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.

FuturaSciences

BIOMES - Canada

Au Canada, il y a aussi des forêts tempérées

FuturaSciences

ASTRONOMY - Apollo 12 and Surveyor 3

 2024 November 15

Apollo 12 and Surveyor 3
Image Credit: NASA, Apollo 12, Alan Bean - Stereo Image Copyright: Kevin Frank

Explanation: Put on your red/blue glasses and gaze across the western Ocean of Storms on the surface of the Moon. The 3D anaglyph features Apollo 12 astronaut Pete Conrad visiting the Surveyor 3 spacecraft in November of 1969. Surveyor 3 had landed at the site on the inside slope of a small crater about 2 1/2 years earlier in April of 1967. Visible on the horizon beyond the far crater wall, Apollo 12's Lunar Module Intrepid touched down less than 200 meters (650 feet) away, easy moonwalking distance from the robotic Surveyor spacecraft. This stereo image was carefully created from two separate pictures (AS12-48-7133, AS12-48-7134) captured on the lunar surface. They depict the scene from only slightly different viewpoints, approximating the separation between human eyes.

BIOMES - Prairies - savanes - brousses

Des prairies, des savanes et des brousses, il y en a aussi dans les régions tempérées.

FuturaSciences

ASTRONOMY - IC 348 and Barnard 3

 2024 November 14

IC 348 and Barnard 3
Image Credit & Copyright: Ashraf Abu Sara

Explanation: A great nebulous region near bright star omicron Persei offers this study in cosmic contrasts. Captured in the telescopic frame the colorful complex of dust, gas, and stars spans about 3 degrees on the sky along the edge of the Perseus molecular cloud some 1000 light-years away. Surrounded by a bluish halo of dust reflected starlight, omicron Persei itself is just left of center. Immediately below it lies the intriguing young star cluster IC 348 recently explored by the James Webb Space Telescope. In silhouette against the diffuse reddish glow of hydrogen gas, dark and obscuring interstellar dust cloud Barnard 3 is at upper right. Of course the cosmic dust also tends to hide newly formed stars and young stellar objects or protostars from prying optical telescopes. At the Perseus molecular cloud's estimated distance, this field of view would span about 50 light-years.