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31.
Here we explore the possibility of a lower limit to velocity or velocity change which is 20 orders of magnitude smaller than the speed of light and explore the various observable signatures including those in cosmic rays and gamma ray bursts. 相似文献
32.
In a recent paper it was suggested that inclusion of mutual gravitational interactions can give a possible scenario for reversing
gravitation collapse and averting a singular phase. We extend this idea to the still unsolved problem of matter collapsing
beyond black hole event horizons. For a comoving observer there is no change in entropy as he goes through the horizon. Matter
collapses to a minimum radius, and then can re-expand with the same entropy. It is shown that phase space inside a collapsing
black hole is also invariant. 相似文献
33.
C. Sivaram 《Astrophysics and Space Science》1984,100(1-2):467-470
It is pointed out that several interesting coincidences and relationships connecting the parameters of cosmology and elementary particle physics suggest that the coupling constants of the weak, strong and electromagnetic interactions do not change with time in Dirac's cosmology. This would be consistent with the stringent limits imposed on their variation by recent data on isotopic abundances. 相似文献
34.
C. Sivaram 《Earth, Moon, and Planets》1986,34(3):231-233
Consideration of the basic physics involved in the structure of the object are used to obtain relationships for the radius, period, angular momentum, etc. of a typical asteroid. The mass-angular momentum relation for asteroids would tend to favour the fragmentation hypothesis. 相似文献
35.
Recent discovery of J1342+0928 using data from the WISE telescope and ground based surveys indicate presence of a supermassive black hole (SMBH) having a mass of 800 million solar mass at a redshift of about 7.6. This imply that the black hole grew to this mass only 690 million years after the universe started expanding. Here we suggest that formation of such SMBH’s so early in the universe is consistent with our present understanding of the phenomena involved by invoking dark matter (DM). 相似文献
36.
We show that the instability induced by viscosity, at the point of bifurcation where the Jacobi ellipsoids branch off from the sequence of Maclaurin spheroids, is not inhibited by the presence of a magnetic field. It has already been shown that a toroidal magnetic field leaves the point of bifurcation unaffected, whereas a magnetic field along the axis of rotation pushes the point of bifurcation to eccentricities higher than the value that obtains in the absence of a magnetic field. 相似文献
37.
A recent model of torsion-modified electrodynamics which breaks the electromagnetic conformal invariance is shown to lead to the generation of magnetic fields in the Early Universe. 相似文献
38.
The dominance of dark energy in the universe has necessitated the introduction of a repulsive gravity source to make q0 negative. The models for dark energy range from a simple Λ term to quintessence, Chaplygin gas, etc. We look at the possibility
of how change of behaviour of missing energy density, from DM to DE, may be determined by the change in the equation of state
of a background fluid instead of a form of potential. The question of cosmic acceleration can be discussed within the framework
of theories which do not necessarily include scalar fields. 相似文献
39.
Source parameters and scaling relations for small earthquakes in Kumaon Himalaya, India 总被引：1，自引：0，他引：1
K. Sivaram Dinesh Kumar S. S. Teotia S. S. Rai K. S. Prakasam 《Journal of Seismology》2013,17(2):579-592
We investigate the scaling relationships among earthquake source parameters using more than 300 good quality broad band seismograms from 30 small earthquakes in the Kumaon Himalaya from the spectral analysis of P and S waves. The average ratio of P/S wave corner frequency is found to be 1.13, which is suggestive of shift in the corner frequency. The estimated seismic moment range from 1.6?×?1013–5.8?×?1015 N?m, while the stress drop varies from 0.6 to 16 bars with 80 % of the events below 10 bars. An analysis of stress drop and apparent stress drop indicates the partial stress drop mechanism in the region. The source radii are between 0.17 and 0.88 km. The total seismic energy varies from 1.79?×?108 to 7.30?×?1011 J. We also observe the variation in seismic energy for a given seismic moment. The scaling relation between the seismic moment and stress drop suggests the breakdown of constant stress drop scaling for the range of seismic moments obtained here for the region. This shows the anomalous behavior of small earthquakes in the region. The study indicates that the stress drop is the dominant scaling factor for the moments studied here. 相似文献
40.
C. Sivaram 《Astrophysics and Space Science》1986,125(1):189-199
The problem of the Universe emerging out of the Planck epoch is discussed. It is pointed out that an earlier exponential expansion phase well before the onset of the GUTs phase transition is essential. Such an expansion can occur owing to the breaking of scale invariance at Planck energies in a unified theory of gravity with other interactions. 相似文献