Earth Archives

Earth ring system - Grok via Astrobiology.com

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Caves, Craters, Mountains, Subsurface, Lava Tubes, Extinction events, Fossils & Paleontology, Gaia - Planetary Perspectives, Impact events, Mapping, Geodesy, Cartography, Bathymetry, Press Release, Water/Hycean Worlds & Oceanography

Earth May Have Had A Ring System 466 Million Years Ago

by Keith CowingSeptember 19, 2024September 19, 2024

In a discovery that challenges our understanding of Earth’s ancient history, researchers have found evidence suggesting that Earth may have had a ring system, which formed around 466 million years […]

The skies above the Amazon are almost always churning with clouds and storms, making the basin one of the most difficult places for scientists to map and monitor. The astronaut photograph above—taken while the International Space Station was over the Brazilian state of Tocantins—captures a common scene from the wet season. Vast pillars of moisture rise via convection and then spread outward into anvil clouds as they collide with the stratosphere. larger image -- NASA

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Gaia - Planetary Perspectives, Habitable Zones, Status Report, Water/Hycean Worlds & Oceanography

Substantial Extension of the Lifetime of the Terrestrial Biosphere

by Keith CowingSeptember 18, 2024September 18, 2024

Approximately one billion years (Gyr) in the future, as the Sun brightens, Earth’s carbonate-silicate cycle is expected to drive CO2 below the minimum level required by vascular land plants, eliminating […]

Upper panels: The peak hydrogen envelope mass fraction at the end of accretion, before any mass loss, shown in colour for the slow, medium and fast host star rotators. The time when 90% of the envelope mass is lost due to solar XUV radiation is shown in white contour lines in Myr. Lower panels: The atomic composition of the outgassed atmospheres of the slow, medium and fast rotator simulations at 300 Myr. Values of R/O < 1 (blue) indicate an atmosphere with free oxygen, a value of R/O=1 (green) imply sufficient oxygen to oxidise H to H2O and C to CO2, and values of R/O > 1 (red) indicate reducing conditions (see definition of R/O in equation 8). The white contour lines in the lower panels show a value of R/O = 1.3. The patch of R/O=0 present for the slow rotator is due to the perseverance of the envelope for those high planetary masses even after 300 Myr, with the magma ocean still providing a significant pressure of free oxygen. -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Lava / magma ocean / Volcanic Worlds, Meteorites & Asteroids, Status Report, Water/Hycean Worlds & Oceanography

Evolution of Gas Envelopes and Outgassed Atmospheres of Rocky Planets Formed via Pebble Accretion

by Keith CowingSeptember 18, 2024September 18, 2024

We present here results of numerical simulations of the formation and early evolution of rocky planets through pebble accretion, with an with an emphasis on hydrogen envelope longevity and the […]

Artist’s rendition of variety of exoplanets featured in the new NASA TESS-Keck Survey Mass Catalog, the largest, single, homogenous analysis of TESS planets released by any survey thus far. Credit: W. M. Keck Observatory/Adam Makarenko

Alpha Centauri, Astrogeology, Beta Pictoris, Ceres, Exoplanets, -moons, -comets, Gas Giants, Icy Worlds, Jupiter, Lava / magma ocean / Volcanic Worlds, Mapping, Geodesy, Cartography, Bathymetry, Mars, Mercury, Neptune, Pluto, Proxima Centauri, Saturn, Status Report, tau Ceti, TRAPPIST-1, Uranus, Venus, Water/Hycean Worlds & Oceanography

Classifications For Exoplanet and Exoplanetary Systems

by Keith CowingSeptember 17, 2024September 17, 2024

When a star is described as a spectral class G2V, we know its approximate mass, temperature, age, and size. At more than 5,700 exoplanets discovered, it is a natural developmental […]

Equatorial cuts from MHD simulations (Opher et al., 2024, 2024, accepted) showing the compression of the heliosphere by interstellar clouds with densities of a) 3000 cm−3 and b) 900 cm−3 , where the color contours show neutral hydrogen density. These events may have occurred 2 and 7 Myr ago as our solar system collided with the LxCC and the edge of the Local Bubble, respectively. The red circle shows Earth’s orbit. One can see that Earth experiences densities up to 6000 cm−3 in case (a) and 1500 cm−3 in case (b). -- astro-ph.EP

Astrochemistry, Atmospheres, Climate, Weather, Interstellar, Space Weather & Heliophysics, Status Report

Earth’s Mesosphere During Possible Encounters With Massive Interstellar Clouds 2 and 7 Million Years Ago

by Keith CowingSeptember 12, 2024September 12, 2024

Our solar system’s path has recently been shown to potentially intersect dense interstellar clouds 2 and 7 million years ago: the Local Lynx of Cold Cloud and the edge of […]

Possible conceptual structures for K2-18 b that are explored previously (Hu 2021; Hu et al. 2021; Tsai et al. 2021; Yu et al. 2021; Madhusudhan et al. 2023b; Shorttle et al. 2024; Wogan et al. 2024) and in this work. -- astro-ph.EP

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Neptune, Status Report, Water/Hycean Worlds & Oceanography

Volatile-rich Sub-Neptunes as Hydrothermal Worlds: The Case of K2-18 b

by Keith CowingSeptember 11, 2024September 11, 2024

Temperate exoplanets between the sizes of Earth and Neptune, known as “sub-Neptunes”, have emerged as intriguing targets for astrobiology. It is unknown whether these planets resemble Earth-like terrestrial worlds with […]

MAJIS images of the Pacific Ocean -- ESA

Biosignatures & Paleobiology, Europa, Ganymede, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Jupiter, Missions & Hardware, Press Release, Water/Hycean Worlds & Oceanography

Astrobiology Mission Update: Juice Confirms That Earth Is Habitable

by Keith CowingSeptember 10, 2024September 10, 2024

During its flyby of Earth on 20 August, ESA’s Jupiter Icy Moons Explorer (Juice) found ingredients for life in Earth’s atmosphere.

Closed diamonds: this study (pyrolite composition at fO2 = IW + 2.0), including ±50 °C uncertainties (described in the note of Table 1); open diamonds: Ishii et al.19 (minimum solidus temperatures, indicated by the red arrows, for a pyrolite composition at estimated IW − 1.2); open circles: Herzberg et al.17 (KLB-1 peridotite composition, estimated IW − 1.2); open squares: Andrault et al.20 (chondritic mantle composition, oxygen fugacity not determined but more oxidized than IW − 1.2); crosses: Pierru et al.22 (pyrolitic mantle composition, oxygen fugacity estimated to be about IW + 2). All data are presented as mean values with ± standard errors (the latter when provided by the authors; Source Data Fig. 1). Dashed lines show predicted solidi at fO2 conditions invoked in siderophile element-based core formation models (IW − 1, IW − 2 and IW − 4), predicted based on equation (1). -- Okayama University

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Habitable Zones, Lava / magma ocean / Volcanic Worlds, Press Release, Water/Hycean Worlds & Oceanography

Uncovering The Role Of Oxygen Concentration In The Formation Of Early Earth Magma Ocean

by Keith CowingAugust 28, 2024August 27, 2024

It is widely accepted that the early Earth largely consisted of molten magma, forming a global ocean of magma. This extreme state of Earth was likely caused by the intense […]

As Juice flew just 6840 km above Southeast Asia and the Pacific Ocean, it snapped a series of images with its onboard monitoring cameras, and collected scientific data with eight of its ten instruments. Larger image

Biosignatures & Paleobiology, Europa, Exploration Gear & Tech, Ganymede, Icy Worlds, Imaging & Spectroscopy, Jupiter, Missions & Hardware, Moon, Status Report, Tricorders & Sensors, Venus, Water/Hycean Worlds & Oceanography

Astrobiology Droid Update: Juice Rerouted To Venus After The First lunar-Earth Flyby

by Keith CowingAugust 21, 2024August 21, 2024

ESA’s Jupiter Icy Moons Explorer (Juice) has successfully completed a world-first lunar-Earth flyby, using the gravity of Earth to send it Venus-bound, on a shortcut to Jupiter through the inner […]

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Gaia - Planetary Perspectives, Moon, Status Report

The Length Of A Day On Earth And Its Impact On The Evolution Of Life

by Keith CowingAugust 19, 2024August 17, 2024

The Earth’s rotation has been decelerating throughout its history due to tidal dissipation, but the variation of the rate of this deceleration through time has not been established. We present […]

Earth

Earth May Have Had A Ring System 466 Million Years Ago

Substantial Extension of the Lifetime of the Terrestrial Biosphere

Evolution of Gas Envelopes and Outgassed Atmospheres of Rocky Planets Formed via Pebble Accretion

Classifications For Exoplanet and Exoplanetary Systems

Earth’s Mesosphere During Possible Encounters With Massive Interstellar Clouds 2 and 7 Million Years Ago

Volatile-rich Sub-Neptunes as Hydrothermal Worlds: The Case of K2-18 b

Astrobiology Mission Update: Juice Confirms That Earth Is Habitable

Uncovering The Role Of Oxygen Concentration In The Formation Of Early Earth Magma Ocean

Astrobiology Droid Update: Juice Rerouted To Venus After The First lunar-Earth Flyby

The Length Of A Day On Earth And Its Impact On The Evolution Of Life

Impact Crater Hydrothermal Systems Support Rapid Microbial Enrichment and Diverse Metabolic Potential

Photometric and Spectroscopic Observations of Comet 2P/Encke’s Nucleus in the Mid-Infrared Wavelength Region

A New Method Maps An Exoplanet’s True Shape

Wavefront-Conditioned Photon Measurements for Exoplanet Spectroscopy: Contrast Limits and Conditional Gains

ExoPAG 35 – Early Career Talks Invitation