Related papers: The Venus Life Equation
It is currently unknown how common life is on exoplanets, or how long planets can remain viable for life. To date, we have a superficial notion of habitability, a necessary first step, but so far lacking an understanding of the detailed…
Recent findings suggest Mars may have been a clement environment for the emergence of life, and may even have compared favorably to Earth in this regard. These findings have revived interest in the hypothesis that prebiotically important…
The atmosphere of Venus remains mysterious, with many outstanding chemical connundra. These include: the unexpected presence of ~10 ppm O2 in the cloud layers; an unknown composition of large particles in the lower cloud layers; and hard to…
The origin of life and the origin of the universe are among the most important problems of science and they might be inextricably linked. Hydro-gravitational-dynamics (HGD) cosmology predicts hydrogen-helium gas planets in clumps as the…
Signs of lightning on Venus have long been sought, including by space missions and ground-based telescopes searching for optical flashes, plasma waves, or radio signatures. These efforts have yielded conflicting findings regarding the…
Few spacecraft have studied the dynamics of Venus' deep atmosphere, which is needed to understand the interactions between the surface and atmosphere. Recent global simulations suggest a strong effect of the diurnal cycle of surface winds…
This paper presents the first structured evaluation of Solar System bodies hypothetically relocated to Earth orbit (1 AU) to assess their potential as alternative habitats. Using comparative criteria, planetary size and gravity, atmospheric…
Giant impacts were common in the early evolution of the Solar System, and it is possible that Venus also experienced an impact. A giant impact on Venus could have affected its rotation rate and possibly its thermal evolution. In this work,…
With the Cassini-Huygens Mission in orbit around Saturn, the large moon Titan, with its reducing atmosphere, rich organic chemistry, and heterogeneous surface, moves into the astrobiological spotlight. Environmental conditions on Titan and…
The availability of bioessential elements for "life as we know it", such as phosphorus (P) or possibly molybdenum (Mo), is expected to restrict the biological productivity of extraterrestrial biospheres. Here, we consider worlds with…
Volcanism on Venus has never been directly observed, but several measurements indicate present-day activity. Volcanism could potentially play a role in climatic processes on Venus, especially in the sulfur cycle like on Earth. Observation…
TRAPPIST-1 d is generally assumed to be at the boundary between a Venus-like world and an Earth-like world, although recently published works on TRAPPIST-1 b and c raise concerns that TRAPPIST-1 d may be similarly devoid of a substantial…
Earth is unusual in bearing life, and in having a large moon. A number of authors have suggested a possible connection between the two, e.g. through lunar stabilisation of the earth's obliquity, or through the effects of the oceanic tides.…
Two habitable planetary states are proposed: an aqua planet like the Earth and a land planet that has a small amount of water. Land planets keep liquid water under larger solar radiation compared to aqua planets. Water loss may change an…
Stellar activity and planetary atmospheric properties have the potential to strongly influence habitability. To date, neither have been adequately studied in the multiverse context, so there has been no assessment of how these effects…
In a multiverse setting, we expect to be situated in a universe that is exceptionally good at producing life. Though the conditions for what life needs to arise and thrive are currently unknown, many will be tested in the coming decades.…
According to the "hard-steps" model, the origin of humanity required "successful passage through a number of intermediate steps" (so-called "hard" or "critical" steps) that were intrinsically improbable with respect to the total time…
The chemical evolution of an exoplanetary Venus-like atmosphere is dependent upon the ultraviolet to near ultraviolet (FUV-NUV) radiation ratio from the parent star, the balance between CO$_{2}$ photolysis and recombination via reactions…
We investigate the prospects for the past or current existence of habitable conditions deep underneath the surfaces of the Moon and Mars as well as generic bound and free-floating extrasolar rocky objects. We construct a simple model that…
I show that exoplanets can be used to test origins scenarios. Origins scenarios start with certain initial conditions, proceed via a network of chemical reactions and, if successful, result in a chemistry that is closer to a living system…