Clouds Archives

Mass mixing ratios and condensate/cloud of the O2/CO2 atmosphere - model 5. The 15 major gas phase species are shown in the left hand side column and the solid and liquid species in the right hand side column.

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Hot And cloudy: High Temperature Clouds In Super-Earths And Sub-Neptunes

by Keith CowingJanuary 26, 2026January 26, 2026

JWST observations provide for the first time evidence for an atmosphere on a rocky exoplanet – 55 Cnc e. The atmosphere of 55 Cnc e is hot with Teq>2000K and […]

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

JWST NIRSpec Finds No Clear Signs Of An Atmosphere On TOI-1685 b

by Keith CowingDecember 18, 2025December 18, 2025

Determining the prevalence of atmospheres on terrestrial planets is a core objective in exoplanetary science. While M dwarf systems offer a promising opportunity, conclusive observations of terrestrial atmospheres have remained […]

Artist concept of a cloudy Earth-like exoplanet with colorful biota in the clouds. Adam B. Langeveld/Carl Sagan Institute. Adapted from NASA/Ames/JPL-Caltech.

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, Water/Hycean Worlds & Oceanography

How To Spot Life In The Clouds On Other Worlds

by Keith CowingNovember 12, 2025

An exoplanet with dense or even total cloud cover could help astronomers searching for signs of life beyond our planet.

Lightning energy and rate values consistent with the required lightning power for Venus. The best-fit curve (best agreement with observational constraints on atmospheric abundance of NO, orange line) is plotted as derived from our atmospheric photochemical-kinetic model, with in-cloud Kzz=700 cm2s−1 . The broader possible power range, as determined from the minimum depletion flux from observational constraints and alternative in-cloud Kzz

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Status Report, Venus

Powerful Lightning On Venus Constrained By Atmospheric NO

by Keith CowingOctober 3, 2025October 3, 2025

Signs of lightning on Venus have long been sought, including by space missions and ground-based telescopes searching for optical flashes, plasma waves, or radio signatures.

Artist’s concept of how rocky, potentially habitable worlds elsewhere in our galaxy might appear. Data gathered by telescopes in space and on the ground suggest that small, rocky planets are common. NASA/JPL-Caltech/R. Hurt

Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Imaging & Spectroscopy, Microbiology & Virology, Status Report, Water/Hycean Worlds & Oceanography

Colors Of Life In The Clouds: Biopigments Of Atmospheric Microorganisms As A New Signature To Detect Life On Planets Like Earth

by Keith CowingSeptember 30, 2025September 30, 2025

When Carl Sagan and Ed Salpeter envisioned potential Sinkers, Floaters, and Hunters living in Jupiter’s clouds in 1976 (C. Sagan & E. E. Salpeter 1976), the nature of life in […]

Raw B band polarization measurements of HD 189733 obtained at Gemini North on UT 1 to 7 Aug 2018, which are dominated by observations on the last night (gold points). Top left: Stokes q (linear polarization) modulation as a function of parallactic angle. Telescope linear polarization is modulated by parallactic angle with amplitude ∆(qTP, uTP) = 0.2620±0.0034% (Wiktorowicz et al. 2023), where the best fit curve from Equation 2a is shown in black. Uncertainties in most data points are smaller than the size of the data points. Top right: Same as at top left but for Stokes u (linear polarization, Equation 2b). Bottom left: Same as at top left but for Stokes v (circular polarization, Equation 2c). Bottom right: Temporal variation of parallactic angle, which rotates rapidly as the target crosses the meridian (black dashed lines) around 20:00 LST. This rapid meridian crossing provides the bulk of the telescope polarization modulation necessary for accurate calibration. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

A Scatter of Light from a Polarized World

by Keith CowingSeptember 25, 2025

Many known exoplanets harbor clouds, which lead to degeneracies in spectroscopic models between particle composition and size. Polarimetry, however, provides independent assessment.

The simulations showed that at -15 to -16 degrees Celsius the polysaccharides are probably the most important ice nuclei over gigantic areas of the oceans in the clean southern hemisphere. The graph shows the percentage of modelled polysaccharide-based marine INPs in the sum of modelled INPs (mineral dust + marine polysaccharides) in the lowest model layer for different temperatures. Credit Roland Schrödner, TROPOS

Analog Studies, Arctic / Antarctic / Alpine, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Icy Worlds, Microbiology & Virology, Press Release, Water/Hycean Worlds & Oceanography

Ocean Sugars Are Responsible For A Large Part Of The Ice Nuclei In Clouds Over Southern Oceans

by Keith CowingJuly 17, 2025July 17, 2025

Current climate models have so far been unable to adequately reproduce the clouds over the Southern Ocean around Antarctica. An international team has now taken an important step towards filling […]

Artist impression of the YSES-1 System consisting of the ~16 Myr Sun-like star in the center, YSES-1 b and its dusty circumplanetary disk (right), and YSES-1 c with silicate clouds in its atmosphere (left). Image: Ellis Bogat.

Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release

Silicate Clouds Discovered In The Atmosphere Of Exoplanet YSES-1 b

by Keith CowingJune 12, 2025

Astrophysicists have gained precious new insights into how distant “exoplanets” form and what their atmospheres can look like, after using the James Webb Telescope to image two young exoplanets in […]

Encircled in purple stratospheric haze, Saturn's largest moon, Titan, appears as a softly glowing sphere in this colorized image taken on July 3, 2004, one day after Cassini's first flyby of that moon. Titan has a dense atmosphere composed primarily of nitrogen with a few percent methane. -- NASA Larger image

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Status Report, Titan, Venus

Measurement of Photochemical Haze Refractive Indices and Hygroscopicity: Influence of CO2 in CH4/H2S/N2 Mixtures

by Keith CowingJune 10, 2025June 10, 2025

Atmospheric organic hazes are widespread across various planetary bodies and have significant effects on both the surface and atmosphere. In this study, we investigate the optical and hygroscopic properties of […]

The top panel shows the different rotational configurations of the exo-Earth labeled by a rotational phase. These images only depict how the portion of the surface visible to the observer changes with rotation and don’t imply that the planet is cloudless. The plots show the reflected light spectra for the different rotational phases as simulated by PSG for a cloudy and a cloud-free exo-Earth respectively. The entire wavelength bandpass is seperated into three regions - (i) ultraviolet (UV) (0.2-0.5 µm), (ii) visible (VIS) (0.5-1 µm) and (iii) near-infrared (NIR) (1-2 µm). The simulated error bars have been removed for the sake of visual clarity. The cloudy planet shows a higher continuum in the reflected light which is attributed to the enhanced albedo in the presence of clouds. The spectrum of a cloudy planet also shows a higher degree of variation between rotational phases due to variable cloud patchiness. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Earth As An Exoplanet: Investigating The Effects Of Cloud Variability On The Direct-imaging Of Atmospheres

by Keith CowingMarch 13, 2025March 13, 2025

A planet’s spectrum is dynamic and only represents a time-dependent snapshot of its properties. Changing atmospheric conditions due to climate and weather patterns, particularly variation in cloud cover, can significantly […]