Atmospheric chemical disequilibrium has been proposed as a method for detecting extraterrestrial biospheres from exoplanet observations. Chemical disequilibrium is potentially a generalized biosignature since it makes no assumptions about particular biogenic gases or metabolisms. Here, we present the first rigorous calculations of the thermodynamic chemical disequilibrium in Solar System atmosp...

Xenon (Xe) is an exceptional tracer for investigating the origin and fate of volatile elements on Earth. The initial isotopic composition of atmospheric Xe remains unknown, as do the mechanisms involved in its depletion and isotopic fractionation compared with other reservoirs in the solar system. Here we present high precision analyses of noble gases trapped in fluid inclusions of Archean quar...

The reconstruction of ancient atmospheric carbon dioxide concentrations is essential to understanding the history of the Earth and life. It is also an important guide to identifying the sensitivity of the Earth system to this greenhouse gas and, therefore, constraining its future impact on climate. However, determining the concentration of CO2 in ancient atmospheres is a challenging endeavour r...

The increasing numbers of rocky, terrestrial exoplanets known to orbit nearby stars (especially M dwarfs) has drawn increased attention the possibility studying these planets' surface properties, and atmospheric compositions & escape histories. Here we report detection secondary eclipse exoplanet GJ1252b using Spitzer Space Telescope's IRAC2 4.5 micron channel. We measure an depth 149(+25/-32) ...

may 20 09 A lf re d T. K A m A ji A n One of the most remarkable features of the solar system is the variety of planetary atmospheres. Earth and Venus are of comparable size and mass, yet the surface of Venus bakes at 460 degrees Celsius under an ocean of carbon dioxide that bears down with the weight of a kilometer of water. Callisto and Titan—planet-size moons of Jupiter and Saturn, respectiv...

The mean values of the radiation balance of the earth's surface, the atmosphere, and the earth-atmosphere system as a whole are well established. However, this does not apply to the parameters of local areas of the earth's surface and the atmosphere above them. The radiation balance of such local objects experiences considerable variations depending on the spatiotemporal distribution of cloud a...