Related papers: A framework for evaluating biosignature potential …
Planet Earth has evolved from an entirely anoxic planet with possibly a different tectonic regime to the oxygenated world with horizontal plate tectonics that we know today. For most of this time, Earth has been inhabited by a purely…
After it was proposed that life on Earth might descend from seeding by an earlier civilization, some authors noted that this alternative offers a testable aspect: the seeds could be supplied with a signature that might be found in extant…
Future space telescopes may be able to directly image $\sim$10 - 100 planets with sizes and orbits consistent with habitable surface conditions ("exo-Earth candidates" or EECs), but observers will face difficulty in distinguishing these…
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…
The search for life beyond the Solar System is a major activity in exoplanet science. However, even if an Earth-like planet were to be found, it is unlikely to be at a similar stage of evolution as the modern Earth. It is therefore of…
A laboratory experiment is suggested in which conditions similar to those in the plume ejecta from Enceladus and, perhaps, Europa are established. Using infrared spectroscopy and polarimetry, the experiment might identify possible…
Understanding the surface and atmospheric conditions of Earth-size, rocky planets in the habitable zones (HZs) of low-mass stars is currently one of the greatest astronomical endeavors. Knowledge of the planetary effective surface…
A central need in the field of astrobiology is generalized perspectives on life that make it possible to differentiate abiotic and biotic chemical systems. A key component of many past and future astrobiological measurements is the…
Technosignatures refer to observational manifestations of technology that could be detected through astronomical means. Most previous searches for technosignatures have focused on searches for radio signals, but many current and future…
The disequilibrium combination of abundant methane and carbon dioxide has been proposed as a promising exoplanet biosignature that is readily detectable with upcoming telescopes such as the James Webb Space Telescope. However, few studies…
We present our analysis of how the detectability of carbon dioxide (CO2) on an Earth-like planet varies with respect to signal-to-noise ratio (SNR), wavelength, and molecular abundance. Using the Bayesian Analysis for Remote Biosignature…
The search for life in the universe is a major theme of astronomy and astrophysics for the next decade. Searches for technosignatures are complementary to searches for biosignatures, in that they offer an alternative path to discovery, and…
A hard difficulty in Astrobiology is the precise definition of what life is. All living beings have a cellular structure, so it is not possible to have a broader concept of life hence the search for extraterrestrial life is restricted to…
In the upcoming decades, one of the primary objectives in exoplanet science is to search for habitable planets and signs of extraterrestrial life in the universe. Signs of life can be indicated by thermal-dynamical imbalance in terrestrial…
The conventional observables to identify a habitable or inhabited environment in exoplanets, such as an ocean glint or abundant atmospheric O$_2$, will be challenging to detect with present or upcoming observatories. Here we suggest a new…
The biosignatures of life on Earth do not remain static, but change considerably over the planet's habitable lifetime. Earth's future biosphere, much like that of the early Earth, will consist of predominantly unicellular microorganisms due…
Life is a complex, dynamic chemical system that requires a dense fluid solvent in which to take place. A common assumption is that the most likely solvent for life is liquid water, and some researchers argue that water is the only plausible…
The search for technosignatures from the Galaxy or the nearby universe raises two main questions: What are the possible characteristics of technosignatures? and How can future searches be optimized to enhance the probability of detection?…
The search for signatures of life beyond Earth has been a major goal of space research and astrobiology for decades. The combination of expanded knowledge on Solar System bodies from past missions and advancements in in-situ detection…
A primary goal of the Habitable Worlds Observatory (HWO) is to detect and measure the abundance of biosignature molecules, such as water (H2O) and oxygen (O2), in the atmosphere of Earth analogs. This is expected to require deep…