Astronomical Quantities Research Articles

A Critical Examination of the Standard Cosmological Model: Toward a Modified Framework for Explaining Cosmic Structure Formation and Evolution

This paper explores the fundamental cosmological principle, with a specific focus on the homogeneity and isotropy assumptions inherent in the Friedmann model that underpins the standard model. We propose a modified redshift model that is based on the spatial distribution of luminous matter, examining three key astronomical quantities: light intensity, number density, and the redshift of galaxies. Our analysis suggests that the model can account for cosmic accelerated expansion without the need for dark energy in the equations. Both simulations and analytical solutions reveal a unique pattern in the formation and evolution of cosmic structures, particularly in galaxy formation. This pattern shows a significant burst of activity between redshifts 0 < z < 0.4, which then progresses rapidly until approximately z ≈ 0.9, indicating that the majority of cosmic structures were formed during this period. Subsequently, the process slows down considerably, reaching a nearly constant rate until around z ≈ 1.6, after which a gradual decline begins. We also observe a distinctive redshift transition around z ≈ 0.9 before the onset of dark-matter-induced accelerated expansion. This transition is directly related to the matter density and is dependent on the geometry of the universe. The model’s ability to explain cosmic acceleration without requiring fine tuning of the cosmological constant highlights its novelty, providing a fresh perspective on the dynamic evolution of the universe.

Updated values of solar gravitational moments J2n using HMI helioseismic inference of internal rotation

ABSTRACT The solar gravitational moments J2n are important astronomical quantities whose precise determination is relevant for solar physics, gravitational theory and high precision astrometry, and celestial mechanics. Accordingly, we propose in the present work to calculate new values of J2n (for n = 1, 2, 3, 4, and 5) using recent two-dimensional rotation rates inferred from the high-resolution Solar Dynamics Observatory / Helioseismic and Magnetic Imager helioseismic data spanning the whole solar activity cycle 24. To this aim, a general integral equation relating J2n to the solar internal density and rotation is derived from the structure equations governing the equilibrium of slowly rotating stars. For comparison purpose, the calculations are also performed using rotation rates obtained from a recently improved analysis of Solar and Heliospheric Observatory / Michelson Doppler Imager heliseismic data for solar cycle 23. In agreement with earlier findings, the results confirmed the sensitivity of high-order moments (n > 1) to the radial and latitudinal distribution of rotation in the convective zone. The computed value of the quadrupole moment J2 (n = 1) is in accordance with recent measurements of the precession of Mercury’s perihelion deduced from high precision ranging data of the MESSENGER spacecraft. The theoretical estimate of the related solar oblateness Δ⊙ is consistent with the most accurate space-based determinations, particularly the one from Reuven Ramathy High-Energy Solar Spectroscopic Imager/Solar Aspect Sensor.

Annexing Marginal Soils for Agricultural Cultivation Using an Organic Source of Fertilizer as a Bioremediation Treatment Option

This study was carried out to ascertain the practicability of using bioremediated, engine-oil-impacted soil for crop cultivation. In this study, bioremediation by land farming and nutrient enhancement was used to treat contaminated soils. In the laboratory, soil samples were homogenized, analyzed, and placed into several reactor vessels including a substrate of poultry droppings and cow dung in various ratios to the contaminated soil. During the first phase of the investigation, contaminated soil without treatment served as a control. The soil matrix was homogenized on a weekly basis, and samples were drawn during the third, fifth, eighth, tenth, and fifteenth weeks for total petroleum hydrocarbon (TPH) reduction and nutrients analysis. The initial concentrations of TPH were diluted upon the addition of the poultry litter and cow dung substrate. Results obtained during the experiment indicate that the amount of nutrients generally decreased as the weeks progressed, and the TPH degradation ranged from 78.27% to 61.84% in the reactor vessels. There was no significant difference (p < .05) in TPH degradation based on the substrate quantities, whereas the TPH reductions in the soil amended with the animal wastes were significantly different from the control sample (soil not amended with animal wastes). In the planting phase, uncontaminated, loamy soil was used as a control (the planting phase control), and the results show that maize planted on the treated soil germinated with no significant difference (p < .05) in the number of leaves and plant heights between the treated samples and the control sample (uncontaminated loamy soil). Analysis of field-scale animal waste requirements for hypothetical TPH contaminated soil covering a certain area shows that inorganic fertilizer application requires lesser quantities with lower costs than using poultry litter and cow dung to supply nutrients to support bioremediation. The study concludes that bioremediation for agricultural purpose is feasible, but it can be better implemented if the astronomical quantities of substrates required for field-scale utilization can be surmounted.

83. Adenoviral Mediated Compartmentalized Liver Transduction Improves Safety and Yields Long-term Transgene Expression in a Porcine Model

To stringently control the viremia associated with conventional routes of vector administration and significantly reduce the astronomical quantities of virus commonly infused in gene therapy, our group described compartmentalized liver transduction. Compartmentalized liver transduction is based on known adenoviral spatio-temporal kinetics and is achieved by the intra-parenchymal injection of a vector dose into a blood flow isolated portion of the liver; perfusion is reestablished after viral endocytosis has been completed (30 min). Given the encouraging results documented in rodents (rats), our group assessed compartmentalized liver transduction in a porcine model. To this end, a surgical device was conceptualized, prototyped and utilized to safely and securely transiently isolate a portion of the liver in 25- 30 kg Vietnamese pigs. Implementing compartmentalized liver transduction in pigs, no viremia was detected during the procedure and transgene expression and presence were confined to the site of vector injection. Neither inflammation, apoptosis or significant biochemical liver damage were observed. Using porcine alpha fetoprotein as a reporter gene, serum levels were documented with low quantities of vector dose (10^5) and prolonged transgene expression was achieved (10 months). Our results further support that compartmetalized liver transduction has profound paradoxic effects on the classic toxicological interactions between the liver and adenovirus. The lack of acute liver inflammation observed suggests that conventional immunolgical thresholds and relays were not triggered. We further postulate that compartmentalized liver transduction induces the local synthesis of tolerance inducing cytokines central to thwarting the acute, intermediate and late adenoviral induced immune responses and are critical in generating an immune priviledge liver compartment capable of long term protein synthesis and secretion. Our results further demonstrate that compartmentalized liver transduction is a safe and effective route of vector delivery with a promising future in the field of gene therapy.

Potential of fruit and vegetable wastes as novel biosorbents: summarizing the recent studies

Fruit and vegetable wastes produced in astronomical quantities from food processing and agriculture industries often cause nuisance in municipal landfills owing to their high biodegradability. Biosorption by these waste-based adsorbents can be used as a cost effective and efficient technique for the removal of toxic heavy metals and dyes from wastewater. Recently, many papers claiming the feasible use of these biosorbents for water decontamination, treatment of industrial and agricultural wastewater and valuable metal recovery have been published. The organic waste-based adsorbents, characterized by good uptake capacity and rapid kinetics are expected to be economically and ecologically viable. This paper presents a judicious and pragmatic review depicting the key advances in implications of the fruit and vegetable wastes in pollution mitigation, the underlying mechanisms, major challenges and the future implementations. This compilation is expected to provide an impetus to the bioremediation research and promote green technology.

Units of relativistic time scales and associated quantities

AbstractThis note suggests nomenclature for dealing with the units of various astronomical quantities that are used with the relativistic time scales TT, TDB, TCB and TCG. It is suggested to avoid wordings like “TDB units” and “TT units” and avoid contrasting them to “SI units”. The quantities intended for use with TCG, TCB, TT or TDB should be called “TCG-compatible”, “TCB-compatible”, “TT-compatible” or “TDB-compatible”, respectively. The names of the units second and meter for numerical values of all these quantities should be used without any adjectives. This suggestion comes from a special discussion forum created within IAU Commission 52 “Relativity in Fundamental Astronomy”.

The Holy Alignment: Geodesic and Astronomical Fundamentals for Calculating the Adjustment of Medieval Naves

It is commonly believed that the longitudinal axes of churches extend exactly in an east-west direction. However, thorough investigations have shown that this is not always correct; rather, both southern and northern deviations of up to about 25° can occur. The angular deviation between the church axis and true east is called the Holy Alignment. This present study presents the possibility that the nave is oriented towards the direction of the sun-rising point on the name day of the patron saint of the church. If several saints share the patronage, the Holy Alignment equals the algebraic sum of the angular distances for each saint. The orientation of a nave can be analyzed by means of common mathematical relations used in geodesy, astronomy and gnomonics. In order to perform such an analysis, it is necessary to know the history of the patronage of the church; the Gauss-Krüger coordinates of the ground plan; and characteristic astronomical quantities at the time the church was built. A calculated example with the saints Andrew, James and Philip for the year 980 illustrates the analysis. An appendix deals with the influence of atmospheric refraction on the apparent altitude of the sun near the horizon.

The Astrophysics of Spectroscopic Studies with the Herschel Space Observatory

The three instruments on the Herschel Space Observatory, HIFI, SPIRE, and PACS, cover together over a decade in frequency, from 450 GHz to 5000 GHz, with spectral resolutions δν/ν between 0.3 and 10 -6 . The equivalent temperature range, defined by T = hν/k is 21 K ≤ T eq ≤ 240 K, and thus for dust emission, Herschel will cover the peak of the Planck function in many sources associated with both quiescent and star-forming molecular clouds, both in the Milky Way and other galaxies. The temperature equivalence of the Herschel frequency range also means that essentially all portions of giant molecular clouds will be well probed by the many spectral lines in the Herschel wavelength range of 0.67 mm to 60 µm. My focus in this paper is on gas phase spectral lines of molecules, atoms, and ions, which will be well resolved with the heterodyne receivers on HIFI, but typically not resolved in Galactic sources with the other two instruments. Kinematic interpretation of spectral lines with HIFI is of great interest, along with determination of temperature, density, and column density. I briefly summarize in this review the most important species for Herschel observations, and discuss how one can derive important astronomical quantities from data obtained with the Herschel Space Observatory. Along with describing techniques for analyzing data from the Herschel instruments, I will cover briefly what supplementary ground–based observations are necessary to extract the most from the valuable observing time of the space–based facility.

Large Synoptic Survey Telescope: From science drivers to reference design

In the history of astronomy, major advances in our understanding of the Universe have come from dramatic improvements in our ability to accurately measure astronomical quantities. Aided by rapid progress in information technology, current sky surveys are changing the way we view and study the Universe. Next- generation surveys will maintain this revolutionary progress. We focus here on the most ambitious survey currently planned in the visible band, the Large Synoptic Survey Telescope (LSST). LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: constraining dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. It will be a large, wide-field ground-based system designed to obtain multiple images covering the sky that is visible from Cerro Pachon in Northern Chile. The current baseline design, with an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg2 field of view, and a 3,200 Megapixel camera, will allow about 10,000 square degrees of sky to be covered using pairs of 15-second exposures in two photometric bands every three nights on average. The system is designed to yield high image quality, as well as superb astrometric and photometric accuracy. The survey area will include 30,000 deg2 with ? &lt; +34.5? , and will be imaged multiple times in six bands, ugrizy, covering the wavelength range 320-1050 nm. About 90% of the observing time will be devoted to a deep- wide-fast survey mode which will observe a 20,000 deg2 region about 1000 times in the six bands during the anticipated 10 years of operation. These data will result in databases including 10 billion galaxies and a similar number of stars, and will serve the majority of science programs. The remaining 10% of the observing time will be allocated to special programs such as Very Deep and Very Fast time domain surveys. We describe how the LSST science drivers led to these choices of system parameters.

Relativistic scaling of astronomical quantities and the system of astronomical units

Context. For relativistic modeling of high-accuracy astronomical data, several time scales are used: barycentric and geocentric coordinate times (TCB and TCG) and two additional time scales (TDB and TT), which are defined as linear functions of TCB and TCG, respectively. Aims. The paper is devoted to a concise, but still detailed, explanation of the reasons and the implications of the relativistic scalings of astronomical quantities induced by the time scales TDB and TT. Methods. We consequently distinguish between quantities and their numerical values expressed in some units. Results. It is argued that the scaled time scales, the scaled spatial coordinates, and the scaled masses should be considered as distinct quantities that can be expressed themselves in any units and not as numerical values of the same quantities expressed in some different, non-SI units (“TDB units” and “TT units”). Along the same lines, the system of astronomical units is discussed in the relativistic framework. The whole freedom in the definitions of the systems of astronomical units for TCB and TDB is demonstrated. A number of possible ways to freeze the freedom are shown and discussed. It is argued that in the future one should think about converting AU into a defined quantity by fixing its value in SI meters.

Astrometry with digital sky surveys: from SDSS to LSST

AbstractMajor advances in our understanding of the Universe have historically come from dramatic improvements in our ability to accurately measure astronomical quantities. The astrometric observations obtained by modern digital sky surveys are enabling unprecedentedly massive and robust studies of the kinematics of the Milky Way. For example, the astrometric data from the Sloan Digital Sky Survey (SDSS), together with half a century old astrometry from the Palomar Observatory Sky Survey (POSS), have enabled the construction of a catalog that includes absolute proper motions as accurate as 3 mas/year for about 20 million stars brighter than V=20, and for 80,000 spectroscopically confirmed quasars which provide exquisite error assessment. We discuss here several ongoing studies of Milky Way kinematics based on this catalog. The upcoming next-generation surveys will maintain this revolutionary progress. For example, we show using realistic simulations that the Large Synoptic Survey Telescope (LSST) will measure proper motions accurate to 1 mas/year to a limit 4 magnitude fainter than possible with SDSS and POSS catalogs, or with the Gaia survey. LSST will also obtain geometric parallaxes with accuracy similar to Gaia's at its faint end (0.3 mas at V=20), and extend them to V=24 with an accuracy of 3 mas. We discuss the impact that these LSST measurements will have on studies of the Milky Way kinematics, and potential synergies with the Gaia survey.

Cause and Effect in Global Warming

I read Phillip Morrison’s review of Spencer R. Weart’s book, The Discovery of Global Warming , in the June 2004 issue of Physics Today, (page 60). Weart’s book contains four graphics and other evidence that apparently convinces Morrison of global warming’s causes.There is evidence of increasing global temperatures and increasing atmospheric carbon dioxide concentrations. Morrison is convinced that one causes the other but never mentions whether Weart says which is the cause and which the effect, or whether he gives evidence to support either case. Solid science, though, does support one case.It is widely known that the largest single repository of CO2 on Earth is the oceans, and that the solubility of CO2 in water drops as the water temperature increases. So clearly a mechanism exists whereby increasing ocean water temperatures (which is where most of the solar energy goes) causes increased out-gassing of CO2 into the atmosphere. Furthermore, Arctic permafrost zones revert to marshy peat bogs when the Arctic warms, and then bacterial activity takes hold and converts decaying ancient vegetation into atmospheric CO2. Both of those processes are happening right now.The Russian Vostok ice cores going back 420 000 years and the Dome-C ice cores going back 730 000 years show that the Antarctic ice sheet has not melted during that time frame, even in the warmest interglacial periods. The ice cores also show periods of rapid global warming accompanied by rapidly increasing atmospheric CO2.Now we know that our sport-utility vehicles did not cause all those CO2 increases back then, but we do understand how global warming causes them. So perhaps Weart can tell us conclusively which of the two is the cause and which the effect; the ice cores seem to give us the answer.By the way, when floating sea ice melts, Archimedes would insist that the level does not change; in particular, it does not go up. That takes care of gravitational energy, but the melting of all that sea ice extracts astronomical quantities of latent heat from the surrounding ocean water and lowers the mean ocean temperature; so the level will go down, not up. And I can suggest a very illuminating experiment for anyone who believes that heat to melt sea ice does not come from the surrounding ocean. © 2005 American Institute of Physics.

The Cambridge Planetary Handbook

It is difficult to find good sources of detailed and complete physical data about the planets and their satellites. Frequently, one needs to consult several different sources to determine astronomical quantities, physical parameters, dynamical parameters, geographical information, and historical information. In The Cambridge Planetary Handbook, Michael E. Bakich provides a fairly up‐to‐date reference of such information on the nine known planets in our solar system, and includes information about many of the satellites of those planets. The book is very appropriate for amateur astronomers or interested lay‐persons, and would serve as a good source book for an introductory lecture course on planetary science. It also has some utility as a scientific reference, and it might provide scientists with interesting material for inclusion in public lectures.

General Relativity And The IAU ResolutionsReport of the IAU WGAS Sub-Working Group on Relativity in Celestial Mechanics and Astrometry (RCMA SWG)

RCMA SWG was appointed by the IAU WGAS (Working Group on Astronomical Standards) in accordance with IAU Resolution C6 (1994) with the aim ‘to provide definitions of the astronomical units, of the quantities linking these astronomical units to the units of the International System (SI), and of other astronomical quantities, compatible with the theory of General Relativity’. It is evident that the relativistic aspects of units of measurement cannot be isolated from the more general problem of astronomical constants and fundamental astronomy concepts in the relativistic framework. Therefore, along with the problem of units the main topics of discussion of RCMA SWG concerned also the IAU (1991) Resolutions on References Systems (RSs) and Time Scales (TSs) and their interpretation in IERS Standards (1992) and IERS Conventions (1996). In what follows we tried to summarize the results of these discussions.

Spherical Trigonometry in the Astronomy of the Medieval Kerala School

Although the methods of plane trigonometry became the cornerstone of classical Indian mathematical astronomy, the corresponding techniques for exact solution of triangles on the sphere’s surface seem never to have been independently developed within this tradition. Numerous rules nevertheless appear in Sanskrit texts for finding the great-circle arcs representing various astronomical quantities; these were presumably derived not by spherics per se but from plane triangles inside the sphere or from analemmatic projections, and were supplemented by approximate formulas assuming small spherical triangles to be plane.

Short-Period Noncontact Close Binary Systems. V. DD Monocerotis

Optical observations of the 0.568 day period eclipsing binary system DD Mon were made. The light- curve analysis reveals that the primary component fills the critical lobe and the secondary component is close to the critical lobe (a semidetached system). The spectral type is assigned to be F5 IV-V, not B5 as given in catalogs. Some astronomical quantities are deduced. The mass of the primary component is estimated to be 0.37Msun which is undermassive for the radius and luminosity, indicating that a considerable amount of its original mass has been lost from the system during the course of evolution.