Tag Archives: History and Philosophy of Physics

Archaeoastronomical study of the historic churches of La Gomera [CL]

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http://arxiv.org/abs/2003.01198


In this paper we discuss the importance of studying the orientation of ancient Christian churches, as a complement to the historical and cultural research of the temples. We present preliminary results of the analysis of the precise spatial orientation of 38 colonial churches located on the Canary Island of La Gomera (Spain). The sample suggests that, although several churches have a canonical orientation within the solar range, a large proportion of them follow a pattern of orientations that is compatible with the steep orography of the island and, therefore, contrasts with the prescriptions contained in the texts of the early Christian writers.

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A. Paolo and A. Gangui
Wed, 4 Mar 20
43/51

Comments: Article in Spanish including 8 figures. Published version available at this http URL

Non-Euclidean Newtonian Cosmology [CL]

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http://arxiv.org/abs/2002.10155


We formulate and solve the problem of Newtonian cosmology under the assumption that the absolute space of Newton is non-Euclidean. In particular, we focus on the negatively-curved hyperbolic space, H3. We point out the inequivalence between the curvature term that arises in the Friedmann equation in Newtonian cosmology in Euclidean space and the role of curvature in the H3 space. We find the generalisation of the inverse-square law and the solutions of the Newtonian cosmology that follow from it. We find the generalisations of the Euclidean Michell ‘black hole’ in H3 and show that it leads to different maximum force and area results to those we have found in general relativity. We show how to add the counterpart of the cosmological constant to the gravitational potential in H3 and explore the solutions and asymptotes of the cosmological models that result. We also discuss the problems of introducing compact topologies in Newtonian cosmologies with non-negative spatial curvature.

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J. Barrow
Tue, 25 Feb 20
61/76

Comments: 11 pages, no figures

Stephen William Hawking: A Biographical Memoir [CL]

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http://arxiv.org/abs/2002.03185


Stephen Hawking’s contributions to the understanding of gravity, black holes and cosmology were truly immense. They began with the singularity theorems in the 1960s followed by his discovery that black holes have an entropy and consequently a finite temperature. Black holes were predicted to emit thermal radiation, what is now called Hawking radiation. He pioneered the study of primordial black holes and their potential role in cosmology. His organisation of and contributions to the Nuffield Workshop in 1982 consolidated the picture that the large-scale structure of the universe originated as quantum fluctuations during the inflationary era. Work on the interplay between quantum mechanics and general relativity resulted in his formulation of the concept of the wavefunction of the universe. The tension between quantum mechanics and general relativity led to his struggles with the information paradox concerning deep connections between these fundamental areas of physics.
These achievements were all accomplished following the diagnosis during the early years of Stephen’s studies as a post-graduate student in Cambridge that he had incurable motor neuron disease — he was given two years to live. Against all the odds, he lived a further 55 years. The distinction of his work led to many honours and he became a major public figure, promoting with passion the needs of disabled people. His popular best-selling book A Brief History of Time made cosmology and his own work known to the general public worldwide. He became an icon for science and an inspiration to all.

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B. Carr, G. Ellis, G. Gibbons, et. al.
Tue, 11 Feb 20
44/81

Comments: 38 pages

Orbital dynamics of highly probable but rare Orionid outbursts possibly observed by the ancient Maya [EPA]

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http://arxiv.org/abs/2002.00106


Using orbital integrations of particles ejected from Comet Halley’s passages between 1404 BC and 240 BC, the authors investigate possible outbursts of the Orionids (twin shower of the Eta Aquariids) that may have been observed in the western hemisphere. In an earlier orbital integration study the authors determined there was a high probability linking probable outbursts of the Eta Aquariid meteor shower with certain events recorded in inscriptions during the Maya Classic Period, AD 250-900. This prior examination was the first scientific inquiry of its kind into ancient meteor outbursts possibly recorded in the western hemisphere where previously no pre-Columbian observations had existed. In the current paper the aim is to describe orbital dynamics of rare but probable Orionid outbursts that would have occurred on or near applicable dates recorded in the Classic Maya inscriptions. Specifically, significant probable outbursts are found in AD 417 and 585 out of 30 possible target years. The driving mechanisms for outbursts in those two years are Jovian 1:6 and 1:7 mean motion resonances acting to maintain compact structures within the Orionid stream for over 1 kyr. Furthermore, an Orionid outburst in AD 585 recorded by China is confirmed.

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J. Kinsman and D. Asher
Tue, 4 Feb 20
35/52

Comments: Monthly Notices of the Royal Astronomical Society. Accepted 2020 January 17. Received 2020 January 3; in original form 2019 May 30. 9 pages, 4 figures

Profiles of James Peebles, Michel Mayor, and Didier Queloz: 2019 Nobel Laureates in Physics [CL]

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http://arxiv.org/abs/2001.08511


The 2019 Nobel Prize in Physics honors three pioneering scientists for their fundamental contributions to basic cosmic questions – Professor James Peebles (Princeton University), Michel Mayor (University of Geneva), and Didier Queloz (University of Geneva and the University of Cambridge) – “for contributions to our understanding of the evolution of the universe and Earth’s place in the cosmos,” with one half to James Peebles “for theoretical discoveries in physical cosmology,” and the other half jointly to Michel Mayor and Didier Queloz “for the discovery of an exoplanet orbiting a solar-type star.” We summarize the historical and scientific backdrop to this year’s Physics Nobel.

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N. Bahcall and A. Burrows
Fri, 24 Jan 20
72/72

Comments: Published in the Proceedings of the National Academies of Science, January 14, 2020, vol. 117, pp. 799-801

The Great Debate [CL]

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http://arxiv.org/abs/2001.00159


A hundred years ago (1920) in the auditorium of the Smithsonian Institution’s U.S. National Museum there were two lectures under the auspices of the George Ellery Hale Lecture series, what has come to be called the ‘Great Debate’. In the debate, Harlow Shapley and Heber Curtis argued over the ‘Scale of the Universe’. Curtis argued that the Universe is composed of many galaxies like our own and they are relatively small. Shapley argued that the Universe was composed of only one big Galaxy. In Shapley’s model, our Sun was far from the center of this great island Universe.

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I. Horvath
Mon, 13 Jan 20
36/61

Comments: In Hungarian. This article was published in the 2020 Astronomical Yearbook (Hungarian, MCSE)

La orientación de las iglesias andinas de la región de Arica y Parinacota, Chile: una aproximación arqueoastronómica [CL]

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http://arxiv.org/abs/1912.12934


The heritage Andean churches of Arica and Parinacota are representative of the majority of Christian churches in the region. Judging by their architecture, materiality and decoration, they have many features in common and are faithful to the intentions of their original builders. However, their geographical locations and the landscape that surrounds these churches show specific features for each of them. In particular, the orientation of the main axes (towards the altar of the churches) shows some diversity. In this extended area, with little attention from parish priests, the local Aymara culture, with its own worldview, surely engaged in a dialogue with the Western tradition in order to design and build the Indian Reductions. In this paper we present the results obtained from the analysis of the precise spatial orientations of all the cataloged churches, employing the tools of archaeoastronomy, as a complement to the architectural, historical and cultural research of the temples. We also comment briefly on some progress that we hope to make in neighboring areas to the region here studied, which include a large number of very old temples and are part, along with the churches here considered, of a common and widespread cultural koine.

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A. Gangui, A. Guillen and M. Pereira
Wed, 1 Jan 20
73/88

Comments: Article in Spanish, PDF document. Published version available at this http URL arXiv admin note: text overlap with arXiv:1803.08599

La orientación de las iglesias andinas de la región de Arica y Parinacota, Chile: una aproximación arqueoastronómica [CL]

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http://arxiv.org/abs/1912.12934


The heritage Andean churches of Arica and Parinacota are representative of the majority of Christian churches in the region. Judging by their architecture, materiality and decoration, they have many features in common and are faithful to the intentions of their original builders. However, their geographical locations and the landscape that surrounds these churches show specific features for each of them. In particular, the orientation of the main axes (towards the altar of the churches) shows some diversity. In this extended area, with little attention from parish priests, the local Aymara culture, with its own worldview, surely engaged in a dialogue with the Western tradition in order to design and build the Indian Reductions. In this paper we present the results obtained from the analysis of the precise spatial orientations of all the cataloged churches, employing the tools of archaeoastronomy, as a complement to the architectural, historical and cultural research of the temples. We also comment briefly on some progress that we hope to make in neighboring areas to the region here studied, which include a large number of very old temples and are part, along with the churches here considered, of a common and widespread cultural koine.

Read this paper on arXiv…

A. Gangui, A. Guillen and M. Pereira
Wed, 1 Jan 20
3/88

Comments: Article in Spanish, PDF document. Published version available at this http URL arXiv admin note: text overlap with arXiv:1803.08599

Einstein and Eddington and the eclipse in Principe: Celebration and science 100 years after [CL]

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http://arxiv.org/abs/1912.08354


On May 29, 1919, at Ro\c{c}a Sundy, Principe island, Eddington confirms Einstein’s general relativity theory for the first time by photographing stars behind the obscured Sun during a total eclipse. History was made. At Sobral, Eddington’s astronomer colleagues photograph the same eclipse and also conclude that light from distant stars suffers a deflection when passing by the gravitational field of the Sun, in accordance with general relativity. With the confirmation of general relativity, a theory of gravitation at a fundamental level, physics became, once and for all, relativist and its future was outlined. The first world war had finished a few months before and the deep wounds between nations were yet to heal. Science wanted to be above it all showing that people could be united by a common goal. This year, the 100 years of this achievement was commemorated with the scientific conference “From Einstein and Eddington to LIGO: 100 years of gravitational light deflection” in Principe to celebrate this landmark event. We report here on this conference of celebration.

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J. Lemos, C. Herdeiro and V. Cardoso
Thu, 19 Dec 19
79/82

Comments: 12 pages, 4 figures

The Legacy of Einstein's Eclipse, Gravitational Lensing [CL]

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http://arxiv.org/abs/1912.07674


A hundred years ago, two British expeditions measured the deflection of starlight by the sun’s gravitational field, confirming the prediction made by Einstein’s General theory of Relativity. One hundred years later many physicists around the world are involved in studying the consequences and use as a research tool, of the deflection of light by gravitational fields, a discipline that today receives the generic name of Gravitational Lensing. The present review aims to commemorate the centenary of Einstein’s Eclipse expeditions by presenting a historical perspective of the development and milestones on gravitational light bending, covering from early XIX century speculations, to its current use as an important research tool in astronomy and cosmology.

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J. Cervantes-Cota, S. Galindo-Uribarri and G. Smoot
Wed, 18 Dec 19
4/71

Comments: 47 pages, 26 figures, accepted in Universe: Feature Papers 2019 – Gravitational Physics

Shadow of the Moon and general relativity: Einstein, Dyson, Eddington and the 1919 light deflection [CL]

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http://arxiv.org/abs/1912.05587


The eclipse of the Sun of 1919 was fundamental in the development of physics and earns a high place in the history of science. Several players took part in this adventure. The most important are Einstein, Dyson, Eddington, the Sun, the Moon, Sobral, and Principe. Einstein’s theory of gravitation, general relativity, had the prediction that the gravitational field of the Sun deflects an incoming light ray from a background star on its way to Earth. The calculation gave that the shift in the star’s position was 1.75 arcseconds for light rays passing at the Sun’s rim. So to test it definitely it was necessary to be in the right places on May 29, 1919, the day of the eclipse. That indeed happened, with a Royal Greenwich Observatory team composed of Crommelin and Davidson that went to Sobral, and that was led at a distance by the Astronomer Royal Frank Dyson, and with Eddington of Cambridge University that went to Principe with his assistant Cottingham. The adventure is fascinating, from the preparations, to the day of the eclipse, the data analysis, the results, and the history that has been made. It confirmed general relativity, and marked an epoch that helped in delineating science in the post eclipse era up to now and into the future. This year of 2019 we are celebrating this enormous breakthrough

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J. Lemos
Fri, 13 Dec 19
17/75

Comments: 63 pages, 39 figures

Outstanding Pulkovo latitude observers Lidia Kostina and Natalia Persiyaninova [IMA]

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http://arxiv.org/abs/1912.05613


Lidia Dmitrievna Kostina and Natalia Romanovna Persiyaninova left a bright mark in the history of the Pulkovo Observatory, as well as in the history of the domestic and international latitude services. In the first place, they were absolute leaders in the latitude observations with the famous zenith telescope ZTF-135. In 1954-2001, they obtained together more than 66’000 highly accurate latitudes, which make about 2/3 of all the observations made by 23 observers with the ZTF-135 after the WW2. They also provided a large contribution to investigation of the instrumental errors, methods of the data analysis, developing of the observing programs. Their results in studies of the latitude variations and polar motion were also highly recognized by the community.

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Z. Malkin, N. Miller and T. Soboleva
Fri, 13 Dec 19
29/75

Comments: Presented at the Journees 2019 “Astrometry, Earth rotation and Reference systems in the Gaia era”, Paris, France, 7-9 Oct 2019

Homogeneity and the causal boundary [CL]

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http://arxiv.org/abs/1911.13199


A Universe with finite age also has a finite causal scale $\chi_\S$, so the metric can not be homogeneous for $\chi>\chi_\S$, as it is usually assumed. To account for this, we propose a new causal boundary condition, that can be fulfil by fixing the cosmological constant $\Lambda$ (a free parameter for gravity). The resulting Universe is inhomogeneous, with possible variation of cosmological parameters on scales $\chi \simeq \chi_\S$. The size of $\chi_\S$ depends on the details of inflation, but regardless of its size, the boundary condition forces $\Lambda/8\pi G $ to cancel the contribution of a constant vacuum energy $\rho_{vac}$ to the measured $\rho_\Lambda \equiv \Lambda/8\pi G + \rho_{vac}$. To reproduce the observed $\rho_{\Lambda} \simeq 2 \rho_m$ today with $\chi_\S \rightarrow \infty$ we then need a universe filled with evolving dark energy (DE) with pressure $p_{DE}> – \rho_{DE}$ and a fine tuned value of $\rho_{DE} \simeq 2 \rho_m$ today. This seems very odd, but there is another solution to this puzzle. We can have a finite value of $\chi_\S \simeq 3 c/H_0$ without the need of DE. This scale corresponds to half the sky at $z \sim 1$ and 60deg at $z \sim 1000$, which is consistent with the anomalous lack of correlations observed in the CMB.

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E. Gaztanaga
Tue, 3 Dec 19
62/90

Comments: 10 pages, 2 figures, invited review at XXXIX Polish Astronomical Society Meeting. arXiv admin note: text overlap with arXiv:1904.08218

Effective field theories as a novel probe of fine-tuning of cosmic inflation [CL]

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http://arxiv.org/abs/1911.05128


The leading account of several salient observable features of our universe today is provided by the theory of cosmic inflation. But an important and thus far intractable question is whether inflation is generic, or whether it is finely tuned—requiring very precisely specified initial conditions. In this paper I argue that a recent, model-independent characterization of inflation, known as the ‘effective field theory (EFT) of inflation’, promises to address this question in a thoroughly modern and significantly more comprehensive way than in the existing literature.
To motivate and provide context for this claim, I distill three core problems with the theory of inflation, which I dub the permissiveness problem, the initial conditions problem, and the multiverse problem. I argue that the initial conditions problem lies within the scope of EFTs of inflation as they are currently conceived, whereas the other two problems remain largely intractable: their solution must await a more complete description of the very early universe. I highlight recent work that addresses the initial conditions problem within the context of a dynamical systems analysis of a specific (state-of-the-art) EFT of inflation, and conclude with a roadmap for how such work might be extended to realize the promise claimed above.

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F. Azhar
Thu, 14 Nov 19
65/68

Comments: 23 pages, 1 figure

Einstein and Eddington and the consequences of general relativity: Black holes and gravitational waves [CL]

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http://arxiv.org/abs/1911.01959


For the celebrations of the 100 years of the observations undertaken by Eddington at the island of Principe and collaborators at Sobral during a total solar eclipse in May 29, 1919, which have confirmed Einstein’s theory of general relativity through the deflection of the incoming light from distant stars due to the spacetime curvature caused by the Sun, we highlight the main aspects of the theory, its tests and applications, focusing on some of its outstanding consequences. These are black holes, the object par excellence of general relativity, and gravitational waves, the gravitational probe for the distant Universe. We also point out some open issues.

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J. Lemos, C. Herdeiro and V. Cardoso
Wed, 6 Nov 19
7/57

Comments: 16 pages, 2 figures

Finely tuned models sacrifice explanatory depth [CL]

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http://arxiv.org/abs/1910.13608


It is commonly argued that an undesirable feature of a theoretical or phenomenological model is that salient observables are sensitive to values of parameters in the model. But in what sense is it undesirable to have such ‘fine-tuning’ of observables (and hence of the underlying model)? In this paper, we argue that the fine-tuning can be interpreted as a shortcoming of the explanatory capacity of the model: in particular it signals a lack of explanatory depth. In support of this argument, we develop a scheme—for models that arise broadly in the sciences—that quantitatively relates fine-tuning of observables described by these models to a lack of depth of explanations based on these models. A significant aspect of our scheme is that, broadly speaking, the inclusion of larger numbers of parameters in a model will decrease the depth of the corresponding explanation. To illustrate our scheme, we apply it in two different settings in which, within each setting, we compare the depth of two competing explanations. The first setting involves explanations for the Euclidean nature of spatial slices of the universe today: in particular, we compare an explanation provided by the big-bang model of the early 1970s with an explanation provided by a general model of cosmic inflation. The second setting has a more phenomenological character, where the goal is to infer from a limited sequence of data points, using maximum entropy techniques, the underlying probability distribution from which these data are drawn. In both of these settings we find that our analysis favors the model that intuitively provides the deeper explanation of the observable(s) of interest. We thus provide an account that unifies two ‘theoretical virtues’ of models used broadly in the sciences—namely, a lack of fine-tuning and explanatory depth—to show that, indeed, finely tuned models sacrifice explanatory depth.

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F. Azhar and A. Loeb
Thu, 31 Oct 19
25/55

Comments: 21 pages, 1 figure

Anthropic Selection of Physical Constants, Quantum Entanglement, and the Multiverse Falsifiability [CL]

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http://arxiv.org/abs/1910.09073


This paper evaluates some important aspects of the multiverse concept. Firstly, the most realistic opportunity for it which is the spacetime variability of the physical constants and may deliver worlds with different physics, hopefully fulfilling the conditions of the anthropic principles. Then, more esoteric versions of the multiverse being the realisation of some abstract mathematics or even logic. Finally, it evaluates the big challenge of getting any signal from “other universes” using recent achievements of the quantum theory.

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M. Dabrowski
Tue, 22 Oct 19
80/91

Comments: 21 pages, 2 figures

MOND vs. dark matter in light of historical parallels [GA]

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http://arxiv.org/abs/1910.04368


MOND is a paradigm that contends to account for the mass discrepancies in the Universe without invoking dark' components, such asdark matter’ and dark energy'. It does so by supplanting Newtonian dynamics and General Relativity, departing from them at very low accelerations. Having in mind historians and philosophers of science, as well as physicists and astronomers, I describe in this review the main aspects of MOND -- its statement, its basic tenets, its main predictions, and the tests of these predictions -- contrasting it with the dark-matter paradigm. I then discuss possible wider ramifications of MOND, for example the potential significance of the MOND constant, $a_0$, and its possible implications for the roots of MOND in cosmology. Along the way I point to parallels with several historical instances of nascent paradigms. In particular, with the emergence of the Copernican world picture, that of quantum physics, and that of relativity. I point to analogies between these paradigms as regards their initial advent, their development, their schematic structure, and their ramifications. For example, the interplay between theories and their corollary laws, and the centrality of a new constant with converging values as deduced from seemingly unrelated manifestations of these laws. I parallel the struggle of the new with the old paradigms, and the appearance of hybrid paradigms at such times of struggle. I also try to identify in the history of those established paradigms a stage that can be likened to that of MOND today.<br><br>
<a href="http://arxiv.org/abs/1910.04368" target="_blank" rel="noopener noreferrer">Read this paper on arXiv...</a><br><br>
<p align="left">M. Milgrom
Fri, 11 Oct 19<br>
71/76<br><br>
Comments: 29 pages, 19 figures, Based on a talk at the conferenceDark Matter & Modified Gravity’, Aachen, February 2019

Edwin P. Hubble, astropolítico [CL]

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http://arxiv.org/abs/1910.01999


Rather than offering chronologically ordered encyclopedic knowledge of a lifetime, only some of the most striking events of the existence of this well-known scientist are here pointed out. Sections: Life; Man of laws; Interest in philosophy; Astronomer, astrophysicist, cosmologist; The discovery of the expansion of the Universe; Reasonable doubt about the expansion; The astropolitician. Apart from his scientific ideas of cosmological scope, his worldview has been that of a pragmatic thinker with training in law, who converts science into a large company and the scientific hypothesis into a convenient truth that deserves to be defended and arrogated, although deep down it is known that such reasons are not exclusive or original and that there are also reasons to defend the opposite thing.
——
M\’as que ofrecer un conocimiento enciclop\’edico cronol\’ogicamente ordenado de toda una vida, se\~nalar\’e solamente algunos de los eventos m\’as llamativos de la existencia del ampliamente reconocido cient\’ifico. Secciones: Vida; Hombre de leyes; Inter\’es por la filosof\’ia; Astr\’onomo, astrof\’isico, cosm\’ologo; El descubrimiento de la expansi\’on del Universo; Duda razonable sobre la expansi\’on; El astropol\’itico. Aparte de sus ideas cient\’ificas de alcance cosmol\’ogico, su cosmovisi\’on ha sido la de un pensador pragm\’atico con formaci\’on de abogado, que convierte la ciencia en una gran empresa y la hip\’otesis cient\’ifica en una verdad conveniente que merece defenderse y arrogarse, aunque en el fondo se sepa que no son exclusivas ni originales tales razones y que hay tambi\’en razones para defender lo contrario.

Read this paper on arXiv…

M. Lopez-Corredoira
Mon, 7 Oct 19
30/42

Comments: 8 pages, in Spanish, to be published as a chapter in “La cosmovisi\’on de los grandes cient\’ificos del siglo XX. Convicciones \’eticas, pol\’iticas, filos\’oficas o religiosas de los protagonistas de las revoluciones cient\’ificas contempor\’aneas”, Juan Arana (Ed.), Ed. Tecnos, Madrid

Why Halley did not discover proper motion and why Cassini did [CL]

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http://arxiv.org/abs/1909.13636


In 1717 Halley compared contemporaneous measurements of the latitudes of four stars with earlier measurements by ancient Greek astronomers and by Brahe, and from the differences concluded that these four stars showed proper motion. An analysis with modern methods shows that the data used by Halley do not contain significant evidence for proper motion. What Halley found are the measurement errors of Ptolemaios and Brahe. Halley further argued that the occultation of Aldebaran by the Moon on 11 March 509 in Athens confirmed the change in latitude of Aldebaran. In fact, however, the relevant observation was almost certainly made in Alexandria where Aldebaran was not occulted. By carefully considering measurement errors Jacques Cassini showed that Halley’s results from comparison with earlier astronomers were spurious, a conclusion partially confirmed by various later authors. Cassini’s careful study of the measurements of the latitude of Arcturus provides the first significant evidence for proper motion.

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F. Verbunt and M. Sluys
Tue, 1 Oct 19
82/90

Comments: 15 pages, 3 figures, accepted for publication in the Journal for the History of Astronomy

The Earliest Candidates of Auroral Observations in Assyrian Astrological Reports: Insights on Solar Activity around 660 BCE [SSA]

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http://arxiv.org/abs/1909.05498


Auroral records found in historical archives and cosmogenic isotopes found in natural archives have served as sound proxies of coronal mass ejections (CMEs) and solar energetic particles (SEPs), respectively, for dates prior to the onset of telescopic sunspot observations in 1610. These space weather events constitute a significant threat to a modern civilization, because of its increasing dependency on an electronic infrastructure. Recent studies have identified multiple extreme space weather events derived from solar energetic particles (SEPs) in natural archives, such as the event in 660 BCE. While the level of solar activity around 660 BCE is of great interest, this had not been within the coverage of the hitherto-known datable auroral records in historical documents that extend back to the 6th century BCE. Therefore, we have examined Assyrian astrological reports in the 8th and 7th centuries BCE, identified three observational reports of candidate aurorae, and dated these reports to approximately 680 BCE — 650 BCE. The Assyrian cuneiform tablets let us extend the history of auroral records and solar activity by a century. These cuneiform reports are considered to be the earliest datable records of candidate aurorae and they support the concept of enhanced solar activity suggested by the cosmogenic isotopes from natural archives.

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H. Hayakawa, Y. Mitsuma, Y. Ebihara, et. al.
Fri, 13 Sep 19
38/70

Comments: Main text 8 pages, references 4 pages, 3 figures, Appendices 6 pages, accepted for publication in the Astrophysical Journal Letters

Paisaje celeste y arqueoastronomía: las iglesias históricas como indicadores de la planimetría de una ciudad ideal [CL]

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http://arxiv.org/abs/1908.09792


According to popular tradition, the Canarian city of San Cristobal de La Laguna, a World Heritage Site by UNESCO since 1999, emerged in the early sixteenth century with a novel organization, in line with a new peaceful social order inspired by the religious doctrine of the millennium and its expression through urban design […] In this paper we briefly discuss some details of these ideas, which propose a planned geometric origin for the city, and the original sources on which they are based. We then look for other indications that in a simpler way might explain some of the notable characteristics of the order and design of La Laguna, where over time a model of traditional Canarian architecture was installed that, during the 17th century, was populated with civil and religious constructions (churches, chapels and convents) with notable creations in carpentry of Mudejar origin, for example coming from the lower Andalusia. To conclude, we show our precise analysis of the orientation of almost all the historical churches and chapels of the city, taken together as an indicator of its planimetry. This study employs the usual tools of archaeoastronomy as a complement to the historical and cultural research of religious constructions. We will see then that a new — and simpler — interpretation of the spatial distribution of the city is possible.

Read this paper on arXiv…

A. Gangui
Tue, 27 Aug 19
26/85

Comments: Article in Spanish, PDF document including 5 figures. Published version available at this http URL in Barroco. Naturaleza y paisaje, edited by N.Campos, La Paz: Vision Cultural, pp. 347-356, 2019

New Astronomy Reviews Special Issue: History of Kepler's Major Exoplanet "Firsts" [EPA]

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http://arxiv.org/abs/1908.03611


NASA’s Kepler Mission revolutionized exoplanet science in the early part of the 2010’s. Looking back from the perspective of the end of that decade, Kepler appears to have burst upon the scene ready for battle, like Athena springing forth, fully formed, from the head of Zeus. The story was not so simple. Kepler’s first major exoplanet discoveries were not announced until more than a year had passed since the spacecraft started collecting scientific data, and by that time many exoplanet scientists not working on the project had become frustrated with the lack of results coming from the Kepler project. But an immense amount of work was required to develop the tools and conceptual framework needed to harvest the abundant field of data that the spacecraft was producing. This issue contains articles describing some of the research efforts, most of which took place behind the scenes, that led to the announcements/publication of several of Kepler’s major exoplanet “firsts”, written by the scientists who led the landmark discovery papers.

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J. Lissauer and J. Eisberg
Tue, 13 Aug 19
65/69

Comments: Editorial

A Transit of Venus Possibly Misinterpreted as an Unaided-Eye Sunspot Observation in China on 9 December 1874 [SSA]

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http://arxiv.org/abs/1908.02452


Large sunspots can be observed with the unaided eye under suitable atmospheric seeing conditions. Such observations are of particular value because the frequency of their appearance provides an approximate indication of the prevailing level of solar activity. Unaided-eye sunspot (UES) observations can be traced back well before the start of telescopic observations of the Sun, especially in the East Asian historical records. It is therefore important to compare more modern, UES observations with the results of telescopic sunspot observations, to gain a better understanding of the nature of the UES records. A previous comparison of Chinese UES records and Greenwich photo-heliographic results between 1874 and 1918 indicated that a few of the UES were apparently not supported by direct photographic evidence of at least one sunspot with a large area. This article reveals that one of the Chinese unaided-eye observations had possibly captured the transit of Venus on 9 December 1874. The Chinese sunspot records on this date are compared with Western sunspot observations on the same day. It is concluded that sunspots on the solar disk were quite small and the transit of Venus was probably misinterpreted as a sunspot by the Chinese local scholars. This case indicates that sunspots or comparable “obscuring” objects with an area as large as 1000 millionths of the solar disk could easily have been seen with the unaided eye under suitable seeing conditions. It also confirms the visibility of sunspots near the solar limb with the unaided eye. This study provides an explanation of the apparent discrepancy between the Chinese UES observation on 9 December 1874 and the Western sunspot observations using telescopes, as well as a basis for further discussion on the negative pairs in 1900 and 1911, apparently without sufficiently large area.

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H. Hayakawa, M. Sôma, K. Tanikawa, et. al.
Thu, 8 Aug 19
51/78

Comments: main text 14 pages, appendices 4 pages, and references 5 pages, and 4 figures: accepted for publication in Solar Physics

"Sufficiently Advanced Technology" for Gravitational Wave Detection [CL]

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http://arxiv.org/abs/1908.02568


The science fiction writer Arthur C. Clarke wrote, “Any sufficiently advanced technology is indistinguishable from magic.” While not magical by any means, the technology used to detect gravitational waves starting in 2015 is surely sufficiently advanced to be remarkable by any ordinary standard. That technology was developed over a period of almost six decades; the people who were directly involved numbered in the thousands. In this article, I give an idiosyncratic account of the history, with a focus on the question of how people learned what measurement technology would be “sufficiently advanced” to succeed in detecting gravitational waves.

Read this paper on arXiv…

P. Saulson
Thu, 8 Aug 19
54/78

Comments: N/A

A Transit of Venus Possibly Misinterpreted as an Unaided-Eye Sunspot Observation in China on 9 December 1874 [SSA]

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http://arxiv.org/abs/1908.02452


Large sunspots can be observed with the unaided eye under suitable atmospheric seeing conditions. Such observations are of particular value because the frequency of their appearance provides an approximate indication of the prevailing level of solar activity. Unaided-eye sunspot (UES) observations can be traced back well before the start of telescopic observations of the Sun, especially in the East Asian historical records. It is therefore important to compare more modern, UES observations with the results of telescopic sunspot observations, to gain a better understanding of the nature of the UES records. A previous comparison of Chinese UES records and Greenwich photo-heliographic results between 1874 and 1918 indicated that a few of the UES were apparently not supported by direct photographic evidence of at least one sunspot with a large area. This article reveals that one of the Chinese unaided-eye observations had possibly captured the transit of Venus on 9 December 1874. The Chinese sunspot records on this date are compared with Western sunspot observations on the same day. It is concluded that sunspots on the solar disk were quite small and the transit of Venus was probably misinterpreted as a sunspot by the Chinese local scholars. This case indicates that sunspots or comparable “obscuring” objects with an area as large as 1000 millionths of the solar disk could easily have been seen with the unaided eye under suitable seeing conditions. It also confirms the visibility of sunspots near the solar limb with the unaided eye. This study provides an explanation of the apparent discrepancy between the Chinese UES observation on 9 December 1874 and the Western sunspot observations using telescopes, as well as a basis for further discussion on the negative pairs in 1900 and 1911, apparently without sufficiently large area.

Read this paper on arXiv…

H. Hayakawa, M. Sôma, K. Tanikawa, et. al.
Thu, 8 Aug 19
20/78

Comments: main text 14 pages, appendices 4 pages, and references 5 pages, and 4 figures: accepted for publication in Solar Physics

"Sufficiently Advanced Technology" for Gravitational Wave Detection [CL]

Posted on by

http://arxiv.org/abs/1908.02568


The science fiction writer Arthur C. Clarke wrote, “Any sufficiently advanced technology is indistinguishable from magic.” While not magical by any means, the technology used to detect gravitational waves starting in 2015 is surely sufficiently advanced to be remarkable by any ordinary standard. That technology was developed over a period of almost six decades; the people who were directly involved numbered in the thousands. In this article, I give an idiosyncratic account of the history, with a focus on the question of how people learned what measurement technology would be “sufficiently advanced” to succeed in detecting gravitational waves.

Read this paper on arXiv…

P. Saulson
Thu, 8 Aug 19
44/78

Comments: N/A

G. Paál and the cosmological revolution [CL]

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http://arxiv.org/abs/1907.11139


Gy\”orgy Pa\’al, the Hungarian cosmologist died in 1992. This article was published twenty-five years later in the Hungarian Astronomical Association (HAA, MCSE in Hungarian) 2017 yearbook for his memory. After short introduction of the history of cosmology we briefly introduce the XX. century cosmological discoveries. For his early years G. Pa\’al studied the large-scale inhomogeneity in the Universe. He was one of the first astronomer who realized some periodicity in the quasar redshift distribution. In the early 90s he also studied the galaxy redshift distribution in the so-called pencil-beam survey and suggested the quasi periodicity can be cause of the late inflation in the Universe namely the Lambda cosmological constant.

Read this paper on arXiv…

L. Balázs
Tue, 6 Aug 19
58/76

Comments: was published in the Hungarian Astronomical Association (HAA, MCSE in Hungarian) 2017 yearbook

Eddington, Lemaitre and the discovery of the expanding universe [CL]

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http://arxiv.org/abs/1907.12297


One of the leading astronomers and theorists of his generation, Arthur Stanley Eddington was an important early proponent of the general theory of relativity in both theory and experiment. Yet when his former student Georges Lemaitre suggested in 1927 that the well-known redshifts of the spiral nebulae could be explained in terms of a relativistic expansion of space, Eddington paid no attention for three years. In this paper, we consider the reasons Lemaitre’s hypothesis attracted little attention when it was first articulated. We review several factors that have previously been discussed in the literature, from Lemaitre’s status as an early-career researcher to his decision to publish in a lesser-known journal, from the language of the article to conceptual difficulties associated with time-varying cosmologies. We discuss two new factors that have not been previously been considered, namely the technical challenge presented by Lematre’s analysis to contemporaneous readers and the preliminary nature of the observational data he used to support his model.

Read this paper on arXiv…

C. O’Raifeartaigh
Tue, 30 Jul 19
36/79

Comments: Conference paper presented at the 2019 Eddington Conference in Paris

100 years of the first experimental test of General Relativity [CL]

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http://arxiv.org/abs/1907.10687


Einsteins general theory of relativity is one of the most important accomplishments in the history of science. Its experimental verification a century ago is therefore an essential milestone that is worth celebrating in full. We reassess the importance of one of the two expeditions that made these measurements possible, a story that involves a sense of adventure and scientific ingenuity in equal measure.

Read this paper on arXiv…

L. Crispino and D. Kennefick
Fri, 26 Jul 19
66/84

Comments: 8 pages, 4 figures

Copernicanism and the Typicality in Time [CL]

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http://arxiv.org/abs/1907.08947


How special (or not) is the epoch we are living in? What is the appropriate reference class for embedding the observations made at the present time? How probable — or else — is anything we observe in the fulness of time? Contemporary cosmology and astrobiology bring those seemingly old-fashioned philosophical issues back into focus. There are several examples of contemporary research which use the assumption of typicality in time (or temporal Copernicanism) explicitly or implicitly, while not truly elaborating upon the meaning of this assumption. The present paper brings attention to the underlying and often uncritically accepted assumptions in these cases. It also aims to defend a more radical position that typicality in time is not — and cannot ever be — well-defined, in contrast to the typicality in space, and the typicality in various specific parameter spaces. This, of course, does not mean that we are atypical in time; instead, the notion of typicality in time is necessarily somewhat vague and restricted. In principle, it could be strengthened by further defining the relevant context, e.g., by referring to typicality within the Solar lifetime, or some similar restricting clause.

Read this paper on arXiv…

M. Ćirković and A. Balbi
Tue, 23 Jul 19
61/72

Comments: 19 pages, 2 figure, accepted for publication in “International Journal of Astrobiology”

Occurrence of Great Magnetic Storms on 6-8 March 1582 [SSA]

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http://arxiv.org/abs/1905.08017


Although knowing the occurrence frequency of severe space weather events is important for a modern society, it is insufficiently known due to the lack of magnetic or sunspot observations, before the Carrington event in 1859 known as one of the largest events during the last two centuries. Here, we show that a severe magnetic storm occurred on 8 March 1582 based on auroral records in East Asia. The equatorward boundary of auroral visibility reached 28.8{\deg} magnetic latitude. The equatorward boundary of the auroral oval is estimated to be 33.0{\deg} invariant latitude (ILAT), which is comparable to the storms on 25/26 September 1909 (~31.6{\deg} ILAT, minimum Dst of -595 nT), 28/29 August 1859 (~36.5{\deg} ILAT), and 13/14 March 1989 (~40{\deg} ILAT, minimum Dst of -589 nT). Assuming that the equatorward boundary is a proxy for the scale of magnetic storms, we presume that the storm on March 1582 was severe. We also found that the storm on March 1582 lasted, at least, for three days by combining European records. The auroral oval stayed at mid-latitude for the first two days and moved to low-latitude (in East Asia) for the last day. It is plausible that the storm was caused by a series of ICMEs (interplanetary coronal mass ejections). We can reasonably speculate that a first ICME could have cleaned up interplanetary space to make the following ICMEs more geo-effective, as probably occurred in the Carrington and Halloween storms.

Read this paper on arXiv…

K. Hattori, H. Hayakawa and Y. Ebihara
Tue, 21 May 19
34/71

Comments: Accepted for publication in the Monthly Notices of the Royal Astronomical Society; main text 10 pages, reference 5 pages, appendix 4 pages, 2 tables, and 6 figures

Kepler-9: the First Multi-Transiting System and the First Transit Timing Variations [EPA]

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http://arxiv.org/abs/1905.04426


Kepler-9, discovered by Holman et al. 2010, was the first system with multiple confirmed transiting planets and the first system to clearly show long-anticipated transit timing variations (TTVs). We review the historical circumstances behind the discovery and characterization of these planets and the publication of Holman et al. 2010. It was the first major novel exoplanet discovery of the Kepler Space Telescope mission. The Kepler pipeline identified two Saturn-radius candidates (called Kepler Objects of Interest or KOIs): KOI-377.01 with a 19-day period and KOI-377.02 with a 39-day period. Even with only 9 transits for KOI-377.01 and 6 of KOI-377.02, the transit times were completely inconsistent with a linear ephemeris and showed strongly anti-correlated variations in transit times. Holman et al. 2010 were able to readily show that these objects were planetary mass, confirming them as bona fide planets Kepler-9b and Kepler-9c. As a multi-transiting system exhibiting strong TTVs, the relative planetary properties (e.g., mass ratio, radius ratio) were strongly constrained, opening a new chapter in comparative planetology. KOI-377.03, a small planet with a 1.5-day period, was not initially discovered by the Kepler pipeline, but was identified during the analysis of the other planets and was later confirmed as Kepler-9d through the BLENDER technique by Torres et al. 2011. Holman et al. 2010 included significant dynamical analysis to characterize Kepler-9’s particular TTVs: planets near resonance show large amplitude anti-correlated TTVs with a period corresponding to the rotation of the line of conjunctions and an additional “chopping” signal due to the changing positions of the planets. We also review the updated properties of this system and propose ideas for future investigations.

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D. Ragozzine and M. Holman
Tue, 14 May 19
47/91

Comments: 15 pages, 1 figure, accepted to New Astronomy Reviews for the Special Issue on Kepler Exoplanet Firsts

Bhasvati of Satananda: In the Pages of Mystery [CL]

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http://arxiv.org/abs/1904.03661


Satanandacharya the astronomer and mathematician of 11th century was born in 1068 C.E. at Purusottamdham Puri of Odisha wrote the scripture Bhasvati in 1099 C.E.. The scripture has significant contribution to world of Astronomy and Mathematics. Satananda has adopted centisimal system for the calculation of position and motion of heavenly bodies, which is similar to present day decimal system. The treaties got the recognition of a scripture of Karana grantha. Commentaries of this work has been made by defferent persons during different time of history. Though it is found to be remade in almost once in each century and was well known all over India and abroad. Presently it is completely lost and no reference is available in ongoing works. The main aim of this paper is to outline and bring to the notice of a wider audience — the genius of Satananda and his contribution to the world of astronomy and Mathematics.

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D. Panda
Tue, 9 Apr 19
28/105

Comments: 17 pages, 1 figure

The Beginning of Gamma Astronomy [CL]

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http://arxiv.org/abs/1903.11296


In the first part of this paper we summarize the discovery and the early study of the gamma-ray bursts. The second part studies the spatial and sky distribution of the bursters. The brightness distribution is also studied. In the conclusion we discuss that these are supporting the cosmological origin of the gamma-ray bursts.

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I. Horvath
Thu, 28 Mar 19
23/69

Comments: in Hungarian

Do the Chinese Astronomical Records Dated AD 776 January 12/13 Describe an Auroral Display or a Lunar Halo? A Critical Re-examination [SSA]

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http://arxiv.org/abs/1903.06806


The enhancement of carbon-14 in tree rings around AD 774/775 has generated wide interest in solar activity at that time. The historical auroral records have been examined critically. Of particular interest was the “white vapour” observed in China on AD 776 January 12/13. Both Usoskin et al. (2013, Astron. Astrophys. 55, L3; U13) and Stephenson (2015, Adv. Sp. Res. 55, 1537; S15) interpreted this record as an auroral display. Subsequently, Neuh\”auser and Neuh\”auser (2015, Astron. Nachr. 336, 225; NN15) proposed five “criteria” for the likeliness of aurorae and on this basis rejected an auroral interpretation. Instead, they interpreted it as a lunar halo, and suggested there were no auroral records as a proxy of solar activity in the interval AD 774-785. We consider if their “lunar halo hypothesis” and their auroral criteria could be of use in future researches on historical auroral candidates. We first show a counter-example for the lunar halo hypothesis from a parallel record on 1882 November 17, which was seen as a whitish colour, in the southerly direction, and near the Moon. We then consider NN15’s criteria on colour, direction, and sky brightness and investigate other counter-examples from early-modern auroral observations. We also consider the extension of the white vapour in AD 776 according to the distribution of Chinese asterisms, and show that its large extension was inconsistent with the lunar halo hypothesis. Conversely, the streaks of white vapour penetrating the eight Chinese asterisms can be reproduced if we consider auroral-ray structures at altitudes between 97 km and 170 km, along geomagnetic field lines between the L-shells L=1.55 and 1.64. Our investigations show that we should consider candidate auroral records in historical documents not on the basis of the newly suggested a priori criteria by NN15 but on all the available observational evidence.

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F. Stephenson, D. Willis, H. Hayakawa, et. al.
Tue, 19 Mar 19
89/100

Comments: 28 pages, 6 figures, accepted for publication in Solar Physics on 5 February 2019

Closing in on the Cosmos: Cosmology's Rebirth and the Rise of the Dark Matter Problem [CL]

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http://arxiv.org/abs/1903.05281


Influenced by the renaissance of general relativity that came to pass in the 1950s, the character of cosmology fundamentally changed in the 1960s as it became a well-established empirical science. Although observations went to dominate its practice, extra-theoretical beliefs and principles reminiscent of methodological debates in the 1950s kept playing an important tacit role in cosmological considerations. Specifically, belief in cosmologies that modeled a “closed universe” based on Machian insights remained influential. The rise of the dark matter problem in the early 1970s serves to illustrate this hybrid methodological character of cosmological science.

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J. Swart
Thu, 14 Mar 19
47/96

Comments: A chapter to be published in the upcoming “Einstein Studies” volume edited by J. Renn, A. Blum and R. Lalli

Multimessenger Research before GW170817 [HEAP]

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http://arxiv.org/abs/1902.03905


Linking the previous research that occurred over the last decades, I will try to provide some objective elements to evaluate the innovation of the joint observation of GW170817 and GRB 170817A and their occurrence detection, in light of preceding experiences regarding the experimental research of association between gamma-ray bursts and gravitational waves. Without debating about the phenomenological properties of astrophysical events, I propose a comparison between that result and the previous experimental research by the interferometer GW community, using a fundamental energy emission law, and including about fifteen years of accredited results regarding coincident detection. From the present review, an intense and old pre-existing activity in the field of multimessenger observations emerges giving a first interesting fact. The widespread opinion that joint detection of GW170817 and GRB 170817A has opened a new method in astrophysics does not find a robust reason. Moreover, some critical points highlight. In the past, applying the same multimessenger method, numerous measures have been taken towards much brighter and much closer sources. Then, it would have been plausible to see joint signals even taking into account a worse sensitivity of the instruments of the time. At current time, there is only one event associated to a subthreshold GRB, compared to a long list of candidate events that would have been much more revealing. If these inconsistencies are admissible enough to lead to a claim, then the question arises about the interpretation of the long previous measurements carried out applying the same multimessenger observation method but without positive responses.

Read this paper on arXiv…

G. Modestino
Tue, 12 Feb 19
11/83

Comments: 11 pages, 2 figures, 2 tables

John Archibald Wheeler: A Biographical Memoir [CL]

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http://arxiv.org/abs/1901.06623


John Archibald Wheeler was a theoretical physicist who worked on both down-to-earth projects and highly speculative ideas, and always emphasized the importance of experiment and observation, even when speculating wildly. His research and insights had large impacts on nuclear and particle physics, the design of nuclear weapons, general relativity and relativistic astrophysics, and quantum gravity and quantum information. But his greatest impacts were through the students, postdocs, and mature physicists whom he educated and inspired.
He was guided by what he called the principle of radical conservatism, inspired by Niels Bohr: base your research on well established physical laws (be conservative), but push them into the most extreme conceivable domains (be radical). He often pushed far beyond the boundaries of well understood physics, speculating in prescient ways that inspired future generations of physicists.
After completing his PhD with Karl Herzfeld at Johns Hopkins University (1933), Wheeler embarked on a postdoctoral year with Gregory Breit at NYU and another with Niels Bohr in Copenhagen. He then moved to a three-year assistant professorship at the University of North Carolina (1935-37), followed by a 40 year professorial career at Princeton University (1937-1976) and then ten years as a professor at the University of Texas, Austin (1976-1987). He returned to Princeton in retirement but remained actively and intensely engaged with physics right up to his death at age 96.

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K. Thorne
Wed, 23 Jan 19
33/111

Comments: This memoir is being published in the Biographical Memoir Series of the US National Academy of Sciences and also that of the Royal Society, in early 2019

On times and shadows: the observational analemma [CL]

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http://arxiv.org/abs/1812.10719


The observation that the shadows of objects change during the course of the day and also for a fixed time during a year led curious minds to realize that the Sun could be used as a timekeeper. However, the daily motion of the Sun has some subtleties, for example, with regards to the precise time at which it crosses the meridian near noon. When the Sun is on the meridian, a clock is used to ascertain this time and a vertical stick determines the angle the Sun is above the horizon. These two measurements lead to the construction of a diagram (called an analemma) as an extremely useful resource for the teaching of astronomy. In this paper we report on the construction of this diagram from roughly weekly observations during more than a year.

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A. Gangui, C. Lastra and F. Karaseur
Mon, 31 Dec 18
39/57

Comments: Published version available at this http URL

On Probability and Cosmology: Inference Beyond Data? [CL]

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http://arxiv.org/abs/1812.04149


Modern scientific cosmology pushes the boundaries of knowledge and the knowable. This is prompting questions on the nature of scientific knowledge. A central issue is what defines a ‘good’ model. When addressing global properties of the Universe or its initial state this becomes a particularly pressing issue. How to assess the probability of the Universe as a whole is empirically ambiguous, since we can examine only part of a single realisation of the system under investigation: at some point, data will run out. We review the basics of applying Bayesian statistical explanation to the Universe as a whole. We argue that a conventional Bayesian approach to model inference generally fails in such circumstances, and cannot resolve, e.g., the so-called ‘measure problem’ in inflationary cosmology. Implicit and non-empirical valuations inevitably enter model assessment in these cases. This undermines the possibility to perform Bayesian model comparison. One must therefore either stay silent, or pursue a more general form of systematic and rational model assessment. We outline a generalised axiological Bayesian model inference framework, based on mathematical lattices. This extends inference based on empirical data (evidence) to additionally consider the properties of model structure (elegance) and model possibility space (beneficence). We propose this as a natural and theoretically well-motivated framework for introducing an explicit, rational approach to theoretical model prejudice and inference beyond data.

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M. Sahlén
Wed, 12 Dec 18
89/92

Comments: 23 pages, 2 figures. Slightly expanded version of contributed chapter. Selected in “The Best Writing on Mathematics 2018”, M. Pitici (Ed.), Princeton University Press 2019

Reasons in favor of a Hubble-Lemaitre-Slipher's (HLS) law [CL]

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http://arxiv.org/abs/1810.12416


Based on historical facts, revisited from a present-day perspective, and on the documented opinions of the scientists involved in the discovery themselves, strong arguments are given in favor of a proposal to include prominent astronomer Vesto Slipher to the suggested addition of Georges Lema\^itre’s name to Hubble’s law on the expansion of the Universe, and thus eventually call it Hubble-Lema\^itre-Slipher’s (HLS) law.

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E. Elizalde
Wed, 31 Oct 18
35/65

Comments: 14 pages, no figures

How the Saha Ionization Equation Was Discovered [CL]

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http://arxiv.org/abs/1810.10898


Although the Saha ionization equation is a standard topic in advanced statistical physics and most professional physicists would have some knowledge of it, the exact nature of Meghnad Saha’s contributions in this subject is not widely known. Based on an analysis of Saha’s original papers and other relevant papers by contemporary scientists, as well as other source materials such as letters exchanged between scientists, I discuss how Saha used the theory of thermal ionization to solve some of the most important astrophysics problems of that era.

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A. Choudhuri
Fri, 26 Oct 18
42/64

Comments: To be published in “Physics News”, journal of Indian Physics Association

Algol as Horus in the Cairo Calendar: the possible means and the motives of the observations [CL]

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http://arxiv.org/abs/1810.06412


An ancient Egyptian Calendar of Lucky and Unlucky Days, the Cairo Calendar (CC), assigns luck with the period of 2.850 days. Previous astronomical, astrophysical and statistical analyses of CC support the idea that this was the period of the eclipsing binary Algol three millennia ago. However, next to nothing is known about who recorded Algol’s period into CC and especially how. Here, we show that the ancient Egyptian scribes had the possible means and the motives for such astronomical observations. Their principles of describing celestial phenomena as activity of gods reveal why Algol received the title of Horus.

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S. Porceddu, L. Jetsu, T. Markkanen, et. al.
Tue, 16 Oct 18
9/83

Comments: 34 pages, 6 figures, accepted in Open Astronomy

Relativity in Argentine culture in the early twentieth century [CL]

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http://arxiv.org/abs/1810.03544


In previous works we have considered various aspects of the reception of the theories of Albert Einstein in our country. In particular, we discussed the impact of his visit to Argentina in 1925, and the precise content of the conferences and scientific publications that Einstein communicated while he was here. We have also discussed, critically, different documents on topics related to the theory of relativity published in the country during the first decades of the last century, in which the technical level was extremely varied. Finally, we have dealt with a forgotten document, which Einstein prepared for his visit but, once in the country, thought it convenient not to communicate. In the present work, which is part of that same line of research, we propose to consider the scientific, cultural and pedagogical career of Enrique Loedel Palumbo (1901-1962), who was one of the main local actors during Einstein’s visit to Argentina. He was also one of the founders of the research on relativity issues in the Rio de la Plata. In addition to his strictly scientific interests, Loedel Palumbo took seriously the pedagogy of science and became interested in philosophical, cultural and artistic problems of his time.

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A. Gangui and E. Ortiz
Tue, 9 Oct 18
50/77

Comments: Article in Spanish, PDF document. Published in Filosofia e Historia de la Ciencia en el Cono Sur. Seleccion de trabajos del IX Congreso y las XXV Jornadas de Epistemologia e Historia de la Ciencia, edited by J.Ahumada et al., Cordoba: Editorial de la UNC, pp. 279-287, 2015. Other related documents available at this http URL

Ya. B. Zeldovich and foundation of the accretion theory [CL]

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http://arxiv.org/abs/1809.11137


This short review is dedicated to academician Yakov Borisovich Zeldovich, the science of his epoch and the creation of modern accretion theory.

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N. Shakura
Mon, 1 Oct 18
10/46

Comments: 11 pages, 25 figures, accepted to special volume of Astronomy Reports

My Life and My Journey through Solar Physics [CL]

Posted on by

http://arxiv.org/abs/1809.09709


This is the talk I gave at the workshop “Solar-Stellar Magnetism: Past, Present and Future” held in Jaipur on 18 February 2018 on the occasion of my 60th year.

Read this paper on arXiv…

A. Choudhuri
Thu, 27 Sep 18
15/68

Comments: Presentation at the workshop “Solar-Stellar Magnetism: Past, Present and Future”

Once FITS, Always FITS? Astronomical Infrastructure in Transition [IMA]

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http://arxiv.org/abs/1809.09224


The FITS file format has become the de facto standard for sharing, analyzing, and archiving astronomy data over the last four decades. FITS was adopted by astronomers in the early 1980s to overcome incompatibilities between operating systems. On the back of FITS’ success, astronomical data became both backwards compatible and easily shareable. However, new advances in astronomical instrumentation, computational technologies, and analytic techniques have resulted in new data that do not work well within the traditional FITS format. Tensions have arisen between the desire to update the format to meet new analytic challenges and adherence to the original edict for FITS files to be backwards compatible. We examine three inflection points in the governance of FITS: a) initial development and success, b) widespread acceptance and governance by the working group, and c) the challenges to FITS in a new era of increasing data and computational complexity within astronomy.

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M. Scroggins and B. Boscoe
Wed, 26 Sep 18
19/69

Comments: N/A

Gauging Fine-Tuning [CEA]

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http://arxiv.org/abs/1809.06220


We introduce a mathematical framework for quantifying fine-tuning in general physical settings. In particular, we identify two distinct perspectives on fine-tuning, namely, a local and a global perspective — and develop corresponding measures. These measures apply broadly to settings characterized by an arbitrary number of observables whose values are dependent on an arbitrary number of parameters. We illustrate our formalism by quantifying fine-tuning as it arises in two pertinent astrophysical settings: (i) in models where a significant fraction of the dark matter in the universe is in the form of primordial black holes, and (ii) in scenarios that derive the fraction of protons in habitable dark-matter halos from underlying models of cosmic inflation.

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F. Azhar and A. Loeb
Tue, 18 Sep 18
45/70

Comments: 13 pages, 6 figures

Beyond Standard Inflationary Cosmology [CL]

Posted on by

http://arxiv.org/abs/1809.04926


The inflationary scenario is not the only paradigm of early universe cosmology which is consistent with current observations. General criteria will be presented which any successful early universe model must satisfy. Various ways, including inflation, will be presented which satisfy these conditions. It will then be argued that if nature is described at a fundamental level by superstring theory, a cosmology without an initial space-time singularity will emerge, and a structure formation scenario which does not include inflation may be realized.

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R. Brandenberger
Fri, 14 Sep 18
9/65

Comments: 18 pages, 9 figures, modified version of a contribution to “Beyond Spacetime” eds. N. Huggett, K. Matsubara and C. Wuethrich (Cambridge Univ. Press, Cambridge, 2018)

Women Scientists Who Made Nuclear Astrophysics [CL]

Posted on by

http://arxiv.org/abs/1809.01045


Female role models reduce the impact on women of stereotype threat, i.e., of being at risk of conforming to a negative stereotype about one’s social, gender, or racial group. This can lead women scientists to underperform or to leave their scientific career because of negative stereotypes such as, not being as talented or as interested in science as men. Sadly, history rarely provides role models for women scientists; instead, it often renders these women invisible. In response to this situation, we present a selection of twelve outstanding women who helped to develop nuclear astrophysics.

Read this paper on arXiv…

C. Hampton, M. Lugaro, P. Papakonstantinou, et. al.
Wed, 5 Sep 18
4/133

Comments: 5 pages; to appear in Springer Proceedings in Physics (Proc. of Intl. Conf. “Nuclei in the Cosmos XV”, LNGS Assergi, Italy, June 2018)

Problems with the dark matter and dark energy hypotheses, and alternative ideas [CEA]

Posted on by

http://arxiv.org/abs/1808.09823


Two exotic elements have been introduced into the standard cosmological model: non-baryonic dark matter and dark energy. The success in converting a hypothesis into a solid theory depends strongly on whether we are able to solve the problems in explaining observations with these dark elements and whether the solutions of these problems are unique within the standard paradigm without recourse to alternative scenarios. We have not achieved that success yet because of numerous inconsistencies, mainly on galactic scales, the non-detection so far of candidate particles for dark matter, and the existence of many alternative hypotheses that might substitute the standard picture to explain the cosmological observations. A review of some ideas and facts is given here.

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M. Lopez-Corredoira
Thu, 30 Aug 18
36/61

Comments: 16 pages, 100 references, published in the proceedings of the Conference “Cosmology on Small Scales 2018: Dark Matter Problem and Selected Controversies in Cosmology” (Prague, September 26-29, 2018): this http URL arXiv admin note: substantial text overlap with arXiv:1701.08720

The Geometry of Spaceborne Synthetic Aperture Radar [CL]

Posted on by

http://arxiv.org/abs/1808.06549


The paper defines a new coordinate system that was developed in 1977-78 for the world’s first digital synthetic aperture radar (SAR) ground processor for images from the Seasat-A satellite. The coordinate system is for the range-Doppler paradigm in the context of a spaceborne platform orbiting a rotating planet. The mathematical expressions for the azimuth FM rate, isodoppler lines, target illumination trajectories and antenna attitude determination from Doppler centroid measurements are derived. The method for transforming the SAR images from that SAR digital signal processor that used these parametric inputs is also presented. The paper concludes with a report of the measurement of the map accuracy of the resulting images.

Read this paper on arXiv…

P. Orth
Tue, 21 Aug 18
61/71

Comments: N/A

On the Observations of the Penetrating Radiation during Seven Balloon Flights [CL]

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http://arxiv.org/abs/1808.02927


At the beginning of the twentieth century, the Austrian (later naturalized American) Victor Hess among others developed a brilliant line of research, leading to the final determination of the extraterrestrial origin of part of the atmospheric radiation. Before his work, the origin of the radiation today called “cosmic rays” was strongly debated, as many scientists thought that these particles came integrally from the crust of the Earth. There was however an active and rich research on the topic. Victor (at that time Viktor) Hess measured in 1912 the rate of discharge of an electroscope that flew aboard an atmospheric balloon. Since the discharge rate increased as the balloon flew at higher altitude, he concluded that the origin of part of the natural radiation could not be terrestrial. For this discovery, Hess was awarded the Nobel Prize in 1936, and his experiment became legendary. The fundamental article published by Victor Hess in 1912, reporting a significant increase of the radiation as altitude increases, is translated and commented here. The decisive measurement was performed in the last of the seven flights on aerostatic balloon described.

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V. Hess
Fri, 10 Aug 18
25/45

Comments: translated, commented by Alessandro De Angelis, Cornelia Arcaro b. Schultz. arXiv admin note: substantial text overlap with arXiv:1103.4392, arXiv:1012.5068, arXiv:1208.6527, arXiv:1101.0398

Yes, Aboriginal Australians Can and Did Discover the Variability of Betelgeuse [CL]

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http://arxiv.org/abs/1808.01862


Recently, a widely publicized claim has been made that the Aboriginal Australians discovered the variability of the red star Betelgeuse in the modern Orion, plus the variability of two other prominent red stars: Aldebaran and Antares. This result has excited the usual healthy skepticism, with questions about whether any untrained peoples can discover the variability and whether such a discovery is likely to be placed into lore and transmitted for long periods of time. Here, I am offering an independent evaluation, based on broad experience with naked-eye sky viewing and astro-history. I find that it is easy for inexperienced observers to detect the variability of Betelgeuse over its range in brightness from V = 0.0 to V = 1.3, for example in noticing from season-to-season that the star varies from significantly brighter than Procyon to being greatly fainter than Procyon. Further, indigenous peoples in the Southern Hemisphere inevitably kept watch on the prominent red star, so it is inevitable that the variability of Betelgeuse was discovered many times over during the last 65 millennia. The processes of placing this discovery into a cultural context (in this case, put into morality stories) and the faithful transmission for many millennia is confidently known for the Aboriginal Australians in particular. So this shows that the whole claim for a changing Betelgeuse in the Aboriginal Australian lore is both plausible and likely. Given that the discovery and transmission is easily possible, the real proof is that the Aboriginal lore gives an unambiguous statement that these stars do indeed vary in brightness, as collected by many ethnographers over a century ago from many Aboriginal groups. So I strongly conclude that the Aboriginal Australians could and did discover the variability of Betelgeuse, Aldebaran, and Antares.

Read this paper on arXiv…

B. Schaefer
Tue, 7 Aug 18
29/68

Comments: N/A

Reconstructed sunspot positions in the Maunder Minimum based on the correspondence of Gottfried Kirch [CL]

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http://arxiv.org/abs/1807.10241


We present reconstructed sunspot positions based on observations reported in letters between Gottfried Kirch and other contemporary astronomers from AD 1680 to 1709, i.e. in the last decades of the Maunder Minimum. The letters were compiled and edited by Herbst (2006). The letters (and observations) from Kirch are mostly by Gottfried Kirch, but some also by his 2nd wife Maria M. Kirch (married 1692) and their son Christfried Kirch (born 1694). Using excerpts from the letters, some with drawings, we found some 35 sunspot groups (often for several days in a row or with interruptions) by Kirch and/or his letter partners (in three cases, only the month is given: 1704 Jan, Feb, 1707 Mar, otherwise always the exact dates) – usually one group at a time. We also found 17 explicit spotless days, several of them new (previously without any known observations). We could constrain the heliographic latitude by Bayesian inference for 19 sunspot groups – five of them completely new (one group 1680 May 20-22 from Kirch and Ihle, one to two groups 1680 Jun 15-23 for Kirch, one group 1684 May 6 from Ihle, and one group 1688 Dec 14-15 from Kirch), while the others mostly agree (within 2sigma) with previously published values for those dates by others. With these data, we then amend the butterfly diagram for the Maunder Minimum. By comparison of our data with the sunspot group catalog in Hoyt & Schatten (1998), we noticed a number of discrepancies, e.g. that dates for British observers in the Maunder Minimum (Flamsteed, Caswell, Derham, Stannyan, Gray, and Sharp) as listed in Hoyt & Schatten (1998) are their original Julian dates, not converted to the Gregorian calendar (10-11 day offset in Hoyt & Schatten). Most of these modifications also apply to the modified sunspot group catalog in Vaquero et al. (2016). We also present two aurorae observed by the Kirchs in 1707 and 1716.

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R. Neuhäuser, R. Arlt and S. Richter
Fri, 27 Jul 18
13/75

Comments: accepted for publication by Astronomische Nachrichten – Astronomical Notes

The Reclassification of Asteroids from Planets to Non-Planets [EPA]

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http://arxiv.org/abs/1805.04115


It is often claimed that asteroids’ sharing of orbits is the reason they were re-classified from planets to non-planets. A critical review of the literature from the 19th Century to the present shows this is factually incorrect. The literature shows the term asteroid was broadly recognized as a subclass of planet for 150 years. On-going discovery of asteroids resulted in a de facto stretching of the concept of planet to include the ever smaller bodies. Scientists found utility in this taxonomic identification as it provided categories needed to argue for the leading hypothesis of planet formation, Laplace’s nebular hypothesis. In the 1950s, developments in planet formation theory found it no longer useful to maintain taxonomic identification between asteroids and planets, Ceres being the sole exception. At approximately the same time, there was a flood of publications on the geophysical nature of asteroids showing them to be geophysically different than the large planets. This is when the terminology in asteroid publications calling them planets abruptly plunged from a high level of usage where it had hovered during the period 1801 – 1957 to a low level that held constant thereafter. This marks the point where the community effectively formed consensus that asteroids should be taxonomically distinct from planets. The evidence demonstrates this consensus formed on the basis of geophysical differences between asteroids and planets, not the sharing of orbits. We suggest attempts to build consensus around planetary taxonomy not rely on the non-scientific process of voting, but rather through precedent set in scientific literature and discourse, by which perspectives evolve with additional observations and information, just as they did in the case of asteroids.

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P. Metzger, M. Sykes, A. Stern, et. al.
Mon, 14 May 18
25/54

Comments: 27 pages, 4 figures

Astrometry history: Hipparcos from 1964 to 1980 [CL]

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http://arxiv.org/abs/1804.10881


Here follow three reports covering different aspects of the early history from 1964 to 1980 of the Hipparcos satellite mission. The first report “Interviews about the creation of Hipparcos” contains interviews from 2017 with scientists about how the mission was conceived up to the begin of technical development. The second report “From TYCHO to Hipparcos 1975 to 1979” is about the Hipparcos development based on new material from my archive. From my 65 years dedicated to the development of astrometry, I argue that very special historical circumstances in Europe were decisive for the idea of space astrometry to become reality: Hipparcos did not just come because astrophysicists needed the data. The third report “Miraculous 1980 for Hipparcos” documents how the approval of the astrometric mission in January 1980 in competition with an astrophysical mission was only achieved with very great difficulty, even after an outstanding astrophysicist had presented overwhelming arguments that the astrometric mission would be scientifically much more important.

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E. Høg
Tue, 1 May 18
62/78

Comments: 52 pages, 7 figures, on the history of satellite astrometry

Sunspot Drawings by Japanese Official Astronomers in 1749-1750 [CL]

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http://arxiv.org/abs/1804.08614


Sunspot observations with telescopes in 18th century were carried out in Japan as well. One of these sunspot observations is recorded in an account called Sansaizusetsu narabini Kansei irai Jissoku Zusetsu (Charts of Three Worlds and Diagrams of Actual Observations since Kansei Era). We analyze manuscripts of this account to show in total 15 sunspot drawings in 1749-1750. These observations were carried out by contemporary official astronomers in Japan, with telescopes covered by zongurasus (< zonglas in Dutch, corresponding to “sunglass” in English). We count their group number of sunspots to locate them in long-term solar activity and show that their observations were situated around the solar maximum in 1749 or 1750. We also computed their locations and areas, while we have to admit the difference of variant manuscripts with one another. These observational records show the spread of sunspot observations not only in Europe but also in Japan and hence may contribute to crosscheck or possibly improve the known sunspot indices.

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H. Hayakawa, K. Iwahashi, M. Fujiyama, et. al.
Wed, 25 Apr 18
28/57

Comments: 2018/4/12 accepted for publication in PASJ

Comments regarding William Herschel April 1787 report of an erupting volcano on the moon: were these observations the manifestation of Impact Melt, produced by a meteorite from the Lyrid meteor shower? [CL]

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http://arxiv.org/abs/1804.08716


We consider that the report by William Herschel on April 19 and 20, 1787, about an erupting volcano on the moon were really the observations of impact melt, produced by a meteorite from the Lyrid meteor shower. According to our investigation the probably resulting crater of this event is a lunar cold spot, with coordinates similar to those given in Herschel report, and we also argue that this impact has very young characteristics.

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W. Bruckman and A. Ruiz
Wed, 25 Apr 18
29/57

Comments: N/A

Einstein's "biggest blunder" – interrogating the legend [CL]

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http://arxiv.org/abs/1804.06768


It is well known that in the early 1930s, Einstein banished the cosmological constant term from his cosmology. He is reputed to have later described the term as his “biggest blunder”, a statement that became one the great legends of 20th century physics. However, many doubts about the statement have been raised in recent years, not least because almost all references to it can be traced back to a single source, the maverick physicist George Gamow. In this paper, we interrogate the legend of Einstein’s “biggest blunder” statement in the context of our recent studies of Einstein’s cosmology in his later years. We find that the remark is very compatible with Einstein’s cosmic models of the 1930s, with his later writings on cosmology, and with independent reports by two other physicists. We also find it quite plausible that Einstein made such a statement to Gamow in particular. We conclude that there is little doubt that Einstein came to view the introduction of the cosmological constant a serious error, and that it is very plausible that he labelled the term his “biggest blunder” on at least one occasion.

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C. O’Raifeartaigh and S. Mitton
Thu, 19 Apr 18
13/47

Comments: 26 pages, 6 figures. Submitted to the European Physical Journal (H)

Archaeoastronomical study of Andean temples in Arica and Parinacota, Chile [CL]

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http://arxiv.org/abs/1803.08599


After a historical and cultural overview of the “Indian republic”, the Andean religiosity and the churches of the highlands of Arica, we detail our archaeoastronomical studies on the orientations of the Andean Christian churches in the region of Arica and Parinacota, and analyze some preliminary results. We conclude with a brief discussion on the patterns of orientation found in our measurements and on their possible causes.

Read this paper on arXiv…

A. Gangui, A. Guillen and M. Pereira
Mon, 26 Mar 18
37/43

Comments: Article in Spanish, PDF document including 8 figures. Published version available at this http URL in Mestizajes en dialogo, edited by N.Campos, La Paz: Vision Cultural, pp. 371-382, 2016

Archaeoastronomical study of Andean temples in Arica and Parinacota, Chile [CL]

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http://arxiv.org/abs/1803.08599


After a historical and cultural overview of the “Indian republic”, the Andean religiosity and the churches of the highlands of Arica, we detail our archaeoastronomical studies on the orientations of the Andean Christian churches in the region of Arica and Parinacota, and analyze some preliminary results. We conclude with a brief discussion on the patterns of orientation found in our measurements and on their possible causes.

Read this paper on arXiv…

A. Gangui, A. Guillen and M. Pereira
Mon, 26 Mar 18
27/43

Comments: Article in Spanish, PDF document including 8 figures. Published version available at this http URL in Mestizajes en dialogo, edited by N.Campos, La Paz: Vision Cultural, pp. 371-382, 2016

Lambda, the Fifth Foundational Constant Considered by Einstein [CL]

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http://arxiv.org/abs/1802.08317


The cosmological constant, usually named Lambda, was introduced by Einstein in 1917 and abandoned by him as his biggest “blunder”. It currently seems to make a spectacular comeback in the framework of the new cosmological standard model. One will explain why, together with the Planck’s constant, the Boltzmann’s constant, the celerity of light and the Newton’s constant, also considered by Einstein, the cosmological constant may play a foundational role in the conceptual framework, an in the metrological framework a role comparable with the one attributed to Avogadro number

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G. Cohen-Tannoudji
Mon, 5 Mar 18
15/45

Comments: 21 pages, 3 figures. Text version of a talk delivered at the BIPM symposium on fundamental constants in September 2017. Submitted for publication in Metrologia

Could a Hexagonal Sunspot Have Been Observed During the Maunder Minimum? [SSA]

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http://arxiv.org/abs/1803.00358


The Maunder Minimum was the period between 1645 and 1715 whose main characteristic was abnormally low and prolonged solar activity. However, some authors have doubted this low level of solar activity during that period by questioning the accuracy and objectivity of the observers. This work presents a particular case of a sunspot observed during the Maunder Minimum with an unusual shape of its umbra and penumbra: a hexagon. This sunspot was observed by Cassini in November 1676, just at the core of the Maunder Minimum. This historical observation is compared with a twin case that occurred recently in May 2016. The conclusion reached is that Cassini’s record is another example of the good quality observations made during the Maunder Minimum, showing the meticulousness of the astronomers of that epoch. This sunspot observation made by Cassini does not support the conclusions of Zolotova and Ponyavin (Astrophys. J. 800, 42, 2015) that professional astronomers in the 17th century only registered round sunspots. Finally, a discussion is given of the importance of this kind of unusual sunspot record for a better assessment of the true level of solar activity in the Maunder Minimum.

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V. Carrasco, J. Vaquero and M. Gallego
Fri, 2 Mar 18
12/61

Comments: 9 pages, 3 figures, accepted for publication in “Solar Physics”

"All that matter … in one Big Bang …," & other cosmological singularities [CL]

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http://arxiv.org/abs/1801.09550


The first part of this paper contains a brief description of the beginnings of modern cosmology, which, the author will argue, was most likely born in the Year 1912. Some of the pieces of evidence presented here have emerged from recent research in the history of science, and are not usually shared with the general audiences in popular science books. Then, the important issue of the formulation of the original Big Bang concept, in the exact words of Fred Hoyle, is discussed. Too often, this is very deficiently explained (when not just misleadingly) in most of the available generalist literature. Other frequent uses of the same words, Big Bang, as to name the initial singularity of the cosmos, and also whole cosmological models, are then addressed, as evolutions of its original meaning. Quantum and inflationary additions to the celebrated singularity theorems by Penrose, Geroch, Hawking and others led to subsequent results by Borde, Guth and Vilenkin. And corresponding corrections to the Einstein field equations have originated, in particular, $R^2$, $f(R)$, and scalar-tensor gravities, giving rise to a plethora of new singularities. For completeness, an updated table with a classification of the same is given.

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E. Elizalde
Tue, 30 Jan 18
21/70

Comments: 22 pages, no figures

Fine-Tuning, Complexity, and Life in the Multiverse [CL]

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http://arxiv.org/abs/1801.06944


The physical processes that determine the properties of our everyday world, and of the wider cosmos, are determined by some key numbers: the ‘constants’ of micro-physics and the parameters that describe the expanding universe in which we have emerged. We identify various steps in the emergence of stars, planets and life that are dependent on these fundamental numbers, and explore how these steps might have been changed, or completely prevented, if the numbers were different. We then outline some cosmological models where physical reality is vastly more extensive than the ‘universe’ that astronomers observe (perhaps even involving many ‘big bangs’), which could perhaps encompass domains governed by different physics. Although the concept of a multiverse is still speculative, we argue that attempts to determine whether it exists constitute a genuinely scientific endeavor. If we indeed inhabit a multiverse, then we may have to accept that there can be no explanation other than anthropic reasoning for some features our world.

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M. Livio and M. Rees
Tue, 23 Jan 18
11/85

Comments: Chapter for the book Consolidation of Fine Tuning, 17 pages, 3 figures

Beyond Falsifiability: Normal Science in a Multiverse [CL]

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http://arxiv.org/abs/1801.05016


Cosmological models that invoke a multiverse – a collection of unobservable regions of space where conditions are very different from the region around us – are controversial, on the grounds that unobservable phenomena shouldn’t play a crucial role in legitimate scientific theories. I argue that the way we evaluate multiverse models is precisely the same as the way we evaluate any other models, on the basis of abduction, Bayesian inference, and empirical success. There is no scientifically respectable way to do cosmology without taking into account different possibilities for what the universe might be like outside our horizon. Multiverse theories are utterly conventionally scientific, even if evaluating them can be difficult in practice.

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S. Carroll
Wed, 17 Jan 18
11/51

Comments: Invited contribution to “Epistemology of Fundamental Physics: Why Trust a Theory?”, eds. R. Dawid, R. Dardashti, and K. Th\’ebault (Cambridge University Press)

The frame of fixed stars in Relational Mechanics [CL]

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http://arxiv.org/abs/1801.00676


Relational mechanics is a gauge theory of classical mechanics whose laws do not govern the motion of individual particles but the evolution of the distances between particles. Its formulation gives a satisfactory answer to Leibniz’s and Mach’s criticisms of Newton’s mechanics: relational mechanics does not rely on the idea of an absolute space. When describing the behavior of small subsystems with respect to the so called “fixed stars”, relational mechanics basically agrees with Newtonian mechanics. However, those subsystems having huge angular momenta will deviate from the Newtonian behavior if they are described in the frame of fixed stars. Such subsystems naturally belong to the field of astronomy; they can be used to test the relational theory.

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R. Ferraro
Mon, 8 Jan 18
18/117

Comments: 12 pages, 1 figure

Einstein en la Argentina: el impacto cientifico de su visita [CL]

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http://arxiv.org/abs/1712.09734


We present a brief review of the impact that Albert Einstein’s visit to Argentina had on the scientific community and on the general public. Among other particularities, his visit was, at a certain point, somewhat disconcerting: not only because of the complexity of his ideas, but also because of his appearance, which did not fit with the image of the wise visitor firmly seated in the minds of his interlocutors. His openness and tendency to ironize, especially in his first interviews with the press, first disorientated journalists and later also some members of his intellectual audience. Einstein, then, forced a revision of both the image of the wise man and that of spacetime.

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A. Gangui and E. Ortiz
Fri, 29 Dec 2017
21/65

Comments: Article in Spanish, PDF document, 19 pages. Published in Visitas culturales en la Argentina, 1898-1936, P. Bruno (ed.), Buenos Aires: Biblos, pp. 167-190, 2014. Other related documents available at this http URL . arXiv admin note: text overlap with arXiv:physics/0506052

Century of $Λ$ [CL]

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http://arxiv.org/abs/1712.09845


The cosmological constant was proposed 100 years ago in order to make the model of static Universe, imagined then by most scientists, possible. Today it is the main candidate for the physical essence causing the observed accelerated expansion of our Universe. But, as well as a hundred years ago, its nature is unknown. This paper is devoted to the story of invention of $\Lambda$ by Albert Einstein in 1917, rejection of it by him in 1931 and returning of it into the science by other scientists during the century.

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B. Novosyadlyj
Fri, 29 Dec 2017
25/65

Comments: 13 pages

On the orientation of the historic churches of Lanzarote: when human necessity dominates over canonical prescriptions [CL]

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http://arxiv.org/abs/1712.09324


We present the analysis of the measured orientations of 30 churches of the island of Lanzarote, in the Canarian archipelago, built prior to 1810, as well as a few buildings of later times, which represent a nearly complete sample of all the island’s Christian sanctuaries. Our study indicates that a definite orientation pattern was followed on the island but, unlike what is often found in most of the Christian world, it has two interpretations. On the one hand, the representative orientation to the east (or west) is present. However, the sample has also a marked orientation towards north-northeast which is, as far as we know, a pattern exclusive to Lanzarote. We discuss the reasons for this pattern and suggest that one possible explanation could be a rather prosaic one, namely, that sometimes needs of everyday life are more relevant than –and push individuals to make decisions at odds with– religious beliefs. This work is the beginning of the first systematic archaeoastronomical study ever conducted with old churches in the Canary Islands [abridged].

Read this paper on arXiv…

A. Gangui, A. Garcia, M. Betancort, et. al.
Wed, 27 Dec 2017
39/56

Comments: Published in The Materiality of the Sky. Proceedings of the 22nd Annual SEAC Conference, 2014, Silva, F. et al (eds.), Lampeter: Sophia Centre Press, pp. 125-134, 2016

Odessa Scientific School of Researchers Of Variable Stars: From V.P.Tsesevich (1907-1983) to Our Days [CL]

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http://arxiv.org/abs/1712.08489


The biography of Vladimir Platonovich Tsesevich (11.11.1907 – 28.10.1983), a leader of the astronomy in Odessa from 1944 to 1983, is briefly reviewed, as well as the directions of study, mainly the highlights of the research of variable stars carried out by the members of the scientific school founded by him. The directions of these studies cover a very wide range of variability types – “magnetic” and “non-magnetic” cataclysmic variables, symbiotic, X-Ray and other interacting binaries, classical eclipsers and “extreme direct impactors”, pulsating variables from DSct and RR through C and RV to SR and M. Improved algorithms and programs have been elaborated for statistically optimal phenomenological and physical modeling. Initially these studies in Odessa were inspired by (“with a capital letter”) Vladimir Platonovich Tsesevich. who was a meticulous Scientist and brilliant Educator, thorough Author and the intelligibly explaining Popularizer, persevering Organizer and cheerful Joker – a true Professor and Teacher. He was “the Poet of the Starry Heavens”.

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I. Andronov
Mon, 25 Dec 17
18/37

Comments: Odessa Astronomical Publications, 2017, 30 (in press)

Staying ahead of the curve: progress in British variable star astronomy [SSA]

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http://arxiv.org/abs/1712.05399


The BAA Variable Star Section is the world’s longest established organisation for the systematic observation of variable stars, having been formed in 1890. Its database contains nearly 3 million measurements going back to 1840 and is an important resource for researchers. The aim of this Presidential Address is to reveal some of the lesser known tales that lie deep within the database. This includes bringing to life stories about some of the people that were involved, especially in the early years, including Joseph Baxendell, Mary Adela Blagg and Arthur Stanley Williams, as well as shedding light on some of the stars that have been observed. Finally we look to the future as the Variable Star Section builds on the legacy of its forebears, ensuring that it shall always stay ahead of the curve.

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J. Shears
Fri, 15 Dec 17
39/72

Comments: 33 pages, 25 Figures. British Astronomical Association Presidential Address, 2016. Accepted for publication in the Journal of the British Astronomical Association

Iwahashi Zenbei's Sunspot Drawings in 1793 in Japan [SSA]

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http://arxiv.org/abs/1711.08143


Three Japanese sunspot drawings associated with Iwahashi Zenbei (1756-1811) are shown here from contemporary manuscripts and woodprint documents with the relevant texts. We revealed the observational date of one of the drawings to be 26 August 1793, and the overall observations lasted for over a year. Moreover, we identified the observational site for the dated drawing at Fushimi in Japan. We then compared his observations with group sunspot number and raw group count from Sunspot Index and Long-term Solar Observations (SILSO) to reveal its data context, and concluded that these drawings filled the gaps in understanding due to the fragmental sunspots observations around 1793. These drawings are important as a clue to evaluate astronomical knowledge of contemporary Japan in the late 19 th century and are valuable as a non-European observation, considering that most sunspot observations up to mid-19 th century are from Europe.

Read this paper on arXiv…

H. Hayakawa, K. Iwahashi, H. Tamazawa, et. al.
Thu, 23 Nov 17
25/52

Comments: 2017/11/16 accepted for publication in Solar Physics

Iwahashi Zenbei's Sunspot Drawings in 1793 in Japan [SSA]

Posted on by

http://arxiv.org/abs/1711.08143


Three Japanese sunspot drawings associated with Iwahashi Zenbei (1756-1811) are shown here from contemporary manuscripts and woodprint documents with the relevant texts. We revealed the observational date of one of the drawings to be 26 August 1793, and the overall observations lasted for over a year. Moreover, we identified the observational site for the dated drawing at Fushimi in Japan. We then compared his observations with group sunspot number and raw group count from Sunspot Index and Long-term Solar Observations (SILSO) to reveal its data context, and concluded that these drawings filled the gaps in understanding due to the fragmental sunspots observations around 1793. These drawings are important as a clue to evaluate astronomical knowledge of contemporary Japan in the late 19 th century and are valuable as a non-European observation, considering that most sunspot observations up to mid-19 th century are from Europe.

Read this paper on arXiv…

H. Hayakawa, K. Iwahashi, H. Tamazawa, et. al.
Thu, 23 Nov 17
28/52

Comments: 2017/11/16 accepted for publication in Solar Physics

One Hundred Years of the Cosmological Constant: from 'Superfluous Stunt' to Dark Energy [CL]

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http://arxiv.org/abs/1711.06890


We present a centennial review of the history of the term known as the cosmological constant. First introduced to the general theory of relativity by Einstein in 1917 in order to describe a universe that was assumed to be static, the term fell from favour in the wake of the discovery of cosmic the expanding universe, only to make a dramatic return in recent times. We consider historical and philosophical aspects of the cosmological constant over four main epochs: (i) the use of the term in static cosmologies (both Newtonian and relativistic; (ii) the marginalization of the term following the discovery of cosmic expansion; (iii) the use of the term to address specific cosmic puzzles such as the timespan of expansion, the formation of galaxies and the redshifts of the quasars; (iv) the re-emergence of the term in today’s Lamda-CDM cosmology. We find that the cosmological constant was never truly banished from theoretical models of the universe, but was sidelined by astronomers for reasons of convenience. We also find that the return of the term to the forefront of modern cosmology did not occur as an abrupt paradigm shift due to one particular set of observations, but as the result of a number of empirical advances such as the measurement of present cosmic expansion using the Hubble Space Telescope, the measurement of past expansion using type SN 1a supernovae as standard candles, and the measurement of perturbations in the cosmic microwave background by balloon and satellite. We give a brief overview of contemporary interpretations of the physics underlying the cosmic constant and conclude with a synopsis of the famous cosmological constant problem.

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C. ORaifeartaigh, M. OKeeffe, W. Nahm, et. al.
Tue, 21 Nov 17
1/79

Comments: 60 pages, 5 figures. Submitted to the European Physical Journal (H)

Les relations de Milne-Barbier-Unsöld ? [SSA]

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http://arxiv.org/abs/1711.07026


This short review aims at clarifying upon the origins of the well-known Eddington-Barbier relationships. The later relate indeed both the emergent specific intensity and the flux to the stellar photospheric source function at certain specific optical depths. Hereafter we shall discuss about the very assumptions used for the original derivation of Barbier (1943). We also point to the fact that Milne (1921) had already formulated these two relations.

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F. Paletou
Tue, 21 Nov 17
66/79

Comments: A historical-educational note on analytical radiative transfer (text in French)

Jet activity in the central BH of the Milky Way in 4th and 14th centuries CE [CL]

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http://arxiv.org/abs/1711.01833


This paper discusses the historical evidence for the jets from the central Black Hole of Galaxy in the 4th and 14th centuries. We suggest that the apparitions of a “lightening cross” during the day time recorded in 312, 351 and 1317 were caused by the line of two jets beamed back-to-back from the central black hole and crossed the visible projection of the Galaxy disc. All three historical accounts that record the flashing signs of a cross give precise time and geographical locations of these astronomical events (the vicinity of Rome, Jerusalem and the vicinity of Moscow respectively) and most importantly the position in the sky in connection to the Sun. These positions coincide with the location of the Milky Way center on the sky in these specific places and dates. Therefore, it is logical to assume that the intersection of the jets and the lighted projection of the Galaxy disc was the source of the cross visions in the Middle Ages.

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O. Piskounova and I. Tamarkina
Tue, 7 Nov 17
66/118

Comments: 9 pages, 10 figures

Long-Lasting Extreme Magnetic Storm Activities in 1770 Found in Historical Documents [SSA]

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http://arxiv.org/abs/1711.00690


Dim red aurora at low magnetic latitudes is a visual and recognized manifestation of geomagnetic storms. The great low-latitude auroral displays seen throughout East Asia on 16-18 September 1770 are considered to manifest one of the greatest storms. Recently found 111 historical documents in East Asia attest that these low-latitude auroral displays were succeeding for almost 9 nights during 10-19 September 1770 in the lowest magnetic latitude areas (< 30{\deg}). This suggests that the duration of the great magnetic storm is much longer than usual. Sunspot drawings from 1770 reveals the fact that sunspots area was twice as large as those observed in another great storm of 1859, which substantiates this unusual storm activities in 1770. These spots likely ejected several huge, sequential magnetic structures in short duration into interplanetary space, resulting in spectacular world-wide aurorae in mid-September 1770. These findings provide new insights about the history, duration, and effects of extreme magnetic storms that may be valuable for those who need to mitigate against extreme events.

Read this paper on arXiv…

H. Hayakawa, K. Iwahashi, Y. Ebihara, et. al.
Fri, 3 Nov 17
5/46

Comments: 2017/10/23 accepted for publication in The Astrophysical Journal Letters

Des premiers travaux de Le Verrier à la découverte de Neptune [CL]

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http://arxiv.org/abs/1710.03688


(in english): Urbain-Jean-Joseph Le Verrier was born in Saint-L\^o on March 11, 1811. He entered the Ecole Polytechnique in 1831, from which he was to emerge 8th two years later. After first devoting himself to chemistry, in 1836 he obtained a position as an astronomy assistant at the Ecole Polytechnique. This choice will decide his future career which culminates with the discovery of Neptune in 1846. Le Verrier wrote more than 200 contributions in the Comptes Rendus de l’Acad\’emie des Sciences. These contributions are very varied: some original articles but also reports on publications published elsewhere, sometimes even simple notes of a single page. The whole set gives a very vivid vision of the development of the science of the XIXth century. At that time, the Comptes Rendus are really a reflection of the debates of the sessions of the Academy. They are published very quickly, and leave a large freedom of speech to the authors. They are therefore a snapshot of the sometimes lively polemics which animated the sessions of the Academy of Sciences. In this limited essay, we will look to the first years of the career of Le Verrier until the discovery of Neptune. (in french) Le Verrier a \’ecrit plus de 200 contributions dans les Comptes Rendus de l’Acad\’emie des Sciences . Ces contributions sont le reflet des d\’ebats des s\’eances de l’Acad\’emie. Ils sont publi\’es tr`es rapidement, et laissent une tr`es grande libert\’e de parole aux auteurs. On y retrouve de mani`ere instantan\’ee les pol\’emiques parfois vives qui ont anim\’e les s\’eances de l’Acad\’emie des sciences. Dans cet essai nous survolerons les premi`eres ann\’ees de la carri`ere de Le Verrier jusqu’`a la d\’ecouverte de Neptune.

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J. Laskar
Wed, 11 Oct 17
14/65

Comments: 19 pages, in french

My chemistry with Francesco [CL]

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http://arxiv.org/abs/1710.03274


Contributed paper to the Conference “Francesco’s Legacy: Star Formation in Space and Time”, in memory of Francesco Palla (1954-2016), held in Florence, June 5-9, 2017

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D. Galli
Wed, 11 Oct 17
29/65

Comments: To be published in “Memorie della Societ`a Astronomica Italiana”

A. G. W. Cameron 1925-2005, Biographical Memoir, National Academy of Sciences [CL]

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http://arxiv.org/abs/1708.05429


Alastair Graham Walker Cameron was an astrophysicist and planetary scientist of broad interests and exceptional originality. A founder of the field of nuclear astrophysics, he developed the theoretical understanding of the chemical elements’ origins and made pioneering connections between the abundances of elements in meteorites to advance the theory that the Moon originated from a giant impact with the young Earth by an object at least the size of Mars. Cameron was an early and persistent exploiter of computer technology in the theoretical study of complex astronomical systems—including nuclear reactions in supernovae, the structure of neutron stars, and planetary collisions.

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D. Arnett
Mon, 21 Aug 17
13/44

Comments: 12 pages, I picture

Records of Auroral Candidates and Sunspots in Rikkokushi, Chronicles of Ancient Japan from Early 7th Century to 887 [SSA]

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http://arxiv.org/abs/1708.01045


In this article, we present the results of the surveys on sunspots and auroral candidates in Rikkokushi, Japanese Official Histories from the early 7th century to 887 to review the solar and auroral activities. In total, we found one sunspot record and 13 auroral candidates in Rikkokushi. We then examine the records of the sunspots and auroral candidates, compare the auroral candidates with the lunar phase to estimate the reliability of the auroral candidates, and compare the records of the sunspots and auroral candidates with the contemporary total solar irradiance reconstructed from radioisotope data. We also identify the locations of the observational sites to review possible equatorward expansion of auroral oval. These discussions suggest a major gap of auroral candidates from the late 7th to early 9th century, which includes the minimum number of candidates reconstructed from the radioisotope data, a similar tendency as the distributions of sunspot records in contemporary China, and a relatively high magnetic latitude with a higher potential for observing aurorae more frequently than at present.

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H. Hayakawa, K. Iwahashi, H. Tamazawa, et. al.
Fri, 4 Aug 17
13/47

Comments: 2017/08/02 accepted for publication in PASJ

Editorial: Special Issue on the Atomic and Molecular Processes in the Ultracold Regime, the Chemical Regime, and Astrophysics [CL]

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http://arxiv.org/abs/1708.00943


This editorial introduces the J. Phys. B: Atomic, Molecular and Optical Physics Special Issue “Atomic and Molecular Processes in the Ultracold Regime, the Chemical Regime and Astrophysics” dedicated to Professor Alexander Dalgarno (1928-2015). After a brief biographical review, short summaries of the contributed papers and their relations to some of Prof. Dalgarno’s work are given.

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J. Babb, R. Cote, H. Sadeghpour, et. al.
Fri, 4 Aug 17
27/47

Comments: 7 pp

Theoretical terms of contemporary cosmology as intellectual artifacts [CL]

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http://arxiv.org/abs/1707.05235


In this paper, the theoretical terms of contemporary cosmology are examined as intellectual artefacts. An ontology and methodology are introduced for this purpose, which includes defining the concept of a hypothetical object. Introducing a hypothetical object is contrasted with the modification of physical laws as alternative ways of explaining the discrepancy between observations and theoretical predictions. Historical examples of theory choice, which involved these alternatives, are discussed. This is followed by a study of theory choice in contemporary cosmology. In particular, the focus is on the case of dark matter and modified gravity as alternative explanations for observed mass discrepancies in galaxies and galaxy clusters. These alternatives are analyzed, and their similarities and differences to the historical examples are pointed out.

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A. Lazutkina
Wed, 19 Jul 17
3/58

Comments: N/A

On the Earthshine depicted in Galileo's watercolors of the Moon [CL]

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http://arxiv.org/abs/1707.05314


With the manuscript of the Sidereus Nuncius preserved at the Biblioteca Nazionale of Florence are included 7 watercolors of the Moon painted by Galileo himself. We suggest that some of them, and in particular the drawing of the 30 Nov 1609 of the very first Moon’s observations, illustrate the phenomenon of the Earthshine of the Moon, which was discussed in some detail in the Sidereus Nuncius to provide evidence of the similarity of Earth to other celestial bodies. The watercolors were used as models for the engraving of the Moon in the Sidereus but, surprisingly, the secondary light had not been reproduced. Galileo may have decided for the inclusion of the passage on the Earthshine only at a very late stage of the editorial process. Galileo’s hesitation shows how contentious was this issue already recognized as a possible discriminant between the different systems of the world.

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P. Molaro
Wed, 19 Jul 17
48/58

Comments: N/A

The sunspot observations by Toaldo and Comparetti at November 1779 [SSA]

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http://arxiv.org/abs/1707.03393


There is a low frequency of sunspot observations in some years of the 17th and 18th century. In particular, the interval 1777-1795 is one of the periods with scarce observations in the databases. In this note, we report a sunspot observation carried out the 3rd November 1779 by Giuseppe Toaldo and Andrea Comparetti.

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F. Dominguez-Castro and J. Vaquero
Thu, 13 Jul 17
35/60

Comments: 3 pages, The Observatory, accepted

Astrometric accuracy during the past 2000 years [IMA]

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http://arxiv.org/abs/1707.01020


The great development of astrometric accuracy since the observations by Hipparchus about 150 BC was documented in 2008 in the first version of the present report. This report is updated, e.g. with recent information on the catalogues before 1800 AD. The development has often been displayed in diagrams showing the accuracy versus time. A new such diagram is provided in a figure and in a .png file (Section 2) and this information will presumably be the main interest for most readers. For the specialist reader however a detailed documentation is provided in order to give confidence in the diagram and to show how our knowledge about astrometric accuracy has improved in the recent twenty years. The history of these diagrams is illustrated in the appendix.

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E. Hog
Wed, 5 Jul 17
47/60

Comments: 28+8 pages, 2+9 figures, the 8 pages is an appendix, update of report No.7 from 2008 in arxiv 1104.4554v2

Arp's Indomitable Universe [CL]

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http://arxiv.org/abs/1705.09696


We present some aspects of the work and personality of Halton Christian Arp (1927-2013).

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D. Soares, M. Neves and A. Assis
Wed, 31 May 17
-201/48

Comments: 9 pages, 4 figures, pp. 185-197 of the book “The Galileo of Palomar: Essays in Memory of Halton Arp” (Apeiron, Montreal, 2017)

Alternative Explanations of the Cosmic Microwave Background: A Historical and an Epistemological Perspective [CL]

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http://arxiv.org/abs/1705.07721


We historically trace various non-conventional explanations for the origin of the cosmic microwave background and discuss their merit, while analyzing the dynamics of their rejection, as well as the relevant physical and methodological reasons for it. It turns out that there have been many such unorthodox interpretations; not only those developed in the context of theories rejecting the relativistic (“Big Bang”) paradigm entirely (e.g., by Alfven, Hoyle and Narlikar) but also those coming from the camp of original thinkers firmly entrenched in the relativistic milieu (e.g., by Rees, Ellis, Rowan-Robinson, Layzer and Hively). In fact, the orthodox interpretation has only incrementally won out against the alternatives over the course of the three decades of its multi-stage development. While on the whole, none of the alternatives to the hot Big Bang scenario is persuasive today, we discuss the epistemic ramifications of establishing orthodoxy and eliminating alternatives in science, an issue recently discussed by philosophers and historians of science for other areas of physics. Finally, we single out some plausible and possibly fruitful ideas offered by the alternatives.

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M. Cirkovic and S. Perovic
Wed, 24 May 17
29/70

Comments: 53 pages, accepted in “The Studies in History and Philosophy of Modern Physics”

Unusual rainbows as auroral candidates: another point of view [SSA]

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http://arxiv.org/abs/1705.06773


Several auroral events that occurred in the past have not been catalogued as such due to fact that they were described in the historical sources with different terminology. Hayakawa et al. (2016) have reviewed historical oriental chronicles and have proposed the terms “unusual rainbow” and “white rainbow” as candidates to auroras. In this work, we present three events that took place in the 18th century in two different settings (the Iberian Peninsula and Brazil) that were originally described with similar definition/wording used by the oriental chronicles, despite the inherent differences in terms associated to oriental and Latin languages. We show that these terms are indeed applicable to the three case studies from Europe and South America. Thus, the auroral catalogues available can be extended for occidental sources with this new terminology.

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V. Carrasco, R. Trigo and J. Vaquero
Mon, 22 May 17
10/51

Comments: 6 pages, accepted for publication in Publ. Astron. Soc. Jpn

Records of Sunspots and Aurora Candidates in the Chinese Official Histories of the Yuán and Míng Dynasties during 1261-1644 [SSA]

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http://arxiv.org/abs/1705.02238


Records of observations of sunspots and auroras in pre-telescopic historical documents provide useful information about past solar activity both in long-term trends and short-term space weather events. In this study, we present the results of a comprehensive survey of the records of sunspots and aurora candidates in the Yu\’ansh\v{i} and M\’ingsh\v{i}, Chinese Official Histories spanning 1261-1368 and 1368-1644, based on continuous observations with well-formatted reportds conducted by contemporary professional astronomers. We then provide a brief comparison of these data with Total Solar Irradiance (TSI) as an indicator of the solar activity during the corresponding periods to show significant active phases between 1350s-80s and 1610s-30s. We then compared the former with contemporary Russian reports for naked-eye sunspots and the latter with contemporary sunspot drawings based on Western telescopic observations. Especially some of the latter are consistent with nitrate signals preserved in ice cores. These results show us some insights on not only minima and maxima of solar activity during 13th – 17th century.

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H. Hayakawa, H. Tamazawa, Y. Ebihara, et. al.
Mon, 8 May 17
24/54

Comments: 2017/4/28 accepted for publication in PASJ

Francesco Fontana and his "astronomical" Telescope [CL]

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http://arxiv.org/abs/1704.05661


In the late 1620s the Neapolitan telescope maker Francesco Fontana was the first to observe the sky using a telescope with two convex lenses, which he had manufactured himself. Fontana succeeded in drawing the most accurate maps of the Moon’s surface of his time, which were to become popular through a number of publications spread all over Europe but without acknowledging the author. At the end of 1645, in a state of declining health and pressed by the need to defend his authorship, Fontana carried out an intense observational campaign, whose results he hurriedly collected in his Novae Coelestium Terrestriumque rerum Observationis (1646), the only book he left to posterity. Fontana observed the Moon’s main craters, as the crater Tycho which he named Fons Major, their radial patterns and the change in their positions due to the Moon’s motions. He observed the gibbosity of Mars at quadrature and, together with the Jesuit G.B. Zupus, he described the phases of Mercury. Fontana observed the two – and occasionally three – major bands of Jupiter, and inferred the rotation movement of the major planets Mars, Jupiter and Saturn, arguing that they could not be attached to an Aristotelian sky. He came close to revealing the ring structure of Saturn. He also suggested the presence of additional moons around Jupiter, Venus and Saturn, which prompted a debate that lasted more than a hundred years. In several places of his book Fontana repeatedly claimed to have conceived the first positive eyepiece in 1608, providing a declaration by Zupus to have used his telescope since 1614. This declaration is still the oldest record mentioning such a device. We finally suggest that the telescopes depicted in the two Allegory of Sight by J. Brueghel the Elder belonging to Albert VII might have been made by Fontana, and that he might have inspired the Sight by Jusepe Ribera (c. 1616).

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P. Molaro
Thu, 20 Apr 17
46/49

Comments: Accepted for publication by the Journal od Astronomical History and Heritage on the 21 March 2017. 26 pages and 13 figures

Testing the Multiverse: Bayes, Fine-Tuning and Typicality [CEA]

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http://arxiv.org/abs/1704.01680


Theory testing in the physical sciences has been revolutionized in recent decades by Bayesian approaches to probability theory. Here, I will consider Bayesian approaches to theory extensions, that is, theories like inflation which aim to provide a deeper explanation for some aspect of our models (in this case, the standard model of cosmology) that seem unnatural or fine-tuned. In particular, I will consider how cosmologists can test the multiverse using observations of this universe.

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L. Barnes
Fri, 7 Apr 17
24/50

Comments: 19 pages, 3 figures. Conference proceedings: to appear in “The Philosophy of Cosmology”, edited by Khalil Chamcham, Joseph Silk, John D. Barrow, and Simon Saunders. Cambridge University Press, 2017

Remarks to the article: New Light on the Invention of the Achromatic Telescope Objective [CL]

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http://arxiv.org/abs/1703.09072


The article analysis was carried out within the confines of the replication project of the telescope, which was used by Mikhail Lomonosov at observation the transit of Venus in 1761. At that time he discovered the Venusian atmosphere. It is known that Lomonosov used Dollond 4.5 feet long achromatic telescope. The investigation revealed significant faults in the description of the approximation method, which most likely was used by J. Dollond & Son during manufacturing of the early achromatic lenses.

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I. Nesterenko
Tue, 28 Mar 17
7/68

Comments: N/A

Remarks to the article: New Light on the Invention of the Achromatic Telescope Objective [CL]

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http://arxiv.org/abs/1703.09072


The article analysis was carried out within the confines of the replication project of the telescope, which was used by Mikhail Lomonosov at observation the transit of Venus in 1761. At that time he discovered the Venusian atmosphere. It is known that Lomonosov used Dollond 4.5 feet long achromatic telescope. The investigation revealed significant faults in the description of the approximation method, which most likely was used by J. Dollond & Son during manufacturing of the early achromatic lenses.

Read this paper on arXiv…

I. Nesterenko
Tue, 28 Mar 17
58/68

Comments: N/A

Where telescopes cannot (yet) see – the Moon as seen by Scriven Bolton, Etienne Trouvelot, Lucien Rudaux, Chesley Bonestell [CL]

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http://arxiv.org/abs/1703.08138


Scientific illustrations, thanks to the vision of great artists fascinated by astronomical research and astronautics, have provided us with an accurate depiction of the possible views which mankind will one day observed from locations other than our planet. In this talk I will pay homage to some of these geniuses who serve science, and underline the scientific, artistic, political, and social implications deriving from a wise use of space-art.

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A. Adamo
Fri, 24 Mar 17
27/41

Comments: 9 pages, 4 figures, published in the proceedings of SEAC 2015 Conference (Rome)

The Early Scientific Contributions of J. Robert Oppenheimer: Why Did the Scientific Community Miss the Black Hole Opportunity? [CL]

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http://arxiv.org/abs/1703.04234


We aim to carry out an assessment of the scientific value of Oppenheimer’s research on black holes in order to determine and weigh possible factors to explain its neglect by the scientific community, and even by Oppenheimer himself. Dealing primarily with the science and looking closely at the scientific culture and the scientific conceptual belief system of the 1930s, the present article seeks to supplement the existent literature on the subject by enriching the explanations and possibly complicating the guiding questions. We suggest a rereading of Oppenheimer as a more intriguing, ahead-of-his-time figure.

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M. Ortega-Rodriguez, H. Solis-Sanchez, E. Boza-Oviedo, et. al.
Tue, 14 Mar 17
63/74

Comments: 19 pages, Phys. Perspect. (2017)