Because of the almost total lack of geological record on the Earth's surface before 4 billion years ago, the history of the Earth during this period is still enigmatic. Here we describe a practical approach to tackle the formidable problems caused by this lack. We propose that examinations of lunar soils for light elements such as He, N, O, Ne, and Ar would shed a new light on this dark age in ...

Ambitious studies of Earth-like extrasolar planets are outlined in the context of an exploration initiative for a return to the Earth's Moon. Two mechanism for linearly polarizing light reflected from Earth-like planets are discussed: 1) Rayleigh-scattering from a planet's clear atmosphere, and 2) specular reflection from a planet's ocean. Both have physically simple and predictable polarized p...

In India, festivals are celebrated with lot of enthusiasm and Diwali is the major festival of light. In this festival, houses are illuminated by lights and sky is illuminated by fireworks. These fireworks though create lot of amusement but also pollute the atmosphere in terms of air pollution. The continuous air pollution monitoring was undertaken during Diwali festival (2014) at residential si...

The performance of an Earth-to-space optical telecommunications system is degraded by distortion (scintillation and tilt) of the beam as it propagates through the turbulent atmosphere. Conventional approaches to correct distortions that are based on natural or artificial guide stars are useful in, for example, astronomical imaging, but have practical difficulties or are not adequate to correct ...

Spaceborne remote sensing provides valuable information about the state of the Earth-atmosphere system and its components in an area-wide and continuous manner. Over the past 50 years a range of satellite platforms carrying many different sensors has been constructed to monitor atmospheric parameters used in meteorological and climatological studies, and the information retrieved from satellite...

A fundamental question for exoplanet habitability is the long-term stability of the planet’s atmosphere. We numerically solve a one-dimensional multi-component hydrodynamic thermosphere/ionosphere model to examine the thermal and chemical responses of the primary CO2 atmospheres of heavy super Earths (6–10 Earth masses) in the habitable zones of typical low-mass M stars to the enhanced soft X-r...

Introduction: Super-rotation is a ubiquitous phenomenon in the four substantial atmospheres possessed by solid bodies in the solar system. The slowly rotating planet, Venus, and moon, Titan, are both well-known to have atmospheres that rotate substantially more quickly than does the solid surface underneath. The more rapidly rotating planets, Mars and Earth, exhibit less spectacular global supe...