Expert Opinion on Astronomy and Astrophysics

Expert Opinion on Astronomy and Astrophysics

Basic info

  • Publisher: whioce
  • Country of publisher: singapore
  • Date added to EuroPub: 2020/Feb/27

Subject and more

  • LCC Subject Category: Astronomy/Astrophysics/Space Science
  • Publisher's keywords: Astronomy, Astrophysics
  • Language of fulltext: english
  • Time from submission to publication: weeks

Publication charges

  • Article Processing Charges (APCs): No
  • Submission charges: No
  • Waiver policy for charges? No

Open access & licensing

  • Type of License:
  • License terms
  • Open Access Statement: No
  • Year open access content began: 2018
  • Does the author retain unrestricted copyright? False
  • Does the author retain publishing rights? False

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This journal has '6' articles

A Study of Supergranulation through Its Parameters

A Study of Supergranulation through Its Parameters

Authors: U. Paniveni
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Abstract

Supergranulation is examined through its various parameters such as Area, perimeter, circularity and fractal dimension. A connection amongst these parameters throws light on the turbulent aspect of this convective feature. Area and perimeter at various latitudes are also studied in detail. The spread shows an asymmetric dispersion with a minimum dimension at around ±25º because there is a theoretical calculation which indicates that the enhanced fields will reduce the supergranular cell sizes (Chandrasekhar, 1961) around these latitudes. A different technique of analysis on a larger sample could consolidate these findings.

Keywords: Sun; Granulation-Sun; Activity-Sun; Photosphere
The Nature of Gamma-ray Bursts in the Framework of the Byuon Theory

The Nature of Gamma-ray Bursts in the Framework of the Byuon Theory

Authors: Yu.A. Baurov, I.F. Malov
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Abstract

Two models of gamma-ray bursts using the theory of byuons (TB) are considered. This theory describes a “life” of special unobservable discrete objects from which the surrounding space and the world of ultimate particles are formed. Basic axioms and some conclusions of this theory are discussed. It is shown that basic problems with nature of gamma-rays bursts can be solved in the framework of this theory not only for bursts connected with supernova explosions but also for those without explosions.

Keywords: gamma-ray bursts; theory of byuons; new non-gauge force
Latitudinal Dependence of Supergranular Area and Fractal Dimension

Latitudinal Dependence of Supergranular Area and Fractal Dimension

Authors: U.Paniveni
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Abstract

A dependence of the area of supergranular cells with respect to the Latitude is studied and it is found that the cells are situated symmetrically about the ±250 latitude. Fractal dimension of the supergranular cells also shows a marginal latitudinal dependence, variation being in the range 1.6–1.7 in the latitudinal limits of ±300. Fractal dimension D for supergranulation is obtained according to the relation P ∝ AD/2 where ‘A is the area and ‘P’ is the perimeter of the supergranular cells. A difference in the fractal dimension between the active and quiet region cells is noted which is conjectured to be due to the magnetic activity level. Supergranular cells are essentially a manifestation of convective phenomena. They can shed light on the physical conditions in the convection zone of the Sun. Moreover, supergranules play a key role in the transport and dispersal of magnetic fields as it is an important step in our quest to understand the solar cycle.

Keywords: Sun; granulation-Sun; activity -Sun; photosphere
Is Spacetime Non-metric?

Is Spacetime Non-metric?

Authors: Mark D. Roberts
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Abstract

If one assumes higher dimensions and that dimensional reduction from higher dimensions produces scalar-tensor theory and also that Palatini variation is the correct method of varying scalar-tensor theory then spacetime is nonmetric. Palatini variation of Jordan frame lagrangians gives an equation relating the dilaton to the object of non-metricity and hence the existence of the dilaton implies that the spacetime connection is more general than that given soley by the Christoffel symbol of general relativity. Transferring from Jordan to Einstein frame, which connection, lagrangian, field equations and stress conservation equations occur are discussed: it is found that the Jordan frame has more information, this can be expressed in several ways, the simplest is that the extra information corresponds to the function multiplying the Ricci scalar in the action. The Einstein frame has the advantages that stress conservation implies no currents and that the field equations are easier to work with. This is illustrated by application to Robertson-Walker spacetime.

Keywords: Jordan frame; Einstein frame; non-metrcity; palatini variation
Quantitative indexing and tardigrade analysis of exoplanets

Quantitative indexing and tardigrade analysis of exoplanets

Authors: Madhu Kashyap Jagadeesh
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Abstract

Search of life elsewhere in the galaxy is very fascinating area for planetary scientists and astrobiologists. Earth Similarity Index (ESI) is defined as geometrical mean of four physical parameters (Such as radius, density, escape velocity and surface temperature), which is ranging from 1 (identical to Earth) to 0 (dissimilar to Earth). In this work, ESI is re-defined as six parameters by introducing the two new physical parameters like revolution and surface gravity and is called as New Earth Similarity Index (NESI). The main focus of this paper is to search Tardigrade water-life on exoplanets by varying the temperature parameter in NESI, which is called as Tardigrade Similarity Index (TSI), which is ranging from 1 (Potentially Tardigrade can survive) to 0 (Tardigrade Cannot survive). The NESI and TSI data is cataloged and analyzed for almost 3370 confirmed exoplanets and the results are discussed.

Keywords: Revolution of exoplanets; Tardigrade Similarity Index; surface gravity of exoplanets; and New Earth Similarity Index
Alternative Reflections on Podkletnov's Gravity Experiments

Alternative Reflections on Podkletnov's Gravity Experiments

Authors: Johann Albers
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Abstract

In the 1990s Eugene Podkletnov published results of experiments which in his opinion proved the effect of gravity shielding. The present paper is concerned with the question, what results may be expected from such experiments on the basis of the "Alternative Reflections on Gravitation", (ARG). The results of these considerations are in excellent agreement with those experiments. There, however, appeared no gravity shielding, but the production of additional, highly focused repulsive forces. Such curious results can hardly be explained on the basis of classical gravitational theories, which deal with attractive forces and their strong decrease with distance.

Keywords: Podkletnov's Gravity Experiments

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