Related papers: Gravity-Assist as a Solution to Save Earth from Gl…
Carbonate-silicate weathering feedback is thought to stabilize Earth's climate on geologic timescales. If climate warms, faster mineral dissolution and increased rainfall speed up weathering, increasing CO2 drawdown and opposing the initial…
There are different methods for finding exoplanets such as radial spectral shifts, astrometrical measurements, transits, timing etc. Gravitational microlensing (including pixel-lensing) is among the most promising techniques with the…
The ultimate climate emergency is a "runaway greenhouse": a hot and water vapour rich atmosphere limits the emission of thermal radiation to space, causing runaway warming. Warming ceases only once the surface reaches ~1400K and emits…
A terrestrial planet in an orbit far outside of the standard habitable zone could maintain surface liquid water as a result of H2-H2 collision-induced absorption by a thick H2 atmosphere. Without a stabilizing climate feedback, however,…
It is argued that a dedicated effort to increase the reflectivity of the surface of our planet by means of, for example, metallic plates would induce an increase in the global albedo which would counteract in part the present global-warming…
The stability of Earth's climate on geological timescales is enabled by the carbon-silicate cycle that acts as a negative feedback mechanism stabilizing surface temperatures via the intake and outgas of atmospheric carbon. On Earth, this…
Earth's earliest sedimentary record contains evidence that surface temperatures were similar to, or perhaps even warmer than modern. In contrast, standard Solar models suggest the Sun was 25% less luminous at this ancient epoch, implying a…
Asteroid impacts with the Earth may have played an essential role in the emergence of life on Earth through their creation of favorable niches for life, changes to the atmosphere and delivery of water. Consequently, we suggest two potential…
We assess the ability of a solid ring to model a global perturbation induced by several thousands of main-belt asteroids. The ring is first studied in an analytical framework that provides an estimate of all the ring's parameters excepting…
The potential habitability of an exoplanet is traditionally assessed by determining if its orbit falls within the circumstellar `habitable zone' of its star, defined as the distance at which water could be liquid on the surface of a planet…
A cratered asteroid acts somewhat like a retroflector, sending light and infrared radiation back toward the Sun, while thermal inertia in a rotating asteroid causes the infrared radiation to peak over the ``afternoon'' part. In this paper a…
The carbon-silicate cycle regulates the atmospheric $CO_2$ content of terrestrial planets on geological timescales through a balance between the rates of $CO_2$ volcanic outgassing and planetary intake from rock weathering. It is thought to…
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…
The search for habitable planets like Earth around other stars fulfils an ancient imperative to understand our origins and place in the cosmos. The past decade has seen the discovery of hundreds of planets, but nearly all are gas giants…
Summary: In the past decade both scientists and laymen have probably heard at least once through the newspapers, TV and Internet that a new asteroid has been discovered with non-zero (sometimes "high") probability of collision with the…
Although the Earth's orbit is never far from circular, terrestrial planets around other stars might experience substantial changes in eccentricity that could lead to climate changes, including possible "phase transitions" such as the…
We generalize the problem of the semi-gray model to cases in which a non-negligible fraction of the stellar radiation falls on the long-wavelength range, and/or that the planetary long-wavelength emission penetrates into the transparent…
Laser ablation of a Near-Earth Object (NEO) on a collision course with Earth produces a cloud of ejecta which exerts a thrust on the NEO, deflecting it from its original trajectory. Ablation may be performed from afar by illuminating an…
We present an adaptation of the ATPM to simultaneously predict the Yarkovsky and YORP effects in the presence of global self-heating that occurs within the large concavities of irregularly shaped asteroids, which has been neglected or…
Human activities degrade the Earth environment at an unprecedented scale and pace, threatening Earth-system stability, resilience and life-support functions. We can of course deny the facts, get angry about them, or try to bargain. Or we…