Related papers: Upper limit on the fraction of alien civilizations…
The exotic range of known planetary systems has provoked an equally exotic range of physical explanations for their diverse architectures. However, constraining formation processes requires mapping the observed exoplanet population to that…
Some astrobiological models suggest that molecular clouds may serve as habitats for extraterrestrial life. This study reviews recent theoretical work addressing the physical and biochemical prerequisites for life in such environments, with…
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…
Upcoming biosignature searches focus on indirect indicators to infer the presence of life on other worlds. Aside from just signaling the presence of life, however, some biosignatures can contain information about the state that a planet's…
One of the most interesting questions that astronomy can hope to answer is: are we alone in our Milky Way galaxy? A detection of an electromagnetic (EM) signal generated by an extraterrestrial technological intelligence, or the presence in…
Agriculture is one of the oldest forms of technology on Earth. The cultivation of plants requires a terrestrial planet with active hydrological and carbon cycles and depends on the availability of nitrogen in soil. The technological…
Hycean planets -- exoplanets with substantial water ice layers, deep surface oceans, and hydrogen-rich atmospheres -- are thought to be favorable environments for life. Due to a relative paucity of atmospheric greenhouse gases, hycean…
An organism that is newly introduced into an existing population has a survival probability that is dependent on both the population density of its environment and the competition it experiences with the members of that population.…
We investigate a new class of habitable planets composed of water-rich interiors with massive oceans underlying H2-rich atmospheres, referred to here as Hycean worlds. With densities between those of rocky super-Earths and more extended…
The habitable zones of low-mass stars are characterized by escape speeds that can be a few times higher than the Earth's orbit around the Sun. Owing to the exponential dependence of the required fuel mass on the terminal speed for chemical…
On the Earth, photosynthetic organisms are responsible for the production of virtually all of the oxygen in the atmosphere. On the land, vegetation reflects in the visible, leading to a red edge that developed about 450 Myr ago and has been…
Radio SETI experiments aim to test the hypothesis that extraterrestrial civilizations emit detectable signals from communication, propulsion, or other technologies. The unprecedented capabilities of next generation radio telescopes,…
This study examines the hypothesis that the rapid development of Artificial Intelligence (AI), culminating in the emergence of Artificial Superintelligence (ASI), could act as a "Great Filter" that is responsible for the scarcity of…
The possibility of achieving quantum communication using photons across interstellar distances is examined. For this, different factors are considered that could induce decoherence of photons, including the gravitational field of…
Exotic interactions between fermions mediated by new bosons beyond the Standard Model may hold the key to several fundamental conundrums on the frontier of physics.However, laboratory searching for exotic interactions on small length scales…
Earth is the only known inhabited planet in the universe to date. However, advancements in the fields of astrobiology and observational astronomy, and the discovery of large varieties of extremophiles with extraordinary capablities to…
In a multiverse context, determining the probability of being in our particular universe depends on estimating its overall habitability compared to other universes with different values of the fundamental constants. One of the most…
The dominant paradigm in assigning "habitability"' to terrestrial planets is to define a circumstellar habitable zone: the locus of orbital radii in which the planet is neither too hot nor too cold for life as we know it. One dimensional…
Of all the issues discussed at {\em Alife VII: Looking Forward, Looking Backward}, the issue of whether it was possible to create an artificial life system that exhibits {\em open-ended evolution} of novelty is by far the biggest. Of the 14…
Results of recent experiment reinstate feasibility to the hypothesis that biomolecular homochirality originates from beta decay. Coupled with hints that this process occurred extraterrestrially suggests aluminum-26 as the most likely…