Encore une jolie photo de la NASA :-)

What's happening to this cloud? Ice crystals in a distant cirrus cloud are acting like little floating prisms. Known informally as a fire rainbow for its flame-like appearance, a circumhorizon arc appears parallel to the horizon. For a circumhorizontal arc to be visible, the Sun must be at least 58 degrees high in a sky where cirrus clouds present below -- in this case cirrus fibrates. The numerous, flat, hexagonal ice-crystals that compose the cirrus cloud must be aligned horizontally to properly refract sunlight in a collectively similar manner. Therefore, circumhorizontal arcs are somewhat unusual to see. The featured fire rainbow was photographed earlier this month near North Fork Mountain in West Virginia, USA.

Traduction deepl.com :
Qu'arrive-t-il à ce nuage ? Des cristaux de glace dans un cirrus lointain agissent comme de petits prismes flottants. Connu sous le nom d'arc-en-ciel de feu pour son aspect de flamme, un arc circumhorizon apparaît parallèlement à l'horizon. Pour qu'un arc circumhorizon soit visible, le Soleil doit se trouver à une hauteur d'au moins 58 degrés dans un ciel où des cirrus sont présents en dessous -- dans ce cas, des cirrus fibrés. Les nombreux cristaux de glace hexagonaux, plats, qui composent le cirrus doivent être alignés horizontalement pour réfracter correctement la lumière du soleil d'une manière collectivement similaire. Par conséquent, les arcs circumhorizontaux sont plutôt inhabituels à voir. L'arc-en-ciel de feu présenté ici a été photographié au début du mois près de North Fork Mountain en Virginie occidentale, aux États-Unis.

Is that one galaxy or three? Toward the right of the featured Hubble image of the massive galaxy cluster Abell 3827 is what appears to be a most unusual galaxy -- curved and with three centers. A detailed analysis, however, finds that these are three images of the same background galaxy -- and that there are at least four more images. Light we see from the single background blue galaxy takes multiple paths through the complex gravity of the cluster, just like a single distant light can take multiple paths through the stem of a wine glass. Studying how clusters like Abell 3827 and their component galaxies deflect distant light gives information about how mass and dark matter are distributed. Abell 3827 is so distant, having a redshift of 0.1, that the light we see from it left about 1.3 billion years ago -- before dinosaurs roamed the Earth. Therefore, the cluster's central galaxies have now surely all coalesced -- in a feast of galactic cannibalism -- into one huge galaxy near the cluster's center.

Très jolie :-)

The Ring Nebula (M57), is more complicated than it appears through a small telescope. The easily visible central ring is about one light-year across, but this remarkably deep exposure - a collaborative effort combining data from three different large telescopes - explores the looping filaments of glowing gas extending much farther from the nebula's central star. This composite image includes red light emitted by hydrogen as well as visible and infrared light. The Ring Nebula is an elongated planetary nebula, a type of nebula created when a Sun-like star evolves to throw off its outer atmosphere to become a white dwarf star. The Ring Nebula is about 2,500 light-years away toward the musical constellation Lyra.

When do cloud bottoms appear like bubbles? Normally, cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. As water droplets grow, an opaque cloud forms. Under some conditions, however, cloud pockets can develop that contain large droplets of water or ice that fall into clear air as they evaporate. Such pockets may occur in turbulent air near a thunderstorm. Resulting mammatus clouds can appear especially dramatic if sunlit from the side. The mammatus clouds pictured here, lasting only a few minutes, were photographed over Regina, Saskatchewan, Canada, just after a storm in 2012.

Étoiles filantes

Joli :-)

Today the Sun reaches its northernmost point in planet Earth's sky. Called a solstice, many cultures mark this date as a change of seasons -- from spring to summer in Earth's Northern Hemisphere and from fall to winter in Earth's Southern Hemisphere. Precisely, the single time of solstice occurs today for some parts of the world, but tomorrow for other regions. The featured image was taken during the week of the 2008 summer solstice at Stonehenge in United Kingdom, and captures a picturesque sunrise involving fog, trees, clouds, stones placed about 4,500 years ago, and a 4.5 billion year old large glowing orb. Even given the precession of the Earth's rotational axis over the millennia, the Sun continues to rise over Stonehenge in an astronomically significant way.

What does the largest moon in the Solar System look like? Jupiter's moon Ganymede, larger than even Mercury and Pluto, has an icy surface speckled with bright young craters overlying a mixture of older, darker, more cratered terrain laced with grooves and ridges. The cause of the grooved terrain remains a topic of research, with a leading hypothesis relating it to shifting ice plates. Ganymede is thought to have an ocean layer that contains more water than Earth -- and might contain life. Like Earth's Moon, Ganymede keeps the same face towards its central planet, in this case Jupiter. The featured image was captured last week by NASA's robotic Juno spacecraft as it passed only about 1000 kilometers above the immense moon. The close pass reduced Juno's orbital period around Jupiter from 53 days to 43 days. Juno continues to study the giant planet's high gravity, unusual magnetic field, and complex cloud structures.

This moon appears multiply strange. This moon was a full moon, specifically called a Flower Moon at this time of the year. But that didn't make it strange -- full moons occur once a month (moon-th). This moon was a supermoon, meaning that it reached its full phase near its closest approach to the Earth in its slightly elliptical orbit. Somewhat strange, a supermoon appears a bit larger and brighter than the average full moon -- and enables it to be called a Super Flower Moon. This moon was undergoing a total lunar eclipse. An eclipsed moon can look quite strange, being dark, unevenly lit, and, frequently, red -- sometimes called blood red. Therefore, this moon could be called a Super Flower Blood Moon. This moon was seen through thin clouds. These clouds created a faint corona around the moon, making it look not only strange, but colorful. This moon was imaged so deeply that the heart of the Milky Way galaxy, far in the background, was visible to its lower right. This moon, this shadow, this galaxy and these colors were all captured last month near Cassilis, NSW, Australia -- with a single shot. (Merged later with two lower shots that better capture the Milky Way.)