![[LEFT]: Schematic of the star–planet–observer geometry defining the phase angle α, measured between the star–planet and planet–observer directions. The hemisphere of the planet facing the star is fully illuminated (gold) at all times, while the opposite hemisphere remains in shadow. The observer sees only the portion of the illuminated hemisphere that is visible at a given α, with full illumination visible only at α = 0◦. [RIGHT]: Illustration of planetary phases along an edge-on orbit, with the star at the center and the observer direction indicated below the orbit. Although the star-facing hemisphere remains illuminated throughout the orbit, the visible fraction of this hemisphere changes with phase angle. Full phase occurs at α = 0◦, quadrature at α = 90◦, and new phase at α = 180 , with gibbous and crescent phases spanning the intermediate ranges. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/The-Impact.png?resize=1200%2C714&ssl=1)
[astro-ph.EP] The under-development NASA Habitable Worlds Observatory (HWO) aims to provide breakthroughs in exoplanet science, yet the most effective approaches to modeling the detection and characterization of potentially Earth-like worlds […]
Biosignatures
Posted inUncategorized
NASA Viking Mission: A Perspective of the Labeled Release Biological Experiment on Mars
[Astrobiology (Journal)] The NASA Viking mission successfully landed three separate biological experiments on Mars in 1976 with a goal to detect microbial processes or materials in samples of the planet’s […]
![This global map of Mars (greys) is overlaid with a map of ice “consistency,” C. Values of C near one (dark blue) indicate a high likelihood of ice in three independent mappings. Lower values of C (lighter blues) indicate lower confidence in ice being present, and indicate detection in at least one dataset. The extreme north and south are both rich in ice (dark blues), ice is absent near the equator, and the presence of ice is uncertain (light blues) in the mid-latitude regions best for astronauts. Credit: Morgan & Putzig et al., 2025; Sizemore et al., 2026 -- [PSI]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Laying-Odds.png?resize=1200%2C719&ssl=1)
Posted inMars
Laying Odds On The Potential For Martian Water
[PSI] We know Mars has water ice in its polar regions, but astronauts (and their solar powered equipment!) would much rather experience life closer to Mars’ equator. As NASA looks […]
![A close-up of the polygon fractures discovered by NASA’s Curiosity Mars rover highlights their honeycomb-like textures. Credit: NASA/JPL-Caltech/MSSS [Larger Image]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Curiosity-Mars.png?resize=1200%2C719&ssl=1)
Posted inMars
Curiosity Mars Rover Discovers A Field Of Honeycomb Textures
[NASA] Mission scientists have never seen so many of the many-sided geologic features in one place on the Red Planet.
Posted inAstronomy & Telescopes
ANDES, The High-resolution Spectrograph Oof The ELT: Simulated Performance Of The CORO Module And Overview Of The High-contrast Capabilities For Exoplanet Observations
[astro-ph.IM] We present the simulated performance of the coronagraph (CORO) module for ANDES, the Extremely Large Telescope (ELT) high-resolution spectrograph.
Posted inOrigin & Evolution of Life
When Polymers Meet Primitive Membranes: How Molecular Cooperation May Have Helped Life Begin
[The Hebrew University of Jerusalem] Researchers have identified a simple form of molecular cooperation that may have helped life’s earliest building blocks become more stable and organized.
Posted inCryobiology
Microbial Diversity In Pyrenean Ice Caves: Extreme Cryogenic Environments As Analogues For Extraterrestrial Habitability
[FEMS Microbes] Pyrenean ice caves are the least studies cryogenic environments that preserve perennial ice. These caves host microbial communities adapted to extreme oligotrophy, low temperatures, and episodic water availability, […]
Posted inMars
Cliffs Of Ice On Mars
[NASA/UA HiRISE] The mid-latitudes of Mars are mostly covered with smooth material that scientists have suspected to be ice for some time. The ground is uniform and dusty and does […]
![Schematic diagram (not to scale) of the experimental apparatus used for benzene ice nucleation and growth studies (adapted from Dubois et al. (2021)). Pressure was measured with a capacitance manometer (P1) and an ion gauge (P2). The inset shows a top view of the cooled sample holder with the positions of the three K-type thermocouple gauges (red dots) used for temperature measurements. The ice sample formed on either or both sides of the silicon substrate/tholin sample (grey), which was in the path of the IR beam of the Thermo Fisher iS50. Infrared transmission spectra were collected with a liquid N2-cooled MCT/A detector. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Experimental-Measurements.png?resize=1200%2C717&ssl=1)
Posted inTitan
Experimental Measurements of Benzene Ice Critical Saturation Ratios on Titan Tholins and Impact on the Microphysical Modeling of Titan’s South Polar Benzene Cloud
[astro-ph.EP] The Cassini Composite Infrared Spectrometer (CIRS) revealed the presence of a benzene (C6H6) ice cloud in Titan’s autumn south polar stratosphere, following the northern spring equinox in August 2009.
Posted inBiosignatures & Paleobiology
Substrate-Agnostic 3x: Biosignatures, Technosignatures, Ecologies
[physics.gen-ph] Substrate-agnostic perspectives are currently attracting increased attention. For example, it has become customary to refer to agnostic biosignatures to reflect the range of alternative extraterrestrial biospheres and to account […]