The requirement that their gravitational binding self-energy density must at least equal the background repulsive dark energy density for large scale cosmic structures implies a mass-radius relation of M/R2 ≈ 1 g/cm2, as ...

In recent papers, it was shown explicitly that the sizes of gravitationally bound large-scale cosmic structures can be constrained from the requirement that their gravitational binding self-energy density should at least ...

The nature of dark matter (DM) and dark energy (DE) which is supposed to constitute about 95% of the energy density of the uni-verse is still a mystery. There is no shortage of ideas regarding the nature of both. While ...

Multilayer X-ray mirrors consist of a coating of a large number of alternate layers of high Z and low Z materials with a typical thickness of 10–100 Å , on a suitable substrate. Such coatings play an important role in ...

The High Altitude GAmma-Ray (HAGAR) experiment is the highest altitude atmospheric Cherenkov sampling array, set up at 4300 m amsl in the Himalayas (Northern India). It constitutes 7 telescopes, each one with seven 90 ...

Coronal magnetic fields evolve quasi-statically over long timescales and dynamically over short timescales. As of now there exist no regular measurements of coronal magnetic fields, and therefore generating the coronal ...

This book is an attempt to demystify the activities of a celestial object such as the Sun appealing to basic physics already available to high school students. Building on simple logic, the contents begin with measurements ...

Daytime VHF radiowave scintillations at Trivandrum are compared with the E-region irregularities at Kodaikanal. It is shown that daytime scintillations at Trivandrum are basically of two categories. One type of scintillations ...