Related papers: The faint young Sun problem
Our Sun and planetary system were born about 4.5 billion years ago. How did this happen and what is our heritage from these early times? This review tries to address these questions from an astrochemical point of view. On the one hand, we…
The oxygenation of Earth's atmosphere 2.3 billion years ago, which on exoplanets is expected to be most detectable via the UV ozone feature at $\sim$0.25 $\mu$m, is often regarded as a sign of the emergence of photosynthetic life. On…
The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal…
We are investigating the possible origin of small-scale anomalies, like the annual stratospheric temperature anomalies. Unexpectedly within known physics, their observed planetary "dependency", does not match concurrent solar activity,…
Before about 500 million years ago, most probably our planet experienced temporary snowball conditions, with continental and sea ices covering a large fraction of its surface. This points to a potential bistability of Earth's climate, that…
The evolution of different forms of photosynthetic life has profoundly altered the activity level of the biosphere, radically reshaping the composition of Earth's oceans and atmosphere over time. However, the mechanistic impacts of a…
Traditionally, the search for life on exoplanets has been predominantly focused on rocky exoplanets. Hycean worlds are a class of habitable sub-Neptunes with planet-wide oceans and H2-rich atmospheres. Their broad range of possible sizes…
Many papers and monographs were written about the modeling the Earth climate and its variability. However there is still an obvious need for a module that presents the fundamentals of climate modeling to students at the undergraduate level.…
The solar chemical composition is an important ingredient in our understanding of the formation, structure and evolution of both the Sun and our solar system. Furthermore, it is an essential reference standard against which the elemental…
Despite major advances in climate science over the last 30 years, persistent uncertainties in projections of future climate change remain. Climate projections are produced with increasingly complex models which attempt to represent key…
This paper describes some of the astronomical effects that could be important for understanding the ice ages, historic climate changes and the recent temperature increase. These include changes in the sun's luminosity, periodic changes in…
Low-mass protostars are less luminous than expected. This luminosity problem is important because the observations appear to be inconsistent with some of the basic premises of star formation theory. Two possible solutions are that stars…
The solar system has changed dramatically since its birth, and so did our understanding of it. A considerable research effort has been invested in the past decade in an attempt to reconstruct the solar system history, including the earliest…
As they keep cooling and contracting, Solar System giant planets radiate more energy than they receive from the Sun. Applying the first and second principles of thermodynamics, one can determine their cooling rate, luminosity, and…
The question of why we age is a fundamental one. It is about who we are, and it also might have critical practical aspects as we try to find ways to age slower. Or to not age at all. Different reasons point at distinct strategies for the…
Waves and oscillations have been observed in the Sun's atmosphere for over half a century. While such phenomena have readily been observed across the entire electromagnetic spectrum, spanning radio to gamma-ray sources, the underlying role…
Modelling of Extreme Scattering Events suggests that the Galaxy's dark matter is an undetected population of cold, AU-sized, planetary-mass gas clouds. None of the direct observational constraints on this picture -- thermal/non-thermal…
The search for habitable conditions and signs of life on exoplanets is a major frontier in modern astronomy. Detecting atmospheric signatures of Earth-like exoplanets is challenging due to their small sizes and relatively thin atmospheres.…
Several researchers have previously identified a severe climatic upheaval in tropical North Africa that began just over 4000 years ago and lasted for about three centuries. The upheaval is known to have occurred shortly after a volcanic…
The solar contribution to global mean air surface temperature change is analyzed by using an empirical bi-scale climate model characterized by both fast and slow characteristic time responses to solar forcing: $\tau_1 =0.4 \pm 0.1$ yr, and…