The Solar System:
"Fontana del Nettuno" ("Fountain of Neptune") by Giovanni Ceccarini (19th century CE; Italian), from 1822-23 (Piazza del Popolo, Rome, Italy).Credit: Giovanni Ceccarini; photographed by Jebulon (Wikimedia Commons) [link]
Why so (really) blue?
This image of Neptune was obtained in visible light by Voyager 2 in 1989. The picture shows the Great Dark Spot and its companion bright smudge; on the west limb of Neptune (lower left), the fast moving bright feature called Scooter and the little dark spot are visible. These clouds were seen to persist for as long as Voyager's cameras could resolve them. North of these, a bright cloud band similar to the south polar streak can be seen.Credit (image and some text): NASA/JPL [link]
Ice? You'll have to be more specific...
How do you create ice XVIII?
In this time-integrated photograph of an X-ray diffraction experiment, giant lasers focus on a water sample to compress it into the superionic phase. Additional laser beams generate an X-ray flash off an iron foil that allows the researchers to take a snapshot of the water in its superionic ice state.Credit (image and some text): Millot, Coppari, Kowaluk (LLNL) [link]
The conditions for creating superionic ice XVIII are difficult to produce on Earth, but exist naturally deep in the interior of the atmospheres of ice giant planets like Uranus and Neptune.
The discovery of superionic ice potentially solves the puzzle of what giant icy planets like Uranus and Neptune are made of. They’re now thought to have gaseous, mixed-chemical outer shells, a liquid layer of ionized water below that, a solid layer of superionic ice comprising the bulk of their interiors, and rocky centers.Credit (image and some text): Moteh, I., 2019, Quanta Magazine [link]
This Voyager 2 photograph of Neptune shows three of the prominent features seen on Neptune in 1989. At the north (top) is the Great Dark Spot, accompanied by bright, white clouds that undergo rapid changes in appearance. To the south of the Great Dark Spot is the bright feature that Voyager scientists have nicknamed "Scooter." Still farther south is the feature called "Dark Spot 2," which has a bright core. Each feature moves eastward at a different velocity, so it is only occasionally that they appear close to each other, such as at the time this image was obtained.
A 1994 observation of Neptune with the Hubble Space Telescope showed that the Great Dark Spot had disappeared. But by 2016, when Neptune was observed again with the Hubble Space Telescope, a new dark spot had appeared.
The full visible-light image of Neptune from the Hubble Space Telescope (left) shows that a new dark feature resides near and below a patch of bright clouds in the planet's southern hemisphere. The dark spot measures roughly 3,000 miles (4,800 kilometers) across. Other high-altitude clouds can be seen at the planet's equatorial region and polar regions.Credit (image and some text): NASA, ESA, and M.H. Wong and J. Tollefson (UC Berkeley) [link]
A cloudy day on Neptune
Hey, guess what? Neptune has rings!
(but they're pretty unimpressive)
This pair of sensitive Voyager 2 images show the full ring system of Neptune. The planet itself would be located in the black strip between the two images on either side. In order to photograph the rings, Neptune has to be blocked out. In the bright reflected sunlight from Neptune, the faint, narrow rings would be washed out and all but invisible.Credit: NASA/JPL [link]
In Neptune's outermost ring, 23,400 km (39,000 miles) out, material mysteriously clumps into three bright arcs. These arcs are probably caused by gravitational interactions with the shepherd moon Galatea, which orbits just inside the ring. Voyager 2 acquired this image as it encountered Neptune in August of 1989.Credit: NASA/JPL [link]
Moons of Neptune
Global color mosaic of Neptune's largest moon, Triton, obtained in 1989 by Voyager 2. With a radius of 1350 km (839 mi), about 22% smaller than Earth's moon, Triton is by far the largest satellite of Neptune. It is one of only three objects in the Solar System known to have a nitrogen-dominated atmosphere (the others are Earth and Saturn's giant moon, Titan). Triton's surface is so cold that most of Triton's nitrogen atmosphere is condensed as frost, making it the only satellite in the Solar System known to have a surface made mainly of nitrogen ice.Credit (image and some text): NASA/JPL/USGS [link]