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The universe is composed of ordinary matter (for example, stars, planets, ourselves), dark matter and dark energy. The estimated percentage of dark matter is about $27\%$ of the entire universe, while $5\%$ is ordinary matter and the remaining part is dark energy. This article introduces the fundamental ingredients that led to conjecture the existence of dark matter and to study its properties. To this result have contributed, directly or indirectly, numerous female mathematicians and astronomers, who we quote to give them the right credit., Comment: 21 pages, in Italian language

A very short, non-technical review of the main problems which are presently open in the context of the gravitational theory and of its cosmological applications, and which are currently under investigation and deep discussion. We will talk in particular about the equivalence principle, the dark matter and dark energy contributions, the cosmological constant, the quantisation of gravity, the dynamics of the very early Universe., Comment: 5 pages, no figures. To be published (in Italian language) on "Ithaca: Sfide", XXI (2023) ISSN: 2282-8079, ESE (Salento University Publishing), http://ithaca.unisalento.it/

Research in foundations of physics is stagnant, as claimed by many scientists during the last years. I suggest that one reason might be the reification of language, particularly of mathematics, which favour the search for answers to wrong questions., Comment: 8 pages, 1 figure. English translation and revision of an essay published in Italian: L. Foschini, "La reificazione della parola contro la scienza''. La Citt\`a del Secondo Rinascimento, n. 99, Giugno 2022, p. 13. Corrected an error I made about Arnold Sommerfeld

The page written by the astronomer Francesco Bianchini (1662-1729) and containing the data of the 1701 winter solstice observed at Santa Maria degli Angeli is presented for the first time in figure 2 and widely discussed along this paper. The great meridian line in the Basilica of Santa Maria degli Angeli in Rome was built in 1701/1702 with the scope to measure the Obliquity of the Earth's orbit in the following eight centuries, upon the will of pope Clement XI. During the winter solstice of 1701 the first measurements of the obliquity have been realized by Francesco Bianchini, the astronomer who designed the meridian line, upgrading the similar instrument realized by Giandomenico Cassini in San Petronio, Bononia. In this paper the accuracy of the data observed by Francesco Bianchini is discussed and compared with up-to-date ephemerides. The modern situation of this historical instrument is also presented., Comment: 9 pages, 4 figures in color, in Italian with English abstract. ISSN 2385-1961

Popularized explanations of the color of the sea often prove to be incomplete or oversimplified, and hence inadequate to become acquainted with the phenomenon in its whole. In this paper, after a historical review of the investigations on the subject in recent centuries and a brief account of the current state of knowledge, the topic is addressed in a more rigorous way adopting a comprehensive and multidisciplinary viewpoint. A phenomenological model providing operational results in educational context is proposed. --- Le spiegazioni del colore del mare proposte a scopo didattico o divulgativo si rivelano spesso incomplete o eccessivamente semplificate, e dunque inadeguate alla comprensione della totalit\`a del fenomeno. In questo articolo, dopo una rassegna storica delle indagini sull'argomento negli ultimi due secoli e un accenno allo stato attuale delle conoscenze, il problema viene affrontato in modo pi\`u rigoroso adottando un punto di vista comprensivo e pluridisciplinare. Viene proposto un modello fenomenologico in grado di fornire risultati operativi in contesto didattico., Comment: 42 pages, 9 figures, in italian, submitted to "Chimica nella Scuola"

In this paper is performed an appraisal of the Olympic Sport Judo effectiveness in the optics of Biomechanics. To broaden the classical view,the field of experimentation is obviously the high level competition in which most of rotational application can be found applied more or less instinctively by high level Athletes. Considering the two biomechanical tools that are the physical basis of judo throws it is possible to obtain such results from the analysis of high competition application:Lever Techniques are enhanced in their effectiveness in three ways: The rotational movements, strictly connected to the Lever techniques mechanics achieving victory in competition, can be extended to the unbalance phase. The rotational movements can be applied in a totally new way putting away even the unbalance that is basic in the Lever techniques. The Lever tool can be hybridized with the Couple tool to lower the energy consumption. Couple Techniques are enhanced in their effectiveness also in three ways: The Couple tool that doesnt need unbalance allowing uke body rotate around his center of mass, is enhanced utilizing the Uke body smaller resistance directions,normally summarized in Diagonal attacks. The vertical rotational movements in the transverse plan with the axis in the sagittal plane can be added to the Couple application with transverse rotation and axis in the frontal plane to overcome some defensive resistance, mainly in the trunk and leg group of Couple techniques,like Uchi Mata or O Soto Gari. The rotational movements enhance the throwing action changing the mechanics of Couple into Lever applying a Torque,both with the direction change of one force or the time delay of his application. This analysis, expanded with a short physical framework, clarifies hidden deep concepts and helps teacher and coaches in their professional work., Comment: 37 pages, 1 Diagram, 7 tables, 97 figures, this paper will be published,in Italian language, without mathematical framework into the Italian Judo Federation Magazine: "Athlon" FIJLKAM Yr 2014 Nu. 2

English: If the current status of theoretical and experimental knowledge in Nuclear Physics could be reduced to a geographical chart or a planisphere, then our epoch would be in some respect comparable to the end of the Medieval age and in other to the beginning of the Reinassance: epochs in which, together with the consolidated knowledge of the Old World, there have been great and revolutionary expeditions as the discovery of America or the periplus of Cape of Good Hope, explorations aimed at reaching the limits that, along the centuries, have lead to more and more engaging scientific discoveries in more and more far away lands, ending only in the twentieth century with the complete mapping of all the continents. Nuclear Physics is living an analogous adventure on the plane of contrast... - Italian: Se lo stato attuale delle conoscenze teoriche e sperimentali della Fisica Nucleare si potesse ridurre a una carta geografica o un mappamondo, allora la nostra epoca si potrebbe paragonare per certi versi alla fine del Medioevo e per altri al Rinascimento: epoche in cui, accanto alla conoscenza consolidata del Vecchio mondo, ci furono grandi e rivoluzionarie spedizioni come la scoperta dell'America o il periplo del Capo di Buona Speranza, esplorazioni geografiche volte al raggiungimento dei limiti che, nel corso dei secoli, hanno portato a scoperte scientifiche sempre pi\`u avvincenti in terre sempre pi\`u lontane, culminate solo nel ventesimo secolo con la completa mappatura di tutte le terre emerse. La Fisica Nucleare sta vivendo un'avventura analoga sul piano della contrapposizione tra la conoscenza acquisita sui nuclei stabili e la scoperta delle sorprendenti propriet\`a esotiche dei nuclei instabili, pi\`u difficili da produrre, da studiare e da comprendere., Comment: 17 pages, 13 figure, in Italian. This paper aims at popularizing the subject of exotic nuclei. - 17 pagine, 13 figure, in Italiano. Questo articolo ha lo scopo di divulgare il tema dei nuclei esotici

In Europe (e.g., in Italy), and in the States, the opinion is widely spreading that the negative consequences of modern progress are the fault of "Science". A lively debate on this topic took place among the famous writer Leonardo Sciascia and Italian physicists like Edoardo Amaldi and Emilio Segre', when Sciascia wrote his known book about the disappearance of Ettore Majorana, a book that presented Majorana (a very reserved theoretical physicist) as an example of the scientist that keeps his discoveries secret when afraid of possible evil applications. We wish to contribute now to such a question, since many special meetings did recently return to it, while celebrating the centenary of Majorana's birth (2006), or 30 years (2005) from Sciascia's book publication. It appeared natural to us to start with the figure of Einstein, who, even if extremely peaceable, supported the atomic bomb construction by his letter to Roosvelt. We discuss first the significance of part of Einsteins's scientific work (which flourished in particular one century ago): We seize this opportunity for presenting a derivation of the "twins paradox", so simple that it has been taught to Senior High School last-year students or University undergraduate students; all the present work, more in general, is addressed mainly to them. In the second part of this paper, we analyse the general meaning of Einstein's contributions to philosophy and pedagogy. The third part is entirely devoted to our main subject, i.e., to discussing the "Responsibility of the Intellectuals". The reader interested chiefly in this last part, can find it re-expounded in a self-contained way in the Appendix. More information in the Contents of this article., Comment: Replaced with minor improvements (typoes, one ref. added,...): 53 pages in Italian, with 7 Figures; source-file in Word. [The occasion for writing this work was a wish to prepare material useful to Senior High School last-year students and Univerity undergraduate students]

Plutarchus, circa 100 AD, in his early book on "astrophysics" --in which he exposed, in a sense, a general theory of gravitation-- wrote the noticeable passage: <>. While Posidonius (circa 135-51 BC) had written: <>. These two examples show how "modern" was part of the ancient Greek physics, frequently overlooked since it is sometimes known through the praiseworthy translations of scholars often competent in humanities, more than in science. [A more extended English summary appears at the beginning of this article, which is in Italian.], Comment: 18 pages, in Italian: but with a more extended summary in English. A preliminary version of this paper did already appear in the journal specified below

This is a brief, popular (non-technical) introduction (in Italian language) to the problem of quantum gravity, to the recent perspective of emergent spacetime and to its (potential) realization in the context of group field theories, in which the universe emerges as a condensate of non-spatiotemporal constituents., Comment: 15 pages, 12 (color) figures; Ithaca class file; published (in Italian language) on "Ithaca: Viaggio nella Scienza", ISSN: 2282-8079, ESE (Salento University Publishing) - http://ithaca.unisalento.it/nr-12_2018/index.html

A brief introduction to gravitational waves, addressing those questions that nowadays more and more frequently arise within a large audience (not only of insiders): what is a gravity wave, how can it be detected and, above all, what impact on modern physical theories may have their recent discovery? Interested readers can also find a few simple technical details and insights in the final Appendices., Comment: Published (in Italian language) on "Ithaca: Viaggio nella Scienza", ISSN: 2282-8079, ESE (Salento University Publishing), http://ithaca.unisalento.it/nr-12_2018/index.html

We report on the retrieval of the last missing papers of the "Senatore folder", given by Majorana to one student of his in Naples in 1938, just before his disappearance. The mentioned manuscript is conserved at the Domus Galilaeana in Pisa (Italy), and was written in French, probably for a conference in Leningrad (or in Kharkov) in 1933 (or in 1934). Majorana was invited to attend to such a conference but, actually, he did not tke part to it. The retrieved text deals with quantum electrodynamics by using the formalism of field quantization. It is here reported, for the first time, in translation. An accurate historical and scientific account is given as well., Comment: 16 pages, latex, amsart, in italian

In this paper we develop a simple model of the penetration process of a long rod through an uniform target. Applying the momentum and energy conservation laws, we derive an analytical relation which shows how the penetration depth depends upon the density of the rod, given a fixed kinetic energy. This work was sparked off by the necessity of understanding the effectiveness of high density penetrators (e.g. depleted uranium penetrators) as anti-tank weapons., Comment: 8 pages, 4 figures and 2 tables. Text in Italian

In this article (after some brief theoretical considerations) a bird-eye view is presented -with the help of nine figures- of the various experimental sectors of physics in which Superluminal motions seem to appear. In particular, a panorama is presented of the experiments with evanescent waves and/or tunnelling photons, and with the "localized Superluminal solutions" to the Maxwell equations (e.g., with the so-called X-shaped ones). The present paper is sketchy, but is followed by a large enough bibliography to allow the interested reader deepening the preferred topic., Comment: 12 pages plus 8 figures. A version in Italian, to be requested to the author, is available too

The declination of the Sun along the year varies according to a sinusoid. Around the solstices this curve is approximated by a parabola. In kinematics a parabola is obtained with a constant acceleration. This acceleration has been estimated in the days 21-29 December 2017, from the measurements taken at the meridian line in the Basilica of Santa Maria degli Angeli in Rome made by Francesco Bianchini in 1702 with purpose of measuring the variation of the obliquity of the ecliptic. The parabola equation is fitted to the data to obtain the solstice's instant with an accuracy of one hour. The departure of the measures is within 4 arcsec (the daytime seeing during these solar transits) from the ephemerides of IMCCE. The pipeline of the algorithm used to obtain the angular data of the center of the Sun, starting from the ground measurements affected by the atmospheric refraction, and corrected by the Cassini equation, is described. Bianchini in 1703 reduced the error on the solstices timings by using the difference in right ascension between the Sun and a star observed at the same meridian line even in daytime (as he did with Sirius in June-July 1703). The present one is an absolute measurement, without stellar references. The meridian diameter is averagely measured 24 arcsec less than the true value, with 20 arcsec of standard deviation, because of different luminosity contrasts in the sky and in the Basilica. Conversely the center of the image is much better defined (the contrast acts symmetrically without moving the center of the image), allowing an accuracy to the nearest arcsecond in the determination of the true obliquity., Comment: 9 pages, 2 figure, 4 links to video of the phenomenon. In Italian with extended English abstract

Around year 2000 the centenary of Planck's thermal radiation formula awakened interest in the origins of quantum theory, traditionally traced back to the Planck's conference on 14 December 1900 at the Berlin Academy of Sciences. A lot of more accurate historical reconstructions, conducted under the stimulus of that recurrence, placed the birth date of quantum theory in March 1905 when Einstein advanced his light quantum hypothesis. Both interpretations are yet controversial, but science historians agree on one point: the emergence of quantum theory from a presumed "crisis" of classical physics is a myth with scarce adherence to the historical truth. This article, written in Italian language, was originally presented in connection with the celebration of the World Year of Phyics 2005 with the aim of bringing these scholarly theses to a wider audience. --- Tradizionalmente la nascita della teoria quantistica viene fatta risalire al 14 dicembre 1900, quando Planck present\`o all'Accademia delle Scienze di Berlino la dimostrazione della formula della radiazione termica. Numerose ricostruzioni storiche pi\`u accurate, effettuate nel periodo intorno al 2000 sotto lo stimolo dell'interesse per il centenario di quell'avvenimento, collocano invece la nascita della teoria quantistica nel marzo del 1905, quando Einstein avanz\`o l'ipotesi dei quanti di luce. Entrambe le interpretazioni sono tuttora controverse, ma gli storici della scienza concordano su un punto: l'emergere della teoria quantistica da una presunta "crisi" della fisica classica \`e un mito con scarsa aderenza alla verit\`a storica. Con questo articolo in italiano, presentato originariamente in occasione delle celebrazioni per il World Year of Phyics 2005, si \`e inteso portare a un pi\`u largo pubblico queste tesi gi\`a ben note agli specialisti., Comment: 11 pages, 2 figures, in Italian, published on Apr. 8, 2005 on the SISSA online magazine "Biblioteca dei 500", ISSN 1722-4306, in website "ULISSE - nella rete della scienza", available at http://ulisse.sissa.it/biblioteca/saggio/2005/Ubib050401s002/at_download/file/Ubib050401s002.pdf (service discontinued as of Jan. 2011)

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 met\`a 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., Comment: 28 pages plus refs. page, 13 figures, 6 effigies, in Italian, re-edited from the version published on Sep. 9, 2005 on the SISSA online magazine "Biblioteca dei 500", ISSN 1722-4306, website "ULISSE - nella rete della scienza", available at http://ulisse.sissa.it/biblioteca/saggio/2005/Ubib050901s002/at_download/file/Ubib050901s002.pdf

In 1931, Dirac advanced a startling prediction about the existence of a new elementary particle, characterized by a magnetic charge of a single polarity: the magnetic monopole. This prediction, that was not based on experimental reasons but on mathematical consistency considerations and the generalization of the formalism of quantum mechanics, illustrates emblematically the Dirac conception of the relationship between physics and mathematics. ----- Nel 1931 Dirac avanz\`o una sorprendente previsione circa l'esistenza di una nuova particella elementare, caratterizzata da una carica magnetica di un'unica polarit\`a: il monopolo magnetico. Questa previsione, che non era fondata su ragioni sperimentali ma su considerazioni di consistenza matematica e sulla generalizzazione del formalismo della meccanica quantistica, illustra emblematicamente la concezione di Dirac del rapporto tra fisica e matematica., Comment: metadata only replacement, 26 pages plus refs. page, 5 figures, in Italian, published on Dec. 24, 2004 in a reduced version on the SISSA online magazine La Biblioteca dei 500, ISSN: 1722-4306 (online), in Ulisse, http://ulisse.sissa.it

The Astrarium made by Jacopo Dondi dell'Orologio in Padua in 1344 is one of the first public horologia in the World, their public utility is also shown through the history of the tower bell of Our Lady of Suffragio in Turin, made by the mathematician Francesco Fa\`a di Bruno in 1866. The tower bell of St. Anthony in Lanciano made by Antonio Cibotti was inaugurated by the Pope Paul VI in 1973 through a radio impulse, and now many tower bells are radio synchronized to the Central European Time within a single second of accuracy., Comment: 9 pages, 3 figures in color, in Italian with English abstract

Gerbert of Aurillac in the Mensura Fistularum explained how to compute the length of organ pipes. The method is shown on two octaves, starting from a fistula of length L=16 units and radius 1 which is equivalent at a monochord of length {\lambda}=18. The adopted acoustic correction for the first octave to the Pythagorean lengths is L={\lambda}-{\alpha}r with {\alpha}=2. The lower octave starts from L=36-2=34 units. The proportion 16:34=34:x is used for obtaining the next diapason. All lengths of the notes of this second octave follow this proportion and no more the additional acoustic correction. Gerbert finds the same multiplicative law for computing pipes and monochord's lengths, opportune constants allow to switch from monochord (12) to lower organ octave (14+1/3+1/144+1/288) to the higher one (13 + 1/2). The purpose of this treatise is to show the same mathematical order, given by God, below different acoustical phenomena. This is a modern perspective in history of science, because experimental data (practical acoustical corrections) are also taken into account. The treatment is limited to pipes of same diameter, and it is no conceived for organ builders. An Italian translation of the core text of the Mensura Fistularum is offered. The experimental measurement of end and mouth corrections for two pipes of different forms and for the flute is presented to support with modern acoustics approach that discussion., Comment: 32 pages, 18 figures, in Italian, ISSN 0392-0305

I fumetti, come i film, spesso utilizzano idee scientifiche "fantasiose". Non ci riferiamo qui alla violazione implicita delle leggi della fisica, cosa permessa in un mondo di fantasia, quanto piuttosto all'uso di spiegazioni fisiche errate che vengono usate in buona fede perch\'e a riflettono convinzioni molto diffuse, ma sbagliate, sull'interpretazione di fenomeni a partire dai principi fisici. D'altra parte questi errori possono servire a illustrare la corretta applicazione della fisica in una maniera molto pi\`u accattivante rispetto alla modalit\'a tradizionale di presentazione. Analizziamo qui l'avventura Paperone ed il deposito sotterraneo di Pezzin e Cavezzano. ----- Comics and cartoon movies sometimes exploit fictitious scientific ideas. It is often the case that these ideas, althought wrong, actually reflect the popular vision of some natural phenomenon. We do not refer here to the implicit violation of physical laws in fictions, a practice allowed by the underlining "poetic licence" of comics. However, sometimes wrong scientific "explanations" are proposed, and those may be accepted by the public without further inspection. On the other hand, these errors may be a good starting point for a didactic illustration of physical principles. We analyse here the comics Paperone ed il deposito sotterraneo (Uncle Scrooge and the underground money bin) by Perrin e Cavezzano., Comment: in Italian

Let's take stock of the situation on one of the most studied astrophysical phenomena during the latest years: the jets escaping from protostars, stellar singularities, GRB and active galactic nuclei., Comment: 7 pages, no figures, 1 table. English translation of the article originally published in Italian on the popular science magazine "Le Stelle", n. 82, March 2010.

By using the Fermi satellite, a group of physicists discovers a new type of gamma-ray active nucleus, Comment: 6 pages. Originally published in Italian on the popular science magazine Darwin, n. 34, November/December 2009

This agile small "book" (in Italian) is an introduction to the life and work of Ettore Majorana, the brightest Italian theoretical physicist of the XX century, regarded by Enrico Fermi as the best theoretician of his time in the world. It consists of ten smooth chapters, only few of them being moderately technical, and of three Appendices: (i) about his inaugural lecture on physics at the University of Naples; (ii) about some notes of his, on the role of the statistical laws in physics and in the social sciences; and (iii) with a recapitulatory biographic outline. The present material is mainly taken from our previous book "Il Caso Majorana: Epistolario, Documenti, Testimonianze", first published (1987, 1991) by Mondadori, Milan, and recently (2000, 2002, 2008) published by Di Renzo Editore, Rome. That book presented practically all the serious documents existing on Majorana's life & work [indeed, almost all the biographical documents have been discovered or collected, during a few decades, by the present author, who was the first to publish them]. Actually, we might address to such a book (c/o www.direnzo.it, "Arcobaleno" series) all the readers interested in more and deeper information., Comment: An agile short "book" of 56 pages, in Italian, consisting in 10 smooth chapters and 3 Appendices. In pdf (the original source-file being in Word)- Replaced eliminating a defect (and better specifying the existing copyright)

From light and physical phenomena to cinema, an interdisciplinary percourse between art and science, from historical and critical references to the ultimate digital frontiers, including digital movies revolution, stereoscopy, holography, interfaces. ----- Dalla luce ed i fenomeni fisici al cinema, un percorso interdisciplinare tra arte e scienza, dalle citazioni storiche e critiche alle ultime frontiere del digitale, inclusi il cinema digitale, la stereoscopia, la olografia, le interfacce., Comment: Comments: in Italian, submitted to Gremese Editore, Digitale e dintorni

In 1927, just after he obtained a full professorship, Enrico Fermi delivered his first course on Theoretical Physics at the Institute of Physics in Rome. The following year Edoardo Amaldi, Emilio Segre' and Ettore Majorana became students of that course. The lectures given in 1927-28, whose content may be easily reconstructed, probably had a deep impact in forming such young students, who participated actively in the Physics researches carried on in Rome soon after. In this perspective, the case of Ettore Majorana is certainly the most important one: as a lecturer, in 1933-36 he planned to give three advanced Physics courses in Rome, before obtaining his full professorship in Theoretical Physics "for high and well-deserved repute" in 1937. From the analysis of the lectures he delivered in Naples in 1938, we can conclude that, in part, Majorana referred to the Fermi lectures he followed as a student, but he also introduced some advanced (for that time) topics, rendering his course a very modern one. Much of these frontier topics were already cited in the programmes of the mentioned three courses he presented few years earlier., Comment: pdf, 13 pages, in italian; to be published in Sapere

We give, for the first time, the critical complete text of a manuscript by Ettore Majorana, conserved in the same file of the lecture notes for his course on Theoretical Physics at the University of Naples. He probably refers to a seminar delivered in that University. Some passages reveal a physical interpretation of the Quantum Mechanics which anticipates of several years the Feynman approach in terms of path integrals, independently of the underlying mathematical formulation., Comment: 16 pages, in italian