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preprint2016arXiv

The last sunset on mainland Europe

This paper documents the places in mainland Europe at which the sun sets latest, by Coordinated Universal Time (UTC), on any given day (distortion due to differences in local standard times is ignored). In contradiction to the naïve assumption that the sun always sets latest at the westernmost point, the point of last sunset changes cyclically over the course of a year due to the changing orientation of the axis of the Earth with respect to the sun. Specifically, between the winter and summer solstices the last sunset shifts successively from Cabo de Sao Vicente (Portugal) to Cabo da Roca (Portugal) to Cabo Tourinan (Spain) to a site near Aglapsvik (Norway) to a location in the Norwegian municipality of Masoy south of Havoysund; and it shifts back again between the summer and winter solstices. There are two days in the year (April 24th and August 18th) on which the last sunset of mainland Europe (shared in those days effectively by Cabo Tourinan and the Aglapsvik area) coincides with the last sunset of mainland Africa, at a site in Western Sahara near Cap Blanc. A similar analysis of the first Spanish sunrise shows that from April 22nd to August 20th it occurs on the Costa Brava at

preprint2016arXiv

La scala dell'energia

In this article, halfway between popularized exposition and historical account, some key moments in the development of atomic theory in its beginnings are discussed. In particular, the events and the major discoveries that have highlighted the discrete structure of the atom's energy levels are presented in their logical and chronological sequence, starting from early studies on the decomposition of light by prisms until the quantum theory. --- In questo articolo, a metà strada tra l'esposizione divulgativa e il resoconto storico, vengono affrontati alcuni momenti significativi dello sviluppo della teoria atomica ai suoi primordi. In particolare, sono presentati, nella loro sequenza logica e cronologica, gli avvenimenti e le scoperte principali che hanno messo in luce la struttura discreta dei livelli di energia dell'atomo, dai primi studi sulla scomposizione della luce coi prismi alla teoria quantistica.

preprint2016arXiv

Artificial Intelligence Probes for Interstellar Exploration and Colonization

A recurring topic in interstellar exploration and the search for extraterrestrial intelligence (SETI) is the role of artificial intelligence. More precisely, these are programs or devices that are capable of performing cognitive tasks that have been previously associated with humans such as image recognition, reasoning, decision-making etc. Such systems are likely to play an important role in future deep space missions, notably interstellar exploration, where the spacecraft needs to act autonomously. This article explores the drivers for an interstellar mission with a computation-heavy payload and provides an outline of a spacecraft and mission architecture that supports such a payload. Based on existing technologies and extrapolations of current trends, it is shown that AI spacecraft development and operation will be constrained and driven by three aspects: power requirements for the payload, power generation capabilities, and heat rejection capabilities. A likely mission architecture for such a probe is to get into an orbit close to the star in order to generate maximum power for computational activities, and then to prepare for further exploration activities. Given current level

preprint2016arXiv

Secrets of Successful Science Projects

Over the past several years, the authors have served as teachers, qualified scientists, mentors, and/or parents on dozens of science projects. These projects ranged from elementary school projects that can be completed in a weekend to high school and college freshmen projects that take a semester or year to complete and yield published scholarly papers and/or compete at the highest national and international levels. This article describes what we have observed to be important to success.

preprint2016arXiv

Long-Term Prospects: Mitigation of Supernova and Gamma-Ray Burst Threat to Intelligent Beings

We consider global catastrophic risks due to cosmic explosions (supernovae, magnetars and gamma-ray bursts) and possible mitigation strategies by humans and other hypothetical intelligent beings. While by their very nature these events are so huge to daunt conventional thinking on mitigation and response, we wish to argue that advanced technological civilizations would be able to develop efficient responses in the domain of astroengineering within their home planetary systems. In particular, we suggest that construction of shielding swarms of small objects/particles confined by electromagnetic fields could be one way of mitigating the risk of cosmic explosions and corresponding ionizing radiation surges. Such feats of astroengineering could, in principle, be detectable from afar by advanced Dysonian SETI searches.

preprint2016arXiv

Dreidel Fairness Study

Are dreidels fair? In other words, does the average dreidel have an equal chance of turning up any one of its four sides? To explore this hypothesis, three different dreidels were each spun hundreds of times with the number of occurrences of each side recorded. It was found that all three dreidels tested -- a cheap plastic dreidel, an old wooden dreidel, and a dreidel that came embossed with a picture of Santa Claus -- were not fair. Statistically, for each dreidel, some sides came up significantly more often than others. Although an unfair dreidel does not necessarily make the game itself unfair, it is conjectured that hundreds of pounds of chocolate have been distributed during Chanukah under false pretenses.

preprint2016arXiv

The golden age of Calcutta physics: Difficulties in reconstructing the history

Classes started in the newly established Physics Department of Calcutta University Science College in 1916. Raman, Bose and Saha were three young members of the small physics faculty consisting of barely half a dozen faculty members. Within about one decade, three extraordinary discoveries came from these young men---Saha ionization equation in 1920, Bose statistics in 1924, Raman effect in 1928. However, fortunes of Calcutta University quickly got intertwined with India's freedom struggle led by Mahatma Gandhi exactly at the same time and the physics group got tragically disrupted. Indian physics never succeeded in reaching that height again. This paper discusses the difficulties in reconstructing a critical history of this Calcutta school of physics during the very short epoch of unmatched brilliance.

preprint2016arXiv

Affordable, Rapid Bootstrapping of the Space Industry and Solar System Civilization

Advances in robotics and additive manufacturing have become game-changing for the prospects of space industry. It has become feasible to bootstrap a self-sustaining, self-expanding industry at reasonably low cost. Simple modeling was developed to identify the main parameters of successful bootstrapping. This indicates that bootstrapping can be achieved with as little as 12 metric tons (MT) landed on the Moon during a period of about 20 years. The equipment will be teleoperated and then transitioned to full autonomy so the industry can spread to the asteroid belt and beyond. The strategy begins with a sub-replicating system and evolves it toward full self-sustainability (full closure) via an in situ technology spiral. The industry grows exponentially due to the free real estate, energy, and material resources of space. The mass of industrial assets at the end of bootstrapping will be 156 MT with 60 humanoid robots, or as high as 40,000 MT with as many as 100,000 humanoid robots if faster manufacturing is supported by launching a total of 41 MT to the Moon. Within another few decades with no further investment, it can have millions of times the industrial capacity of the United State

preprint2016arXiv

Bifurcation Adds Flavor to Basketball

We report an emergence of bifurcation in basketball, a single-particle system governed by Newtonian mechanics. When shooting the basketball, the obvious control parameters are the launch speed and the launch angle. We propose to use the three-dimensional velocity phase-space volume associated with the given launch parameters to quantify the difficulty of the shooting. The optimal launch angle that maximizes the associated phase-space volume undergoes a bifurcation as the launch speed is increased, if the shooter is farther than a critical distance away from the hoop. Thus, the bifurcation makes it very important to control the launch speed accurately. If the air resistance is removed, the bifurcation disappears and the phase-space volume distribution becomes dispersionless and shrinks in magnitude.

preprint2006arXiv

String Theory and Einstein's Dream

This article contains a short review of the current status of string theory.

preprint2007arXiv

Quantum-like Probabilistic Models outside Physics

We present a quantum-like (QL) model in that contexts (complexes of e.g. mental, social, biological, economic or even political conditions) are represented by complex probability amplitudes. This approach gives the possibility to apply the mathematical quantum formalism to probabilities induced in any domain of science. In our model quantum randomness appears not as irreducible randomness (as it is commonly accepted in conventional quantum mechanics, e.g., by von Neumann and Dirac), but as a consequence of obtaining incomplete information about a system. We pay main attention to the QL description of processing of incomplete information. Our QL model can be useful in cognitive, social and political sciences as well as economics and artificial intelligence. In this paper we consider in a more detail one special application -- QL modeling of brain's functioning. The brain is modeled as a QL-computer.

preprint2016arXiv

Space Development and Space Science Together, an Historic Opportunity

The national space programs have an historic opportunity to help solve the global-scale economic and environmental problems of Earth while becoming more effective at science through the use of space resources. Space programs will be more cost-effective when they work to establish a supply chain in space, mining and manufacturing then replicating the assets of the supply chain so it grows to larger capacity. This has become achievable because of advances in robotics and artificial intelligence. It is roughly estimated that developing a lunar outpost that relies upon and also develops the supply chain will cost about 1/3 or less of the existing annual budgets of the national space programs. It will require a sustained commitment of several decades to complete, during which time science and exploration become increasingly effective. At the end, this space industry will capable of addressing global-scale challenges including limited resources, clean energy, economic development, and preservation of the environment. Other potential solutions, including nuclear fusion and terrestrial renewable energy sources, do not address the root problem of our limited globe and there are real questio

preprint2016arXiv

The motion of two identical masses connected by an ideal string symmetrically placed over a corner

We introduce a novel, two-mass system that slides up an inclined plane while its center of mass moves down. The system consists of two identical masses connected by an ideal string symmetrically placed over a corner-shaped support. This system is similar to a double-cone that rolls up an inclined set of V-shaped rails. We find the double-cone's motion easy to demonstrate but difficult to analyze. Our example here is more straightforward to follow, and the experimental observations are in good agreement with the theoretical predictions.

preprint2016arXiv

Music and astronomy. II. unitedsoundsofcosmos

We have been congratulated on the stage by a Nobel laureate (he was our curtain raiser), played our music in planetariums, museums, observatories throughout Spain and at the end of the meeting of the ESO telescopes time allocation committee, shocked audiences in rock concerts, written monthly on Musica Universalis, made the second concert in 3D in Spain after Kraftwerk and broadcasted it live in Radio 3, mixed our music with poetry read aloud by scientists, composed the soundtracks of CARMENES, QUIJOTE, ESTRACK and the Gaia first data release, made a videoclip on how computer simulates the formation of stars... All those moments will not be lost in time like tears in rain, but put together in Bilbao during the 2016 meeting of the Spanish Astronomical Society.

preprint2011arXiv

The Accelerating Universe

In this article we review the discovery of the accelerating universe using type Ia supernovae. We then outline ways in which dark energy - component that causes the acceleration - is phenomenologically described. We finally describe principal cosmological techniques to measure large-scale properties of dark energy. This chapter complements other articles in this book that describe theoretical understanding (or lack thereof) of the cause for the accelerating universe.

preprint2016arXiv

Designing, Building, Measuring and Testing a Constant Equivalent Fall Height Terrain Park Jump

Previous work has presented both a theoretical foundation for designing terrain park jumps that control landing impact and computer software to accomplish this task. US ski resorts have been reluctant to adopt this more engineered approach to jump design, in part due to questions of feasibility. The present study demonstrates this feasibility. It describes the design, construction, measurement and experimental testing of such a jump. It improves on previous efforts with more complete instrumentation, a larger range of jump distances, and a new method for combining jumper- and board-mounted accelerometer data to estimate equivalent fall height, a measure of impact severity. It unequivocally demonstrates the efficacy of the engineering design approach, namely that it is possible and practical to design and build free style terrain park jumps with landing surface shapes that control for landing impact as predicted by the theory.

preprint2016arXiv

VR 'SPACE OPERA': Mimetic Spectralism in an Immersive Starlight Audification System

This paper describes a system designed as part of an interactive VR opera, which immerses a real-time composer and an audience (via a network) in the historical location of Gobeklitepe, in southern Turkey during an imaginary scenario set in the Pre-Pottery Neolithic period (8500-5500 BCE), viewed by some to be the earliest example of a temple, or observatory. In this scene music is generated, where the harmonic material is determined based on observations of light variation from pulsating stars, that would have theoretically been overhead on the 1st of October 8000 BC at 23:00 and animal calls based on the reliefs in the temple. Based on the observations of the stars V465 Per, HD 217860, 16 Lac, BG CVn and KIC 6382916, frequency collections were derived and applied to the generation of musical sound and notation sequences within a custom VR environment using a novel method incorporating spectralist techniques. Parameters controlling this 'resynthesis' can be manipulated by the performer using a Leap Motion controller and Oculus Rift HMD, yielding both sonic and visual results in the environment. The final opera is to be viewed via Google Cardboard and delivered over the Int

preprint2016arXiv

Apocalypse Now? Reviving the Doomsday Argument

Whether the fate of our species can be forecast from its past has been the topic of considerable controversy. One refutation of the so-called Doomsday Argument is based on the premise that we are more likely to exist in a universe containing a greater number of observers. Here we present a Bayesian reformulation of the Doomsday Argument which is immune to this effect. By marginalising over the spatial configuration of observers, we find that any preference for a larger total number of observers has no impact on the inferred local number. Our results remain unchanged when we adopt either the Self-Indexing Assumption (SIA) or the Self-Sampling Assumption (SSA). Furthermore the median value of our posterior distribution is found to be in agreement with the frequentist forecast. Humanity's prognosis for the coming century is well approximated by a global catastrophic risk of 0.2% per year.

preprint2016arXiv

Astronomical Alignments of the Sun Temple site in Mesa Verde National Park

Summer 2015 marked the 100th anniversary of the excavation by J.W. Fewkes of the Sun Temple in Mesa Verde National Park, Colorado; an ancient ceremonial complex of unknown purpose, prominently located atop a mesa, constructed by the Pueblo Indians approximately 1000 years ago. In this analysis we perform a digital survey of the site, and examine the possibility that four key tower-like elements of the complex were used for observation of the rise or set of celestial bodies known to be sacred to the Pueblo Indians. We find statistically significant evidence that the site was used for astronomical observation of the rise and/or set of nearly all such bodies. The Sun Temple appears to represent the most comprehensive prehistoric astronomical observatory yet uncovered.

preprint2016arXiv

Application of Monte Carlo Simulations to Improve Basketball Shooting Strategy

The underlying physics of basketball shooting seems to be a straightforward example of the Newtonian mechanics that can easily be traced by numerical methods. However, a human basketball player does not make use of all the possible basketball trajectories. Instead, a basketball player will build up a database of successful shots and select the trajectory that has the greatest tolerance to small variations of the real world. We simulate the basketball player's shooting training as a Monte Carlo sequence to build optimal shooting strategies, such as the launch speed and angle of the basketball, and whether to take a direct shot or a bank shot, as a function of the player's court positions and height. The phase space volume that belongs to the successful launch velocities generated by Monte Carlo simulations are then used as the criterion to optimize a shooting strategy that incorporates not only mechanical, but human factors as well.

preprint2016arXiv

The Story of the Neutrino

This is an elementary review of the history and physics of neutrinos. The story of the discovery of neutrino mass through neutrino oscillations is described in some detail. Experiments on solar neutrinos and atmospheric neutrinos played an important part. Recent advances are summarized and future developments are indicated.

preprint2016arXiv

What's wrong with the Platonic ideal of space and time?

This is a chapter for an upcoming book, "Space, Time, and the Limits of Human Understanding", edited by Shyam Wuppuluri and Giancarlo Ghirardi. I first present the classical picture of flat space and ever-flowing time, as generally accepted until about 1900, discuss the challenges posed by modern physics and the adjustments required by special relativity, general relativity and quantum mechanics, and finally consider (and reject) a recent hypothesis that space-time is essentially discrete. Ultimately, none of the simple answers to "what is space-time?" stand up to reality. We have more work ahead of us!

preprint2016arXiv

Air modes of the Bacon internal resonator banjo

Sound measurements on a sequence of related, similar constructions with slightly different dimensions confirm a simple picture of the air modes of the internal resonator banjo's body. For the purpose of this study, the air modes are decoupled from the soundboard (i.e., [drum] head) modes by replacing the head with 3/4" plywood. The resulting characteristic features survive the strong coupling of the air modes to the head and are in accord with the qualitative distinctions recognized by banjo players.

preprint2016arXiv

Binocular disparity as an explanation for the moon illusion

We present another explanation for the moon illusion, the phenomenon in which the moon looks larger near the horizon than near the zenith. In our model of the moon illusion, the sky is considered a spatially-contiguous and geometrically-smooth surface. When an object such as the moon breaks the contiguity of the surface, instead of perceiving the object as appearing through a hole in the surface, humans perceive an occlusion of the surface. Binocular vision dictates that the moon is distant, but this perception model contradicts our binocular vision, dictating that the moon is closer than the sky. To resolve the contradiction, the brain distorts the projections of the moon to increase the binocular disparity, which results in an increase in the perceived size of the moon. The degree of distortion depends upon the apparent distance to the sky, which is influenced by the surrounding objects and the condition of the sky. As the apparent distance to the sky decreases, the illusion becomes stronger. At the horizon, apparent distance to the sky is minimal, whereas at the zenith, few distance cues are present, causing difficulty with distance estimation and weakening the illusion.

316 works