Extinction events Archives

3D view of a typical simulation setup. SW density distribution (color scale), Earth magnetic field lines (red lines), and Sun magnetic field (pink lines). The bold pink arrows indicate the orientation of the IMF (Southward orientation). The green lines indicate the SW velocity stream lines. -- astro-ph.EP

Atmospheres, Climate, Weather, Extinction events, Habitable Zones, Space Weather & Heliophysics, Status Report

On Earth’s Habitability Over The Sun’s Main-sequence History: Joint Influence Of Space Weather And Earth’s Magnetic Field Evolution

by Keith CowingNovember 8, 2023

The aim of this study is to analyze the Earth habitability with respect to the direct exposition of the Earth atmosphere to the solar wind along the Sun’s evolution on […]

Microfossils are contained within black chert like the ones seen here. CREDIT Provided by Erica Barlow

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Extinction events, Fossils & Paleontology, Microbiology & Virology, Origin & Evolution of Life, Press Release

New Microfossils Suggest An Earlier Rise In Complex Life On Earth

by Keith CowingNovember 7, 2023November 7, 2023

Microfossils from Western Australia may capture a jump in the complexity of life that coincided with the rise of oxygen in Earth’s atmosphere and oceans, according to an international team […]

Schematic diagrams highlighting the interesting components of emission from a binary neutron star merger at two different temporal and spatial scales. In (a), the system is shown at sub-parsec scales and within the first few years after the merger. The locations of gamma-ray emission in the dynamical ejecta and the cocoon surrounding the jet are highlighted, as well as the X-ray emission from the interaction between the jet and the interstellar medium (ISM). While the jet and cocoon emission are short-lived, the afterglow produces continuum emission for many years. Only the emitted X-rays produce the fluence that could be lethal. The kilonova, i.e., the UV/optical/IR emission powered by radioactivity in the ejecta, is also shown for additional context, but is undetectable after a week. In (b), the larger, late-time structure of the remnant is shown with the long-since dissipated jet location indicated. The explosion from the merger will launch a strong shock that sweeps out a bubble-like structure as it expands through the ISM, which is a source of potentially threatening cosmic rays. -- astro-ph.HE

Astronomy & Telescopes, Extinction events, Radiation, Status Report

Could A Kilonova Kill: A Threat Assessment

by Keith CowingOctober 19, 2023October 19, 2023

Binary neutron star mergers (BNS) produce high-energy emissions from several physically different sources, including a gamma-ray burst (GRB) and its afterglow, a kilonova, and, at late times, a remnant many […]

Detection of the runaway greenhouse threshold. From simulated radius and instellation measurements of a large (N = 500) survey, we compute the moving average (blue confidence intervals) and fit the runaway greenhouse hypothesis to it (Eqn. 4, random draws from the posterior in red). The pattern is detected with high significance. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Extinction events, Gaia - Planetary Perspectives, Habitable Zones, Imaging & Spectroscopy, Status Report

Bioverse: The Habitable Zone Inner Edge Discontinuity as an Imprint of Runaway Greenhouse Climates on Exoplanet Demographics

by Keith CowingOctober 10, 2023October 9, 2023

Long-term magma ocean phases on rocky exoplanets orbiting closer to their star than the runaway greenhouse threshold – the inner edge of the classical habitable zone – may offer insights […]

Volcanic ash is formed from minerals trapped in a silicate glass, as shown here under a microscope. Reactions with gases from the volcanic plume and atmosphere also form salt crystals on the ash surface, like these asterisk-shaped salts on an ash particle from the 2021 Tajogaite eruption on La Palma, in the Canary Islands, Spain.

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Extinction events, Impact events, Press Release

Cornell Fills Data Gap For Volcanic Ash Effects On Earth Systems

by Keith CowingOctober 4, 2023October 4, 2023

Volcanic ash is no ordinary dust: It gets injected into the atmosphere, climbs to the stratosphere, impacts climate, powders roadways and clogs jet engines.

Three dimensional view of the magnetised stellar wind for Models I and II. The surface magnetic field from March-June 2016 reconstructed by Bellotti et al. (2023) is used at the boundary of the models. The grey streamlines are the magnetic field lines embedded in the wind. The rotation axis of the star is along the z⋆-axis. The two-dimensional cut is placed at the x⋆z⋆ plane, and for indication, the orbital distance of the planet is shown by the translucent sphere at 14.56 R⋆ ≃ 0.028 au. The contour shows the wind velocity and the Alfvén surface is shown by the translucent outer surface. Models I and II predict stellar wind mass-loss rates of 1.1 × 10−15 M⊙ yr−1 and 2.5 × 10−14 M⊙ yr−1 -- astro-ph.SR .

Exoplanets, -moons, -comets, Extinction events, Habitable Zones, Space Weather & Heliophysics, Status Report

The Space Weather Around The Exoplanet GJ 436 b. II. Stellar Wind-exoplanet Interactions

by Keith CowingSeptember 5, 2023September 5, 2023

The M dwarf star GJ 436 hosts a warm-Neptune that is losing substantial amount of atmosphere, which is then shaped by the interactions with the wind of the host star. […]

Gravity map of the Kaapvaal Craton. The Vredefort structure does not have a prominent gravity high or low compared to the surrounding craton. Data from the South African Council for Geoscience. Craton boundary from Hasterok et al. (2022).

Analog Studies, Astrogeology, Caves, Craters, Mountains, Subsurface, Lava Tubes, Extinction events, Fossils & Paleontology, Impact events, Press Release

Earth’s Most Ancient Impact Craters Are Disappearing

by Keith CowingAugust 8, 2023August 8, 2023

Earth’s oldest craters could give scientists critical information about the structure of the early Earth and the composition of bodies in the solar system as well as help to interpret […]

Stellar irradiation comparison for the four inner planets of the Solar System (upper panel) and the LP 890-9 planetary system (lower panel), with scaled planetary radii. The Venus Zone (yellow shade) (Kane et al. 2014) and HZ (blue shade) transition gradually due to the complex climate feedback that may push planets into Earth-like or Venus-like states within the orbital range. HZ limit (solid blue) shown: inner empirical ‘Recent Venus’; and outer ‘Maximum Greenhouse’ limit. A ‘Runaway Greenhouse’ flux limit is also indicated following 1D (black dashed) (Kopparapu et al. 2014) and 3D (black dotted) climate modelling (Kopparapu et al. 2017).

Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Extinction events, Habitable Zones, Press Release, Venus

Venus Atmosphere In 3D Prepares Future Observations Of Rocky Exoplanets

by Keith CowingJune 15, 2023June 15, 2023

The Venus atmosphere may be used as a natural laboratory to understand the evolution of Earth-like planets, according to a study led by the Instituto de Astrofísica e Ciências do […]

Artist's impression of how astronomical forces affect the Earth's motion, climate, and ice sheets. CREDIT NAOJ

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Extinction events, Press Release

Astronomical Forces Control Earth’s Ice Age Cycles

by Keith CowingMay 17, 2023May 17, 2023

A research team, composed of climatologists and an astronomer, have used an improved computer model to reproduce the cycle of ice ages (glacial periods) 1.6 to 1.2 million years ago.

Astronomers using the Gemini South telescope in Chile, operated by NSF’s NOIRLab, have observed the first compelling evidence of a dying Sun-like star engulfing an exoplanet. The “smoking gun” of this event was seen in a long and low-energy outburst from the star — the telltale signature of a planet skimming along a star’s surface. This never-before-seen process may herald the ultimate fate of Earth when our own Sun nears the end of its life in about five billion years. Credit: International Gemini Observatory/NOIRLab/NSF/AURA/M. Garlick/M. Zamani

Astronomy & Telescopes, Exoplanets, -moons, -comets, Extinction events, Imaging & Spectroscopy, Press Release

Watching A Star Devour A Planet: The Ultimate Fate Of Earth?

by Keith CowingMay 4, 2023May 4, 2023

By studying countless stars at various stages of their evolution, astronomers have been able to piece together an understanding of the life cycle of stars and how they interact with […]