Neptune Archives

Models for Neptune and Uranus derived in this study expressed as density versus radius. Contour colors show density. Key elements of the models are labelled. The bright narrow band at the base of the envelope in each case is the boundary region stable against convection, ∼ 120 km and ∼ 180 km wide in the cases of Neptune and Uranus, respectively. -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Ice Giant, Lava / magma ocean / Volcanic Worlds, Neptune, Status Report, Uranus, Water/Hycean Worlds & Oceanography

Ice Giants Revisited: Uranus And Neptune As Magma Ocean Worlds

by Keith CowingJune 18, 2026June 18, 2026

Uranus and Neptune are commonly interpreted as volatile-rich “ice giants”, an assumption that underpins most interior models.

Integrated flux for ALMA’s CO(3-2) line measurement. Superposed as black circles on Neptune’s map are the beam positions observed onto the planet and used for the spatially resolved retrievals. The filled red circle in the lower-left corner indicates the size and orientation of the beam. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Ice Giant, Neptune, Status Report

Latitudinal Variations In Neptune’s Temperature Profile Observed With ALMA

by Keith CowingMay 26, 2026May 26, 2026

Despite the low solar irradiation it receives, Neptune shows a very active atmosphere with some of the most intense dynamics observed in Solar System atmospheres. Characterizing the atmospheric temperature profiles […]

Details of the interior models of Uranus and Neptune. Top: Illustration of the three-layer internal structure model assumed. Both the envelope and mantle contain hydrogen, helium, ices, and rocks, with the mantle expected to have a higher concentration of ices and rocks. The core is composed entirely of rocks. Bottom: Envelope metallicity versus mantle metallicity for interior models of Uranus and Neptune. Each dot represents a model that fits both the gravitational data and radius of the respective planet. The color scale indicates the core mass. -- astro-ph.EP

Astrogeology, Exoplanets, -moons, -comets, Ice Giant, Icy Worlds, Neptune, Status Report, Uranus

Reassessing Planetary Composition: Evidence Of Rock-dominated Envelopes In Uranus And Neptune

by Keith CowingApril 17, 2026April 17, 2026

Although Uranus and Neptune are commonly classified as ice giants, their exact compositions remain poorly constrained. Recent studies of outer Solar System bodies challenge the traditional view that these planets […]

Fully corrected and calibrated albedos of Titan (yellow), Saturn (green), Uranus (blue), and Neptune (red) covering 0.3 µm to 2.1 µm, offset for clarity. Regions of strong telluric absorption are masked in lighter shades, and it should be noted that they are less reliably corrected. The flat regions in the UV were flagged as bad pixels in all images by X-shooter. We also highlight a vertical discontinuity between the VIS and NIR arms of Titan, which is likely due to weather inconsistency. The colors used for these objects are the same in the following figures. -- Astronomy & Astrophysics

Astrochemistry, Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gas Giants, Ice Giant, Jupiter, Mars, Mercury, Neptune, Saturn, Status Report, Titan, Uranus

HiDef Neighbors: Solar System Objects As Exoplanet Analogs I. Gaseous Objects, Planets, Planetary Systems, And Small Bodies

by Keith CowingMarch 27, 2026

Context. Intermediate-resolution spectral observations are vital tools for characterizing the composition and physical properties of Solar System bodies in detail. At present, the planets and moons of our Solar System […]

Ice Giant, Icy Worlds, Neptune, Status Report, Triton, Water/Hycean Worlds & Oceanography

Neptune’s Obliquity Was Likely Engendered By Triton’s Tidal Evolution

by Keith CowingMarch 21, 2026March 21, 2026

Neptune’s present axial tilt of approximately 28 deg. with respect to its orbital plane can be explained by collisions that its primordial core may have experienced with surrounding planetary embryos […]

The Pale Blue Dot is a photograph of Earth taken Feb. 14, 1990, by NASA’s Voyager 1 at a distance of 3.7 billion miles (6 billion kilometers) from the Sun. The image inspired the title of scientist Carl Sagan's book, "Pale Blue Dot: A Vision of the Human Future in Space," in which he wrote: "Look again at that dot. That's here. That's home. That's us." The above image, “Pale Blue Dot Revisited,” was created in 2020 for the 30th anniversary of the iconic picture. The updated version used modern image-processing software and techniques to revisit the well-known Voyager view, while attempting to respect the original data and intent of those who planned the images. NASA/JPL-Caltech Larger image

Imaging & Spectroscopy, Interstellar, Jupiter, Mars, Mercury, Neptune, Press Release, Uranus, Venus

Pale Blue Dot Anniversary

by Keith CowingFebruary 14, 2026February 14, 2026

The Pale Blue Dot is a photograph of Earth taken on Feb. 14, 1990, by NASA’s Voyager 1 spacecraft. Earth appears as a tiny speck of light suspended in a […]

Outer Planets Assessment Group (OPAG) -- NASA

Conferences and Meetings, Ice Giant, Neptune, Status Report, Uranus

OPAG Town Hall at AGU Fall Meeting 2025: December 18

by Keith CowingDecember 13, 2025December 13, 2025

The Outer Planets Assessment Group (OPAG) will hold a Town Hall at the AGU meeting in New Orleans, LA. Please join us for a community discussion! The steering committee will […]

(left) This zoomed-in image of Uranus, captured by Webb’s Near-Infrared Camera (NIRCam) Feb. 6, 2023. The planet displays a blue hue in this representative-color image, made by combining data from two filters (F140M, F300M) at 1.4 and 3.0 microns, which are shown here as blue and orange, respectively.(right) Webb’s Near-Infrared Camera (NIRCam) image of Neptune, taken on July 12, 2022, brings the planet’s rings into full focus for the first time in more than three decades. -- NASA/STSCI

Astrogeology, Atmospheres, Climate, Weather, Ice Giant, Magnetic Fields, Electromagnetism, bioelectricity,, Neptune, Press Release, Uranus

Uranus And Neptune Might Be Rock Giants

by Keith CowingDecember 10, 2025December 10, 2025

The planets in the Solar System are typically divided into three categories based on their composition: the four terrestrial rocky planets (Mercury, Venus, Earth and Mars), followed by the two […]

Astrochemistry, Astrogeology, Exoplanets, -moons, -comets, Ice Giant, Missions & Hardware, Neptune, Status Report, Uranus

Ice Giants Pre-Decadal Survey Mission Study Report

by Keith CowingNovember 20, 2025November 19, 2025

The Ice Giants Study was commissioned by NASA to take a fresh look (as of 2017) at science priorities and concepts for missions to the Uranus and Neptune systems in […]

Illustration of atmosphere–mantle–core coupling across rocky embryos to gas-rich planets. Mantle convection acts as a planetary-scale “conveyor belt,” facilitating chemical communication between the atmosphere and the core. The efficiency of this volatile cycling—potentially probed by the He 1083 nm feature, especially when combined with H Lyman-α—depends on the partition coefficients derived in this study. It governs the redistribution of H and He, the timescale of primordial atmosphere retention, aspects of redox balance in secondary atmospheres, and model predictions for the abundances of atmospheric CHNOPS species, ultimately shaping the H-to-He ratio in the atmospheres of Earth- to Neptune-like planets. -- physics.ao-ph

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Ice Giant, Icy Worlds, Neptune, Status Report, Water/Hycean Worlds & Oceanography

The Fate of Hydrogen and Helium: From Planetary Embryos to Earth- and Neptune-like Worlds

by Keith CowingNovember 3, 2025November 3, 2025

Hydrogen, helium, silicates, and iron are key building blocks of rocky and gas-rich planets, yet their chemical interactions remain poorly constrained.