Related papers: The Venus Life Equation
It is not currently possible to create a living organism ab initio due to the overwhelming complexity of biological systems. In fact, the origin of life mechanism, this being how biological organisms form from non-living matter, is unknown.…
The study of origins of life on Earth and the search for life on other planets are closely linked. Prebiotic chemical scenarios can help prioritize planets as targets for the search for life as we know it and can provide informative priors…
Terrestrial exoplanets orbiting within or near their host stars' habitable zone are potentially apt for life. It has been proposed that time-series measurements of reflected starlight from such planets will reveal their rotational period,…
We explore the likelihood that early remains of Earth, Mars, and Venus have been preserved on the Moon in high enough concentrations to motivate a search mission. During the Late Heavy Bombardment, the inner planets experienced frequent…
Standard definitions of habitability assume that life requires the presence of planetary gravity wells to stabilize liquid water and regulate surface temperature. Here the consequences of relaxing this assumption are evaluated. Temperature,…
Mars provides a critical analog to once habitable exoplanets that have since lost their surface liquid water. The current atmospheric state of Mars retains the chemical fingerprints of that transition, including isotopic signatures of…
There is growing evidence that brown dwarfs may be comparable to main-sequence stars in terms of their abundance. In this paper, we explore the prospects for the existence of life on Earth-like planets around brown dwarfs. We consider the…
The origins of life stands among the great open scientific questions of our time. While a number of proposals exist for possible starting points in the pathway from non-living to living matter, these have so far not achieved states of…
The Gaia hypothesis postulates that life regulates its environment to be favorable for its own survival. Most planets experience numerous perturbations throughout their lifetimes such as asteroid impacts, volcanism, and the evolution of…
Earth is the only planet known to harbor life and, as a result, the search for habitable and inhabited planets beyond the Solar System commonly focuses on analogs to our planet. However, Earth's atmosphere and surface environment have…
Mars, Venus and Earth are expected to have started in a hot molten state. Here, we discuss how these three terrestrial planets diverged in their evolution and what mechanisms could be the cause. We discuss that early-on after magma ocean…
A major goal in the search for extraterrestrial life is the detection of liquid water on the surface of exoplanets. On terrestrial planets, volcanic outgassing is a significant source of atmospheric and surface water and a major contributor…
A habitable zone of a star is defined as a range of orbits within which a rocky planet can support liquid water on its surface. The most intriguing question driving the search for habitable planets is whether they host life. But is the age…
How do habitable environments arise and evolve within the context of their planetary systems? This is one fundamental question, and it can be addressed partly by identifying how planets in habitable zones obtain water. Historically,…
Water and land surfaces on a planet interact with gases in the atmosphere and with radiation from the star. These interactions define the environments that prevail on the planet, some of which may be more amenable to prebiotic chemistry,…
We propose an abiotic geological mechanism that accounts for the abundance of phosphine detected by Greaves et al., 2020. We hypothesize that trace amounts of phosphides formed in the mantle would be brought to the surface by volcanism, and…
Whereas the Solar System has Mars and Europa as the best candidates for finding fossil/extant life as we know it - based on complex carbon compounds and liquid water - the 263 (non-pulsar) planetary systems around other stars as known at 15…
The variational method with constraints recently developed by Verkley and Gerkema to describe maximum-entropy atmospheric profiles is generalized to ideal gases but with temperature-dependent specific heats. In so doing, an extended and non…
Is life a common outcome of physical and chemical processes in the universe? Within our own solar system, a successful search for even primitive life, were it to have an origin independent from life on Earth, would dramatically advance a…
Liquid water oceans are at the center of our search for life on exoplanets because water is a strict requirement for life as we know it. However, oceans are dynamic habitats---and some oceans may be better hosts for life than others. In…