habitability Archives

Phanerozoic biodiversity curves. (a) Total Phanerozoic diversity based on raw data82 divided into its three main Evolutionary Faunas (EF), i.e. the Cambrian trilobites, the Paleozoic brachiopods, and the modern gastropods. Tese are three distinct types of fauna whose diversity pattern expanded and contracted in a similar fashion throughout the diferent phases of the Phanerozoic. Each EF includes specifc taxonomic classes that were most abundant during (but not limited to) a certain period in Earth’s history. Furthermore, the EFs successively replaced one another as the principal group throughout the Phanerozoic. Te red arrows represent the Big Five mass extinction events, including the Ordovician–Silurian extinction (~445 Ma ago), Devonian extinction (~375 Ma ago), Permian–Triassic extinction (~250 Ma ago), Triassic-Jurassic extinction (~200 Ma ago) and the Cretaceous-tertiary extinction (~66 Ma ago)81. (b) Corrected biodiversity curve using the shareholder quorum subsampling (SQS) sample standardization method34. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Habitable Zones, Status Report

Variations In Climate Habitability Parameters And Their Effect On Earth’s Biosphere During The Phanerozoic Eon

by Keith CowingAugust 16, 2023August 16, 2023

Essential insights on the characterization and quality of a detectable biosphere are gained by analyzing the effects of its environmental parameters. We compiled environmental and biological properties of the Phanerozoic […]

Mantle temperature field and velocity field of superEarth 55 Cancri e for the reference model. High velocities (larger than three times the mean mantle velocity) are plotted with a red arrow. The magma ocean is indicated in red (fully molten) and orange (partially molten). -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Lava / magma ocean / Volcanic Worlds, Status Report

Interior Dynamics Of Super-Earth 55 Cancri e

by Keith CowingAugust 3, 2023May 11, 2024

The ultra-short-period super-Earth 55 Cancri e has a measured radius of 1.8 Earth radii. Previous thermal phase curve observations suggest a strong temperature contrast between the dayside and nightside of […]

The full modern-Earth high-resolution spectrum from the spectral grid in Susemiehl et al. (accepted), with a zero cloud fraction. We show the full resolution (R) of 500 (shown in pink, top panel), the spectrum binned to R=140 that are used in the nested sampling simulations conducted in this work, (shown in purple, middle panel), and a spectrum at R=70 for reference (shown in dark purple, bottom panel). We also present the bandpass centers used in this study as dots (only in the top panel), and the first and last 20% bandpasses shaded in grey. We note that bandpasses overlap heavily with each other, so we only show the first and last for clarity. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Bayesian Analysis for Remote Biosignature Identification on exoEarths (BARBIE) I: Using Grid-Based Nested Sampling in Coronagraphy Observation Simulations for H2O

by Keith CowingAugust 3, 2023

Detecting H2O in exoplanet atmospheres is the first step on the path to determining planet habitability. Coronagraphic design currently limits the observing strategy used to detect H2O, requiring the choice […]

Mineral-laden water emerging from a hydrothermal vent on the Niua underwater volcano in the Lau Basin, southwest Pacific Ocean. As the water cools, minerals precipitate to form tower-like “chimneys.” Image taken during 2016 cruise “Virtual Vents.” USGS

Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Extremeophiles and Extreme Environments, Habitable Zones, Icy Worlds, Mars, Origin & Evolution of Life, Press Release, Tricorders & Sensors

Organic Biosignature Degradation in Hydrothermal and Serpentinizing Environments: Implications for Life Detection on Icy Moons and Mars

by Keith CowingAugust 2, 2023August 2, 2023

Evidence of liquid water is a primary indicator of habitability on the icy moons in our outer solar system as well as on terrestrial planets such as Mars.

Purine (left) and pyrimidine (right) are stable for two weeks in a range of sulfuric acid concentrations found in the Venus clouds. We have incubated 30-40 mg of each base in 81-98% w/w D2SO4 for two weeks. After the two-week incubation, we measured 1D 13C NMR spectra (solid line spectra), at each of the tested acid concentrations, and compared them to the original 1D 13C NMR spectra collected after ~30-48 h (dashed line spectra and Figure S11). The two-week spectra and the ~30-48 h spectra look virtually identical for all tested concentrations, confirming long-term stability of the compounds in concentrated sulfuric acid solvent. From top to bottom are different concentrations (by weight) of sulfuric acid in water: 98% D2SO4/2% D2O; 94% D2SO4/6% D2O; 88% D2SO4/12% D2O; 81% D2SO4/19% D2O with DMSO-d6 as a reference and at room temperature. All peaks are consistent with the molecules being stable and the structure not being affected by the concentrated sulfuric acid solvent. For two-week stability of other compounds see Figures S12-S14. -- astro-ph.EP

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Extremeophiles and Extreme Environments, Habitable Zones, Press Release, Venus

Stability Of Nucleic Acid Bases In Concentrated Sulfuric Acid: Implications For The Habitability Of Venus’ Clouds

by Keith CowingJuly 24, 2023July 24, 2023

What constitutes a habitable planet is a frontier to be explored and requires pushing the boundaries of our terracentric viewpoint for what we deem to be a habitable environment.

Top: Top-of-atmosphere number flux from the Sun and TRAPPIST-1 (left y-axis). Also co-plotted are the photolysis cross-sections of CO2 (right abscissa). Bottom: CO2 cross-sections weighted by the stellar emission of TRAPPIST-1 and the Sun. The bluer spectrum of TRAPPIST-1 increases the weight of shortwave σCO2 , which is larger, driving an increase in σUV,g. -- astro-ph.EP

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Exoplanets, -moons, -comets, Habitable Zones, Status Report

A Re-Appraisal of CO/O2 Runaway On Habitable Planets Orbiting Low-Mass Stars

by Keith CowingJuly 19, 2023July 19, 2023

Efforts to spectrally characterize the atmospheric compositions of temperate terrestrial exoplanets orbiting M-dwarf stars with the James Webb Space Telescope (JWST) are now underway. Key molecular targets of such searches […]

Artist’s impression, frozen world with sub-surface ocean CREDIT Lujendra Ojha

Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Europa, Exoplanets, -moons, -comets, Habitable Zones, Press Release, Water/Hycean Worlds & Oceanography

Study Increases The Probability Of Finding Water On Other Worlds By x100

by Keith CowingJuly 11, 2023July 11, 2023

A new analysis shows that there are probably many more Earth-like exoplanets with liquid water than had been thought, significantly increasing the chance of finding life. The work finds that […]

Plots showing log-log (left) vs semi-log (right) Age vs. Rotation relationships for the early (top) and mid-late (bottom) M dwarfs. As shown in the plots, the data of both groups are better linearized in semi-log form. It is perhaps possible that each ‘segment’ of the log-log plots represents a real evolutionary stage – e.g., the first segment is pre-main sequence evolution and the second represents the interiors of the M dwarfs synchronizing – and the semi-log plots merge these two distinct stages. However, given the current data and spread of rotation rates in the clusters, such a firm conclusion can’t be drawn here. -- astro-ph.SR

Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Living With a Red Dwarf: The Rotation-Age Relationship of M Dwarfs

by Keith CowingJuly 5, 2023July 5, 2023

Age is a fundamental stellar property, yet for many stars it is difficult to reliably determine. For M dwarfs it has been notoriously so. Due to their lower masses, core […]

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Habitable Zones, Imaging & Spectroscopy, Status Report, Venus

Stability Of Nucleic Acid Bases In Concentrated Sulfuric Acid: Implications For The Habitability Of Venus’ Clouds

by Keith CowingJuly 3, 2023July 3, 2023

What constitutes a habitable planet is a frontier to be explored and requires pushing the boundaries of our terracentric viewpoint for what we deem to be a habitable environment.

Comparison between HST and AstroSat-measured SEDs of HIP 23309 in the FUV (1300-1700 A). Top plot shows data in linear y-scale with error bars; bottom plot is identical to top plot except with log y-scale and omission of error bars for easier viewing. The cyan and black data correspond to the unbinned HST and UVIT data, respectively. The blue points correspond to HST data degraded to the approximate quality of the AstroSat data, to enable a closer comparison. The green points correspond to the AstroSat data binned down by a factor of 5, to improve SNR and enable better visual comparison. We assumed Gaussian uncorrelated noise when rebinning the AstroSat data. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

UV Spectral Characterization of Low-Mass Stars With AstroSat UVIT for Exoplanet Applications: The Case Study of HIP 23309

by Keith CowingJune 29, 2023June 29, 2023

Characterizing rocky exoplanet atmospheres is a key goal of exoplanet science, but interpreting such observations will require understanding the stellar UV irradiation incident on the planet from its host star.

habitability

Variations In Climate Habitability Parameters And Their Effect On Earth’s Biosphere During The Phanerozoic Eon

Interior Dynamics Of Super-Earth 55 Cancri e

Bayesian Analysis for Remote Biosignature Identification on exoEarths (BARBIE) I: Using Grid-Based Nested Sampling in Coronagraphy Observation Simulations for H2O

Organic Biosignature Degradation in Hydrothermal and Serpentinizing Environments: Implications for Life Detection on Icy Moons and Mars

Stability Of Nucleic Acid Bases In Concentrated Sulfuric Acid: Implications For The Habitability Of Venus’ Clouds

A Re-Appraisal of CO/O2 Runaway On Habitable Planets Orbiting Low-Mass Stars

Study Increases The Probability Of Finding Water On Other Worlds By x100

Living With a Red Dwarf: The Rotation-Age Relationship of M Dwarfs

Stability Of Nucleic Acid Bases In Concentrated Sulfuric Acid: Implications For The Habitability Of Venus’ Clouds

UV Spectral Characterization of Low-Mass Stars With AstroSat UVIT for Exoplanet Applications: The Case Study of HIP 23309

Early-career Graduate Students Host An Exclusive, NASA-funded Astrobiology Conference

Intimate Link Between Prebiotic Chemistry And Meteorites: Mechanisms Of Organic Molecule Formation

Microbial Mats Influence The Isotopic Composition And Provenance of Soil Organic Matter In The McMurdo Dry Valleys, Antarctica

Beyond The Prebiotic Soup: Solid Organic Films And Protocell-Like Formation in Prebiotic Discharge Experiments

From Searching For Extraterrestrial Biosignatures To Exploring The Origins Of Life: A Prebiotic Chemistry Perspective