BIOMES - La Corse

La Corse, au cœur de l’environnement méditerranéen

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ASTRONOMY - Earthset from Orion

 2024 November 20

Earthset from Orion
Image Credit: NASA, Artemis 1

Explanation: Eight billion people are about to disappear in this snapshot from space taken on 2022 November 21. On the sixth day of the Artemis I mission, their home world is setting behind the Moon's bright edge as viewed by an external camera on the outbound Orion spacecraft. Orion was headed for a powered flyby that took it to within 130 kilometers of the lunar surface. Velocity gained in the flyby maneuver was used to reach a distant retrograde orbit around the Moon. That orbit is considered distant because it's another 92,000 kilometers beyond the Moon, and retrograde because the spacecraft orbited in the opposite direction of the Moon's orbit around planet Earth. Orion entered its distant retrograde orbit on November 25. Swinging around the Moon, Orion reached a maximum distance (just over 400,000 kilometers) from Earth on November 28, exceeding a record set by Apollo 13 for most distant spacecraft designed for human space exploration. The Artemis II mission, carrying 4 astronauts around the moon and back again, is scheduled to launch no earlier than September 2025.

BIOMES - Autriche

Les belles couleurs automnales des forêts tempérées d’Autriche

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ASTRONOMY - Undulatus Clouds over Las Campanas Observatory

2024 November 19

Undulatus Clouds over Las Campanas Observatory
Image Credit & Copyright: Yuri Beletsky (Carnegie Las Campanas Observatory, TWAN); h/t: Alice Allen

Explanation: What's happening with these clouds? While it may seem that these long and thin clouds are pointing toward the top of a hill, and that maybe a world-famous observatory is located there, only part of that is true. In terms of clouds, the formation is a chance superposition of impressively periodic undulating air currents in Earth's lower atmosphere. Undulatus, a type of Asperitas cloud, form at the peaks where the air is cool enough to cause the condensation of opaque water droplets. The wide-angle nature of the panorama creates the illusion that the clouds converge over the hill. In terms of land, there really is a world-famous observatory at the top of that peak: the Carnegie Science's Las Campanas Observatory in the Atacama Desert of Chile. The two telescope domes visible are the 6.5-meter Magellan Telescopes. The featured coincidental vista was a surprise but was captured by the phone of a quick-thinking photographer in late September. 

METEOROLOGIE - La violence d'un orage en Arizona

La violence d'un orage en Arizona. © Edward Mitchell 

Ce cliché capturé en pose longue à Peoria, en Arizona (États-Unis), montre la violence des orages qui frappent cet état désertique lors la période de la mousson sud-américaine, au cours de l'été. Au milieu de la photo, trône un magnifique saguaro, cactus géant typique de la région.

ASTRONOMY - Stars and Dust in the Pacman Nebula

 2024 November 18

Stars and Dust in the Pacman Nebula
Image Credit & Copyright: Malcolm Loro

Explanation: Stars can create huge and intricate dust sculptures from the dense and dark molecular clouds from which they are born. The tools the stars use to carve their detailed works are high energy light and fast stellar winds. The heat they generate evaporates the dark molecular dust as well as causing ambient hydrogen gas to disperse and glow. Pictured here, a new open cluster of stars designated IC 1590 is nearing completion around the intricate interstellar dust structures in the emission nebula NGC 281, dubbed the Pac-man Nebula because of its overall shape. The dust cloud just above center is classified as a Bok Globule as it may gravitationally collapse and form a star -- or stars. The Pacman Nebula lies about 10,000 light years away toward the constellation of Cassiopeia.

ASTRONOMY - LDN 1471: A Windblown Star Cavity

 2024 November 17

LDN 1471: A Windblown Star Cavity
Image Credit: Hubble, NASA, ESA; Processing & License: Judy Schmidt

Explanation: What is the cause of this unusual parabolic structure? This illuminated cavity, known as LDN 1471, was created by a newly forming star, seen as the bright source at the peak of the parabola. This protostar is experiencing a stellar outflow which is then interacting with the surrounding material in the Perseus Molecular Cloud, causing it to brighten. We see only one side of the cavity -- the other side is hidden by dark dust. The parabolic shape is caused by the widening of the stellar-wind blown cavity over time. Two additional structures can also be seen either side of the protostar; these are known as Herbig-Haro objects, again caused by the interaction of the outflow with the surrounding material. What causes the striations on the cavity walls, though, remains unknown. The featured image was taken by NASA and ESA’s Hubble Space Telescope after an original detection by the Spitzer Space Telescope.

BIOMES - Nouvelle Calédonie

Les forêts sèches de Nouvelle-Calédonie en grand danger

FuturaSciences

ASTRONOMY - Pluto at Night

2024 November 16

Pluto at Night
Image Credit: NASA, Johns Hopkins Univ./APL, Southwest Research Institute

Explanation: The night side of Pluto spans this shadowy scene. In the stunning spacebased perspective the Sun is 4.9 billion kilometers (almost 4.5 light-hours) behind the dim and distant world. It was captured by far flung New Horizons in July of 2015 when the spacecraft was at a range of some 21,000 kilometers from Pluto, about 19 minutes after its closest approach. A denizen of the Kuiper Belt in dramatic silhouette, the image also reveals Pluto's tenuous, surprisingly complex layers of hazy atmosphere. Near the top of the frame the crescent twilight landscape includes southern areas of nitrogen ice plains now formally known as Sputnik Planitia and rugged mountains of water-ice in the Norgay Montes. 

METEOROLOGIE - Ciel de feu à Barcelone

Ce ciel de feu spectaculaire a été pris en photo à Barcelone en Espagne : on peut y voir des nuages lenticulaires très bien formés, par l'action du vent sur les reliefs, et illuminés par la lumière du coucher de soleil.

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