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1
MacLachlan, James. "The Role of Astronomy in the History of Science". International Astronomical Union Colloquium 105 (1990): 45–46. http://dx.doi.org/10.1017/s0252921100086371.
Testo completoAbstract (sommario):
This historian of science offers a few samples of the kinds of understandings his students will be subjected to. (a) In early times, Britons used careful observations of astronomical events to establish their calendar; (b) In the 4th century BC, Aristotle used the spheres of Eudoxus to establish his cosmological principles; (c) In the second century of our era, Ptolemy made astronomy scientific, partly for the sake of astrological predictions; (d) In the fifteenth century, Columbus used crude astronomical observations to find latitude, (e) In the sixteenth century, Copernicus revised Ptolemaic astronomy in order to improve its fit with Aristotelian cosmology, and in the process challenged that cosmology; (f) Kepler used Tycho’s more precise data to destroy heavenly circularity; (g) In the early seventeenth century, Galileo based his renovation of motion studies on the investigative style he learned from Ptolemy, coupled with mathematics learned from Euclid and Archimedes.
2
REID, FRANCIS. "Isaac Frost's Two Systems of Astronomy (1846): plebeian resistance and scriptural astronomy". British Journal for the History of Science 38, n. 2 (25 maggio 2005): 161–77. http://dx.doi.org/10.1017/s0007087405006710.
Testo completoAbstract (sommario):
In early nineteenth-century London audiences flocked to a variety of lectures and shows on astronomical topics. While the religious and social positions of the lecturers and showmen varied significantly, the vast majority adopted a Newtonian cosmology incorporating a belief in the plurality of worlds. This paper focuses on Isaac Frost's 1846 book Two Systems of Astronomy in an attempt to gain a fuller understanding of how some thinkers in plebeian London responded to and resisted this emergent astronomical orthodoxy. Central to this analysis is research that reveals how changes in the intellectual world of Frost and his Muggletonian co-religionists prompted this formerly non-proselytizing Protestant sect to become increasingly vocal during the nineteenth century. This research is based upon a thorough examination of the Muggletonian archive in the British Library together with a collection of approximately thirty Muggletonian letters deposited in the Oxfordshire Records Office in 1993 and not examined by previous historians. It is concluded that the unorthodox or anti-Newtonian cosmologies advanced by several early nineteenth-century thinkers were often intellectually coherent and embodied in receptive social contexts.
3
Smeenk, Chris. "Predictability crisis in early universe cosmology". Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 46 (maggio 2014): 122–33. http://dx.doi.org/10.1016/j.shpsb.2013.11.003.
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Włodarczyk, Jarosław, Richard L. Kremer e Howard C. Hughes. "Edward Gresham, Copernican Cosmology, and Planetary Occultations in Pre-Telescopic Astronomy". Journal for the History of Astronomy 49, n. 3 (agosto 2018): 269–305. http://dx.doi.org/10.1177/0021828618790302.
Testo completoAbstract (sommario):
This article introduces an understudied source in the history of astronomy, the Astrostereon or the Discourse of the Falling of the Planet (1603). Written by the English astrologer Edward Gresham, this text presents, among other things, the earliest known set of predicted planetary occultations (for 1603–1604) and the use of these phenomena to defend the Copernican cosmology. We analyse those predictions and then briefly survey all known pre-telescopic observations of reported planetary occulations and the motivations for such observations. These data suggest that for early observers, the greater the difference in apparent brightness between the two occulting bodies, the greater the angular separation could be for an occultation nonetheless to be reported. An appendix seeks to explain this finding by considering several factors known from modern experimental analyses of human visual performance.
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Kragh, Helge. "Early dynamical world models: A historical review". Proceedings of the International Astronomical Union 5, S260 (gennaio 2009): 182–88. http://dx.doi.org/10.1017/s1743921311002262.
Testo completoAbstract (sommario):
AbstractModels of the universe, in the sense of solutions to the cosmological field equations, took their start in 1917 with Einstein's closed universe. During the next two decades they were developed to comprise evolving models, some of them cyclic and some of them with a definite age. The history of this development, as it occurred up to the mid 1930s, is reviewed. It is argued that in 1930-31, cosmology experienced a kind of paradigm shift.
6
Dayal, Pratika. "Early galaxy formation and its large-scale effects". Proceedings of the International Astronomical Union 15, S352 (giugno 2019): 43. http://dx.doi.org/10.1017/s1743921320001106.
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AbstractGalaxy formation in the first billion years mark a time of great upheaval in the history of the Universe: the first galaxies started both the ‘metal age’ as well as the era of cosmic reionization. I will start by reviewing the dust production mechanisms and dust masses for high-redshift galaxies which will be revolutionized in the ALMA era. I will then show how the JWST will be an invaluable experiment to shed light on the impact of reionization feedback on early galaxy formation. As we look forward towards the era of 21cm cosmology, I will highlight the crucial and urgent synergies required between 21cm facilities (such as the SKA) and galaxy experiments (JWST, E-ELT and Subaru to name a few) to understand the physics of the epoch of reionization that remains a crucial frontier in the field of astrophysics and physical cosmology. Time permitting, I will try to give a flavour of how the assembly of early galaxies, accessible with the forthcoming JWST, can provide a powerful testbed for Dark Matter models beyond ‘Cold Dark Matter’.
7
Endress, Gerhard. "Averroes' De Caelo Ibn Rushd's Cosmology in his Commentaries on Aristotle's On the Heavens". Arabic Sciences and Philosophy 5, n. 1 (marzo 1995): 9–49. http://dx.doi.org/10.1017/s0957423900001934.
Testo completoAbstract (sommario):
Averroes defended philosophy by returning to the true Aristotle. For this purpose, Aristotle's book “On the Heaven,” in which he explained the eternity, uniqueness and movement of the universe, occupied a place of special importance. But the Aristotelian philosopher had a hard time holding his own in the face of contradictions within the book and with respect to Aristotle's later works. In his early Compendium, later Paraphrase, and final Long Commentary of De Caelo, Ibn Rushd continued the efforts of the Hellenistic commentators in order to integrate all the elements of his doctrine into a unified system, to harmonize his early cosmology with his later Metaphysics – the early doctrine of natural movement of the elements, and of the self-moving star-souls (a Platonic element), with the doctrine of potency and actuality and the theory of the First Mover – and to uphold his models of homocentric planetary spheres against the mathematical paradigm of Ptolemaic astronomy. By insisting throughout on demonstrative arguments based on rational principles, he asserted the philosophers' claim to irrefutable truth.
8
Brandenberger, Robert. "Do we have a theory of early universe cosmology?" Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 46 (maggio 2014): 109–21. http://dx.doi.org/10.1016/j.shpsb.2013.09.008.
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Longair, M. S. "The Astrophysics of the Future". International Astronomical Union Colloquium 123 (1990): 421–26. http://dx.doi.org/10.1017/s0252921100077381.
Testo completoAbstract (sommario):
It is with some trepidation that I set down these thoughts. The history of physics and astronomy is littered with pontifications about the future, most of which simply end up embarrassing their authors. There are many projects which can be regarded as very safe bets but these might not be the ones which totally transform the nature of the discipline. The situation is analogous to that in the early 1950s when extragalactic astronomy simply meant optical astronomy since there was no other way of carrying out such studies – few would regard that as an adequate position nowadays. Similarly, it is difficult nowadays to imagine cosmology without the Microwave Background Radiation. Thus, the problem for the prognosticator is to tread the narrow line between science fiction and a simple extrapolation of what we do now with our facilities. It is in the spirit of this meeting to concentrate upon space observatories but I believe that it is instructive to look at the whole of astronomy, both from space and from the ground.
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Menci, N., M. Castellano, P. Santini, E. Merlin, A. Fontana e F. Shankar. "High-redshift Galaxies from Early JWST Observations: Constraints on Dark Energy Models". Astrophysical Journal Letters 938, n. 1 (1 ottobre 2022): L5. http://dx.doi.org/10.3847/2041-8213/ac96e9.
Testo completoAbstract (sommario):
Abstract Early observations with JWST have led to the discovery of an unexpectedly large density (stellar-mass density ρ * ≈ 106 M ⊙ Mpc−3) of massive galaxies (stellar masses M * ≥ 1010.5 M ⊙) at extremely high redshifts z ≈ 10. While such a result is based on early measurements that are still affected by uncertainties currently under consideration by several observational groups, its confirmation would have a strong impact on cosmology. Here we show that—under the most conservative assumptions and independently of the baryon physics involved in galaxy formation—such galaxy abundance is not only in tension with the standard ΛCDM cosmology but provides extremely tight constraints on the expansion history of the universe and on the growth factors corresponding to a wide class of Dynamical Dark Energy (DDE) models. Adopting a parameterization w = w 0 + w a (1 − a) for the evolution of the DDE equation of the state parameter w with the expansion factor a, we derive constraints on combinations of (w 0, w a ) that rule out with confidence level >2σ a major portion of the parameter space (w 0, w a ) allowed (or even favored) by existing cosmological probes.
11
Kibble, T. W. B. "Phase Transitions and Topological Defects in the Early Universe". Australian Journal of Physics 50, n. 4 (1997): 697. http://dx.doi.org/10.1071/p96076.
Testo completoAbstract (sommario):
Our present theories of particle physics and cosmology, taken together, suggest that very early in its history, the universe underwent a series of phase transitions, at which topological defects, similar to those formed in some condensed matter transitions, may have been created. Such defects, in particular cosmic strings, may survive long enough to have important observable effects in the universe today. Predicting these effects requires us to estimate the initial defect density and the way that defects subsequently evolve. Very similar problems arise in condensed matter systems, and recently it has been possible to test some of our ideas about the formation of defects using experiments with liquid helium-3 (in collaboration with the Low Temperature Laboratory in Helsinki). I shall review the present status of this theory.
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Yakovlev, Dmitry, e Alexander Kaminker. "Nearly Forgotten Cosmological Concept of E. B. Gliner". Universe 9, n. 1 (11 gennaio 2023): 46. http://dx.doi.org/10.3390/universe9010046.
Testo completoAbstract (sommario):
E. B. Gliner started his scientific career in 1963 at the age of 40. In 1965, when the existence of the cosmological constant λ seemed unnecessary to most cosmologists, he renewed interest in the problem by emphasizing a material interpretation of de Sitter space (i.e., the space curved in the presence of λ). According to that interpretation, the curvature is produced by a cosmological vacuum (now identified as dark energy of the universe). In 1970, Gliner proposed a description of exponential expansion (or contraction) of the universe at the early (or late) evolution stage dominated by cosmological vacuum. In 1975, Gliner (with I. G. Dyminikova) suggested a model of the early universe free of Big Bang singularity, and developed a scenario of nonsingular Friedmann cosmology. Many of these findings were used in the modern inflation scenarios of the universe, first proposed by A. A. Starobinsky (1979) and A. Guth (1981) and greatly multiplied later. However, these inflation scenarios differ from the scenario of Gliner and Dymnikova, and Gliner’s contribution to cosmology is nearly forgotten. The history and the essence of this contribution are outlined, as well the difference from the inflation theories.
13
Liu, Gaochao. "Study on the Star Formation History and Evolution of Early-type Galaxies and its Cosmology Application". Publications of the Astronomical Society of the Pacific 126, n. 936 (febbraio 2014): 194–95. http://dx.doi.org/10.1086/675261.
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Arbuzova, E. V. "Deviations of R2 cosmology from the Einstein’s General Relativity". International Journal of Modern Physics A 35, n. 36 (30 dicembre 2020): 2044026. http://dx.doi.org/10.1142/s0217751x20440261.
Testo completoAbstract (sommario):
The cosmological history of the universe in the [Formula: see text] gravity is studied starting from the “very beginning” up to the present time. The primordial inflationary expansion of the universe is considered and it is shown that the gravitational particle production by the oscillating curvature, [Formula: see text], led to a consistent transition to the Friedmann cosmology, but the cosmological evolution in the early universe strongly differed from the standard one. It is shown that the effects of gravitational production of particles had a significant influence on the evolution of the universe.
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Zadeh, M. Abdollahi, e A. Sheykhi. "Sign-changeable interacting agegraphic dark energy in Brans–Dicke cosmology". Canadian Journal of Physics 98, n. 7 (luglio 2020): 643–49. http://dx.doi.org/10.1139/cjp-2018-0846.
Testo completoAbstract (sommario):
We explore a spatially homogeneous and isotropic Friedmann–Robertson–Walker (FRW) universe that is filled with agegraphic dark energy (ADE) with mutual interaction with pressureless dark matter in the background of Brans–Dicke (BD) theory. We consider both original and a new type of ADE (NADE) and further assume that the sign of the interaction term can change during the history of the universe. We obtain the equation of the state parameter, the deceleration parameter, and the evolutionary equation for the sign-changeable interacting ADE and NADE in BD cosmology. We find that in both models, the equation of the state parameter, wD, cannot cross the phantom line, although they can predict the universe evolution from the early deceleration phase to the late time acceleration, compatible with observations. We also investigate the sound stability of these models and find out that both models cannot show a signal of stability for different model parameters.
16
Ayala, Lucia. "The Universe in Images: an Art-Historical Approach to the Plurality of Worlds". Culture and Cosmos 16, n. 1 and 2 (ottobre 2012): 283–303. http://dx.doi.org/10.46472/cc.01216.0247.
Testo completoAbstract (sommario):
The idea of a plurality of worlds, consolidated in the seventeenth and eighteenth centuries, is one of the most inspiring and exciting chapters in the history of astronomy. Nevertheless, one crucial aspect has yet to be written. In this paper I propose to recompose the fascinating visual mosaic around the subject, in order to establish the basis for a largely forgotten iconography. It represents a key period in the evolution of the notions around the large-scale structure of the universe, one of the milestones in Early Modern cosmology. This tradition continued until the nineteenth century, when astronomers such as William Herschel still considered the existence of multiple similar inhabited systems. Today, when extrasolar planets and the cosmic web are in the forefront of the astrophysical vocabulary and its images are so popular, reflecting on the visual genealogy of this field acquires special relevance. This paper invites the reader to look at the sky through a telescope provided with art historical lenses.
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Romanello, Massimiliano, Nicola Menci e Marco Castellano. "The Epoch of Reionization in Warm Dark Matter Scenarios". Universe 7, n. 10 (29 settembre 2021): 365. http://dx.doi.org/10.3390/universe7100365.
Testo completoAbstract (sommario):
In this paper we investigate how the Reionization process is affected by early galaxy formation in different cosmological scenarios. We use a semi-analytic model with suppressed initial power spectra to obtain the UV Luminosity Function in thermal Warm Dark Matter and sterile neutrino cosmologies. We retrace the ionization history of intergalactic medium with hot stellar emission only, exploiting fixed and variable photons escape fraction models (fesc). For each cosmology, we find an upper limit to fixed fesc, which guarantees the completion of the process at z<6.7. The analysis is tested with two limit hypothesis on high-z ionized hydrogen volume fraction, comparing our predictions with observational results.
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Williams, L. L. "Variation of the Gravitational Constant in the Radiation-Dominated Universe". Physics Research International 2012 (15 febbraio 2012): 1–4. http://dx.doi.org/10.1155/2012/567873.
Testo completoAbstract (sommario):
The unification of classical electrodynamics and general relativity within the context of five-dimensional general relativity (Kaluza, 1921, and Thiry, 1948) contains a scalar field which may be identified with the gravitational constant, G. The field equations of this theory are solved under conditions of the Robertson-Walker metric for flat space, for a radiation-dominated universe—a model appropriate for the early history of our universe. This leads to a cosmology wherein G is inversely proportional to the Robertson-Walker scale factor. This result is discussed in the context of the Dirac large number hypothesis and in the context of an expression for G in terms of atomic constants.
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Smit-Keding, Nicholas. "'Absurd' Rationalist Cosmology: Copernicus, Kepler, Descartes and the Religious Basis for the end to Aristotelian Dogma". Constellations 7, n. 1 (10 gennaio 2016): 7. http://dx.doi.org/10.29173/cons27051.
Testo completoAbstract (sommario):
Current popular narratives regarding the history of astronomy espouse the narrative of scientific development arising from clashes between observed phenomena and dogmatic religious scripture. Such narratives consider the development of our understandings of the cosmos as isolated episodes in ground-breaking, world-view shifting events, led by rational, objective and secular observers. As observation of astronomical development in the early 1600s shows, however, such a narrative is false. Developments by Johannes Kepler, for instance, followed earlier efforts by Nicholas Copernicus to refine Aristotelian-based dogma with observed phenomena. Kepler's efforts specifically were not meant to challenge official Church teachings, but offer a superior system to what was than available, based around theological justifications. Popular acceptance of a heliocentric model came not from Kepler's writings, but from the philosophical teachings of Rene Descartes. Through strictly mathematical and philosophical reasoning, Descartes not only rendered the Aristotelian model baseless in society, but also provided a cosmological understanding of the universe that centred our solar system within a vast expanse of other stars. The shift than, from the Aristotelian geocentric model to the heliocentric model, came not from clashes between theology and reason, but from negotiations between theology and observed phenomena.
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Kite, Thomas, Andrea Ravenni, Subodh P. Patil e Jens Chluba. "Bridging the gap: spectral distortions meet gravitational waves". Monthly Notices of the Royal Astronomical Society 505, n. 3 (29 maggio 2021): 4396–405. http://dx.doi.org/10.1093/mnras/stab1558.
Testo completoAbstract (sommario):
ABSTRACT Gravitational waves (GWs) have the potential to probe the entirety of cosmological history due to their nearly perfect decoupling from the thermal bath and any intervening matter after emission. In recent years, GW cosmology has evolved from merely being an exciting prospect to an actively pursued avenue for discovery, and the early results are very promising. As we highlight in this paper, spectral distortions (SDs) of the cosmic microwave background (CMB) uniquely probe GWs over six decades in frequency, bridging the gap between astrophysical high- and cosmological low-frequency measurements. This means SDs will not only complement other GW observations, but will be the sole probe of physical processes at certain scales. To illustrate this point, we explore the constraining power of various proposed SD missions on a number of phenomenological scenarios: early-universe phase transitions (PTs), GW production via the dynamics of SU(2) and ultralight U(1) axions, and cosmic string (CS) network collapse. We highlight how some regions of parameter space were already excluded with data from COBE/FIRAS , taken over two decades ago. To facilitate the implementation of SD constraints in arbitrary models, we provide GW2SD. This tool calculates the window function, which easily maps a GW spectrum to an SD amplitude, thus opening another portal for GW cosmology with SDs, with wide reaching implications for particle physics phenomenology.
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Rafelski, Johann, Jeremiah Birrell, Andrew Steinmetz e Cheng Tao Yang. "A Short Survey of Matter-Antimatter Evolution in the Primordial Universe". Universe 9, n. 7 (27 giugno 2023): 309. http://dx.doi.org/10.3390/universe9070309.
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We offer a survey of the matter-antimatter evolution within the primordial Universe. While the origin of the tiny matter-antimatter asymmetry has remained one of the big questions in modern cosmology, antimatter itself has played a large role for much of the Universe’s early history. In our study of the evolution of the Universe we adopt the position of the standard model Lambda-CDM Universe implementing the known baryonic asymmetry. We present the composition of the Universe across its temperature history while emphasizing the epochs where antimatter content is essential to our understanding. Special topics we address include the heavy quarks in quark-gluon plasma (QGP), the creation of matter from QGP, the free-streaming of the neutrinos, the vanishing of the muons, the magnetism in the electron-positron cosmos, and a better understanding of the environment of the Big Bang Nucleosynthesis (BBN) producing the light elements. We suggest but do not explore further that the methods used in exploring the early Universe may also provide new insights in the study of exotic stellar cores, magnetars, as well as gamma-ray burst (GRB) events. We describe future investigations required in pushing known physics to its extremes in the unique laboratory of the matter-antimatter early Universe.
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Ho, Shu-Yu, Pyungwon Ko e Dibyendu Nanda. "Light thermal self-interacting dark matter in the shadow of non-standard cosmology". Journal of Cosmology and Astroparticle Physics 2024, n. 04 (1 aprile 2024): 055. http://dx.doi.org/10.1088/1475-7516/2024/04/055.
Testo completoAbstract (sommario):
Abstract In this paper, we construct a viable model for a GeV scale self-interacting dark matter (DM), where the DM was thermally produced in the early universe. Here, a new vector-like fermion with a dark charge under the U(1)_D gauge symmetry serves as a secluded WIMP DM and it can dominantly annihilate into the light dark gauge boson and singlet scalar through the dark gauge interaction. Also, the self-interaction of DM is induced by the light dark gauge boson via the same gauge interaction. In addition to these particles, we further introduce two Weyl fermions and a doublet scalar, by which the dark gauge boson produced from s-wave DM annihilations can mostly decay into active neutrinos after the dark symmetry breaking such that the CMB bound on the DM with low masses can be eluded. In order to have a common parameter region to explain the observed relic abundance and self-interaction of DM, we also study this model in a non-standard cosmological evolution, where the cosmic expansion driven by a new field species is faster than the standard radiation-dominated universe during the freeze-out of DM. Reversely, one can also use the self-interacting nature of light thermal DM to examine the non-standard cosmological history of the universe.
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Zu, Lei, Chi Zhang, Hou-Zun Chen, Wei Wang, Yue-Lin Sming Tsai, Yuhsin Tsai, Wentao Luo e Yi-Zhong Fan. "Exploring mirror twin Higgs cosmology with present and future weak lensing surveys". Journal of Cosmology and Astroparticle Physics 2023, n. 08 (1 agosto 2023): 023. http://dx.doi.org/10.1088/1475-7516/2023/08/023.
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Abstract We explore the potential of precision cosmological data to study non-minimal dark sectors by updating the cosmological constraint on the mirror twin Higgs model (MTH). The MTH model addresses the Higgs little hierarchy problem by introducing dark sector particles. In this work, we perform a Bayesian global analysis that includes the latest cosmic shear measurement from the DES three-year survey and the Planck CMB and BAO data. In the early Universe, the mirror baryon and mirror radiation behave as dark matter and dark radiation, and their presence modifies the Universe's expansion history. Additionally, the scattering between mirror baryon and photon generates the dark acoustic oscillation process, suppressing the matter power spectrum from the cosmic shear measurement. We demonstrate how current data constrain these corrections to the ΛCDM cosmology and find that for a viable solution to the little hierarchy problem, the proportion of MTH dark matter cannot exceed about 30% of the total dark matter density, unless the temperature of twin photon is less than 30% of that of the standard model photon. While the MTH model is presently not a superior solution to the observed H 0 tension compared to the ΛCDM+ΔN eff model, we demonstrate that it has the potential to alleviate both the H 0 and S 8 tensions, especially if the S 8 tension persists in the future and approaches the result reported by the Planck SZ (2013) analysis. In this case, the MTH model can relax the tensions while satisfying the DES power spectrum constraint up to k ≲ 10 hMpc-1. If the MTH model is indeed accountable for the S 8 and H 0 tensions, we show that the future China Space Station Telescope (CSST) can determine the twin baryon abundance with a 10% level precision.
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Boylan-Kolchin, Michael, e Daniel R. Weisz. "Uncertain times: the redshift–time relation from cosmology and stars". Monthly Notices of the Royal Astronomical Society 505, n. 2 (31 maggio 2021): 2764–83. http://dx.doi.org/10.1093/mnras/stab1521.
Testo completoAbstract (sommario):
ABSTRACT Planck data provide precise constraints on cosmological parameters when assuming the base ΛCDM model, including a 0.17 per cent measurement of the age of the Universe, $t_0=13.797 \pm 0.023\, {\rm Gyr}$. However, the persistence of the ‘Hubble tension’ calls the base ΛCDM model’s completeness into question and has spurred interest in models such as early dark energy (EDE) that modify the assumed expansion history of the Universe. We investigate the effect of EDE on the redshift–time relation z↔t and find that it differs from the base ΛCDM model by at least ${\approx } 4{{\ \rm per\ cent}}$ at all t and z. As long as EDE remains observationally viable, any inferred t ← z or z ← t quoted to a higher level of precision do not reflect the current status of our understanding of cosmology. This uncertainty has important astrophysical implications: the reionization epoch – 10 > z > 6 – corresponds to disjoint lookback time periods in the base ΛCDM and EDE models, and the EDE value of t0 = 13.25 ± 0.17 Gyr is in tension with published ages of some stars, star clusters, and ultrafaint dwarf galaxies. However, most published stellar ages do not include an uncertainty in accuracy (due to, e.g. uncertain distances and stellar physics) that is estimated to be $\sim 7\!-\!10{{\ \rm per\ cent}}$, potentially reconciling stellar ages with $t_{0,\rm EDE}$. We discuss how the big data era for stars is providing extremely precise ages ($\lt 1{{\ \rm per\ cent}}$) and how improved distances and treatment of stellar physics such as convection could result in ages accurate to $4\!-\!5{{\ \rm per\ cent}}$, comparable to the current accuracy of t↔z. Such precise and accurate stellar ages can provide detailed insight into the high-redshift Universe independent of a cosmological model.
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Melia, Fulvio. "J1342+0928 supports the timeline in the Rh = ct cosmology". Astronomy & Astrophysics 615 (luglio 2018): A113. http://dx.doi.org/10.1051/0004-6361/201832752.
Testo completoAbstract (sommario):
Aims. The discovery of quasar J1342+0928 (z = 7.54) reinforces the time compression problem associated with the premature formation of structure in Λ cold dark matter (ΛCDM). Adopting the Planck parameters, we see this quasar barely 690 Myr after the big bang, no more than several hundred Myr after the transition from Pop III to Pop II star formation. Yet conventional astrophysics would tell us that a 10 M⊙ seed, created by a Pop II/III supernova, should have taken at least 820 Myr to grow via Eddington-limited accretion. This failure by ΛCDM constitutes one of its most serious challenges, requiring exotic “fixes”, such as anomalously high accretion rates, or the creation of enormously massive (~ 105 M⊙) seeds, neither of which is ever seen in the local Universe, or anywhere else for that matter. Indeed, to emphasize this point, J1342+0928 is seen to be accreting at about the Eddington rate, negating any attempt at explaining its unusually high mass due to such exotic means. In this paper, we aim to demonstrate that the discovery of this quasar instead strongly confirms the cosmological timeline predicted by the Rh = ct Universe. Methods. We assume conventional Eddington-limited accretion and the time versus redshift relation in this model to calculate when a seed needed to start growing as a function of its mass in order to reach the observed mass of J1342+0928 at z = 7.54. Results. Contrary to the tension created in the standard model by the appearance of this massive quasar so early in its history, we find that in the Rh = ct cosmology, a 10 M⊙ seed at z ~ 15 (the start of the Epoch of Reionization at t ~ 878 Myr) would have easily grown into an 8 × 108 M⊙ black hole at z = 7.54 (t ~ 1.65 Gyr) via conventional Eddington-limited accretion.
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Dhawan, Suhail, Justin Alsing e Sunny Vagnozzi. "Non-parametric spatial curvature inference using late-Universe cosmological probes". Monthly Notices of the Royal Astronomical Society: Letters 506, n. 1 (4 giugno 2021): L1—L5. http://dx.doi.org/10.1093/mnrasl/slab058.
Testo completoAbstract (sommario):
ABSTRACT Inferring high-fidelity constraints on the spatial curvature parameter, ΩK, under as few assumptions as possible, is of fundamental importance in cosmology. We propose a method to non-parametrically infer ΩK from late-Universe probes alone. Using Gaussian processes (GPs) to reconstruct the expansion history, we combine cosmic chronometers (CCs) and type Ia supernovae (SNe Ia) data to infer constraints on curvature, marginalized over the expansion history, calibration of the CC and SNe Ia data, and the GP hyper-parameters. The obtained constraints on ΩK are free from parametric model assumptions for the expansion history and are insensitive to the overall calibration of both the CC and SNe Ia data (being sensitive only to relative distances and expansion rates). Applying this method to Pantheon SNe Ia and the latest compilation of CCs, we find ΩK = −0.03 ± 0.26, consistent with spatial flatness at the $\mathcal {O}(10^{-1})$ level, and independent of any early-Universe probes. Applying our methodology to future baryon acoustic oscillations and SNe Ia data from upcoming Stage IV surveys, we forecast the ability to constrain ΩK at the $\mathcal {O}(10^{-2})$ level.
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Stevens, Jordan, Hasti Khoraminezhad e Shun Saito. "Constraining the spatial curvature with cosmic expansion history in a cosmological model with a non-standard sound horizon". Journal of Cosmology and Astroparticle Physics 2023, n. 07 (1 luglio 2023): 046. http://dx.doi.org/10.1088/1475-7516/2023/07/046.
Testo completoAbstract (sommario):
Abstract Spatial curvature is one of the most fundamental parameters in our current concordance flat ΛCDM model of the Universe. The goal of this work is to investigate how the constraint on the spatial curvature is affected by an assumption on the sound horizon scale. The sound horizon is an essential quantity to use the standard ruler from the Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations (BAOs). As an example, we study the curvature constraint in an axion-like Early Dark Energy (EDE) model in light of recent cosmological datasets from Planck, the South Pole Telescope (SPT), and the Atacama Cosmology Telescope (ACT), as well as BAO data compiled in Sloan Digital Sky Survey Data Release 16. We find that, independent of the CMB datasets, the EDE model parameters are constrained only by the CMB power spectra as precisely and consistently as the flat case in previous work, even with the spatial curvature. We also demonstrate that combining CMB with BAO is extremely powerful to constrain the curvature parameter even with a reduction of the sound-horizon scale in an EDE model, resulting in Ω K = -0.0058± 0.0031 in the case of ACT+BAO after marginalizing over the parameters of the EDE model. This constraint is as competitive as the Planck+BAO result in a ΛCDM model, Ω K = -0.0001± 0.0018.
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Garau, Rodolfo. "Explaining Astrological Influence with Cartesian Natural Philosophy: Peter Megerlin’s Manuscript Astrologia Cartesiana (ASHB1530, circa 1680)". Early Science and Medicine 27, n. 5 (29 novembre 2022): 486–525. http://dx.doi.org/10.1163/15733823-20220058.
Testo completoAbstract (sommario):
Abstract Action at a distance was one of the key features of astrology. Once a thriving discipline, astrology in the early modern period entered a crisis that ultimately culminated in its marginalization from the domain of scholarly recognition. Critics of astrology took issue, among other things, with the causative process of the supposed astrological action at a distance – traditionally based on the light shed by celestial bodies – denying that light could be a conduit of astrological influence. In response to such criticisms, some astrologers attempted to explain astrological influence based on different theoretical and natural-philosophical foundations, as, for instance, by employing Cartesianism. This paper focuses on the so far-unpublished manuscript Laurenziana ASHB1530, Astrologia Cartesiana, by the German astronomer, mathematician and astrologer Peter Megerlin (1623–1686), a professor in Basel. It shows Megerlin’s eclectic use of Cartesian elements in his treatment of the natural-philosophical bases of astrology, paying particular attention to his attempt to explain astrological influence on corpuscularian grounds. It also contributes to the reconstruction of Megerlin’s biographical and scholarly profile, focusing on the significance of his engagement with Copernican cosmology and astrology in seventeenth-century Basel.
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An, Rui, Vera Gluscevic, Erminia Calabrese e J. Colin Hill. "What does cosmology tell us about the mass of thermal-relic dark matter?" Journal of Cosmology and Astroparticle Physics 2022, n. 07 (1 luglio 2022): 002. http://dx.doi.org/10.1088/1475-7516/2022/07/002.
Testo completoAbstract (sommario):
Abstract The presence of light thermally coupled dark matter affects early expansion history and production of light elements during the Big Bang Nucleosynthesis. Specifically, dark matter that annihilates into Standard Model particles can modify the effective number of light species in the universe N eff, as well as the abundance of light elements created buring BBN. These quantities in turn affect the cosmic microwave background (CMB) anisotropy. We present the first joint analysis of small-scale temperature and polarization CMB anisotropy from Atacama Cosmology Telescope (ACT) and South Pole Telescope (SPT), together with Planck data and the recent primordial abundance measurements of helium and deuterium to place comprehensive bounds on the mass of light thermal-relic dark matter. We consider a range of models, including dark matter that couples to photons and Standard-Model neutrinos. We discuss the sensitivity of the inferred mass bounds on measurements of N eff, primordial element abundances and the baryon density, and quantify the sensitivity of our results to a possible existence of additional relativistic species. We find that the combination of ACT, SPT, and Planck generally leads to the most stringent mass constraint for dark matter that couples to neutrinos, improving the lower limit by 40%–80%, with respect to previous Planck analyses. On the other hand, the addition of ACT and SPT leads to a slightly weaker bound on electromagnetically coupled particles, due to a shift in the preferred values of Y p and N eff driven by the ground based experiments. In most scenarios, the combination of CMB data has a higher constraining power than the primordial abundance measurements alone, with the best results achieved when all data are combined. Combining all CMB measurements with primordial abundance measurements, we rule out masses below ∼4 MeV at 95% confidence, for all models. We show that allowing for new relativistic species can weaken the mass bounds for dark matter that couples to photons by up to an order of magnitude or more. Finally, we discuss the reach of the next generation of the CMB experiments in terms of probing the mass of the thermal relic dark matter.
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Arias, Paola, Nicolás Bernal, Dimitrios Karamitros, Carlos Maldonado, Leszek Roszkowski e Moira Venegas. "New opportunities for axion dark matter searches in nonstandard cosmological models". Journal of Cosmology and Astroparticle Physics 2021, n. 11 (1 novembre 2021): 003. http://dx.doi.org/10.1088/1475-7516/2021/11/003.
Testo completoAbstract (sommario):
Abstract We study axion dark matter production from a misalignment mechanism in scenarios featuring a general nonstandard cosmology. Before the onset of Big Bang nucleosynthesis, the energy density of the universe is dominated by a particle field ϕ described by a general equation of state ω. The ensuing enhancement of the Hubble expansion rate decreases the temperature at which axions start to oscillate, opening this way the possibility for axions heavier than in the standard window. This is the case for kination, or in general for scenarios with ω > 1/3. However, if ω < 1/3, as in the case of an early matter domination, the decay of ϕ injects additional entropy relative to the case of the standard model, diluting this way the preexisting axion abundance, and rendering lighter axions viable. For a misalignment angle 0.5 < θ_i < π/√(3), the usual axion window becomes expanded to 4 × 10-9 eV ≲ ma ≲ 2 × 10-5 eV for the case of an early matter domination, or to 2 × 10-6 eV ≲ ma ≲ 10-2 eV for the case of kination. Interestingly, the coupling axion-photon in such a wider range can be probed with next generation experiments such as ABRACADABRA, KLASH, ADMX, MADMAX, and ORGAN. Axion dark matter searches may therefore provide a unique tool to probe the history of the universe before Big Bang nucleosynthesis.
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SUNYAEV, RASHID A., e RISHI KHATRI. "UNAVOIDABLE CMB SPECTRAL FEATURES AND BLACKBODY PHOTOSPHERE OF OUR UNIVERSE". International Journal of Modern Physics D 22, n. 07 (giugno 2013): 1330014. http://dx.doi.org/10.1142/s0218271813300140.
Testo completoAbstract (sommario):
Spectral features in the CMB energy spectrum contain a wealth of information about the physical processes in the early Universe, z ≲ 2 × 106. The CMB spectral distortions are complementary to all other probes of cosmology. In fact, most of the information contained in the CMB spectrum is inaccessible by any other means. This review outlines the main physics behind the spectral features in the CMB throughout the history of the Universe, concentrating on the distortions which are inevitable and must be present at a level observable by the next generation of proposed CMB experiments. The spectral distortions considered here include spectral features from cosmological recombination, resonant scattering of CMB by metals during reionization which allows us to measure their abundances, y-type distortions during and after reionization and μ-type and i-type (intermediate between μ and y) distortions created at redshifts z ≳ 1.5 × 104.
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Cunningham, Clifford. "<italic>Cosmology in the Early Modern Age: A Web of Ideas</italic>, by Paolo Bussotti and Brunello Lotti." Journal of Astronomical History and Heritage 26, n. 2 (1 giugno 2023): 533–35. http://dx.doi.org/10.3724/sp.j.1440-2807.2023.06.56.
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Heurtier, L., A. Moursy e L. Wacquez. "Cosmological imprints of SUSY breaking in models of sgoldstinoless non-oscillatory inflation". Journal of Cosmology and Astroparticle Physics 2023, n. 03 (1 marzo 2023): 020. http://dx.doi.org/10.1088/1475-7516/2023/03/020.
Testo completoAbstract (sommario):
Abstract In supergravity, the dynamics of the sgoldstino – superpartner of the goldstino superfield associated with the breaking of supersymmetry at low energy – can substantially modify the dynamics of inflation in the primordial Universe. So-called sgoldstinoless models assume the existence of a nilpotency constraint S 2 = 0 that effectively removes the sgoldstino from the theory. Such models were proposed to realise non-oscillatory inflation scenarios with a single scalar field, which feature a long period of kination at the end of inflation, and therefore a non-standard post-inflationary cosmology. Using effective operators, we propose models in which the sgoldstino is stabilized close to the origin to reproduce the nilpotent constraint. We show that small sgoldstino fluctuations may lead to a sizeable back-reaction on the cosmological history. We study the effect of this back-reaction on the inflation observables measured in the cosmic microwave background and confront the model to a series of constraints including limits on ΔN eff. We show that the peculiar form of the potential in the large supersymmetry breaking scale limit can generate peaks in the scalar power spectrum produced from inflation. We study how certain perturbation modes may re-enter the horizon during or after kination and show that a large supersymmetry breaking scale may lead to the formation of primordial black holes with various masses in the early Universe.
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Cunningham, Clifford. "<italic>Unifying Heaven and Earth: Essays in the History of Early Modern Cosmology</italic>, edited by Miguel Granada, Patrick Boner and Dario Tessicini." Journal of Astronomical History and Heritage 23, n. 1 (1 aprile 2020): 219–20. http://dx.doi.org/10.3724/sp.j.1440-2807.2020.01.12.
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Korol, V., S. Toonen, A. Klein, V. Belokurov, F. Vincenzo, R. Buscicchio, D. Gerosa et al. "Populations of double white dwarfs in Milky Way satellites and their detectability with LISA". Astronomy & Astrophysics 638 (giugno 2020): A153. http://dx.doi.org/10.1051/0004-6361/202037764.
Testo completoAbstract (sommario):
Context. Milky Way dwarf satellites are unique objects that encode the early structure formation and therefore represent a window into the high redshift Universe. So far, their study has been conducted using electromagnetic waves only. The future Laser Interferometer Space Antenna (LISA) has the potential to reveal Milky Way satellites through gravitational waves emitted by double white dwarf (DWD) binaries. Aims. We investigate gravitational wave signals that will be detectable by LISA as a possible tool for the identification and characterisation of the Milky Way satellites. Methods. We used the binary population synthesis technique to model the population of DWDs in dwarf satellites and we assessed the impact on the number of LISA detections when making changes to the total stellar mass, distance, star formation history, and metallicity of satellites. We calibrated predictions for the known Milky Way satellites on their observed properties. Results. We find that DWDs emitting at frequencies ≳3 mHz can be detected in Milky Way satellites at large galactocentric distances. The number of these high frequency DWDs per satellite primarily depends on its mass, distance, age, and star formation history, and only mildly depends on the other assumptions regarding their evolution such as metallicity. We find that dwarf galaxies with M⋆ > 106 M⊙ can host detectable LISA sources; the number of detections scales linearly with the satellite’s mass. We forecast that out of the known satellites, Sagittarius, Fornax, Sculptor, and the Magellanic Clouds can be detected with LISA. Conclusions. As an all-sky survey that does not suffer from contamination and dust extinction, LISA will provide observations of the Milky Way and dwarf satellites galaxies, which will be valuable for Galactic archaeology and near-field cosmology.
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Zuccato, Marco. "Bruce S. Eastwood. Ordering the Heavens: Roman Astronomy and Cosmology in the Carolingian Renaissance. (History of Science and Medicine Library, 4; Medieval and Early Modern Science, 8.) xxii + 452 pp., figs., app., bibl., index. Leiden: Brill, 2007. €99 (cloth)." Isis 99, n. 4 (dicembre 2008): 823–24. http://dx.doi.org/10.1086/597690.
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Bothun, G. "The motion of test particles and cosmological interpretations: the role of MOND". Canadian Journal of Physics 93, n. 2 (febbraio 2015): 139–50. http://dx.doi.org/10.1139/cjp-2014-0165.
Testo completoAbstract (sommario):
Throughout history, observations of the motions of objects in the Universe have provided the foundation for various cosmological models. In many cases, the invoked causes of the observed motion appeal to mysterious elements. Indeed, the very first test motion was that of the retrograde motion of Mars, which lead to a required epicycle to save the model (e.g., Ptolemy’s unmoving Earth). By the early 1840s, from approximately 50 years of orbital data (since its 1789 discovery) it was apparent that Uranus was disobeying the Newtonian rules in its orbit and speculation mounted that a “large unseen mass” was perturbing the orbit. Using Uranus as a test particle then yields the first notion of dark matter (DM). Alas, it was not DM but merely Neptune, discovered in September 1846. By 1859 enough data had been gathered to reveal that Mercury is also not obeying Newtonian physics but rather revealing curved space–time. The continuation of this history is now set in scales larger than the Solar System. Observations suggest two basic choices: (i) gravity is fully understood and Newton’s second law is invariant (except in very strong gravity) and observed motions on galactic scales require the existence of DM (a currently unproven “epicycle”) or (ii) Newton’s second law can be modified (e.g., MOND) in certain low acceleration scale environments. In this contribution we discuss the case for and against MOND on various scales and conclude that neither MOND nor our current cosmology (ΛCDM) consistently explain all observed phenomena. In general, MOND works much better on small scales than ΛCDM but encounters difficulties on large scales. Moreover, the nature of the acoustic power spectrum of the CMB now pretty clearly shows that a fully baryonic Universe is ruled out, thus necessitating some DM component. But this should not diminish the consideration of MOND as its introduced acceleration scale; ao is fully consistent with the observed structural properties of galaxies in a way that the DM halo paradigm cannot match. Indeed, despite many attempts to falsify MOND, it has always come back from its proclaimed death to provide unique insights into the gravitational nature of galaxies, consistently raising the specter that our current understanding of gravity acting over large spatial scales may be flawed.
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Motsnyi, F. V. "Nobel Prize Level Scientific Discoveries of a Heir of Zaporizhian Cossacks". Statistics of Ukraine 88, n. 1 (8 maggio 2020): 131–38. http://dx.doi.org/10.31767/su.1(88)2020.01.15.
Testo completoAbstract (sommario):
In this work, three fundamental discoveries of the Ukraine-born Prof. George A. Gamow are presented from a single scientific and methodological point of view. Each of them is truly worth of the Nobel Prize – the most prestigious recognition of achievements of a scientist.
We trace the emergence of G. Gamow as one of the most outstanding scientists of the twentieth century – encyclopaedist, theoretical physicist by heart, astrophysicist and biophysicist, talented and brilliant popularizer of science, whose works are readable in one go, as well as the author of unforgettable pranks and jokes.
Gamow was a Fellow of the Danish Royal Academy of Sciences, the American Academy of Arts and Sciences, the International Astronomical Union, the American Physical Society, an honorary doctor of countless universities. Although his name is little known in Ukraine, the history of science would be incomplete without him.
From an early age G. Gamow has shown a great interest in scientific research, using a microscope to look for erythrocytes and a telescope to observe the Halley comet. He graduated from the Faculty of Physics and Mathematics of Leningrad State University, where he followed classes of Professor O. Friedman, founder of the evolutionary cosmology. He has undergone training at the University of Goettingen, the center of theoretical physics at the time, worked for Nobel Prize winners Professors E. Rutherford and N. Bohr. At the age of 28, G. Gamow, by the recommendation of academician V. Vernadskyi, became the member of the Academy of Sciences of USSR, the youngest member in the entire history of its existence.
Throughout his life, G. Gamow was interested in the fundamental scientific problems and made numerous world-class discoveries that are written by golden letters in the treasury of the human civilization. He has found explanation to the E. Rutherford’s experiments with alpha particles (tunnelling effect); introduced the empirical formula of Geiger – Nettoll, connecting the energy of alpha particles to the half-life of radioactive nuclei. G. Gamow is one of the pioneers of the liquid-drop model of a nucleus, and the application of nuclear physics to the evolution of stars. He proposed a fantastic hypothesis about the early universe, suggesting it being not only super dense but also very hot. He also built the Big Bang theory, which led to the existence of relic radiation (space microwave background) with the characteristic temperature of 5–7 degrees above the absolute zero, detected by methods of radio astronomy. He proposed a triplet model of the genetic code - the alphabet of life with three-letter words, experimentally proven by X-ray structural studies of DNA and empirically established rules of E. Chargaff. These discoveries have greatly contributed not only to the development of the modern science, but to the industrial and economic expansion of humanity.
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Arendse, Nikki, Radosław J. Wojtak, Adriano Agnello, Geoff C. F. Chen, Christopher D. Fassnacht, Dominique Sluse, Stefan Hilbert et al. "Cosmic dissonance: are new physics or systematics behind a short sound horizon?" Astronomy & Astrophysics 639 (luglio 2020): A57. http://dx.doi.org/10.1051/0004-6361/201936720.
Testo completoAbstract (sommario):
Context. Persistent tension between low-redshift observations and the cosmic microwave background radiation (CMB), in terms of two fundamental distance scales set by the sound horizon rd and the Hubble constant H0, suggests new physics beyond the Standard Model, departures from concordance cosmology, or residual systematics. Aims. The role of different probe combinations must be assessed, as well as of different physical models that can alter the expansion history of the Universe and the inferred cosmological parameters. Methods. We examined recently updated distance calibrations from Cepheids, gravitational lensing time-delay observations, and the tip of the red giant branch. Calibrating the baryon acoustic oscillations and type Ia supernovae with combinations of the distance indicators, we obtained a joint and self-consistent measurement of H0 and rd at low redshift, independent of cosmological models and CMB inference. In an attempt to alleviate the tension between late-time and CMB-based measurements, we considered four extensions of the standard ΛCDM model. Results. The sound horizon from our different measurements is rd = (137 ± 3stat. ± 2syst.) Mpc based on absolute distance calibration from gravitational lensing and the cosmic distance ladder. Depending on the adopted distance indicators, the combined tension in H0 and rd ranges between 2.3 and 5.1 σ, and it is independent of changes to the low-redshift expansion history. We find that modifications of ΛCDM that change the physics after recombination fail to provide a solution to the problem, for the reason that they only resolve the tension in H0, while the tension in rd remains unchanged. Pre-recombination extensions (with early dark energy or the effective number of neutrinos Neff = 3.24 ± 0.16) are allowed by the data, unless the calibration from Cepheids is included. Conclusions. Results from time-delay lenses are consistent with those from distance-ladder calibrations and point to a discrepancy between absolute distance scales measured from the CMB (assuming the standard cosmological model) and late-time observations. New proposals to resolve this tension should be examined with respect to reconciling not only the Hubble constant but also the sound horizon derived from the CMB and other cosmological probes.
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Boccaletti, Dino. "The Waters above the Firmament: An Exemplary Case of Faith-Reason Conflict". Perspectives on Science and Christian Faith 73, n. 3 (settembre 2021): 166–68. http://dx.doi.org/10.56315/pscf9-21boccaletti.
Testo completoAbstract (sommario):
THE WATERS ABOVE THE FIRMAMENT: An Exemplary Case of Faith-Reason Conflict by Dino Boccaletti. Cham, Switzerland: Springer, 2020. 136 pages. Hardcover; $99.99. ISBN: 9783030441678. Paperback; $69.99. ISBN: 9783030441685. *The Waters Above the Firmament is a fascinating tour through the exegetical history of an offbeat subject: the waters above the firmament. In both popular and scholarly conversations about science and religion, a few subjects tend to dominate the landscape, with the topic of origins dominating the conversation since Darwin's day. Interestingly, however, the "waters above the firmament" references have been largely overlooked, even though they bear on the cosmology and view of creation held by biblical authors. In this volume, physicist Dino Boccaletti takes readers through an in-depth tour of how these passages have been understood by Christian exegetes from the early centuries of the Christian era through the seventeenth century. *The driving question tackled by the exegetes is how to understand the following verses from the first chapter of the book of Genesis: "And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters. And God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament: and it was so. And God called the firmament Heaven. And the evening and the morning were the second day" (Gen. 1:6-8, KJV). *In the history of exegesis of this passage (and others that build on it, such as Psalm 148:4, "Praise him, ye heavens of heavens, and ye waters that be above the heavens"), many different theories about its meaning have been put forward. In our own day, those familiar with the young-earth creation (YEC) movement may have heard a bit of exegesis of this passage from a peculiarly YEC point of view. In their hands, it is sometimes understood to teach that the earth was surrounded by a canopy of water that made the whole world a paradise and reduced the harmful effects of the sun, enabling people to live the centuries-long lives described in Genesis. The canopy was then collapsed to become the source of the waters that flooded the earth in the days of Noah. *Boccaletti does not address that claim. Instead, he presents a historical overview that marches chronologically through the works of classical, medieval, and early modern commentators, trying to interpret a claim that seems to be plainly contradictory to common sense: that there is a shell of water surrounding the earth, or maybe the whole cosmos. While there was no definitive scientific refutation of this view in either the classical or medieval world, its prima facie implausibility nevertheless led to a persistent apparent conflict between faith and reason that needed to be contended with if the Bible's authority was to remain intact. There is also the thorny question of uncovering the cosmology that gave rise to such a description, along with its background in extra-biblical writings. *Boccaletti describes the first few centuries of Christianity, during which there were primarily three approaches to understanding the passage in question. First, it could be allegorized so that the waters were representative of something else, such as exalted spiritual beings who worship God. The second approach was to accept something like an ancient Near Eastern belief that the earth is shaped like a flat disc, and add the literal claim that there is an aqueous shell above it. The third, and most difficult, was to try to reconcile Greek cosmology with the claim about the waters. Incorporating the Greek picture, which posited a spherical earth at the center of the cosmos, led to the most creative, and sometimes convoluted, interpretive schemes. For example, Boccaletti brings us into Augustine's discussion about a theory that the waters above the firmament are held in place by God in order to cool and slow down the movement of the outer planets, which would otherwise overheat owing to their great velocities. Thus the waters above the firmament might serve to temper the heat of the empyrean. While many exegetes in the first millennium would also endorse this view or a variation on it, some thinkers, such as John Scotus Eriugena, would deny that such waters existed at all. No consensus was reached during the Middle Ages about which of these approaches was superior. *Boccaletti describes the increasing pressure to abandon the geocentric model owing to sixteenth- and seventeenth-century astronomers such as Copernicus and Galileo, and how those theories in astronomy were received by interpreters of the Bible. For reasons unrelated to science, Protestant thinkers such as Luther and Calvin began to consult sources outside the Latin interpretive tradition, most significantly the Hebrew text in which Genesis was originally written. Both men considered it vital to embrace the highest possible view of biblical authority, and inclined toward believing the waters were just that: waters, held in place in the heavenlies by a mysterious work of God. Allegories were rejected, as was the burgeoning heliocentrism of the day. Catholic interpreters of the period such as Benedictus Pererius and David Pareus also turned back to the Hebrew text, freeing themselves from the strictures of the Latin Vulgate of Jerome and its limitations about what firmamentum might mean. Thus they could posit that Moses's teaching in Hebrew, aimed at the everyman of his day, was consistent with the reasonable, common-sense claim that the waters above the firmament are just clouds, making the firmament the sky rather than the outer heavens. *Boccaletti does an excellent job of collecting the sources that address the passage in question. The book contains innumerable lengthy quotations that give context to the exegetes' perspectives, and he also provides helpful background to each thinker. There are over thirty interpreters presented in depth, scores more referred to, and abundant primary source materials. Boccaletti adds helpful commentary and interpretation of his own, including a nice comparison of the cosmology of Moses and the Greeks, guiding the reader through the development of interpretive movements and then situating them in their historical setting. In fact, if there is a complaint it might be that there is much more background than is needed to understand the various interpretations in question--but those who love history will revel in his thoroughness. *Despite Boccaletti's comprehensiveness and attention to detail, there were a few things a reader might expect to find that were not a part of this work. Billing itself as "An Exemplary Case of Faith-Reason Conflict," one might have anticipated more depth of analysis of the underlying methodological, epistemic, and exegetical issues. There were descriptions of some of those things, but they were not very well developed. Readers looking to get some new insights into those aspects of faith-reason conflicts--looking for a beefier treatment of theology and philosophy--will likely be disappointed. Along those lines, it is not at all clear what Boccaletti thinks we should take away from his careful study about faith-reason conflicts. What should we conclude? What are the lessons? He does not make it clear. The book is rich with history and primary sources, but very light on insight about the nature of science-religion tensions and how to resolve them; those looking for a new angle on these perennial problems may need to look elsewhere. But for those who desire to immerse themselves in all the intriguing commentary about the waters above the firmament throughout the first seventeen centuries of Christian history, this book will be a real treat. *Reviewed by Bradley L. Sickler, University of Northwestern, St. Paul, MN 55113
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Shrimplin, Valerie. "Francesco Borromini and the Cultural Context of Kepler’s Harmonice Mundi". Culture and Cosmos 25, n. 0102 (ottobre 2021): 107–23. http://dx.doi.org/10.46472/cc.01225.0211.
Testo completoAbstract (sommario):
The idea of circular domed architecture as imitative of the flat earth covered by the 'Dome of Heaven' was established from Byzantine times up to its revival during the Renaissance. Yet the cosmological symbolism of the circular dome was replaced in the early seventeenth century when elliptical, oval or other geometrically-inspired domes became a key feature of the Baroque. The move away from circular to oval or elliptical forms by architects such as Borromini coincides with the new cosmology and Kepler's view of elliptical orbits as the basis for the structure of the universe. Building on his Mysterium Cosmographicum (1596) and the view of perfect, regular nested solids as the basis for the organisation of the planets, Kepler focused on the ellipse as underlying the mechanics of the universe. His realisation that the universe was not based on perfect circular motion but on elliptical orbits (with the sun at one of the foci) was developed in Harmonice Mundi, linked to concepts of harmony and proportion. In turn, the work of the architect Borromini (as at S. Carlo alle Quattro Fontane 1638-41 and S. Ivo della Sapienza 1642) involve novel and complex geometric designs that significantly align Kepler's astronomical ideas. Mathematical precision underlies Borromini's seemingly extravagant schemes, in the same way that Kepler's theories sought harmony in the universe. Documentary evidence to substantiate a claim of the influence of Kepler’s theories on Borromini has yet to be found. However, it is significant that Borromini's patron in Rome was Cardinal Barberini (later Pope Urban VIII) who was well-known for his interest in astronomy. Kepler's mathematical methodology and interpretation of the geometrical structure of the universe may have appealed to Borromini and his patrons on many levels. It cannot be mere coincidence that the use of such mathematical forms in ecclesiastical architecture comes in at around the same times as Kepler's writings.
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Verde, Licia, Emilio Bellini, Cassio Pigozzo, Alan F. Heavens e Raul Jimenez. "Early cosmology constrained". Journal of Cosmology and Astroparticle Physics 2017, n. 04 (13 aprile 2017): 023. http://dx.doi.org/10.1088/1475-7516/2017/04/023.
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Filloux, Charline, J. A. de Freitas Pacheco, Fabrice Durier e Joseph Silk. "Evolution of Supermassive Black Holes". Proceedings of the International Astronomical Union 5, S267 (agosto 2009): 202. http://dx.doi.org/10.1017/s1743921310006228.
Testo completoAbstract (sommario):
Cosmological simulations describing both the evolution of supermassive black holes and their host galaxies were performed by using the tree PM-SPH code GADGET-2 (Springel 2005). Physical mechanisms affecting the dynamics and the physical conditions of the gas (ionization and cooling processes, local heating by stars, injection of mechanical energy by supernovae, chemical enrichment) were introduced in the present version of the code (Filloux 2009). Black holes in a state of accretion (AGNs) also inject mechanical energy in the surrounding medium, contributing for quenching the star formation activity. In all simulations a ΛCDM cosmology was adopted (h = 0.7, ΩΛ=0.7, Ωm=0.3, Ωb=0.046 and σ8=0.9). Simulations were performed in a volume with a side of 50h−1 Mpc, starting at z = 50 and through the present time (z = 0). For low and intermediate resolution runs, the initial gas mass particles are respectively 5.35× 108M⊙ and 3.09×108M⊙. Black holes (BHs) are represented by collisionless particles and seeds of 100 M⊙ were introduced in density peaks at z = 15, growing either by accretion or coalescence. The accretion rate from the “disk mode” is based on a turbulent viscous thin disk model whereas in the “spherical mode” the rate is given by the Bondi–Hoyle formula. When accreting matter, jets, modeled by conical regions perpendicular to the disk plane, inject kinetic energy into the surrounding medium. Two models were tested: in the first, the injected energy rate is about 10% of the gravitational energy rate released in the accretion process while in the second, the injected energy rate is based on the Blandford & Znajek (1977) mechanism. All simulations give, at z = 0, similar black hole mass function but they overestimate slightly the BH density for masses above ~ 108M⊙. The resulting BH density in this mass range is affected by feedback processes since they control the amount of gas available for accretion. The present simulations are not able to produce very massive BHs (~109M⊙) at z ~ 6. However the evolution of the BH mass density derived from our simulations are in quite good agreement with that derived from the QSO luminosity function. This indicates that our simulations reproduce quite well the average accretion rate history of BHs. Correlations between the BH mass and properties of the host galaxy (velocity dispersion for bulge systems or the stellar mass or the dark halo mass) are also well reproduced. In conclusion, these exploratory simulations reproduce the data at z = 0 quite well. However, the present adopted recipe for the accretion rate in the “disk mode” seems to be inefficient to produce massive BHs as early as z ~ 6. Higher resolution simulations including a new approach for modeling the “disk mode” are presently under way and that particular difficulty is expected to be solved.
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Loewe, Michael, e Henry Rosemont. "Explorations in Early Chinese Cosmology". Numen 33, n. 1 (giugno 1986): 171. http://dx.doi.org/10.2307/3270131.
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Rosito, M. S., P. B. Tissera, S. E. Pedrosa e Y. Rosas-Guevara. "Assembly of spheroid-dominated galaxies in the EAGLE simulation". Astronomy & Astrophysics 629 (settembre 2019): A37. http://dx.doi.org/10.1051/0004-6361/201834720.
Testo completoAbstract (sommario):
Context. Despite the insights gained in the last few years, our knowledge about the formation and evolution scenario for the spheroid-dominated galaxies is still incomplete. New and more powerful cosmological simulations have been developed that together with more precise observations open the possibility of more detailed study of the formation of early-type galaxies (ETGs). Aims. The aim of this work is to analyse the assembly histories of ETGs in a Λ cold dark matter cosmology, focussing on the archeological approach given by the mass-growth histories. Methods. We inspected a sample of dispersion-dominated galaxies selected from the largest volume simulation of the EAGLE project. This simulation includes a variety of physical processes such as radiative cooling, star formation (SF), metal enrichment, and stellar and active galactic nucleus (AGN) feedback. The selected sample comprised 508 spheroid-dominated galaxies classified according to their dynamical properties. Their surface brightness profile, the fundamental relations, kinematic properties, and stellar-mass growth histories are estimated and analysed. The findings are confronted with recent observations. Results. The simulated ETGs are found to globally reproduce the fundamental relations of ellipticals. All of them have an inner disc component where residual younger stellar populations (SPs) are detected. A correlation between the inner-disc fraction and the bulge-to-total ratio is reported. We find a relation between kinematics and shape that implies that dispersion-dominated galaxies with low V/σL (where V is the average rotational velocity and σL the one dimensional velocity dispersion) tend to have ellipticity smaller than ∼0.5 and are dominated by old stars. On average, less massive galaxies host slightly younger stars. More massive spheroids show coeval SPs while for less massive galaxies (stellar masses lower than ∼1010 M⊙), there is a clear trend to have rejuvenated inner regions, showing an age gap between the inner and the outer regions up to ∼2 Gyr, in apparent contradiction with observational findings. We find evidences suggesting that both the existence of the disc components with SF activity in the inner region and the accretion of satellite galaxies in outer regions could contribute to the outside-in formation history in galaxies with low stellar mass. On the other hand, there are non-negligible uncertainties in the determination of the ages of old stars in observed galaxies. Stronger supernova (SN) feedback and/or the action of AGN feedback for galaxies with stellar masses lower than 1010 M⊙ could contribute to prevent the SF in the inner regions.
46
Vukovic, Ivan. "Kant's early theology, cosmology and cosmogony". Theoria, Beograd 47, n. 1-2 (2004): 51–78. http://dx.doi.org/10.2298/theo0402051v.
Testo completoAbstract (sommario):
The author of this paper analyses the theological, cosmological and cosmogonical ideas that Kant defended in his first book, The General History of Nature and Theory of Heavens, and claims that they were the result of his attempt to synthetise Leibnitzian theology with Newtonian physics. Furthermore, the author claims that these early ideas are the source of Kant's later conceptions of morality, law and history of human race.
47
Liu, Lihui. "Moduli stabilisation in early superstring cosmology". Journal of Physics: Conference Series 343 (8 febbraio 2012): 012068. http://dx.doi.org/10.1088/1742-6596/343/1/012068.
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Singh, C. P. "Bulk viscous cosmology in early Universe". Pramana 71, n. 1 (luglio 2008): 33–48. http://dx.doi.org/10.1007/s12043-008-0139-4.
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49
Lilly, Simon, Rachel L. Webster, L. Campusano, S. Charlot, L. DaCosta, D. Koo, O. Lahav et al. "Commission 47: Cosmology". Proceedings of the International Astronomical Union 1, T26A (dicembre 2005): 291–98. http://dx.doi.org/10.1017/s1743921306004728.
Testo completoAbstract (sommario):
Abstract2002–2005 has seen rapid progress in cosmology with the publication of the 1st year WMAP results and analyses of large scale red-shift surveys, ushering in an era of “precision cosmology”. There has been steady progress, too, in the discovery and study of quasars and galaxies in the early Universe.
50
Audren, Benjamin, Julien Lesgourgues, Karim Benabed e Simon Prunet. "Conservative constraints on early cosmology with MONTEPYTHON". Journal of Cosmology and Astroparticle Physics 2013, n. 02 (4 febbraio 2013): 001. http://dx.doi.org/10.1088/1475-7516/2013/02/001.
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