Gaia Archives

Maps of annual mean sea ice and continental precipitation (A) and annual mean sea surface temperature (in ocean regions) and surface air temperature (over continents) (B) for simulations with Earth-like ocean salinity (35 g/kg) and obliquity (23.5◦ ), at Archean instellation on the left and present-day instellation on the right. Land contours mapped in the figure (in black) are more detailed than the actual Earth-like continent configuration used in the model. -- astro-ph.EP

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Status Report, Terraforming & Geoengineering, Water/Hycean Worlds & Oceanography

Synergistic Effects of Ocean Salinity and Planetary Obliquity Enhance Habitability of Cold Exo-Earths

by Keith CowingMay 6, 2026May 6, 2026

Past work has shown that ocean salinity and planetary obliquity both influence the climates of Earth-like exoplanets throughout the habitable zone of Sun-like stars. The effects of salinity and obliquity […]

STEHM flow chart. Green hexagons are input parameters that are calculated by ExoPlex. Orange hexagons are input parameters set within STEHM. Yellow stadiums are components that are explored by STEHM. Arrows indicate how each section of the code interacts with the others. On the bottom right there is a yellow stadium indicating a choice of tectonic regime. This paper is based on a planet with stagnant lid tectonics, however future versions of the STEHM code will also include plate tectonics. -- astro-ph.EP

AI - Data - Apps - Cybernetics, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Status Report, Water/Hycean Worlds & Oceanography

Smaller Than Earth Habitability Model (STEHM): The Lower Size Limit for Atmosphere Retention in the Habitable Zone

by Keith CowingMay 4, 2026May 4, 2026

With recent advances in exoplanet observational techniques enabling the discovery of increasingly smaller planets, a crucial question emerges in the search for habitable planets: how small can a planet be […]

Starting from the top left corner and moving in a clockwise direction are the companions we detected to 2MASS J01283952-1458042, PM J02024+1034 A, 2MASS J05103956+2946479, 2MASS J07171706-0501031, 2MASS J10430293-0912410, and 2MASS J19445376-2337591. These reconstructed images sometimes contain a third “ghost peak” due to low SNR resulting in a lack of phase information. As noted in Section 3.1, the companions to 2MASS J05103956+2946479 and 2MASS J07171706-0501031 are unbound. -- astro-ph.SR

Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report, Stellar Cartography

The POKEMON Speckle Survey of Nearby M dwarfs. IV. Distance-Limited Catalog (POKEMON-DLC)

by Keith CowingApril 29, 2026April 29, 2026

The Solar Neighborhood is dominated by stars smaller, colder, and fainter than the Sun: the M dwarfs.

a, (i), Lepidodendron reconstruction; (ii), leaf and leaf scar of Lepidodendron; (iii), Lepidodendron strobile and sporangia; (iv), Lepidodendron sporophyll and sporangia; (v), Lepidodendron sporophyll. b, (i), Tomiostrobus reconstruction, modified after ref. 13; (ii) to (iv), Tomiostrobus (= Annalepis) sporophyll with sporangia from Permian–Triassic transitional Kayitou Formation in South China. c, (i), Pleuromeia reconstruction based on in situ Pleuromeia fossil from Middle Triassic Badong Formation in South China; (ii), Pleuromeia vegetative leaf from Middle Triassic Badong Formation in South China; (iii), Pleuromeia sanxiaensis sporophyll with sporangia from Middle Triassic Badong Formation in South China; (iv), Pleuromeia marginulata sporophyll with sporangia from Middle Triassic Badong Formation in South China. d, (i), One possible reconstruction of the Lepacyclotes (= Annalepis) based on in situ fossils from Middle Triassic Badong Formation in South China; (ii), adaxial side of the Lepacyclotes (= Annalepis) sporophyll with sporangia; (iii), abaxial side of the Lepacyclotes (= Annalepis) sporophyll. e, (i), Another possible reconstruction of the Lepacyclotes (= Annalepis) based on in situ fossils from Middle Triassic Badong Formation in South China; (ii), adaxial side of the Lepacyclotes (= Annalepis) zelleri sporophyll with sporangia from Middle Triassic Badong Formation in South China. f, Lepacyclotes (= Annalepis) zelleri sporophyll assemblage in circle from Middle Triassic Badong Formation in South China. g, adaxial side of the Lepacyclotes (= Annalepis) brevicystis sporophyll with sporangia from Middle Triassic Badong Formation in South China, modified after ref. 29. h, (i), Isoetes sketch; (ii) adaxial side of the Isoetes sporophyll with sporangia. The grey circle inside the sporophyll shows sporangium. -- Nature Ecology & Evolution

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Extinction events, Fossils & Paleontology, Gaia - Planetary Perspectives, Impact events, Origin & Evolution of Life, Plant Biology, Press Release

How Primitive Plants Evolved To Survive Earth’s Most Catastrophic Extinction Event

by Keith CowingApril 21, 2026April 21, 2026

How primitive plants evolved to survive Earth’s most catastrophic extinction event.

Down to the core. From left to right: When rebuilt outside of living cells, CorM forms dynamic filaments. Cryo-electron microscopy (cryo-EM) image of purified CorM filaments. Successive zoom-ins show the reconstructed 3D electron density map of the CorM filament, followed by the corresponding atomic model, illustrating the filaments’ assembly into a bipolar double-stranded filament. Credit© Springstein et al. / Science

Astropharmacy / Biotechnology, Biophysics, Biosignatures & Paleobiology, Gaia - Planetary Perspectives, Genomics, Proteomics, Bioinformatics, Habitable Zones, Microbiology & Virology, Nanotechnology & SynBio, Press Release

Anabaena Learns A New Trick – Cyanobacteria Surprise Scientists With Evolutionary Shift

by Keith CowingApril 17, 2026April 17, 2026

Photosynthetic bacteria helped shape Planet Earth. Among them are cyanobacteria that produced the oxygen in our atmosphere and made complex life possible, captivating scientists for decades. Now, researchers at the […]

[L] NASA ID: art002e000192 art002e000192 (April 3, 2026) -- NASA [R] art002e000193 (April 3, 2026) -- NASA

Artemis & Lunar Exploration, Astronauts and Explorers, Gaia - Planetary Perspectives, Habitable Zones, Imaging & Spectroscopy, People Of Astrobiology, Status Report, Water/Hycean Worlds & Oceanography

Our Home World As Seen From Spaceship Integrity During Artemis II

by Keith CowingApril 11, 2026

Left: A view of Earth taken by NASA astronaut and Artemis II Commander Reid Wiseman from one of the Orion spacecraft’s window after completing the translunar injection burn on April […]

A schematic diagram of the hycean Lotka-Volterra model we implement in this work. The schematic shows how various parameters in our model are connected in a vertical, one-dimensional water column.

Ecological Modelling Of Hycean Worlds

by Keith CowingMarch 25, 2026

New observations are opening the possibility of characterising habitable environments in exoplanetary systems, with the recent example of the candidate hycean world K2-18 b.

Paleopoles based on averages of sample Virtual Geomagnetic Poles (VGPs) rather than site VGPs.

Astrogeology, Biogeochemical Cycles & Geobiology, Gaia - Planetary Perspectives, Press Release

Study Shows Movement Of Tectonic Plates 3.5 Billion Years Ago

by Keith CowingMarch 24, 2026March 24, 2026

The history of the Earth is written on the great tablets of tectonic plates.

Strength of key long-term feedbacks governing Earth’s climate system (D. S. Abbot 2016; D. D. B. Koll & T. W. Cronin 2018; C. W. Arnscheidt & D. H. Rothman 2020; P. Forster et al. 2021). Each bar represents the feedback parameter in W m−2 K−1, estimated from Earth system model assessments and paleoclimate constraints. The upper axis shows the approximate feedback strength associated with a 50 K climate perturbation, representative of transitions between major states (e.g., snowball to temperate). Feedbacks are sorted by magnitude. Negative values (blue) represent stabilizing feedback that dampens temperature changes, while positive values (orange) indicate destabilizing feedback that amplifies them. Outgoing longwave radiation and the carbonate–silicate cycle are among the strongest stabilizing processes, while the ice–albedo feedback exerts a strong destabilizing influence. Models incorporating the three dominant types of feedback explain the general behavior of Earth’s long-term mean climate. -- The Planetary Science Journal

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Status Report

Not Earth-like Yet Temperate? More Generic Climate Feedback Configurations Still Allow Temperate Climates in Habitable Zone Exo-Earth Candidates

by Keith CowingMarch 20, 2026March 20, 2026

Earth’s climate is influenced by over a dozen types of feedback, but only three dominate its long-term climate behavior. Models of the exoplanet habitable zone (HZ) assume that this is […]

Allan Hills, Antarctica Credit: Photo by Austin Carter, COLDEX

Arctic / Antarctic / Alpine, Atmospheres, Climate, Weather, Gaia - Planetary Perspectives, Habitable Zones, Press Release

Course Correction Needed Quickly To Avoid Pathway To ‘Hothouse Earth’ Scenario

by Keith CowingFebruary 15, 2026February 15, 2026

Scientists say multiple Earth system components appear closer to destabilization than previously believed, putting the planet in increased danger of following a “hothouse” path driven by feedback loops that can […]

Gaia

Synergistic Effects of Ocean Salinity and Planetary Obliquity Enhance Habitability of Cold Exo-Earths

Smaller Than Earth Habitability Model (STEHM): The Lower Size Limit for Atmosphere Retention in the Habitable Zone

The POKEMON Speckle Survey of Nearby M dwarfs. IV. Distance-Limited Catalog (POKEMON-DLC)

How Primitive Plants Evolved To Survive Earth’s Most Catastrophic Extinction Event

Anabaena Learns A New Trick – Cyanobacteria Surprise Scientists With Evolutionary Shift

Our Home World As Seen From Spaceship Integrity During Artemis II

Ecological Modelling Of Hycean Worlds

Study Shows Movement Of Tectonic Plates 3.5 Billion Years Ago

Not Earth-like Yet Temperate? More Generic Climate Feedback Configurations Still Allow Temperate Climates in Habitable Zone Exo-Earth Candidates

Course Correction Needed Quickly To Avoid Pathway To ‘Hothouse Earth’ Scenario

Alta-X Drone Tests Future Astrobiology / Astrogeology Droid Technology

Landforms In Ares Vallis Carved Out By Ancient Water Flow

Evolution of Stellar Activity and Habitable Zone (EATEN): III. X-ray Activity of Dwarfs in Open Clusters and Field Stars

Radial Velocity Detection Of The TRAPPIST-1 Planetary System With SPIRou And NIRPS

Structure Of An RNA polymerase Ribozyme Replication Complex