mesosphere Archives - Astrobiology

Meteorite heading through Earth's atmosphere -- Grok via Astrobiology.com

Atmospheres, Climate, Weather, Away Teams & Field Reports, Impact events, Meteorites & Asteroids, Planetary Protection & Biosafety, Sample Return, Status Report

Century-Scale Effect Of Climate Change On Meteorite Falls

by Keith CowingAugust 28, 2025

Climate change is inducing a global atmospheric contraction above the tropopause (~10 km), leading to systematic decrease in neutral air density.

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 […]

Contour plot of temperatures from the atmospheric structure model, using CIRS observations from 2015 and 2017 at pressures higher than 10−6 bar to 3 × 10−4 bar and UVIS observations at pressures lower than 10−6 to 2 × 10−8 bar, where the quoted pressure limits depend on latitude. The temperatures in the coverage gap between the instruments were filled in to match the H2 density vs. radius in the thermosphere. The black diamonds show the location of the CH4 homopause, taken where CH4 volume mixing ratio equals 5 × 10−5 . A cartoon illustrating speculated low-latitude upwelling is depicted with dashed arrows near the high-altitude homopause levels. astro-ph.EP

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Imaging & Spectroscopy, Missions & Hardware, Saturn, Status Report

A Pole-to-Pole Map Of Hydrocarbons In Saturn’s Upper Stratosphere And Mesosphere

by Keith CowingMay 6, 2024May 6, 2024

We analyze data from the final two years of the Cassini mission to retrieve the distributions of methane, ethane, acetylene, ethylene, and benzene in Saturn’s upper stratosphere and mesosphere from […]

Weighting function distribution for nadir and limb viewing geometries for the 2017 observation. Beam locations were placed such that the top-of-atmosphere latitudes matched for both locations for each observation, taking into account Titan’s tilt. Weighting distributions are not coadded, as plotted, but calculated individually for each extraction region. Titan’s solid body radius (2575 km; dashed circle), top of atmosphere (1200 km above the surface; solid circle), and top-of-atmosphere latitudes are shown. The FWHM of the ALMA beam is denoted by the dashed ellipses. -- astro-ph.EP

Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Status Report, Titan

Variability in Titan’s Mesospheric HCN and Temperature Structure as Observed by ALMA

by Keith CowingFebruary 6, 2024February 6, 2024

The temperature structure of Titan’s upper atmosphere exhibits large variability resulting from numerous spatially and temporally irregular external energy sources, seasonal changes, and the influence of molecular species produced via […]

View of Jupiter’s north polar region seen as Pioneer 11 left the Jovian system in December 1974. -- NASA.gov

Particles, Environments And Possible Ecologies In The Jovian Atmosphere

by Keith CowingMay 1, 1976July 3, 2026

The eddy diffusion coefficient is estimated as a function of altitude, separately for the Jovian troposphere and mesosphere. Complex organic molecules produced by the Ly alpha photolysis of methane may […]