the right balance is therefore crucial. May we recommend aiming for a level 4 cheekiness on a scale of 1-5., Comment: 4 pages, 4 figures, 1 meme. Submitted to Acta Prima Aprila

The most frequently used indicators for the productivity and impact of scientists are the total number of publication ($N_{pub}$), total number of citations ($N_{cit}$) and the Hirsch (h) index. Since the seminal paper of Hirsch, in 2005, it is largely debated whether the h index can be considered as an indicator independent of $N_{pub}$ and $N_{cit}$. Exploiting the Paretian form for the distribution of citations for the papers authored by a researcher, here we discuss scaling relations between h, $N_{pub}$ and $N_{cit}$. The analysis incorporates the Gini index as an inequality measure of citation distributions and a recently proposed inequality kernel, gintropy (resembling to the entropy kernel). We find a new upper bound for the h value as a function of the total number of citations, confimed on massive data collected from Google Scholar. Our analyses reveals also that the individualized Gini index calculated for the citations received by the publications of an author peaks around 0.8, a value much higher than the one characteristic for the usual socio-economic inequalities., Comment: 12 pages, 6 Figures, Latex

In 1926 Albert Einstein gave a clear explanation of the physical processes involved in the meander formation and evolution in open channels (Einstein, 1926). Although this work is far from being recognized as one of his greatest achievements, such as his annus mirabilis papers in 1905, he shows a truly remarkable didactic skills that make it easy to understand even to the non-specialist. In particular, a brilliant explanation of the tea leaf paradox can be found in this paper of 1926, presented as a simple experiment for clarifying the role of Earth rotation and flow curvature in the differential river banks erosion. This work deserves to be considered as a pioneering work that has laid a basic knowledge in currently very active research fields in fluvial geomorphology, estuarine physics, and hydraulic engineering. In response to the curiosity aroused and transmitted to the authors over the years by undergraduates and MSc. students, and also due to its historical and scientific significance, we present here the Spanish translation of Einstein's original work published in German in 1926 in Die Naturwissenschaften (Einstein, 1926). Einstein's drawings have not been interpreted, but just updated preserving their original spirit.

This paper is a continuation of a series of works, devoted to various aspects of the 1908 Tunguska event. It is devoted to the Evenki accounts of the 1908 Tunguska event collected in 1920s - 1930s. It is important to research accounts of Evenki who were rather close to the epicenter. The Evenki accounts are important also, because Evenki are natural hunters and pathfinders - their lives depend on their memory and vision. Most of the reviewed in this work accounts were collected at the Evenki conference, when telling a lie was considered to be a serious misconduct. These Evenki accounts are compared with other Tunguska accounts. Also weather conditions associated with the Tunguska event are considered. Some manifestations of the Tunguska event are discussed., Comment: 51 pages, 5 pictures

Light pollution is recognized as a global issue that, like other forms of anthropogenic pollution, has significant impact on ecosystems and adverse effects on living organisms. Multiple evidence suggests that it has been increasing at an unprecedented rate at all spatial scales. Chile, which thanks to its unique environmental conditions has become one of the most prominent astronomical hubs of the world, seems to be no exception. In this paper we present the results of the first observing campaign aimed at quantifying the effects of artificial lights at night (ALAN) on the brightness and colors of Chilean sky. Through the analysis of photometrically calibrated all-sky images captured at four representative sites with an increasing degree of anthropization, and the comparison with state-of-the-art numerical models, we show that significant levels of light pollution have already altered the appearance of the natural sky even in remote areas. Our observations reveal that the light pollution level recorded in a small town of the Coquimbo Region is comparable with that of Flagstaff, a ten times larger Dark Sky city, and that a mid-size urban area door to the Atacama Desert displays photometric indicators of night sky quality that are typical of the most densely populated regions of Europe. Our results suggest that there is still much to be done in Chile to keep the light pollution phenomenon under control and thus preserve the darkness of its night sky - a natural and cultural heritage that is our responsibility to protect., Comment: 26 pages, 18 figures, 5 tables, accepted for publication in AJ

Science-AI Symbiotic Group at Seven Square Academy, Naigaon was formed in 2023 with the purpose of bringing school students to the forefronts of science research by involving them in hands on research. In October 2023 a new project was started with the goal of studying the lunar surface by real-time observations and open source data. Twelve students/members from grades 8, 9, 10 participated in this research attempt wherein each student filled an observation metric by observing the Moon on various days with a Bresser Messier 150mm/1200mm reflector Newtonian telescope. After the observations were done, the members were assigned various zones on the lunar near side for analysis of geological features. Then a data analysis metric was filled by each of students with the help of Lunar Reconnaissance Orbiter Camera's/ LROC's quickmap open access data hosted by Arizona State University. In this short paper a brief overview of this project is given. One example each of observation metric and data analysis metric is presented. This kind of project has high impact for school science education with minimal costs. This project can also serve as an interesting science outreach program for organisations looking forward to popularise planetary sciences research at school level., Comment: 14 pages, 7 figures

Quantum teleportation is a concept that fascinates and confuses many people, in particular, given that it combines quantum physics and the concept of teleportation. With quantum teleportation likely to play a key role in several communication technologies and the quantum internet in the future, it is imperative to create learning tools and approaches that can accurately and effectively communicate the concept. Recent research has indicated the importance of teachers enthusing students about the topic of quantum physics. Therefore, educators at both high school and early university level need to find engaging and perhaps unorthodox ways of teaching complex, yet interesting topics such as quantum teleportation. In this paper, we present a paradigm to teach the concept of quantum teleportation using the Christmas gift-bringer Santa Claus. Using the example of Santa Claus, we use an unusual context to explore the key aspects of quantum teleportation, and all without being overly abstract. In addition, we outline a worksheet designed for use in the classroom setting which is based on common naive conceptions from quantum physics. This worksheet will be evaluated as a classroom resource to teach quantum teleportation in a subsequent study., Comment: 11 + 8 pages, 3 figures, v2: as published

In July 2021, faculty from the UAlbany Department of Physics participated in a week-long field expedition with the organization UAPx to collect data on UAPs in Avalon, California, located on Catalina Island, and nearby. This paper reviews both the hardware and software techniques which this collaboration employed, and contains a frank discussion of the successes and failures, with a section about how to apply lessons learned to future expeditions. Both observable-light and infrared cameras were deployed, as well as sensors for other (non-EM) emissions. A pixel-subtraction method was augmented with other similarly simple methods to provide initial identification of objects in the sky and/or the sea crossing the cameras' fields of view. The first results will be presented based upon approximately one hour in total of triggered visible/night-vision-mode video and over 600 hours of untriggered (far) IR video recorded, as well as 55 hours of (background) radiation measurements. Following multiple explanatory resolutions of several ambiguities that were potentially anomalous at first, we focus on the primary remaining ambiguity captured at approximately 4am Pacific Time on Friday, July 16: a dark spot in the visible/near-IR camera possibly coincident with ionizing radiation that has thus far resisted a prosaic explanation. We conclude with quantitative suggestions for serious researchers in this still-nascent field of hard-science-based UAP studies, with an ultimate goal of identifying UAPs without confirmation bias toward either mundane or speculative conclusions., Comment: 43 pages, 16 figures, 2 tables, 18 equations, and 64 references

Theory of Relativity (Special and General) is one of the most influential theories of the 20th century and has changed the way we view the world. It is part of many undergraduate curriculums and it is often suggested that it should be integrated into an upper secondary curriculum. Special Theory of Relativity combines time and space whereas General Theory of Relativity describes gravity as a geometric property of spacetime. As it describes abstract phenomena, students encounter several difficulties understanding its basic principles and consequences. In this paper, we present the research that we conducted in order to detect the aforementioned difficulties. This research constitutes a part of a more general study concerning the integration of Special and General Relativity into an upper secondary and undergraduate curriculum. The sample consisted of 45 non-major physics undergraduate students. The purpose of our study was to determine and categorize the difficulties students face when they study the principles of the Theory of Relativity and its consequences. The results of our research indicate that student face many obstacles when trying to interpret phenomena described by the Relativity and confuse Special and General Relativity principles. These results dictate us to create an educational approach that tackle the difficulties found., Comment: Electronic Proceedings of the ESERA 2015

Many countries and commercial organizations have shown great interest in constructing Martian base. In-situ resource utilization (ISRU) provides a cost-effective way to achieve this ambitious goal. In this paper, we proposed to use Martian soil simulant to produce fiber to satisfy material requirement for the construction of Martian base. The composition, melting behavior and fiber forming process of soil simulant was studied, and continuous fiber with a maximum strength of 1320 MPa was obtained on a spinning facility. The findings of this study demonstrate the feasibility of ISRU to prepare Martian fiber from the soil on the Mars, offering a new way to get key materials for the construction of Martian base.

Vast amounts of (open) data are increasingly used to make arguments about crisis topics such as climate change and global pandemics. Data visualizations are central to bringing these viewpoints to broader publics. However, visualizations often conceal the many contexts involved in their production, ranging from decisions made in research labs about collecting and sharing data to choices made in editorial rooms about which data stories to tell. In this paper, we examine how data visualizations about climate change and COVID-19 are produced in popular science magazines, using Scientific American, an established English-language popular science magazine, as a case study. To do this, we apply the analytical concept of data journeys (Leonelli, 2020) in a mixed methods study that centers on interviews with Scientific American staff and is supplemented by a visualization analysis of selected charts. In particular, we discuss the affordances of working with open data, the role of collaborative data practices, and how the magazine works to counter misinformation and increase transparency. This work provides an empirical contribution by providing insight into the data (visualization) practices of science communicators and demonstrating how the concept of data journeys can be used as an analytical framework., Comment: 44 pages, 4 figures, 3 boxes

Historically there were two main reasons to assign the 1908 Tunguska event to a spacebody infall: a) newspaper notes about a fall of a meteorite near the town of Kansk (later claimed to be false); b) eyewitnesses reports about seeing luminous phenomena in the sky. This paper examines accounts of the Siberian eyewitnesses about luminous phenomena in the sky, collected in 1908, immediately after the event. The conducted generalization of the available accounts reported in 1908 indicates that eyewitnesses reported several types of luminous phenomena., Comment: 47 pages, 8 pictures

Astronomers occasionally detect an object having unexpected shape, unexplainable photometry, or unprecedented spectra that are inconsistent with our contemporary knowledge of the universe. Upon careful assessment, many of these anomalies are discarded as mere noise, contamination, or faulty analysis. But some anomalies survive scrutiny to yield new astronomical objects and physical processes. Examples of validated anomalies include quasars, pulsars, and periodic Doppler shifts of Sun-like stars caused by the gravitational pull of orbiting planets. Other anomalies persist as mysteries, including Fast Radio Bursts, dark energy, 'Oumuamua as an alien spaceship, and simultaneously vanishing stars. Advanced technological life may present astronomers with anomalies that require carefully designed observations from multiple vantage points simultaneously and with real-time spectroscopy., Comment: 9 pages. This paper is for the general public

In a paper by Alberto Caballero, a methodology is stated for estimating the probability of an exoplanet alien civilization having malicious intentions toward the human civilization after being messaged by it and estimating the number of malicious exoplanet civilizations in the Milky Way. Caballero states his paper attempts to provide these estimates. Caballero's methodology uses questionable hypotheses and excludes important parameters, indicating his methodology and estimates should be rejected., Comment: 9 pages, no figures

Human habitation across multiple planets requires communication and social connection between planets. When the infrastructure of a deep space network becomes mature, immersive cyberspace, known as the Metaverse, can exchange diversified user data and host multitudinous virtual worlds. Nevertheless, such immersive cyberspace unavoidably encounters latency in minutes, and thus operates in a turn-taking manner. This Blue Sky paper illustrates a vision of an interplanetary Metaverse that connects Earthian and Martian users in a turn-based Metaverse. Accordingly, we briefly discuss several grand challenges to catalyze research initiatives for the `Digital Big Bang' on Mars., Comment: Accepted Paper in ACM ICMI 2022 (Blue Sky Track)

Technosignatures refer to observational manifestations of technology that could be detected through astronomical means. Most previous searches for technosignatures have focused on searches for radio signals, but many current and future observing facilities could also constrain the prevalence of some non-radio technosignatures. This search could thus benefit from broader participation by the astronomical community, as contributions to technosignature science can also take the form of negative results that provide statistically meaningful quantitative upper limits on the presence of a signal. This paper provides a synthesis of the recommendations of the 2020 TechnoClimes workshop, which was an online event intended to develop a research agenda to prioritize and guide future theoretical and observational studies technosignatures. The paper provides a high-level overview of the use of current and future missions to detect exoplanetary technosignatures at ultraviolet, optical, or infrared wavelengths, which specifically focuses on the detectability of atmospheric technosignatures, artificial surface modifications, optical beacons, space engineering and megastructures, and interstellar flight. This overview does not derive any new quantitative detection limits but is intended to provide additional science justification for the use of current and planned observing facilities as well as to inspire astronomers conducting such observations to consider the relevance of their ongoing observations to technosignature science. This synthesis also identifies possible technology gaps with the ability of current and planned missions to search for technosignatures, which suggests the need to consider technosignature science cases in the design of future mission concepts., Comment: Accepted for publication in Acta Astronautica

In 2016, a star KIC 8462852 caught the world's attention due to a paper by citizen scientists who noticed its seemingly unexplainable brightness variations. The forward theory was offered - KIC 8462852 is surrounded by a Dyson sphere, a megastructure made by an alien civilization to collect all energy output from their star. Finally, in 2018, its light curve showed chromaticity more characteristic of the dust (from comets or asteroids) rather than of something made from solid material, but the world was woken up to the idea of megastructures. But, in Dyson's time, only Solar System planets were known; it took more than 20 years to realize that nature has no problem making planets and does it with a flair -- the total number of planets in the Galaxy is estimated to be in billions. With such abundance of planets, there would be no need to destroy the entire planetary system to make one sphere. Instead, a civilization can expand to a system that has planet(s) in the habitable zone (HZ), or a planet can be moved into it. Alternatively, a free-floating planet (FFP) can be captured and moved into the HZ. These shifts can be performed at a constant low-thrust acceleration using high power directional lasers, resulting in a gradual spiral transfer from one orbit to another. We propose here to search for ETI by looking for high-power laser technosignatures and consider merits of such signatures. We suggest to specifically pay attention to the multiple planetary systems that have Strange Exoplanetary Architectures (SEA) - unusual planetary arrangements that cannot be explained by current planetary formation theories, because these could be the result of ETI moving planets intentionally to suit their needs., Comment: 11 page, 7 figures

The Defense Department and NASA are investigating the possibility that aliens are currently surveilling Earth. This aligns with some search-for-extraterrestrial-intelligence (SETI) theorists who have concluded that ET's best strategy for opening a channel of communication is to send artificially intelligent probes to our Solar System for that purpose. This is a golden age for traditional SETI, which is currently well funded, with most of the world's radio telescopes now engaged in the hunt. One way or another, contact with aliens may be imminent. There has been no planning among nations for the aftermath of a first detection. This paper advocates for such planning and diplomacy.

Human space exploration and settlement of other planets is becoming increasingly technologically feasible, while mission concepts for remote and crewed missions to nearby star systems continue to be developed. But the long-term success of space settlement also requires extensions and advances in models of governance. This paper provides a synthesis of the physical factors that will constrain the application of sovereignty in space as well as legal precedent on Earth that likely applies to any crewed or uncrewed missions to other stellar systems. The Outer Space Treaty limits the territorial expansion of states into space, but the requirements for oversight of nongovernmental agencies and retention of property ownership enable the extension of state jurisdiction into space. Pragmatic constraints from historical precedent on Earth suggest that new space treaties will be unlikely to succeed and new global space agencies may have limited jurisdiction over states, while hard constraints of the space environment require adherence to technical capabilities, political feasibility, and long-term sustainability. These factors form a three-prong test for assessing the viability of interstellar governance models. This discussion of interstellar governance is intended to further the conversation about sovereignty in space prior to the first intentional launch of any interstellar spacecraft., Comment: Submitted to JBIS for the 8th Interstellar Symposium special issue

In this paper we discuss computer simulations of de Sitter and anti de Sitter spacetimes, which are maximally symmetric, relativistic analogs of non-Euclidean geometries. We present prototype games played in these spacetimes; such games and visualizations can help the players gain intuition about these spacetimes. We discuss the technical challenges in creating such simulations, and discuss the geometric and relativistic effects that can be witnessed by the players., Comment: ICCS 2024

Human interactions create social networks forming the backbone of societies. Individuals adjust their opinions by exchanging information through social interactions. Two recurrent questions are whether social structures promote opinion polarisation or consensus in societies and whether polarisation can be avoided, particularly on social media. In this paper, we hypothesise that not only network structure but also the timings of social interactions regulate the emergence of opinion clusters. We devise a temporal version of the Deffuant opinion model where pairwise interactions follow temporal patterns and show that burstiness alone is sufficient to refrain from consensus and polarisation by promoting the reinforcement of local opinions. Individuals self-organise into a multi-partisan society due to network clustering, but the diversity of opinion clusters further increases with burstiness, particularly when individuals have low tolerance and prefer to adjust to similar peers. The emergent opinion landscape is well-balanced regarding clusters' size, with a small fraction of individuals converging to extreme opinions. We thus argue that polarisation is more likely to emerge in social media than offline social networks because of the relatively low social clustering observed online. Counter-intuitively, strengthening online social networks by increasing social redundancy may be a venue to reduce polarisation and promote opinion diversity., Comment: 9 pages, 6 figures. Comments (e.g. missing references, suggestions, ...) are welcomed

Trailing the modern ideas of sociophysics, a minimalistic thermodynamic model of society is proposed, which consists of three social ingredients: people, economy, and entropy. Employing the universal van der Waals equation of state, many important relationships are discovered, including laws of econophysics. A paramount finding is that the Second Law of thermodynamics governs irreversible social evolution, revealing the power of social liberty and economic freedom., Comment: The paper is dedicated to Karl Marx (1818-1883) and Josiah W. Gibbs (1839-1903)

More often than not a lunch time conversation will veer off into bizarre and uncharted territories. In rare instances these frontiers of conversation can lead to deep insights about the Universe we inhabit. This paper details the fruits of one such conversation. In this paper we will answer the question: How many cows do you need to form a planetoid entirely comprised of cows, which will support a methane atmoosphere produced by the planetary herd? We will not only present the necessary assumptions and theory underpinning the cow-culations, but also present a thorough (and rather robust) discussion of the viability of, and implications for accomplishing, such a feat.

The Astro2020 report outlines numerous recommendations that could significantly advance technosignature science. Technosignatures refer to any observable manifestations of extraterrestrial technology, and the search for technosignatures is part of the continuum of the astrobiological search for biosignatures. The search for technosignatures is directly relevant to the "World and Suns in Context" theme and "Pathways to Habitable Worlds" program in the Astro2020 report. The relevance of technosignatures was explicitly mentioned in "E1 Report of the Panel on Exoplanets, Astrobiology, and the Solar System," which stated that "life's global impacts on a planet's atmosphere, surface, and temporal behavior may therefore manifest as potentially detectable exoplanet biosignatures, or technosignatures" and that potential technosignatures, much like biosignatures, must be carefully analyzed to mitigate false positives. The connection of technosignatures to this high-level theme and program can be emphasized, as the report makes clear the purpose is to address the question "Are we alone?" This question is also presented in the Explore Science 2020-2024 plan as a driver of NASA's mission. This white paper summarizes the potential technosignature opportunities within the recommendations of the Astro2020 report, should they be implemented by funding agencies. The objective of this paper is to demonstrate the relevance of technosignature science to a wide range of missions and urge the scientific community to include the search for technosignatures as part of the stated science justifications for the large and medium programs that include the Infrared/Optical/Ultraviolet space telescope, Extremely Large Telescopes, probe-class far-infrared and X-ray missions, and various facilities in radio astronomy., Comment: Unsolicited white paper by the NExSS Working Group on Technosignatures, 11 pages