A space hurricane over the Earth’s polar ionosphere

The Polar Ionosphere: Editorial

The polar cliff in the morning sector of the ionosphere

By “polar cliff” we mean the steep increase in the ionization density observed in the morning sector of the polar ionosphere. Here the properties of this remarkable feature are investigated. The data set consists of electron density and temperature measurements obtained by the Dynamics Explorer 2 satellite. Only data recorded in the Northern Hemisphere winter are considered (solar zenith angle≥...

FAST Observations of Electromagnetic Stresses Applied to the Polar Ionosphere

The Fast Auroral Snapshot Explorer (FAST), with its 83 inclination orbit and 4000 km apogee, is ideally suited for investigation of the high latitude perturbations to the geomagnetic field. These data can be used to determine fieldaligned currents, but here we emphasize the perturbations themselves, rather than their spatial gradient. This allows us to more readily visualize the forces applied ...

Earths: Rare in Time, Not Space?

We compare two recent astrobiological approaches to the solution of the problem of the “Great Silence” (or Fermi’s paradox): the “rare Earth” hypothesis of Ward and Brownlee, and the phase-transition scenario of Annis. We show that they have important similarities, as far as self-selection of intelligent observers is concerned. In order to better illuminate the differences, we consider the dura...

On the polar derivative of a polynomial

For a polynomial p(z) of degree n, having all zeros in |z|< k, k< 1, Dewan et al [K. K. Dewan, N. Singh and A. Mir, Extension of some polynomial inequalities to the polar derivative, J. Math. Anal. Appl. 352 (2009) 807-815] obtained inequality between the polar derivative of p(z) and maximum modulus of p(z). In this paper we improve and extend the above inequality. Our result generalizes certai...