water world Archives

D/H ratio in Solar System objects. Comets exhibit large variations between 1 and 3 times Vienna Standard Mean Ocean Water (VSMOW). The red diamond and arrow mark the revised value of 2.59 ± 0.36 × 10−4 in comet 67P/C-G.2 -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Comets and Asteroids, Habitable Zones, Icy Worlds, Impact events, Status Report, Water/Hycean Worlds & Oceanography

Isotopic Composition Of Cometary Water And The Origin Of Earth’s Oceans

by Keith CowingSeptember 3, 2025September 3, 2025

Studies of the water content and isotopic composition of water-rich asteroids and comets are of key interest for understanding the late accretion stage of the Solar System cometary and chondritic […]

Illustration of the soot line and water ice line structure of protoplanetary disks, and the three chemically distinct planet archetypes. -- astro-ph.EP

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Soot Planets Instead Of Water Worlds

by Keith CowingAugust 26, 2025August 26, 2025

Some low-density exoplanets are thought to be water-rich worlds that formed beyond the snow line of their protoplanetary disc, possibly accreting coequal portions of rock and water.

Synthetic atmospheric transmission spectra of Ross 176 b. Left: Fiducial models for clear or hazy H/He atmospheres with scaled solar abundances. Right: Model for a steam H2O atmosphere. Simulated measurements with error bars are shown for the observation of one (left) or ten (right) transits with JWST NIRISS-SOSS, NIRSpec-G395H, and MIRI-LRS configurations. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exploration Gear & Tech, Habitable Zones, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

Discovery Of A Transiting Hot Water-world Candidate Orbiting Ross 176 With TESS And CARMENES

by Keith CowingJuly 22, 2025July 22, 2025

The case of Ross 176 is a late K-type star that hosts a promising water-world candidate planet. The star has a radius of R∗=0.569±0.020R⊙ and a mass of M⋆ = […]

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Habitable Zones, Icy Worlds, Status Report, Water/Hycean Worlds & Oceanography

On The Relative Humidity Of Earth’s Atmosphere

by Keith CowingJuly 17, 2025July 17, 2025

Water vapour is highly subsaturated in much of the Earth’s atmosphere. This has important consequences for water vapour feedback, and also for general phenomena such as the runaway greenhouse.

The glass sponge, Advhena magnifica, prior to being collected in 2016 at a depth of ~2,000 meters (6,560 feet). Scientists call this class of sponges “glass” because their skeletons are made of silica (glass). Their bodies contain fascinating tissues that consist of many nuclei within a single membrane, and these tissues help conduct electrical signals across the sponge making them able to respond quickly to external stimuli. Image courtesy of the NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.

Away Teams & Field Reports, Biosignatures & Paleobiology, Exploration Gear & Tech, Fossils & Paleontology, Mapping, Geodesy, Cartography, Bathymetry, Nomenclature, Systematics, Natural History, Press Release, Robotics/Rovers/UAVs, ROVs/Submersibles/Diving, Sample Return, Science Fiction, Water/Hycean Worlds & Oceanography

Ocean Planet Exploration And Taxonomy: Naming A Strange New Species

by Keith CowingJuly 14, 2025July 14, 2025

Editor’s note: one day we will begin a detailed exploration of ocean worlds other than our own. Hopefully they will be habitable – and inhabited. Given that we still find […]

The instantaneous Vtid on Proxima b at periastron (a) and at apastron (b), and the orbital-mean amplitude of tidal potential (Vtid) on Proxima b (c) and on Earth (d). -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Status Report, Water/Hycean Worlds & Oceanography

Ocean Tides On Asynchronously Rotating Planets Orbiting Low-mass Stars

by Keith CowingJuly 12, 2025July 12, 2025

Planets in the liquid-water habitable zone of low-mass stars experience large tidal forces, 103 to 104 times those on Earth, due to the small distance between the habitable zone and […]

(a) Galileo Solid State Imaging (SSI) false color data of Europa’s leading hemisphere and Tara Regio (credit: NASA, JPL/Caltech, PIA01295). (b) Illustration of chaos on Europa (credit: NASA, GSFC, PIA00840), showing hypothesized geologic communication between its subsurface ocean and surface (chaos formation mechanisms summarized in e.g., Daubar et al. 2024). (c) Spectral map showing the distribution of irradiated NaCl on Europa, highlighting its concentration in and around Tara Regio (modified from Trumbo et al. 2019). -- astro-ph.IM

Ariel, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Ceres, Enceladus, Europa, Habitable Zones, Icy Worlds, Status Report, Water/Hycean Worlds & Oceanography

Assessing Ocean World Habitability With HWO

by Keith CowingJuly 11, 2025July 11, 2025

The instrument payload of the future Habitable Worlds Observatory (HWO) will span a wide range of wavelengths, including the ultraviolet (UV) region that cannot be easily accessed from the ground […]

A schematic of four observing programs (science cases) proposed in this HWO science case to discover and characterize life beyond Earth. -- astro-ph.EP

Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Imaging & Spectroscopy, Origin & Evolution of Life, Plant Biology, Press Release, Water/Hycean Worlds & Oceanography

Detecting Alien Living Worlds And Photosynthetic Life Using Imaging Polarimetry With The HWO Coronagraph

by Keith CowingJuly 8, 2025July 8, 2025

Our Earth, being the only living planet that we know, provides us with clues that photosynthetic life-forms may be dominant on other exoplanets for billions of years.

Planetary reflectivity (top; total flux) and polarization (bottom; polarized flux) as a function of scattering angle (or phase angle) and wavelength (colors). Glories, rainbows, Rayleigh scattering, and ocean glint generate strong polarization signatures and subtle reflectance signatures. (Figure from Vaughan et al. 2023). -- astro-ph.IM

Astronomy & Telescopes, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

Detecting Surface Liquid Water On Exoplanets

by Keith CowingJuly 8, 2025July 8, 2025

Planets with large bodies of water on their surface will have more temperate and stable climates, and such planets are the ideal places for life-as-we-know-it to arise and evolve.