Tag Archives: History and Philosophy of Physics

Fifty years of cosmological particle creation [CL]

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http://arxiv.org/abs/1702.07132


In the early sixties Leonard Parker discovered that the expansion of the universe can create particles out of the vacuum, opening a new and fruitfull field in physics. We give a historical review in the form of an interview that took place during the Conference ERE2014 (Valencia 1-5, September, 2014).

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L. Parker and J. Navarro-Salas
Fri, 24 Feb 17
35/50

Comments: 8 pages

Why Boltzmann Brains Are Bad [CL]

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http://arxiv.org/abs/1702.00850


Some modern cosmological models predict the appearance of Boltzmann Brains: observers who randomly fluctuate out of a thermal bath rather than naturally evolving from a low-entropy Big Bang. A theory in which most observers are of the Boltzmann Brain type is generally thought to be unacceptable, although opinions differ. I argue that such theories are indeed unacceptable: the real problem is with fluctuations into observers who are locally identical to ordinary observers, and their existence cannot be swept under the rug by a choice of probability distributions over observers. The issue is not that the existence of such observers is ruled out by data, but that the theories that predict them are cognitively unstable: they cannot simultaneously be true and justifiably believed.

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S. Carroll
Mon, 6 Feb 17
8/43

Comments: 27 pages. Invited submission to a volume on Current Controversies in Philosophy of Science, eds. Shamik Dasgupta and Brad Weslake

Einstein's 1917 Static Model of the Universe: A Centennial Review [CL]

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http://arxiv.org/abs/1701.07261


We present a historical review of Einstein’s 1917 paper ‘Cosmological Considerations in the General Theory of Relativity’ to mark the centenary of a key work that set the foundations of modern cosmology. We find that the paper followed as a natural next step after Einstein’s development of the general theory of relativity and that the work offers many insights into his thoughts on relativity, astronomy and cosmology. Our review includes a description of the observational and theoretical background to the paper; a paragraph-by-paragraph guided tour of the work; a discussion of Einstein’s views of issues such as the relativity of inertia, the curvature of space and the cosmological constant. Particular attention is paid to little-known aspects of the paper such as Einstein’s failure to test his model against observation, his failure to consider the stability of the model and a mathematical oversight in his interpretation of the role of the cosmological constant. We discuss the insights provided by Einstein’s reaction to alternate models of the universe proposed by Willem de Sitter, Alexander Friedman and Georges Lema\^itre. Finally, we consider the relevance of Einstein’s static model of the universe for today’s ’emergent’ cosmologies.

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C. ORaifeartaigh, M. OKeeffe, W. Nahm, et. al.
Thu, 26 Jan 17
65/68

Comments: Submitted to the European Physical Journal (H).70-page review, 4 figures

Evidence for a White-light Flare on 10 September 1886 [SSA]

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http://arxiv.org/abs/1701.05910


We present evidence for the occurrence of a white-light flare on 10 September 1886. It represents the third of such rare events reported in the history of astronomy. The flare was mentioned by Valderrama (1886, L’Astronomie 5, 388). In this article we have used the original logbook of the observer, J. Valderrama y Aguilar, an amateur astronomer that lived in Madrid and Santa Cruz de Tenerife at that time.

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J. Vaquero, M. Vazquez and J. Almeida
Tue, 24 Jan 17
11/63

Comments: 11 pages, 3 figures, accepted for publication in Solar Physics

A maximum magnetic moment to angular momentum conjecture [CL]

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http://arxiv.org/abs/1701.06343


Conjectures play a central role in theoretical physics, especially those that assert an upper bound to some dimensionless ratio of physical quantities. In this paper we introduce a new such conjecture bounding the ratio of the magnetic moment to angular momentum in nature. We also discuss the current status of some old bounds on dimensionless and dimensional quantities in arbitrary spatial dimension. Our new conjecture is that the dimensionless Schuster-Wilson-Blackett number, c{\mu}/JG^{(1/2)}, where {\mu} is the magnetic moment and J is the angular momentum, is bounded above by a number of order unity. We verify that such a bound holds for charged rotating black holes in those theories for which exact solutions are available, including the Einstein-Maxwell theory, Kaluza-Klein theory, the Kerr-Sen black hole, and the so-called STU family of charged rotating supergravity black holes. We also discuss the current status of the Maximum Tension Conjecture, the Dyson Luminosity Bound, and Thorne’s Hoop Conjecture.

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J. Barrow and G. Gibbons
Tue, 24 Jan 17
15/63

Comments: 24 pages, no figures

The role of cosmology in modern physics [CL]

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http://arxiv.org/abs/1701.04469


Subject of this article is the relationship between modern cosmology and fundamental physics, in particular general relativity as a theory of gravity on one side, together with its unique application in cosmology, and the formation of structures and their statistics on the other. It summarises arguments for the formulation for a metric theory of gravity and the uniqueness of the construction of general relativity. It discusses symmetry arguments in the construction of Friedmann-Lema\^itre cosmologies as well as assumptions in relation to the presence of dark matter, when adopting general relativity as the gravitational theory. A large section is dedicated to $\Lambda$CDM as the standard model for structure formation and the arguments that led to its construction, and to the of role statistics and to the problem of scientific inference in cosmology as an empirical science. The article concludes with an outlook on current and future developments in cosmology.

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B. Schaefer
Wed, 18 Jan 17
28/61

Comments: 9 pages, invited contribution to the workshop “Why trust a theory?”, Dec.2015 in Munich

Records of sunspot and aurora activity during 581-959 CE in Chinese official histories in the periods of Suí, Táng, and the Five Dynasties and Ten Kingdoms [CL]

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http://arxiv.org/abs/1612.03283


Recent studies of radioisotopes in tree rings or ice cores suggest that extreme space weather events occurred in the pre-telescope age. Observational records of naked-eye sunspots and low-latitude auroras in historical documents in pre-telescopic age can provide useful information on past solar activity. In this paper, we present the results of a comprehensive survey of records of sunspots and auroras in Chinese official histories from the 6th century to the 10th century, in the period of Su\’i, T\’ang, the Five Dynasties and Ten Kingdoms. These official histories contain records of continuous observations with well-formatted reports conducted under the policy of the government. A brief comparison of the frequency of observations of sunspots and auroras with the observations of radioisotopes as an indicator of solar activity during the corresponding periods is provided. Based on our data, we survey and compile the records of sunspots and auroras in historical documents from variouslocations and in several languages, and ultimately provide these as open data to the scientific community.

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H. Tamazawa, A. Kawamura, H. Hayakawa, et. al.
Tue, 13 Dec 16
20/77

Comments: 2016/12/10 accepted for publication in PASJ

Breaking symmetry, breaking ground [CL]

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http://arxiv.org/abs/1612.03192


I give a short commentary on a seminal article by T W B Kibble in 1976, “Topology of cosmic domains and strings”.

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M. Hindmarsh
Tue, 13 Dec 16
69/77

Comments: Published in J. Phys. A as part of a series of Viewpoints on 50 influential papers, celebrating the 50th anniversary of the Journal of Physics series. The article is dedicated to Tom, who died while it was being prepared

Historical Auroras in the 990s: Evidence for Great Magnetic Storms [SSA]

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http://arxiv.org/abs/1612.01106


Recently, a significant carbon-14 enhancement in the year 994 in tree rings has been found, suggesting an extremely large cosmic ray flux event during a short period. The origin of this particular cosmic ray event has not been confirmed, but one possibility is that it is of solar origin. Contemporary historical records of low latitude auroras can be used as supporting evidence for intense solar activity around that time. We investigated the previously reported as well as the new records found in contemporary observations from the 990s to determine potential auroras. Records of potential red auroras in the late 992 and early 993 were found around the world, i.e. in the Korean Peninsula, Germany, and the Island of Ireland, suggesting the occurrence of an intense geomagnetic storm driven by solar activity.

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H. Hayakawa, H. Tamazawa, Y. Uchiyama, et. al.
Tue, 6 Dec 16
23/71

Comments: 2016/12/01 accepted for publication in Solar Physics. Due to the matter of license, we cannot show some figures on the preprint version. Please see the published version in Solar Physics for the figures

Earliest Datable Records of Aurora-like Phenomena in the Astronomical Diaries from Babylonia [SSA]

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http://arxiv.org/abs/1611.05197


The Astronomical Diaries from Babylonia (ADB) are an excellent source of information of natural phenomena, including astronomical ones, in pre-Christ era because it contains the record of highly continuous and systematic observations. In this article we present results of a survey of aurora-like phenomena in ADB, spanning from BCE 652 to BCE 61. We have found 9 records of aurora-like phenomena. Philological and scientific examinations suggest 5 of them can be considered as likely candidate for aurora observations. They provide unique information about the solar and aurora activities in the first millennium BCE.

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H. Hayakawa, Y. Mitsuma, Y. Ebihara, et. al.
Thu, 17 Nov 16
14/57

Comments: 2016/11/16 Accepted publication in Earth, Planets and Space

The earliest drawings of datable auroras and a two-tail comet from the Syriac Chronicle of Zūqnīn [CL]

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http://arxiv.org/abs/1610.08690


People have probably been watching the sky since the beginning of human history. Observers in pre-telescopic ages recorded anomalous events and these astronomical records in the historical documents provide uniquely valuable information for modern scientists. Records with drawings are particularly useful, as the verbal expressions recorded by pre-telescopic observers, who did not know the physical nature of the phenomena, are often ambiguous. However, drawings for specific datable events in the historical documents are much fewer than the verbal records. Therefore, in this paper, we show the possible earliest drawings of datable auroras and a two-tail comet in a manuscript of the Chronicle of Z\=uqn\=in, a Syriac chronicle up to 775/776 CE to interpret their nature. They provide not only the historical facts in the realm around Amida but also information about low-latitude aurora observations due to extreme space weather events and the existence of sun-grazing comets.

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H. Hayakawa, Y. Mitsuma, Y. Fujiwara, et. al.
Wed, 2 Nov 16
31/55

Comments: 2016/10/26 accepted for publication in PASJ. Due to the matter of license, we cannot show some figures on the preprint version. Please see the published version in PASJ for the figures

The contrivance of Neptune [EPA]

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http://arxiv.org/abs/1610.06424


Celebrating 170th anniversary of the discovery of Neptune, I review the story of the discovery that startled the world. The story is an interplay of scientific triumph and human weakness and an example of how science works in a socio-political context.

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D. Krajnovic
Fri, 21 Oct 16
35/47

Comments: A somewhat expanded version of the article published in A&G (October 2016). It differs in two additional text boxes pertaining to the Titius-Bode rule and the naming of the planet, and a correction to the table with pre-discovery sightings of Neptune. 17 pages, two figures and six explanatory boxes. Numeration of figures, tables and boxes is different from the published version

A Brief History of Gravitational Waves [CL]

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http://arxiv.org/abs/1609.09400


This review describes the discovery of gravitational waves. We recount the journey of predicting and finding those waves, since its beginning in the early twentieth century, their prediction by Einstein in 1916, theoretical and experimental blunders, efforts towards their detection, and finally the subsequent successful discovery.

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J. Cervantes-Cota, S. Galindo-Uribarri and G. Smoot
Fri, 30 Sep 16
8/75

Comments: 30 pages

East Asian Observations of Low Latitude Aurora during the Carrington Magnetic Storm [SSA]

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http://arxiv.org/abs/1608.07702


The magnetic storm around 1859 September 2, caused by so-called Carrington flare, was the most intense in the history of modern scientific observations, and hence is considered to be the benchmark event for space weather. The magnetic storm caused worldwide observations of auroras even at very low latitudes such as Hawaii, Panama, or Santiago, and the available magnetic field measurement at Bombay, India, showed two peaks: the main was the Carrington event which occurred in day time in East Asia, and a second storm after the Carrington event which occurred at night in East Asia. In this paper, we present a result from surveys of aurora records in East Asia, which provides new information of the aurora activity of this important event. We found some new East Asian records of low latitude aurora observations caused by the storm which occurred after the Carrington event. The size of the aurora belt of the second peak of the Carrington magnetic storm was even wider than usual low-latitude aurora events.

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H. Hayakawa, K. Iwahashi, H. Tamazawa, et. al.
Tue, 30 Aug 16
7/78

Comments: 2016/08/26 accepted for publication in PASJ. Due to the matter of license, we cannot show some figures on the preprint version. Please see the published version in PASJ for the figures

Life and space dimensionality: A brief review of old and new entangled arguments [CL]

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http://arxiv.org/abs/1608.05298


A general sketch on how the problem of space dimensionality depends on anthropic arguments is presented. Several examples of how life has been used to constraint space dimensionality (and vice-versa) are reviewed. In particular, the influences of three-dimensionality in the solar system stability and the origin of life on Earth are discussed. New constraints on space dimensionality and on its invariance in very large spatial and temporal scales are also stressed.

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F. Caruso
Mon, 22 Aug 2016
25/40

Comments: 13 pages

How supernovae became the basis of observational cosmology [SSA]

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http://arxiv.org/abs/1608.04192


This paper is dedicated to the discovery of one of the most important relationships in supernova cosmology – the relation between the peak luminosity of Type Ia supernovae and their luminosity decline rate after maximum light. The history of this relationship is quite long and interesting. The relationship was independently discovered by the American statistician and astronomer Bert Woodard Rust and the Soviet astronomer Yury Pavlovich Pskovskii in the 1970s. Using a limited sample of Type I supernovae they were able to show that the brighter the supernova is, the slower its luminosity declines after maximum. Only with the appearance of CCD cameras could Mark Phillips re-inspect this relationship on a new level of accuracy using a better sample of supernovae. His investigations confirmed the idea proposed earlier by Rust and Pskovskii.

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M. Pruzhinskaya and S. Lisakov
Tue, 16 Aug 16
36/57

Comments: 13 pages, 10 figures

Aurora Candidates from the Chronicle of Qīng Dynasty in Several Degrees of Relevance [SSA]

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http://arxiv.org/abs/1608.02739


We present the result of the survey of sunspots and auroras in ${\it Q\bar{\imath}ngsh\check{\imath}ga\check{o}}$, the draft chronicle of ${\it Q\bar{\imath}ng}$ dynasty, for the period of 1559-1912 CE, as a sequel of the series of works surveying historical sunspot and aurora records, and providing online data to the scientific community regarding the attained results. In total of this ${\it Q\bar{\imath}ngsh\check{\imath}ga\check{o}}$ survey, we found 111 records of night-sky luminous events with the keywords such as vapor (${\it q\grave{\imath}}$), cloud (${\it y\acute{u}n}$), and light (${\it gu\bar{a}ng}$), which may indicate auroras as well as some other phenomena. Similarly keyword survey for sunspots were done, but no sunspot record was found. In comparison with the aurora records in the western world, we found 14 of the 111 records have a corresponding record of simultaneous observation in the western world and hence are very likely to be aurora. In order to investigate the likeliness of the rest of the record being aurora, we calculated the lunar age and the phase of a solar cycle for each record. After these calculations, notable fraction of these records clustered near the full moon were found statistically doubtful in considerations with atmospheric optics, meanwhile a few records near the new moon could be more likely interpreted as auroras including three records during the Maunder minimum.

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A. Kawamura, H. Hayakawa, H. Tamazawa, et. al.
Wed, 10 Aug 16
25/47

Comments: 34 pages, 5 figures, 2 tables, accepted for publication in PASJ

Lessons from Mayan Astronomy [CL]

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http://arxiv.org/abs/1608.01731


The Mayan culture collected exquisite astronomical data for over a millennium. However, it failed to come up with the breakthrough ideas of modern astronomy because the data was analyzed within a mythological culture of astrology that rested upon false but mathematically sophisticated theories about the Universe. Have we learned the necessary lessons to prevent our current scientific culture from resembling Mayan Astronomy? Clearly, data collection by itself is not a guarantee for good science as commonly assumed by funding agencies. A vibrant scientific culture should cultivate multiple approaches to analyzing existing data and to collecting new data.

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A. Loeb
Mon, 8 Aug 16
26/61

Comments: 4 pages, 1 figure, to be published

Lo Gnomone Clementino Astronomia Meridiana in Basilica [IMA]

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http://arxiv.org/abs/1607.06601


The Clementine Gnomon realized in 1702 by the astronomer Francesco Bianchini (1661-1729) upon the will of Pope Clement XI (1700-1721) in the Basilica of Santa Maria degli Angeli in Rome is fully reviewed about its scientific functions.

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C. Sigismondi
Mon, 25 Jul 16
4/55

Comments: 78 pages, with color images and photo. Text in Italian

Bayesian isochrone fitting and stellar ages [GA]

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http://arxiv.org/abs/1607.03000


Stellar evolution theory has been extraordinarily successful at explaining the different phases under which stars form, evolve and die. While the strongest constraints have traditionally come from binary stars, the advent of asteroseismology is bringing unique measures in well-characterised stars. For stellar populations in general, however, only photometric measures are usually available, and the comparison with the predictions of stellar evolution theory have mostly been qualitative. For instance, the geometrical shapes of isochrones have been used to infer ages of coeval populations, but without any proper statistical basis. In this chapter we provide a pedagogical review on a Bayesian formalism to make quantitative inferences on the properties of single, binary and small ensembles of stars, including unresolved populations. As an example, we show how stellar evolution theory can be used in a rigorous way as a prior information to measure the ages of stars between the ZAMS and the Helium flash, and their uncertainties, using photometric data only.

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D. Valls-Gabaud
Tue, 12 Jul 16
11/71

Comments: 43 pages, Proceedings of the Evry Schatzman School of Stellar Astrophysics “The ages of stars”, EAS Publications Series, Volume 65

Interpretation of the historic Yemeni reports of supernova SN 1006: early discovery in mid-April 1006 ? [CL]

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http://arxiv.org/abs/1607.02915


The recently published Yemeni observing report about SN 1006 from al-Yamani clearly gives AD 1006 Apr $17 \pm 2$ (mid-Rajab 396h) as first observation date. Since this is about 1.5 weeks earlier than the otherwise earliest reports (Apr 28 or 30) as discussed so far, we were motivated to investigate an early sighting in more depth. We searched for additional evidences from other areas like East Asia and Europe. We found that the date given by al-Yamani is fully consistent with other evidence, including: (a) SN 1006 “rose several times half an hour after sunset” (al-Yamani), which is correct for the location of Sana in Yemen for the time around Apr 17, but it would not be correct for late Apr or early May; (b) the date (3rd year, 3rd lunar month, 28th day wuzi, Ichidai Yoki) for an observation of a guest star in Japan is inconsistent (there is no day wuzi in that lunar month), but may be dated to Apr 16 by reading wuwu date rather than a wuzi date; (c) there is observational evidence that SN 1006 was observed in East Asia early or mid April; for the second half of April, a bad weather (early monsoon) period is not unlikely — there is a lack of night reports; (d) the observer in St. Gallen reported to have seen SN 1006 “for three months”, which must have ended at the very latest on AD 1006 Jul 10, given his northern location, so that his observations probably started in April. We conclude that the correctly reported details give quite high confidence in the fully self-consistent report of al-Yamani, so that the early discovery date should be considered seriously.

Read this paper on arXiv…

R. Neuhaeuser, D. Neuhaeuser, W. Rada, et. al.
Tue, 12 Jul 16
39/71

Comments: 11 pages, 2 figures, 1 table (in press) in Astronomical Notes 2016

Dawes Review 5: Australian Aboriginal Astronomy and Navigation [IMA]

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http://arxiv.org/abs/1607.02215


The traditional cultures of Aboriginal Australians include a significant astronomical component, perpetuated through oral tradition, ceremony, and art. This astronomical knowledge includes a deep understanding of the motion of objects in the sky, which was used for practical purposes such as constructing calendars and for navigation. There is also evidence that traditional Aboriginal Australians made careful records and measurements of cyclical phenomena, recorded unexpected phenomena such as eclipses and meteorite impacts, and could determine the cardinal points to an accuracy of a few degrees. Putative explanations of celestial phenomena appear throughout the oral record, suggesting traditional Aborig- inal Australians sought to understand the natural world around them, in the same way as modern scientists, but within their own cultural context. There is also a growing body of evidence for sophisticated navigational skills, including the use of astronomically based songlines. Songlines are effectively oral maps of the landscape, and are an efficient way of transmitting oral navigational skills in cultures that do not have a written language. The study of Aboriginal astronomy has had an impact extending beyond mere academic curiosity, facilitating cross-cultural understanding, demonstrating the intimate links between science and culture, and helping students to engage with science.

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R. Norris
Mon, 11 Jul 16
2/62

Comments: Accepted by PASA

Scientific Realism and Primordial Cosmology [CL]

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http://arxiv.org/abs/1606.04071


We discuss scientific realism from the perspective of modern cosmology, especially primordial cosmology: i.e. the cosmological investigation of the very early universe.
We first (Section 2) state our allegiance to scientific realism, and discuss what insights about it cosmology might yield, as against “just” supplying scientific claims that philosophers can then evaluate. In particular, we discuss: the idea of laws of cosmology, and limitations on ascertaining the global structure of spacetime. Then we review some of what is now known about the early universe (Section 3): meaning, roughly, from a thousandth of a second after the Big Bang onwards(!).
The rest of the paper takes up two issues about primordial cosmology, i.e. the very early universe, where “very early” means, roughly, much earlier (logarithmically) than one second after the Big Bang: say, less than $10^{-11}$ seconds. Both issues illustrate that familiar philosophical threat to scientific realism, the under-determination of theory by data—on a cosmic scale.
The first issue (Section 4) concerns the difficulty of observationally probing the very early universe. More specifically, the difficulty is to ascertain details of the putative inflationary epoch. The second issue (Section 5) concerns difficulties about confirming a cosmological theory that postulates a multiverse, i.e. a set of domains (universes) each of whose inhabitants (if any) cannot directly observe, or otherwise causally interact with, other domains. This again concerns inflation, since many inflationary models postulate a multiverse.
For all these issues, it will be clear that much remains unsettled, as regards both physics and philosophy. But we will maintain that these remaining controversies do not threaten scientific realism.

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F. Azhar and J. Butterfield
Tue, 14 Jun 16
4/67

Comments: 52 pages. An abridged version will appear in “The Routledge Handbook of Scientific Realism”, ed. Juha Saatsi

Monitoring the Solar Radius from the Royal Observatory of the Spanish Navy during the Last Quarter-Millennium [SSA]

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http://arxiv.org/abs/1606.03932


The solar diameter has been monitored at the Royal Observatory of the Spanish Navy (today the Real Instituto y Observatorio de la Armada: ROA) almost continuously since its creation in 1753 (i.e. during the last quarter of a millennium). After a painstaking effort to collect data in the historical archive of this institution, we present here the data of the solar semidiameter from 1773 to 2006, making up an extensive new database for solar-radius measurements can be considered. We have calculated the solar semidiameter from the transit times registered by the observers (except values of the solar radius from the modern Danjon astrolabe, which were published by ROA). These data were analysed to reveal any significant long-term trends, but no such trends were found. Therefore, the data sample confirms the constancy of the solar diameter during the last quarter of a millennium (approximately) within instrumental and methodological limits. Moreover, no relationship between solar radius and the new sunspot-number index has been found from measurements of the ROA. Finally, the mean value for solar semidiameter (with one standard deviation) calculated from the observations made in the ROA (1773-2006), after applying corrections by refraction and diffraction, is equal to 958.87″ \pm 1.77″

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J. Vaquero, M. Gallego, J. Ruiz-Lorenzo, et. al.
Tue, 14 Jun 16
61/67

Comments: 26 pages, 7 figures, to be published in Solar Physics

History of "Anomalous" Atmospheric Neutrino Events: A First Person Account [CL]

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http://arxiv.org/abs/1606.00665


The modern picture of the neutrino as a multiple mass highly mixed neutral particle has emerged over 40 years of study. Best known of the issues leading to this picture was the apparent loss of neutrinos coming from the sun. This article describes another piece of evidence that supports the picture; the substantial reduction of high energy muon type neutrinos observed in nature. For much of the 40 year period, before the modern picture emerged this observation was known as the “atmospheric neutrino anomaly”, since as will be seen, these neutrinos originate in the Earth’s atmosphere.
This paper describes the discovery of the atmospheric neutrino anomaly. We explore the scientific context and motivations in the late 1970’s from which this work emerged. The gradual awareness that the observations of atmospheric neutrinos were not as expected took place in the 1983-1986 period.

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J. LoSecco
Fri, 3 Jun 16
8/46

Comments: 46 pages, 24 figures. To be published in Physics in Perspective

The infinite turn and speculative explanations in cosmology [CL]

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http://arxiv.org/abs/1604.06773


Infinity, in various guises, has been invoked recently in order to `explain’ a number of important questions regarding observable phenomena in science, and in particular in cosmology. Such explanations are by their nature speculative. Here we introduce the notions of relative infinity, closure, and economy of explanation and ask: to what extent explanations involving relative or real constructed infinities can be treated as reasonable?

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R. Tavakol and F. Gironi
Mon, 25 Apr 16
8/40

Comments: N/A

Sunspot numbers based on historic records in the 1610s – early telescopic observations by Simon Marius and others [SSA]

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http://arxiv.org/abs/1604.03724


Hoyt & Schatten (1998) claim that Simon Marius would have observed the sun from 1617 Jun 7 to 1618 Dec 31 (Gregorian calendar) all days, except three short gaps in 1618, but would never have detected a sunspot — based on a quotation from Marius in Wolf (1857), but misinterpreted by Hoyt & Schatten. Marius himself specified in early 1619 that “for one and a half year … rather few or more often no spots could be detected … which was never observed before” (Marius 1619). The generic statement by Marius can be interpreted such that the active day fraction was below 0.5 (but not zero) from fall 1617 to spring 1619 and that it was 1 before fall 1617 (since August 1611). Hoyt & Schatten cite Zinner (1952), who referred to Zinner (1942), where observing dates by Marius since 1611 are given, but which were not used by Hoyt & Schatten. We present all relevant texts from Marius where he clearly stated that he observed many spots in different form on and since 1611 Aug 3 (Julian) = Aug 13 (Greg.) (on the first day together with Ahasverus Schmidnerus), 14 spots on 1612 May 30 (Julian) = Jun 9 (Greg.), which is consistent with drawings by Galilei and Jungius for that day, the latter is shown here for the first time, at least one spot on 1611 Oct 3 and/or 11 (Julian), i.e. Oct 13 and/or 21 (Greg.), when he changed his sunspot observing technique, he also mentioned that he has drawn sunspots for 1611 Nov 17 (Julian) = Nov 27 (Greg.), in addition to those clearly datable detections, there is evidence in the texts for regular observations. … Sunspots records by Malapert from 1618 to 1621 show that the last low-latitude spot was seen in Dec 1620, while the first high-latitude spots were noticed in June and Oct 1620, so that the Schwabe cycle turnover (minimum) took place around that time, …

Read this paper on arXiv…

R. Neuhaeuser and D. Neuhaeuser
Thu, 14 Apr 16
37/53

Comments: 40 pages with 6 tables and 13 figures (paper in press), Astronomical Notes 2016

The orientation as a signature of cultural identity: The historic churches of Lanzarote [CL]

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http://arxiv.org/abs/1604.03863


The orientation of Christian churches is a well-known distinctive feature of their architecture. There is a general tendency to align their apses in the solar range, favoring orientations close to the east (astronomical equinox), although the alignments in the opposite direction, namely, with the apse towards the west, are not unusual. The case of the churches built in northwest Africa before the arrival of Islam is paradigmatic in this regard, and may reflect earlier traditions. The Canary Islands is the western end of this North African cultural koine, so we thought it would be relevant to study a compact set of old churches in one of the islands of the archipelago, choosing to start our project with Lanzarote. We have measured the orientation of a total of 30 churches built prior to 1810, as well as a few buildings of later times, nearly a complete sample of all the island Christian sanctuaries. The analysis of this sample indicates that a definite orientation pattern was followed on the island but, unlike the standard one often found in most of the Christian world, this prototype is twofold. On the one hand, the representative orientation to the east (or west) is present. However, the sample has also a marked orientation towards the north-northeast, which is as far as we know a pattern exclusive of Lanzarote. We analyze the reasons for this rule and suggest that one possible explanation could be a rather prosaic one, namely, that sometimes earthly needs are more relevant than religious beliefs.

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A. Gangui, A. Garcia, M. Betancort, et. al.
Thu, 14 Apr 16
49/53

Comments: Article in Spanish, PDF document including 1 table and 11 figures. Tabona, Revista de Prehistoria y Arqueologia, 20, in press 2016. Published version available at this http URL

An Arabic report about supernova SN 1006 by Ibn Sina (Avicenna) [SSA]

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http://arxiv.org/abs/1604.03798


We present here an Arabic report about supernova 1006 (SN 1006) written by the famous Arabic scholar Ibn Sina (Lat. Avicenna, AD 980-1037), which was not discussed in astronomical literature before. The short observational report about a new star is part of Ibn Sina’s book called al-Shifa’, a work about philosophy including physics, astronomy, and meteorology. We present the Arabic text and our English translation. After a detailed discussion of the dating of the observation, we show that the text specifies that the transient celestial object was stationary and/or tail-less (“a star among the stars”), that it “remained for close to three months getting fainter and fainter until it disappeared”, that it “threw out sparks”, i.e. it was scintillating and very bright, and that the color changed with time. The information content is consistent with the other Arabic and non-Arabic reports about SN 1006. Hence, it is quite clear that Ibn Sina refers to SN 1006 in his report, given as an example for transient celestial objects in a discussion of Aristotle’s “Meteorology”. Given the wording and the description, e.g. for the color evolution, this report is independent from other reports known so far.

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R. Neuhaeuser, C. Ehrig-Eggert and P. Kunitzsch
Thu, 14 Apr 16
53/53

Comments: 7 pages with 1 figure, paper in press, Astronomical Notes 2016

Archaeoastronomy and the orientation of old churches [CL]

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http://arxiv.org/abs/1604.00260


Cultural astronomy is an interdisciplinary area of research that studies how perceptions and concepts related to the sky are part of the worldview of a culture. One of its branches, archaeoastronomy, focuses on the material remains of past peoples and tries to investigate their practices and astronomical knowledge. In this context, the orientation of Christian churches is now considered a distinctive feature of their architecture that repeats patterns from early Christian times. There is a general tendency to align their altars in the solar range, with preference for orientations towards the east. Here we present recent data from our measurements of astronomical orientations of old churches located in two –geographically and culturally– very distant regions, and we discuss the results in the light of the historical and cultural knowledge surrounding these temples.

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A. Gangui
Mon, 4 Apr 16
43/61

Comments: Published version available at this http URL

Limits of time in cosmology [CL]

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http://arxiv.org/abs/1603.05449


We provide a discussion of some main ideas in our project about the physical foundation of the time concept in cosmology. It is standard to point to the Planck scale (located at $\sim 10^{-43}$ seconds after a fictitious “Big Bang” point) as a limit for how far back we may extrapolate the standard cosmological model. In our work we have suggested that there are several other (physically motivated) interesting limits — located at least thirty orders of magnitude before the Planck time — where the physical basis of the cosmological model and its time concept is progressively weakened. Some of these limits are connected to phase transitions in the early universe which gradually undermine the notion of ‘standard clocks’ widely employed in cosmology. Such considerations lead to a ‘scale problem’ for time which becomes particularly acute above the electroweak phase transition (before $\sim 10^{-11}$ seconds). Other limits are due to problems of building up a cosmological reference frame, or even contemplating a sensible notion of proper time, if the early universe constituents become too quantum. This ‘quantum problem’ for time arises e.g. if a pure quantum phase is contemplated at the beginning of inflation at, say, $\sim 10^{-34}$ seconds.

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S. Rugh and H. Zinkernagel
Fri, 18 Mar 16
1/53

Comments: 20 pages, 1 figure. To appear in “The Philosophy of Cosmology”; edited by K. Chamcham, J. Silk, J. Barrow and S. Saunders. Cambridge University Press, 2016

The scientific impact of Einstein's visit to Argentina, in 1925 [CL]

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http://arxiv.org/abs/1603.03792


The arrival of Albert Einstein in Argentina in 1925 had an impact, equally relevant, on the scientific community and on the general public. In this paper we discuss that visit from three different perspectives. Firstly, we consider the conditions that allowed for such visit to be possible. Then we focus on the institutional actors that facilitated it, as well as on the expertise and written references on topics related to relativity theory circulating at the time in the local community. In the last section we consider the implications of that visit for the local scientific environment.

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A. Gangui and E. Ortiz
Tue, 15 Mar 16
10/77

Comments: PDF document, 11 pages; Other related documents available at this http URL

"Unusual Rainbow and White Rainbow" A new auroral candidate in oriental historical sources [SSA]

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http://arxiv.org/abs/1603.02374


Solar activity has been recorded as auroras or sunspots in various historical sources. These records are of much importance for investigating both long-term solar activities and extremely intense solar flares. In previous studies, they were recorded as “vapor,” “cloud,” or “light,” especially in oriental historical sources; however, the terminology was not discussed adequately and is still quite vague. In this paper, we suggest the possibility of “unusual rainbow” and “white rainbow” as candidates of historical auroras in oriental historical sources and examine if it is probable. This discovery will help us to make more comprehensive historical auroral catalogues and require us to add these terms to auroral candidates in oriental historical sources.

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H. Hayakawa, H. Isobe, A. Kawamura, et. al.
Wed, 9 Mar 16
19/71

Comments: Accepted by Publ. Astron. Soc. Japan

Spectra of conditionalization and typicality in the multiverse [CEA]

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http://arxiv.org/abs/1601.05938


An approach to testing theories describing a multiverse, that has gained interest of late, involves comparing theory-generated probability distributions over observables with their experimentally measured values. It is likely that such distributions, were we indeed able to calculate them unambiguously, will assign low probabilities to any such experimental measurements. An alternative to thereby rejecting these theories, is to conditionalize the distributions involved by restricting attention to domains of the multiverse in which we might arise. In order to elicit a crisp prediction, however, one needs to make a further assumption about how typical we are of the chosen domains. In this paper, we investigate interactions between the spectra of available assumptions regarding both conditionalization and typicality, and draw out the effects of these interactions in a concrete setting; namely, on predictions of the total number of species that contribute significantly to dark matter. In particular, for each conditionalization scheme studied, we analyze how correlations between densities of different dark matter species affect the prediction, and explicate the effects of assumptions regarding typicality. We find that the effects of correlations can depend on the conditionalization scheme, and that in each case atypicality can significantly change the prediction. In doing so, we demonstrate the existence of overlaps in the predictions of different “frameworks” consisting of conjunctions of theory, conditionalization scheme and typicality assumption. This conclusion highlights the acute challenges involved in using such tests to identify a preferred framework that aims to describe our observational situation in a multiverse.

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F. Azhar
Mon, 25 Jan 16
32/56

Comments: 14 pages, 3 figures. Accepted for publication in Physical Review D

Kardashev's Classification at 50+: A Fine Vehicle with Room for Improvement [EPA]

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http://arxiv.org/abs/1601.05112


We review the history and status of the famous classification of extraterrestrial civilizations given by the great Russian astrophysicist Nikolai Semenovich Kardashev, roughly half a century after it has been proposed. While Kardashev’s classification (or Kardashev’s scale) has often been seen as oversimplified, and multiple improvements, refinements, and alternatives to it have been suggested, it is still one of the major tools for serious theoretical investigation of SETI issues. During these 50+ years, several attempts at modifying or reforming the classification have been made; we review some of them here, together with presenting some of the scenarios which present difficulties to the standard version. Recent results in both theoretical and observational SETI studies, especially the G-hat infrared survey (2014-2015), have persuasively shown that the emphasis on detectability inherent in Kardashev’s classification obtains new significance and freshness. Several new movements and conceptual frameworks, such as the Dysonian SETI, tally extremely well with these developments. So, the apparent simplicity of the classification is highly deceptive: Kardashev’s work offers a wealth of still insufficiently studied methodological and epistemological ramifications and it remains, in both letter and spirit, perhaps the worthiest legacy of the SETI “founding fathers”.

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M. Cirkovic
Thu, 21 Jan 16
37/52

Comments: 15 pages, 2 figures, 2 tables

Transition of the Sunspot Number from Zurich to Brussels in 1980: A Personal Perspective [CL]

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http://arxiv.org/abs/1512.06229


The Swiss Federal Observatory, which had been founded in 1863 by Rudolf Wolf, was dissolved in connection with the retirement of Max Waldmeier in 1979. The determination of the Zurich sunpot number, which had been a cornerstone activity of the observatory, was then discontinued by ETH Zurich. A smooth transition of the responsibility for the sunspot number from Zurich to Brussels could however be achieved in 1980, through which it was possible to avoid a discontinuity in this important time series. Here we describe the circumstances that led to the termination in Zurich, how Brussels was chosen for the succession, and how the transfer was accomplished.

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J. Stenflo
Tue, 22 Dec 15
72/78

Comments: N/A

Tribute to an astronomer: the work of Max Ernst on Wilhelm Tempel [CL]

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http://arxiv.org/abs/1512.05540


In 1964-1974, the German artist Max Ernst created, with the help of two friends, a series of works (books, movie, paintings) related to the astronomer Wilhelm Tempel. Mixing actual texts by Tempel and artistic features, this series pays homage to the astronomer by recalling his life and discoveries. Moreover, the core of the project, the book Maximiliana or the Illegal Practice of Astronomy, actually depicts the way science works, making this artwork a most original tribute to a scientist.

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Y. Naze
Fri, 18 Dec 15
10/70

Comments: 18 pages, accepted by JHA

The Baltic Meetings 1957 to 1967 [CL]

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http://arxiv.org/abs/1512.01925


The Baltic meetings of astronomers from Northern Germany and Scandinavia began in 1957 and gathered up to 70 participants. Reports of the presentations are available from all meetings, providing an overview of the interests of astronomers in this part of the world 50 years ago. Most interesting to see for a young astronomer in our days, I think, is that a large part of the time was about astrometry. This focus on astrometry was the basis for the scientific knowhow which made the idea of space astrometry realistic, resulting in the approval by ESA of the first astrometry satellite Hipparcos in 1980 which brought a revolution of high-precision astrometry of positions, motions and distances of stars. The correspondence with ten observatories shows that only one of them has any archive of letters at all from the 1950s, that is in Copenhagen where about 7000 letters on scientific and administrative matters are extant.

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E. Hog
Tue, 8 Dec 15
1/71

Comments: 11 pages, 3 figures

Young astronomer in Denmark 1946 to 1958 [CL]

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http://arxiv.org/abs/1512.01924


This is a personal account of how I became an astronomer. Fascinated by the stars and planets in the dark sky over Lolland, an island 100 km south of Copenhagen, the interest in astronomy was growing. Encouraged by my teachers, I polished mirrors and built telescopes with generous help from the local blacksmith and I observed light curves of variable stars. Studies at the Copenhagen University from 1950 gradually led me deeper into astronomy, especially astrometry (the astronomy of positions), guided by professor Bengt Str\”omgren and my mentor dr. phil. Peter Naur. I was lucky to take part in the buildup of the new observatory at Brorfelde during the first difficult years and the ideas I gathered there have contributed to the two astrometry satellites Hipparcos and Gaia launched by the European Space Agency (ESA) in respectively 1989 and 2013.

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E. Hog
Tue, 8 Dec 15
8/71

Comments: 30 pages, 9 figures

The Fourth Microlensing Planet Revisited [CL]

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http://arxiv.org/abs/1512.01329


The fourth microlensing planet, otherwise known as OGLE-2005-BLG-169Lb, was discovered by a collaboration of US, NZ, Polish and UK astronomers in 2005-2006. Recently the results were confirmed by the Hubble Space Telescope and by the Keck Observatory. OGLE-2005-BLG-169Lb is the first microlensing planet to receive such confirmation. Its discovery and confirmation are described here in an historical context.

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P. Yock
Mon, 7 Dec 15
11/46

Comments: 9 pages, 8 figures

Early Telescopes and Ancient Scientific Instruments in the Paintings of Jan Brueghel the Elder [IMA]

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http://arxiv.org/abs/1512.01347


Ancient instruments of high interest for research on the origin and diffusion of early scientific devices in the late XVI – early XVII centuries are reproduced in three paintings by Jan Brueghel the Elder. We investigated the nature and the origin of these instruments, in particular the spyglass depicted in a painting dated 1609-1612 that represents the most ancient reproduction of an early spyglass, and the two sophisticated spyglasses with draw tubes that are reproduced in two paintings, dated 1617-1618. We suggest that these two instruments may represent early examples of keplerian telescopes. Concerning the other scientific instruments, namely an astrolabe, an armillary sphere, a nocturnal, a proportional compass, surveying instruments, a Mordente’s compass, a theodolite, etc., we point out that most of them may be associated with Michiel Coignet, cosmographer and instrument maker at the Court of the Archduke Albert VII of Hapsburg in Brussels.

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P. Selvelli and P. Molaro
Mon, 7 Dec 15
26/46

Comments: Published in Astronomy and its instruments before and after Galileo, Edited by Luisa Pigatto and Valeria Zanini 2009, p193-208

General Relativity in Post Independence India [CL]

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http://arxiv.org/abs/1511.02241


The most outstanding contribution to general relativity in this era came in 1953 (published in 1955 \cite{akr}) in the form of the Raychaudhri equation. It is in 1960s that the observations began to confront the eupherial theory and thus began exploration of GR as a legitimate physical theory in right earnest. The remarkable discoveries of cosmic microwave background radiation, quasars, rotating Kerr black hole and the powerful singularity theorems heralded a new canvas of relativistic astrophysics and cosmology. I would attempt to give a brief account of Indian participation in these exciting times.

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N. Dadhich
Fri, 4 Dec 15
28/64

Comments: 16 pages, latex

A brief history of the multiverse [CL]

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http://arxiv.org/abs/1512.01203


The theory of the inflationary multiverse changes the way we think about our place in the world. According to its most popular version, our world may consist of infinitely many exponentially large parts, exhibiting different sets of low-energy laws of physics. Since these parts are extremely large, the interior of each of them behaves as if it were a separate universe, practically unaffected by the rest of the world. This picture, combined with the theory of eternal inflation and anthropic considerations, may help to solve many difficult problems of modern physics, including the cosmological constant problem. In this article I will briefly describe this theory and provide links to the some hard to find papers written during the first few years of the development of the inflationary multiverse scenario.

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A. Linde
Fri, 4 Dec 15
61/64

Comments: 12 pages, 1 figure

Atomic beings and the discovery of gravity [CEA]

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http://arxiv.org/abs/1511.05431


We aim to bring a new perspective about some aspects of the current research in Cosmology. We start with a brief introduction about the main developments of the field in the last century; then we introduce an analogy that shall elucidate the main difficulties that observational sciences involve, which might be part of the issue related to some of the contemporary cosmological problems. The analogy investigates how microscopic beings could ever discover and understand gravitational phenomena.

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G. Conto and G. Franzmann
Wed, 18 Nov 15
56/61

Comments: 16 pages, 2 figures

Astronomy and Astrophysics in the Philosophy of Science [CL]

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http://arxiv.org/abs/1510.03284


This article looks at philosophical aspects and questions that modern astrophysical research gives rise to. Other than cosmology, astrophysics particularly deals with understanding phenomena and processes operating at “intermediate” cosmic scales, which has rarely aroused philosophical interest so far. Being confronted with the attribution of antirealism by Ian Hacking because of its observational nature, astrophysics is equipped with a characteristic methodology that can cope with the missing possibility of direct interaction with most objects of research. In its attempt to understand the causal history of singular phenomena it resembles the historical sciences, while the search for general causal relations with respect to classes of processes or objects can rely on the “cosmic laboratory”: the multitude of different phenomena and environments, naturally provided by the universe. Furthermore, the epistemology of astrophysics is strongly based on the use of models and simulations and a complex treatment of large amounts of data.

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S. Anderl
Tue, 13 Oct 15
61/64

Comments: 14 pages, This is a draft of a chapter “Astronomy and Astrophysics” that has been accepted for publication by Oxford University Press in the forthcoming book “The Oxford Handbook of Philosophy of Science” edited by Paul Humphreys due for publication in May 2016

Presumable European aurorae in the mid AD 770s were halo displays [CL]

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http://arxiv.org/abs/1508.07955


The interpretation of the strong 14-C variation around AD 775 as one (or several) solar super-flare(s) by, e.g., Usoskin et al. (2013) is based on alleged aurora sightings in the mid AD 770s in Europe: A “red cross/crucifix” in AD 773/4/6 from the Anglo-Saxon Chronicle, “inflamed shields” in AD 776 (both listed in the aurora catalogue of Link 1962), and “riders on white horses” in AD 773 (newly proposed as aurora in Usoskin et al. 2013), the two latter from the Royal Frankish Annals. We discuss the reports about these three sightings in detail here. We can show that all three were halo displays: The “red cross” or “crucifix” is formed by the horizontal arc and a vertical pillar of light (either with the Sun during sunset or with the moon after sunset); the “inflamed shields” and the “riders on white horses” were both two mock suns, especially the latter narrated in form of a Christian adaptation of the antique dioscuri motive. While the latter event took place early in AD 774 (dated AD 773 in Usoskin et al. 2013), the two other sightings have to be dated AD 776, i.e. anyway too late for being in connection with a 14-C rise that started before AD 775. We also sketch the ideological background of those sightings and there were many similar reports throughout that time. In addition, we present a small drawing of a lunar halo display with horizontal arc and vertical pillar forming a cross for shortly later, namely AD 806 June 4, the night of full moon, also from the Anglo-Saxon Chronicle; we also show historic drawings of solar and lunar halo crosses from G. Kirch and Helevius and a modern photograph.

Read this paper on arXiv…

D. Neuhaeuser and R. Neuhaeuser
Tue, 1 Sep 15
76/82

Comments: 17 pages with 6 figures Astronomical Notes in press

The Grand Aurorae Borealis Seen in Colombia in 1859 [CL]

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http://arxiv.org/abs/1508.06365


On Thursday, September 1, 1859, the British astronomer Richard Carrington, for the first time ever, observes a spectacular gleam of visible light on the surface of the solar disk, the photosphere. The Carrington Event, as it is nowadays known by scientists, occurred because of the high solar activity that had visible consequences on Earth, in particular reports of outstanding aurorae activity that amazed thousands of people in the western hemisphere during the dawn of September 2. The geomagnetic storm, generated by the solar-terrestrial event, had such a magnitude that the auroral oval expanded towards the equator, allowing low latitudes, like Panama’s 9$^\circ$ N, to catch a sight of the aurorae. An expedition was carried out to review several historical reports and books from the northern cities of Colombia, allowing the identification of a narrative from Monter\’ia, Colombia (8$^\circ$ 45′ N), that describes phenomena resembling those of an aurorae borealis, such as fire-like lights, blazing and dazzling glares, and the appearance of an immense S-like shape in the sky. The very low latitude of the geomagnetic north pole in 1859, the lowest value in over half a millennia, is proposed to have allowed the observations of auroral events at locations closer to the equator, and supports the historical description found in Colombia. The finding of such chronicle represents one of the most complete descriptions of low-latitude sightings of aurorae caused by the Carrington Event.

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F. Cardenas, S. Sanchez and S. Dominguez
Thu, 27 Aug 15
24/71

Comments: 26 pages, 10 figures. Accepted for publication in Advances in Space Research

Supernova SN 1006 in two historic Yemeni reports [CL]

Posted on by

http://arxiv.org/abs/1508.06126


We present two Arabic texts of historic observations of supernova SN 1006 from Yemen as reported by al-Yamani and Ibn al-Dayba (14th to 16th century AD). An English translation of the report by the latter was given before (Stephenson & Green 2002), but the original Arabic text was not yet published. In addition, we present for the first time the earlier report, also from Yemen, namely by al-Yamani in its original Arabic and with our English translation. It is quite obvious that the report by Ibn al-Dayba is based on the report by al-Yamani (or a common source), but the earlier report by al-Yamani is more detailed and in better (Arabic) language. We discuss in detail the dating of these observations. The most striking difference to other reports about SN 1006 is the apparent early discovery in Yemen in the evening of 15th of Rajab of the year 396h (i.e. AD 1006 Apr 17 \pm 2 on the Julian calendar), as reported by both al-Yamani and Ibn al-Dayba. i.e. about 1.5 weeks earlier than the otherwise earliest known reports. We also briefly discuss other information from the Yemeni reports on brightness, light curve, duration of visibility, location, stationarity, and color.

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W. Rada and R. Neuhaeuser
Wed, 26 Aug 15
31/62

Comments: 9 pages with 3 figures

The Duhem-Quine thesis and the dark matter problem [CL]

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http://arxiv.org/abs/1507.06282


There are few opportunities in introductory physics for a genuine discussion of the philosophy of science, especially in cases where the physical principles are straightforward and the mathematics is simple. Terrestrial classical mechanics satisfies these requirements, but students new to physics usually carry too many incorrect or misleading preconceptions about the subject for it to be analyzed epistemologically. The problem of dark matter, and especially the physics of spiral galaxy velocity rotation curves, is a straightforward application of Newton’s laws of motion and gravitation, and is just enough removed from everyday experience to be analyzed from a fresh perspective. It is proposed to teach students about important issues in the philosophy of physics, including Bacon’s induction, Popper’s falsifiability, and the Duhem-Quine thesis, all in light of the dark matter problem. These issues can be discussed in an advanced classical mechanics course, or, with limited simplification, at the end of a first course in introductory mechanics. The goal is for students to understand at a deeper level how the physics community has arrived at the current state of knowledge.

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M. Reynolds
Thu, 23 Jul 15
37/39

Comments: 15 pages, 3 figures, submitted to the American Journal of Physics

Constraining The Hubble Parameter Using Distance Modulus – Redshift Relation [CEA]

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http://arxiv.org/abs/1507.02734


Using the relation between distance modulus (m-M) and redshift (z), deduced from Friedman-Robertson-Walker (FRW) metric and assuming different values of deceleration parameter (q0). We constrained the Hubble parameter (h). The estimates of the Hubble parameters we obtained using the median values of the data obtained from NASA Extragalactic Database (NED), are: h=0.7+/-0.3 for q0=0, h=0.6+/-0.3, for q0=1 and h=0.8+/-0.3, for q0=-1. The corresponding age ({\tau}) and size (R) of the observable universe were also estimated as: {\tau}=15+/-1 Gyrs, R=(5+/-2)x10^3 Mpc, {\tau}=18+/-1 Gyrs, R=(6+/-2)x10^3 Mpc and {\tau}=13+/-1 Gyrs, R=(4+/-2)x10^3 Mpc for q0=0, q0=1 and q0=-1 respectively.

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C. Onuchukwu and A. Ezeribe
Mon, 13 Jul 15
33/48

Comments: 12 pages, 3 figures

Greek Astronomy PhDs: The last 200 years [CL]

Posted on by

http://arxiv.org/abs/1507.02585


We have recently compiled a database with all doctoral dissertations (PhDs) completed in modern Greece (1837-2014), in the general area of astronomy and astrophysics, as well as in space and ionospheric physics. A preliminary statistical analysis of the data is presented, along with a discussion of the general trends observed.

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V. Charmandaris
Fri, 10 Jul 15
3/53

Comments: 8 pages, 7 figures, (original file also available at this http URL )

Dark matter, Mach's ether and the QCD vacuum [CL]

Posted on by

http://arxiv.org/abs/1507.00460


Here is proposed the idea of linking the dark matter issue, (considered as a major problem of contemporary research in physics) with two other open theoretical questions, one, almost centenary about the existence of an unavoidable ether in general relativity agreeing with the Mach’s principle, and one more recent about the properties of the quantum vacuum of the quantum field theory of strong interactions, QuantumChromodynamics (QCD). According to this idea, on the one hand, dark matter and dark energy that, according to the current standard model of cosmology represent about 95% of the universe content, can be considered as two distinct forms of the Mach’s ether, and, on the other hand, dark matter, as a perfect fluid emerging from the QCD vacuum could be modeled as a Bose Einstein condensate.

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G. Cohen-Tannoudji
Fri, 3 Jul 15
3/50

Comments: N/A

Ars combinatoria and cosmological models: interactions and survival in a Cuzco school painting of the XVIII century [CL]

Posted on by

http://arxiv.org/abs/1506.07916


“The Lord made me a very great favor in an imaginary vision” wrote Maria de Agreda in the seventeenth century, “His Majesty put me at the foot of a beautiful Ladder, and showed me I had to climb it.” These words refer to the spiritual ascent, present in the Judeo-Christian tradition, and crystallized in the visions of prophets and Catholic saints. Genesis (18: 10-22) narrates that Jacob, going to Haran, slept on some stones and saw a ladder between heaven and earth along which angels were ascending and descending. From this dream, the symbolic union between heaven and earth has been figured with stairs, ascribing to it different meanings over the centuries. On the steps of the ladder people saw a metaphor for the graduality of ascent; Benedict used a ladder of twelve steps of humility in his Regula, and in the seventh century AD John Climacus, Bishop of Sinai, established a thirty-step Scala Paradisi of meditation leading to God. In this work we discuss the historical echoes of the Benedictine rule, together with Climacus’ voice in the desert and the visualization of celestial mysteries, in the case of the Cuzco school painting Allegory of the firmament, with the representation of the planets’ seven heavens (XVIII century). In this way we try and analyze the intersection between science and mysticism in the representation of the heavenly stairs, in order to show the cultural anchorage of the symbology employed in these cases [abridged].

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A. Gangui, G. Siracusano and J. Rey-Marquez
Mon, 29 Jun 15
9/41

Comments: Article in Spanish, PDF document including 10 figures. Published version available at this http URL in Migraciones y Rutas del Barroco, edited by N.Campos, La Paz: Vision Cultural, p. 57-70, 2014

Prediction and typicality in multiverse cosmology [CEA]

Posted on by

http://arxiv.org/abs/1506.08101


In the absence of a fundamental theory that precisely predicts values for observable parameters, anthropic reasoning attempts to constrain probability distributions over those parameters in order to facilitate the extraction of testable predictions. The utility of this approach has been vigorously debated of late, particularly in light of theories that claim we live in a multiverse, where parameters may take differing values in regions lying outside our observable horizon. Within this cosmological framework, we investigate the efficacy of top-down anthropic reasoning based on the weak anthropic principle. We argue contrary to recent claims that it is not clear one can either dispense with notions of typicality altogether or presume typicality, in comparing resulting probability distributions with observations. We show in a concrete, top-down setting related to dark matter, that assumptions about typicality can dramatically affect predictions, thereby providing a guide to how errors in reasoning regarding typicality translate to errors in the assessment of predictive power. We conjecture that this dependence on typicality is an integral feature of anthropic reasoning in broader cosmological contexts, and argue in favour of the explicit inclusion of measures of typicality in schemes invoking anthropic reasoning, with a view to extracting predictions from multiverse scenarios.

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F. Azhar
Mon, 29 Jun 15
24/41

Comments: 13 pages, 1 figure. arXiv admin note: text overlap with arXiv:hep-th/0508006 by other authors

Edgar Allan Poe: the first man to conceive a Newtonian evolving Universe [CL]

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http://arxiv.org/abs/1506.05218


The notion that we live in an evolving universe was established only in the twentieth century with the discovery of the recession of galaxies by Hubble and with the Lemaitre and Friedmann’s interpretation in the 1920s.
However, the concept of an evolving universe is intrinsically tied to the law of universal gravitation, and it is surprising that it remained unrecognized for more than two centuries. A remarkable exception to this lack of awareness is represented by Poe. In Eureka (1848), the writer developed a conception of an evolving universe following the reasoning that a physical universe cannot be static and nothing can stop stars or galaxies from collapsing on each other. Unfortunately this literary work was, and still is, very little understood both by the literary critics and scientists of the time. We will discuss Poe’s cosmological views in their historical scientific context, highlighting the remarkable insights of the writer, such as those dealing with the Olbers paradox, the existence of other galaxies and of a multi-universe.

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P. Molaro and A. Cappi
Thu, 18 Jun 15
45/60

Comments: Proceedings of the seventh conference on the Inspiration of Astronomical Phenomena (INASP VII) Bath, October 2010

Records of sunspot and aurora during CE 960-1279 in the Chinese chronicle of the Song dynasty [SSA]

Posted on by

http://arxiv.org/abs/1506.03715


Records of sunspots and aurora observations in pre-telescopic historical documents can provide useful information about solar activity in the past. This is also true for extreme space weather events, as they may have been recorded as large sunspots observed by the naked eye or as low-latitude auroras. In this paper, we present the results of a comprehensive survey of records of sunspots and auroras in the Songshi, a Chinese formal chronicle spanning the tenth to the thirteenth century. This chronicle contains a record of continuous observations with well-formatted reports conducted as a policy of the government. A brief comparison of the frequency of observations of sunspots and auroras and the observations of radioisotopes as an indicator of the solar activity during corresponding periods is provided. This paper is the first step of our project in which we survey and compile the records of sunspots and aurora in historical documents from various locations and languages, ultimately providing it to the science community as online data.

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H. Hayakawa, H. Tamazawa, A. Kawamura, et. al.
Fri, 12 Jun 15
5/47

Comments: Accepted for for publication in Earth, Planets and Space. This manuscript includes the original texts in Chinese, which is omitted in the version published in EPS

A new perspective on steady-state cosmology: from Einstein to Hoyle [CL]

Posted on by

http://arxiv.org/abs/1506.01651


We recently reported the discovery of an unpublished manuscript by Albert Einstein in which he attempted a ‘steady-state’ model of the universe, i.e., a cosmic model in which the expanding universe remains essentially unchanged due to a continuous formation of matter from empty space. The manuscript was apparently written in early 1931, many years before the steady-state models of Fred Hoyle, Hermann Bondi and Thomas Gold. We compare Einstein’s steady-state cosmology with that of Hoyle, Bondi and Gold and consider the reasons Einstein abandoned his model. The relevance of steady-state models for today’s cosmology is briefly reviewed.

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C. ORaifeartaigh and S. Mitton
Fri, 5 Jun 15
37/63

Comments: To be published in the ‘Proceedings of the 2014 Institute of Physics International Conference on the History of Physics’, Cambridge University Press. arXiv admin note: substantial text overlap with arXiv:1504.02873, arXiv:1402.0132

Editorial for the Special Issue 100 Years of Chronogeometrodynamics: The Status of the Einstein's Theory of Gravitation in Its Centennial Year [CL]

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http://arxiv.org/abs/1504.05789


The present Editorial introduces the Special Issue dedicated by the journal Universe to the General Theory of Relativity, the beautiful theory of gravitation of Einstein, a century after its birth. It reviews some of its key features in a historical perspective, and, in welcoming distinguished researchers from all over the world to contribute it, some of the main topics at the forefront of the current research are outlined.

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L. Iorio
Thu, 23 Apr 15
61/61

Comments: LaTex2e, 41 pages, no figures, no tables, 311 references, peer-reviewed. Accepted for publication in Universe

Milestones of general relativity: Hubble's law (1929) and the expansion of the universe [CL]

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http://arxiv.org/abs/1504.03606


Hubble’s announcement of the magnitude-redshift relation \cite{Hub29} brought about a major change in our understanding of the Universe. After tracing the pre-history of Hubble’s work, and the hiatus in our understanding which his underestimate of distances led to, this review focuses on the development and success of our understanding of the expanding universe up to the present day, and the part which General Relativity plays in that success.

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M. MacCallum
Wed, 15 Apr 15
63/68

Comments: To appear in Classical and Quantum Gravity as one of the Milestones of General Relativity series

A new perspective on Einstein's philosophy of cosmology [CL]

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http://arxiv.org/abs/1504.02873


It has recently been discovered that Einstein once attempted – and subsequently abandoned – a ‘steady-state’ model of the universe, i.e., a cosmic model in which the expanding universe remains essentially unchanged due to a continuous creation of matter from empty space. The discovery offers several new insights into Einstein’s cosmology, from his view of the role of the cosmological constant to his attitude to the question of cosmic origins. More generally, Einstein’s exploration of steady-state cosmology casts new light on his philosophical journey from a static, bounded cosmology to the dynamic, evolving universe, and is indicative of a pragmatic, empiricist approach to cosmology.

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C. ORaifeartaigh
Tue, 14 Apr 15
58/87

Comments: 20 pages, 2 figures. To be published in the book ‘The Philosophy of Cosmology: Foundations and Perspectives’ (Cambridge University Press)

Einstein's cosmology review of 1933: a new perspective on the Einstein-de Sitter model of the cosmos [CL]

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http://arxiv.org/abs/1503.08029


We present a first English translation and analysis of a little-known review of relativistic cosmology written by Albert Einstein in late 1932. The article, which was published in 1933 in a book of Einstein papers translated into French, contains a substantial review of static and dynamic relativistic models of the cosmos, culminating in a discussion of the Einstein-de Sitter model. The article offers a valuable contemporaneous insight into Einstein’s cosmology in the 1930s and confirms that his interest lay in the development of the simplest model of the cosmos that could account for observation, rather than an exploration of all possible cosmic models. The article also confirms that Einstein did not believe that simplistic relativistic models could give an accurate description of the early universe.

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C. ORaifeartaigh, M. OKeeffe, W. Nahm, et. al.
Mon, 30 Mar 15
42/65

Comments: Accepted for publication in the European Physical Journal (H). Includes an English translation of a little-known review of cosmology written by Albert Einstein in 1933. 20 pages, 4 figures

Some Generalities About Generality [CL]

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http://arxiv.org/abs/1503.05723


We survey a variety of cosmological problems where the issue of generality has arisen. This is aimed at providing a wider context for many claims and deductions made when philosophers of science choose cosmological problems for investigation. We show how simple counting arguments can be used to characterise parts of the general solution of Einstein’s equations when various matter fields are present and with different spatial topologies. Applications are described to the problem of singularities, static cosmological models, cosmic no hair theorems, the late-time isotropisation of cosmological models, and the number of parameters needed to describe a general astronomical universe.

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J. Barrow
Fri, 20 Mar 15
3/55

Comments: 26 pages, no figures, chapter for volume ‘Foundations and Perspectives on Cosmology and Philosophy’

The sunspot observations by Rheita in 1642 [CL]

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http://arxiv.org/abs/1502.06772


The correct interpretation of a fragment of Rheita about a sunspot observation in 1642 has crucial importance in estimating the amplitude of the solar cycle just before the Maunder Minimum. We show here that this record has been misinterpreted, presenting the original Latin text and a modern English translation.

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J. Gomez and J. Vaquero
Wed, 25 Feb 15
24/55

Comments: 3 pages, submitted to “The Observatory”

Satio Hayakawa and dawn of high-energy astrophysics in Japan [CL]

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http://arxiv.org/abs/1502.04294


Pioneering works and stimulation by S. Hayakawa for the development of high-energy astrophysics in Japan.

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J. Nishimura
Tue, 17 Feb 15
38/60

Comments: 2014 Fermi Symposium proceedings – eConf C14102.1

How to collect matches that will catch fire [IMA]

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http://arxiv.org/abs/1502.00709


How can we select a cohort of promising astrophysicists before they have made their discoveries? This is the fundamental challenge of academic planning. I argue that science can only blossom if young researchers are rewarded for acquired skills and growth rather than inherited academic ancestry.

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A. Loeb
Wed, 4 Feb 15
28/59

Comments: 3 pages, submitted for publication

Majorana and the theoretical problem of photon-electron scattering [CL]

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http://arxiv.org/abs/1501.06838


Relevant contributions by Majorana regarding Compton scattering off free or bound electrons are considered in detail, where a (full quantum) generalization of the Kramers-Heisenberg dispersion formula is derived. The role of intermediate electronic states is appropriately pointed out in recovering the standard Klein-Nishina formula (for free electron scattering) by making recourse to a limpid physical scheme alternative to the (then unknown) Feynman diagram approach. For bound electron scattering, a quantitative description of the broadening of the Compton line was obtained for the first time by introducing a finite mean life for the excited state of the electron system. Finally, a generalization aimed to describe Compton scattering assisted by a non-vanishing applied magnetic field is as well considered, revealing its relevance for present day research.

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M. Mauro, S. Esposito and A. Naddeo
Wed, 28 Jan 15
46/58

Comments: latex, amsart, 10 pages, 1 figure

Avoiding Intellectual Stagnation: The Starship as an Expander of Minds [CL]

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http://arxiv.org/abs/1501.04249


Interstellar exploration will advance human knowledge and culture in multiple ways. Scientifically, it will advance our understanding of the interstellar medium, stellar astrophysics, planetary science and astrobiology. In addition, significant societal and cultural benefits will result from a programme of interstellar exploration and colonisation. Most important will be the cultural stimuli resulting from expanding the horizons of human experience, and increased opportunities for the spread and diversification of life and culture through the Galaxy. Ultimately, a programme of interstellar exploration may be the only way for human (and post-human) societies to avoid the intellectual stagnation predicted for the “end of history”.

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I. Crawford
Tue, 20 Jan 15
21/76

Comments: Published in the Journal of the British Interplanetary Society

Blurring Out Cosmic Puzzles [CL]

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http://arxiv.org/abs/1412.4382


The Doomsday argument and anthropic reasoning are two puzzling examples of probabilistic confirmation. In both cases, a lack of knowledge apparently yields surprising conclusions. Since they are formulated within a Bayesian framework, they constitute a challenge to Bayesianism. Several attempts, some successful, have been made to avoid these conclusions, but some versions of these arguments cannot be dissolved within the framework of orthodox Bayesianism. I show that adopting an imprecise framework of probabilistic reasoning allows for a more adequate representation of ignorance in Bayesian reasoning and explains away these puzzles.

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Y. Benetreau-Dupin
Tue, 16 Dec 14
27/78

Comments: 15 pages, 1 figure. To appear in Philosophy of Science (PSA 2014)

The quest for collapsed/frozen stars in single-line spectroscopic binary systems [CL]

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http://arxiv.org/abs/1411.1116


Black holes are now commonplace, among the stars, in Galactic centers, and perhaps other places. But within living memory, their very existence was doubted by many, and few chose to look for them. Zeldovich and Guseinov were first, followed by Trimble and Thorne, using a method that would have identified HDE 226868 as a plausible candidate, if it had been in the 1968 catalogue of spectroscopic binaries. That it was not arose from an unhappy accident in the observing program of Daniel M. Popper long before the discovery of X-ray binaries and the identification of Cygnus X-1 with that hot, massive star and its collapsed companion.

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V. Trimble
Thu, 6 Nov 14
45/67

Comments: Key Words: Black holes, collapsed stars, Cygnus X-1, HDE 226868, spectroscopic binaries Journal: The Zeldovich Universe Genesis and Growth of the Cosmic Web IAU Symposium 308, 23-28 June 2014, Tallinn, Estonia) this http URL

Ralph A. Alpher, George Antonovich Gamow, and the Prediction of the Cosmic Microwave Background Radiation [CL]

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http://arxiv.org/abs/1411.0172


The first prediction of the existence of “relict radiation” or radiation remaining from the “Big Bang” was made in 1948. This derived from the seminal dissertation work of Ralph A. Alpher. He was a doctoral student of George A. Gamow and developed several critical advances in cosmology in late 1946, 1947, and 1948. Alpher developed the ideas of “hot” big bang cosmology to a high degree of physical precision, and was the first to present the idea that radiation, not matter, predominated the early universal adiabatic expansion first suggested by A. Friedmann in the early 1920s. Alpher and Herman predicted the residual relic black-body temperature in 1948 and 1949 at around 5 K. However, to this day, this prediction, and other seminal ideas in big bang cosmology, have often been attributed erroneously to the better-known George A. Gamow. This article reviews some of the more egregious and even farcical errors in the scholarly literature about Ralph A. Alpher and his place in the history of big bang cosmology. Two such errors are that (a) Alpher was a fictive person; or (b) that like the French mathematician Nicolas Bourbaki, Alpher was a “conglomerate” of theoreticians.

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V. Alpher
Tue, 4 Nov 14
14/76

Comments: 10 pages, 4 figures

Relational Mechanics as a gauge theory: Machianization and dragging effect in galactic halos [CL]

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http://arxiv.org/abs/1410.6509


The elimination of absolute space from the body of mechanics is achieved by gauging translations and rotations in the kinetic energy of an isolated system. As a result, the gauge invariant Lagrangian leads to equations of motion that can be used in any frame. Nevertheless, there are privileged frames where Newton’s equations are valid, but they are determined by the matter distribution of the universe (Machianization). The relational equations of motion shows that there exists a dragging effect in galactic halos that contributes to the rotation curves. On the other hand, the absence of an absolute time is characteristic of parametrized systems, which are systems possessing an internal time. Parametrized systems with potentials that are proportional to inverse square distances are as well gauge invariant under scalings (shape-dynamics).

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R. Ferraro
Tue, 28 Oct 14
65/67

Comments: 15 pages, 1 figure

The Barolo Palace: medieval astronomy in the streets of Buenos Aires [CL]

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http://arxiv.org/abs/1410.6506


Cultural heritage relating to the sky in the form of sundials, old observatories and the like, are commonly found in many cities in the Old World, but rarely in the New. This paper examines astronomical heritage embodied in the Barolo Palace in Buenos Aires. While references to Dante Alighieri and his poetry are scattered in streets, buildings and monuments around the Western world, in the city of Buenos Aires, the only street carrying Dante’s name is less than three blocks long and, appropriately, is a continuation of Virgilio street. A couple of Italian immigrants -a wealthy businessman, Luis Barolo, and an imaginative architect, Mario Palanti- foresaw this situation nearly a century ago, and did not save any efforts or money with the aim of getting Dante and his cosmology an appropriate monumental recognition, in reinforced concrete. The Barolo Palace is a unique combination of both astronomy and the worldview displayed in the Divine Comedy, Dante’s poetic masterpiece. It is known that the Palace’s design was inspired by the great poet, but the details are not recorded; this paper relies on Dante’s text to consider whether it may add to our understanding of the building. Although the links of the Palace’s main architectural structure with the three realms of the Comedy have been studied in the past, its unique astronomical flavor has not been sufficiently emphasized. The word of God, as interpreted by the Fathers of the Church in Sacred Scripture, Aristotle’s physics and Ptolemy’s astronomy, all beautifully converge in Dante’s verses, and the Barolo Palace reflects this.

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A. Gangui
Mon, 27 Oct 14
17/58

Comments: 28 pages, 14 figures. PDF document. arXiv admin note: substantial text overlap with arXiv:1304.6439

Interferometry meets the third and fourth dimensions in galaxies [CL]

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http://arxiv.org/abs/1410.3534


Radio astronomy began with one array (Jansky’s) and one paraboloid of revolution (Reber’s) as collecting areas and has now reached the point where a large number of facilities are arrays of paraboloids, each of which would have looked enormous to Reber in 1932. In the process, interferometry has contributed to the counting of radio sources, establishing superluminal velocities in AGN jets, mapping of sources from the bipolar cow shape on up to full grey-scale and colored images, determining spectral energy distributions requiring non-thermal emission processes, and much else. The process has not been free of competition and controversy, at least partly because it is just a little difficult to understand how earth-rotation, aperture-synthesis interferometry works. Some very important results, for instance the mapping of HI in the Milky Way to reveal spiral arms, warping, and flaring, actually came from single moderate-sized paraboloids. The entry of China into the radio astronomy community has given large (40-110 meter) paraboloids a new lease on life.

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V. Trimble
Wed, 15 Oct 14
41/58

Comments: Virginia Trimble 2014, in IAU Symp. 309 “Galaxy in 3D across the Universe”, B.L. Ziegler, F. Combes, H. Dannerbauer, M. Verdugo, Eds. (Cambridge: Cambridge Uni. Press) in press NOTE – Should be “Galaxies” not “Galaxy”

Philosophical Issues of Black Holes [CL]

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http://arxiv.org/abs/1409.3318


Black holes are extremely relativistic objects. Physical processes around them occur in a regime where the gravitational field is extremely intense. Under such conditions, our representations of space, time, gravity, and thermodynamics are pushed to their limits. In such a situation philosophical issues naturally arise. In this chapter I review some philosophical questions related to black holes. In particular, the relevance of black holes for the metaphysical dispute between presentists and eternalists, the origin of the second law of thermodynamics and its relation to black holes, the problem of information, black holes and hypercomputing, the nature of determinisim, and the breakdown of predictability in black hole space-times. I maintain that black hole physics can be used to illuminate some important problems in the border between science and philosophy, either epistemology and ontology.

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G. Romero
Fri, 12 Sep 14
17/61

Comments: 32 pages, 4 figures. To be published as a chapter in the book: Advances in Black Holes Research, Abraham Barton (Editor). Nova Science Publishers. ISBN: 978-1-63463-168-6

A transient event in AD 775 reported by al-Tabari: A bolide – not a nova, supernova, or kilonova [CL]

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http://arxiv.org/abs/1408.2936


Given that the cause for the strong increase in 14C in AD 774/5 in Japanese and German trees is still a matter of debate (e.g. short Gamma-Ray Burst or solar super-flare), we have searched in Arabic chronicles for reports about unusual transient celestial events. In the {\em History of al-Tabari we found two (almost identical) reports about such an event. The group around caliph al-Mansur observed a transient event while on the way from Baghdad to Mecca on AD 775 Aug 29 – Sep 1 (Julian calendar), most probably during the morning twilight of AD 775 Aug 29. A celestial object kawkab was seen to fall or set inqadda, and its trace atharuhu was seen for at least tens of minutes (up to 70-90 min) during morning twilight. The reports use the Arabic words kawkab and athar(uhu), which were also used in the known Arabic reports about supernovae SN 1006 and 1054, so that one might consider an interpretation as a nova-like event. The kawkab (celestial object) was observed only during the morning twilight at a brightness of probably between about -3 and 0 mag. Such a brightness and time-scale would be expected for optical kilonovae (at 3 to 9 kpc) in the context of short Gamma-Ray Bursts. There are no similar reports from eastern Asia for this time. However, the short reports are fully consistent with a bolide: The word kawkab can be used for meteor, the verb inqadda normally means “falling down”, the word atharuhu can mean “its trace”. We therefore prefer the interpretation as bolide. We discuss in detail how to convert the Muslim calendar date to a date in the Julian calendar using first the calculated Islamic calendar and then considering the time when the crescent new moon could be visible at the given location.

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R. Neuhaeuser and P. Kunitzsch
Thu, 14 Aug 14
10/54

Comments: 12 pages with three figures, paper in press (Astronomical Notes 2014)

A solar super-flare as cause for the 14C variation in AD 774/5 ? [SSA]

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http://arxiv.org/abs/1408.2934


We present further considerations regarding the strong 14C variation in AD 774/5. For its cause, either a solar super-flare or a short Gamma-Ray Burst were suggested. We show that all kinds of stellar or neutron star flares would be too weak for the observed energy input at Earth in AD 774/5. Even though Maehara et al. (2012) present two super-flares with 10e35 erg of presumably solar-type stars, we would like to caution: These two stars are poorly studied and may well be close binaries, and/or having a M-type dwarf companion, and/or may be much younger and/or much more magnetic than the Sun – in any such case, they might not be true solar analog stars. From the frequency of large stellar flares averaged over all stellar activity phases (maybe obtained only during grand activity maxima), one can derive (a limit of) the probability for a large solar flare at a random time of normal activity: We find the probability for one flare within 3000 years to be possibly as low as 0.3 to 0.008 considering the full 1 sigma error range. Given the energy estimate in Miyake et al. (2012) for the AD 774/5 event, it would need to be \sim 2000 stronger than the Carrington event as solar super-flare. If the AD 774/5 event as solar flare would be beamed (to an angle of only 24 deg), 100 times lower energy would be needed. A new AD 774/5 energy estimate by Usoskin et al. (2013) with a different carbon cycle model, yielding 4 or 6 time lower 14C production, predicts 4-6 times less energy. If both reductions are applied, the AD 774/5 event would need to be only 4 times stronger than the Carrington event in 1859 (if both had similar spectra). However, neither 14C nor 10Be peaks were found around AD 1859. Hence …

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R. Neuhaeuser and V. Hambaryan
Thu, 14 Aug 14
23/54

Comments: 15 pages, 3 figures, paper in press in Astronomical Notes 2014

The Chinese comet observation in AD 773 January [CL]

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http://arxiv.org/abs/1408.2929


The strong 14C increase in the year AD 774/5 detected in one German and two Japanese trees was recently suggested to have been caused by an impact of a comet onto Earth and a deposition of large amounts of 14C into the atmosphere (Liu et al. 2014). The authors supported their claim using a report of a historic Chinese observation of a comet ostensibly colliding with Earth’s atmosphere in AD 773 January. We show here that the Chinese text presented by those authors is not an original historic text, but that it is comprised of several different sources. Moreover, the translation presented in Liu et al. is misleading and inaccurate. We give the exact Chinese wordings and our English translations. According to the original sources, the Chinese observed a comet in mid January 773, but they report neither a collision nor a large coma, just a long tail. Also, there is no report in any of the source texts about “dust rain in the daytime” as claimed by Liu et al. (2014), but simply a normal dust storm. Ho (1962) reports sightings of this comet in China on AD 773 Jan 15 and/or 17 and in Japan on AD 773 Jan 20 (Ho 1962). At the relevant historic time, the Chinese held that comets were produced within the Earth’s atmosphere, so that it would have been impossible for them to report a “collision” of a comet with Earth’s atmosphere. The translation and conclusions made by Liu et al. (2014) are not supported by the historical record. Therefore, postulating a sudden increase in 14C in corals off the Chinese coast precisely in mid January 773 (Liu et al. 2014) is not justified given just the 230Th dating for AD 783 \pm 14.

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J. Chapman, M. Csikszentmihalyi and R. Neuhaeuser
Thu, 14 Aug 14
54/54

Comments: 4 pages with one figure, paper in press in Astronomical Notes 2014

Maximum Tension: with and without a cosmological constant [CL]

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http://arxiv.org/abs/1408.1820


We discuss various examples and ramifications of the conjecture that there exists a maximum force (or tension) in general relativistic systems. We contrast this situation with that in Newtonian gravity, where no maximum force exists, and relate it to the existence of natural units defined by constants of Nature and the fact that the Planck units of force and power do not depend on Planck’s constant. We discuss how these results change in higher dimensions where the Planck units of force are no longer non-quantum. We discuss the changes that might occur to the conjecture if a positive cosmological constant exists and derive a maximum force bound using the Kottler-Schwarzschild-de Sitter black hole.

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J. Barrow and G. Gibbons
Mon, 11 Aug 14
38/55

Comments: 12 pages, no figures

Jayant Vishnu Narlikar [CL]

Posted on by

http://arxiv.org/abs/1407.4367


An essay on Jyant Narlikar in the Living Legends of Indian Science series of the journal Current Science.

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N. Dadhich
Mon, 4 Aug 14
11/40

Comments: 8 pages in triple column with 4 photographs

The representations of the sky among the Tomaraho [CL]

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http://arxiv.org/abs/1408.0221


The Tom\’ar\~aho is an ethnic group of the Paraguayan Chaco who maintained close contact with nature and developed original ways of explaining and understanding it. This article presents the first results of an interdisciplinary project seeking to provide a detailed analysis of different astronomical elements in the imagined sky of the Tom\’ar\~aho.

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G. Sequera and A. Gangui
Mon, 4 Aug 14
29/40

Comments: Article in Spanish, PDF document including 10 figures

Einstein's steady-state theory: an abandoned model of the cosmos [CL]

Posted on by

http://arxiv.org/abs/1402.0132


We present a translation and analysis of an unpublished manuscript by Albert Einstein in which he attempted to construct a ‘steady-state’ model of the universe. The manuscript, which appears to have been written in early 1931, demonstrates that Einstein once explored a cosmic model in which the mean density of matter in an expanding universe is maintained constant by the continuous formation of matter from empty space. This model is very different to previously known Einsteinian models of the cosmos (both static and dynamic) but anticipates the later steady-state cosmology of Hoyle, Bondi and Gold in some ways. We find that Einstein’s steady-state model contains a fundamental flaw and suggest that it was abandoned for this reason. We also suggest that he declined to explore a more sophisticated version because he found such theories rather contrived. The manuscript is of historical interest because it reveals that Einstein debated between steady-state and evolving models of the cosmos decades before a similar debate took place in the cosmological community.

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C. ORaifeartaigh, B. McCann, W. Nahm, et. al.
Fri, 25 Jul 14
25/57

Comments: 22 pages, 2 figures. Includes first English translation of unpublished Einstein manuscript. Accepted for publication in Eur.Phys.J.(H)

Einstein's cosmic model of 1931 revisited: an analysis and translation of a forgotten model of the universe [CL]

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http://arxiv.org/abs/1312.2192


We present a translation and analysis of a cosmic model published by Einstein in 1931. The paper, which is not widely known, features a model of a universe that undergoes an expansion followed by a contraction, quite different to his static model of 1917 or the monotonic Einstein-de Sitter model of 1932. The paper offers many insights into the cosmology of Albert Einstein in the light of the first evidence for an expanding universe, and we discuss his views of issues such as the curvature of space, the cosmological constant, the singularity and the timespan of the expansion. We argue that retrospective descriptions of this model as cyclic or periodic are not historically or mathematically accurate. We find that calculations in the paper of the matter density and radius of the universe contain a numerical error, a finding that is supported by writing on a blackboard used by Einstein during a lecture at Oxford University in May 1931. Our article concludes with a general discussion of his philosophy of cosmology.

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C. Raifeartaigh and B. McCann
Fri, 25 Jul 14
44/57

Comments: Accepted for publication in the European Physical Journal (H). The article includes a first English translation of Einstein’s 1931 SAW paper and the discovery of an error in Einstein’s calculation of the matter density of the universe. 30 pages, 2 figures

The contribution of VM Slipher to the discovery of the expanding universe [CL]

Posted on by

http://arxiv.org/abs/1212.5499


A brief history of the discovery of the expanding universe is presented, with an emphasis on the seminal contribution of VM Slipher. It is suggested that the well-known Hubble graph of 1929 could also be known as the Hubble-Slipher graph. It is also argued that the discovery of the expanding universe matches the traditional view of scientific advance as a gradual process of discovery and acceptance, and does not concur with the Kuhnian view of science progressing via abrupt paradigm shifts.

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C. Raifeartaigh
Fri, 25 Jul 14
47/57

Comments: 13 pages, 2 figures. Accepted for publication in the proceedings of the conference “Origins of the Expanding Universe: 1912-1932”, M. J. Way & D. Hunter, eds., ASP Conf. Ser., Vol. 471 in press

Lessons from the Milky Way: the Kapteyn Universe [CL]

Posted on by

http://arxiv.org/abs/1407.2632


Jacobus Cornelius Kapteyn (1851-1922) presented a model for the distribution of stars in space together with a dynamical interpretation in terms of an equilibrium between the gravitational field of the stars and their random motion and rotation. In the vertical direction Kapteyn’s results are substantially correct. Usually the Kapteyn Universe is described as being flawed due to neglect of interstellar absorption. Kapteyn was led to adopt this on the basis of widely accepted evidence by Shapley on an absence of reddening of stars in globular clusters. But another, equally important misconception was Kapteyn’s interpretation of the two Star Streams as manifestations of two groups of stars rotating around a center in opposite directions. This was supported by the observation of very different mixes in stellar types in the two streams. Had Kapteyn adopted the absorption as he himself had determined it he would not have been able to arrive at a consistent picture.

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P. Kruit
Fri, 11 Jul 14
10/49

Comments: To appear in LESSONS FROM THE LOCAL GROUP: A Conference in Honour of David Block and Bruce Elmegreen, eds. Freeman, K.C., Elmegreen, B.G., Block, D.L.and Woolway, M., Springer: New York

Searching Signals in Chinese Ancient Records for the $^{14}$C Increases in AD 774-775 and in AD 992-993 [CL]

Posted on by

http://arxiv.org/abs/1406.7306


According to the analysis of the $^{14}$C content of two Japanese trees over a period of approximately 3000 years at high time resolution, Miyake (2012) found a rapid increase at AD 774-775 and later on at AD 992-993 (Miyake 2013). This corresponds to a high-energy event happened within one year that input $\gamma$-ray energy about 7$\times{}$10$^{24}$erg to the Earth, leaving the origin a mystery. Such strong event should have an unusual optical counterpart, and have been recorded in historical literature. We searched Chinese historical materials around AD 744-775 and AD 992-993, but no remarkable event was found except a violent thunderstorm in AD 775. However, the possibility of a thunderstorm containing so much energy is still unlikely. We conclude the event caused the $^{14}$C increase is still unclear. This event most probably has no optical counterpart, and short gamma-ray burst, giant flare of a soft gamma-ray repeater and terrestrial $\gamma$-ray flash may all be the candidates.

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Y. Chai and Y. Zou
Tue, 1 Jul 14
33/70

Comments: 8 pages, 3 figures

Are There Many Worlds? [CL]

Posted on by

http://arxiv.org/abs/1406.7215


It is often thought that the existence of other worlds cannot be scientifically verified and therefore should be treated as philosophical speculation. I disagree. In this paper, I describe several methods for determining that other worlds exist, even without interacting with them. These methods are based on the following premise: if there are many worlds, then the statistical properties of a natural process are biased when measured by an observer whose existence was influenced by the process. The bias is always in the same direction, making the process appear more beneficial for the existence of the observer than it actually is. I suggest several potential ways of measuring the bias, show through a simple model of population dynamics how the bias is generated, and briefly consider whether our current drop in population growth is evidence of many worlds.

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A. Gerig
Mon, 30 Jun 14
40/41

Comments: 7 pages, 3 figures

Astronomy of two Indian tribes: Banjaras and Kolams [CL]

Posted on by

http://arxiv.org/abs/1406.3044


We report field studies of the astronomical beliefs of two Indian tribes: the Banjaras and the Kolams. The Banjaras are an ancient tribe connected with the gypsies of Europe while the Kolams have been foragers until recently. They share their landscape with each other and also with the Gonds whose astronomy was reported previously (Vahia and Halkare, 2013). The primary profession of the Banjaras was trade, based on the large-scale movement of goods over long distances, but their services were taken over by the railways about one hundred years ago. Since then the Banjaras have begun the long journey to a sedentary lifestyle. Meanwhile, the Kolams were foragers until about fifty years ago when the Government of India began to help them lead a settled life.
Here, we compare their astronomical beliefs of the Banjaras and the Kolams, which indicate the strong sense of identity that each community possesses. Our study also highlights their perspective about the sky and its relation to their daily lives. We show that apart from the absolute importance of the data on human perception of the sky, the data also reveal subtle aspects of interactions between physically co-located but otherwise isolated communities as well as their own lifestyles. We also show that there is a strong relationship between profession and perspective of the sky.

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M. Vahia, G. Halkare, K. Menon, et. al.
Fri, 13 Jun 14
26/46

Comments: 20 pages, 5 images and 5 tables

A Life of Fun Playing With Solar Magnetic Fields (Special Historical Review) [CL]

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http://arxiv.org/abs/1405.3481


This invited memoire describes my fortunate life, which has been enriched by meeting many wonderful people. The story starts at home and university, and continues with accounts of St Andrews and trips to the USA, together with musings on the book “Solar MHD”. The nature and results of collaborations with key people from abroad and with students is mentioned at length. Finally, other important aspects of my life are mentioned briefly before wrapping up.

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E. Priest
Thu, 15 May 14
29/55

Comments: Invited Memoire in the Journal Solar Physics

On the Benefits of Promoting Diversity of Ideas [IMA]

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http://arxiv.org/abs/1405.2954


A common flaw of astronomers is to believe that they know the truth even when data is scarce. I provide ten examples where this approach led to wrong strategic decisions in research plans, causing unnecessary delays in finding the truth. In order to make the discovery process more efficient, I advocate affirmative action for diversity of ideas by telescope-time allocation committees and funding agencies.

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A. Loeb
Wed, 14 May 14
32/48

Comments: 4 pages, submitted for publication

Dark Energy, Paradigm Shifts, and the Role of Evidence [CL]

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http://arxiv.org/abs/1405.1350


We comment on cases in the history of Astronomy, which may shed some light on the current established but enigmatic concordance model of Cosmology. Should the model be understood by adding new entities such as Dark Matter and Dark Energy, or by modifying the underlying theory? For example, the prediction and discovery of planet Neptune can be regarded as analogous to finding a dark component; while explaining the anomalous perihelion precession of Mercury by General Relativity can be taken as analogous to the possibility that modified gravity is an alternative to dark components of the universe. In this paper, we revise this analogy coming from the history of astronomy with an eye to illustrating some of the similarities and differences between the two cases.

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O. Lahav and M. Massimi
Wed, 7 May 14
38/58

Comments: 8 pages, 2 pictures, 1 table, to appear in the RAS journal Astronomy & Geophysics (2014)

Philosophical aspects of modern cosmology [CL]

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http://arxiv.org/abs/1404.5854


This paper is a short introduction to a special issue on philosophy of cosmology, published in the May 2014 issue of Studies in History and Philosophy of Modern Physics. I briefly introduce the philosophy of cosmology, and then provide a short outline of the contents of the papers in the special issue. The contributors are George Ellis, Dominico Giulini, Marc Lachi\`eze-Rey, Helge Kragh, Jeremy Butterfield, Jean-Christophe Hamilton, Mart\’in L\’opez-Corredoira, Brigitte Falkenburg, Robert Brandenberger and Chris Smeenk. I conclude with a few remarks on the relationship between aesthetics and cosmology.

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H. Zinkernagel
Fri, 25 Apr 14
2/65

Cosmic Conundrums [CL]

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http://arxiv.org/abs/1404.3128


What do we do when cosmology raises questions it cannot answer? These include the existence of a multiverse and the universality of the laws of physics. We cannot settle any of these issues by experiment, and this is where philosophers enter the debate. Drawing the line between philosophy and physics has never been easy. Perhaps it is time to stop trying. The interface is ripe for exploration.

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J. Silk
Tue, 15 Apr 14
26/73

Songlines and Navigation in Wardaman and other Australian Aboriginal Cultures [CL]

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http://arxiv.org/abs/1404.2361


We discuss the songlines and navigation of the Wardaman people, and place them in context by comparing them with corresponding practices in other Australian Aboriginal language groups, using previously unpublished information and also information drawn from the literature. Songlines are effectively oral maps of the landscape, enabling the transmission of oral navigational skills in cultures that do not have a written language. In many cases, songlines on the earth are mirrored by songlines in the sky, enabling the sky to be used as a navigational tool, both by using it as a compass, and by using it as a mnemonic

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R. Norris and B. Harney
Thu, 10 Apr 14
2/57

A historical perspective on Modified Newtonian Dynamics [CL]

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http://arxiv.org/abs/1404.0531


I review the history and development of Modified Newtonian Dynamics (MOND) beginning with the phenomenological basis as it existed in the early 1980s. I consider Milgrom’s papers of 1983 introducing the idea and its consequences for galaxies and galaxy groups, as well as the initial reactions, both negative and positive. The early criticisms were primarily on matters of principle, such as the absence of conservation laws and perceived cosmological problems; an important step in addressing these issues was the development of the Lagrangian-based non-relativistic theory of Bekenstein and Milgrom. This theory led to the development of a tentative relativistic theory that formed the basis for later multi-field theories of gravity. On an empirical level the predictive success of the idea with respect to the phenomenology of galaxies presents considerable challenges for cold dark matter. For MOND the essential challenge remains the absence of a generally accepted theoretical underpinning of the idea and, thus, cosmological predictions. I briefly review recent progress in this direction. Finally I discuss the role and sociology of unconventional ideas in astronomy in view of a strongly entrenched standard paradigm.

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R. Sanders
Thu, 3 Apr 14
27/45

Ya. B. Zeldovich (1914-1987): Chemist, Nuclear Physicist, Cosmologist [CL]

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http://arxiv.org/abs/1403.1537


Ya.B. Zeldovich was a pre-eminent Soviet physicist whose seminal contributions spanned many fields ranging from physical chemistry to nuclear and particle physics, and finally astrophysics and cosmology. March 8, 2014 marks Zeldovich’s birth centenary, and this article attempts to convey the zest with which Zeldovich did science, and the important role he played in fostering and mentoring a whole generation of talented Scientists.

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V. Sahni
Fri, 7 Mar 14
1/47

A Critical Look at the Standard Cosmological Picture [CL]

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http://arxiv.org/abs/1303.2549


The discovery that the Universe is accelerating in its expansion has brought the basic concept of cosmic expansion into question. An analysis of the evolution of this concept suggests that the paradigm that was finally settled into prior to that discovery was not the best option, as the observed acceleration lends empirical support to an alternative which could incidentally explain expansion in general. I suggest, then, that incomplete reasoning regarding the nature of cosmic time in the derivation of the standard model is the reason why the theory cannot coincide with this alternative concept. Therefore, through an investigation of the theoretical and empirical facts surrounding the nature of cosmic time, I argue that an enduring three-dimensional cosmic present must necessarily be assumed in relativistic cosmology—and in a stricter sense than it has been. Finally, I point to a related result which could offer a better explanation of the empirically constrained expansion rate.

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D. Janzen
Thu, 6 Mar 14
33/53

A Medieval Multiverse: Mathematical Modelling of the 13th Century Universe of Robert Grosseteste [CL]

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http://arxiv.org/abs/1403.0769


In his treatise on light, written in about 1225, Robert Grosseteste describes a cosmological model in which the Universe is created in a big-bang like explosion and subsequent condensation. He postulates that the fundamental coupling of light and matter gives rises to the material body of the entire cosmos. Expansion is arrested when matter reaches a minimum density and subsequent emission of light from the outer region leads to compression and rarefaction of the inner bodily mass so as to create nine celestial spheres, with an imperfect residual core. In this paper we reformulate the Latin description in terms of a modern mathematical model. The equations which describe the coupling of light and matter are solved numerically, subject to initial conditions and critical criteria consistent with the text. Formation of a universe with a non-infinite number of perfected spheres is extremely sensitive to the initial conditions, the intensity of the light and the transparency of these spheres. In this “medieval multiverse”, only a small range of opacity and initial density profiles lead to a stable universe with nine perfected spheres. As in current cosmological thinking, the existence of Grosseteste’s universe relies on a very special combination of fundamental parameters.

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R. Bower, T. S%2E, B. Tanner, et. al.
Wed, 5 Mar 14
40/75

George Howard Herbig, 1920-2013 [CL]

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http://arxiv.org/abs/1402.6686


A great astronomer, George Herbig, passed away in Honolulu on October 12, 2013, at the age of 93. His life and career were long and productive, and consistently dedicated to the careful, thorough research that earned him his reputation. Herbig spent most of his career at Lick Observatory, first as a graduate student, and then from 1949 to 1987 as a staff member, rising through the ranks to Astronomer and becoming Professor as well when the observatory moved to the University of California at Santa Cruz in the late 1960s. Herbig retired from UCSC in 1987 and spent the remainder of his life in Honolulu at the Institute for Astronomy of the University of Hawai`i.

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D. Soderblom
Thu, 27 Feb 14
23/59

Charles Michie Smith – founder of the Kodaikanal (Solar Physics) Observatory and beginnings of physical astronomy in India [CL]

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http://arxiv.org/abs/1402.6189


It has been about 115 years since the establishment of Kodaikanal Observatory as an extension of the original Madras Observatory, which has evolved into the present Indian Institute of Astrophysics at Bangalore. It is also the first mountain observatory in India. Charles Michie Smith was the man who selected the site, established the observatory and directed it for the first 12 years. He was also the man who recruited John Evershed, discoverer of the famous Evershed effect and established Kodaikanal Observatory as a major centre for solar physics. Michie Smith, the person and the establishment of Kodaikanal Observatory are discussed here in the context of the early studies in physical astronomy (observational astrophysics) in India.

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N. Rao, A. Vagiswari and C. Birdie
Wed, 26 Feb 14
36/51

Bhavnagar Telescope: the most widely travelled telescope in the country [CL]

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http://arxiv.org/abs/1402.5732


In the last decade of the 19th century Maharaja Takhtasingji Observatory was built at Poona (1888-1912) under the supervision of K.D.Naegamavala, with the grant from Maharaja of Bhavnagar (from where the name Bhavnagar Telescope must have originated. The story of this telescope from its inception to the current status is traced. IIA Archives has been extensively used to resource information for this note.

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N. Rao, C. Birdie and A. Vagiswari
Tue, 25 Feb 14
1/59