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09/09/2024
INVENTIONS A L'HORIZON 2050 - Des aliments sur mesure
ASTRONOMY - Mars: Moon- Craters and Volcanos
2024 September 9
Image Credit: ESA, DLR, FU Berlin, Mars Express; Processing & CC BY 2.0 License: Andrea Luck; h/t: Phil Plait
Explanation: If you could fly over Mars, what might you see? The featured image shows exactly this in the form of a Mars Express vista captured over a particularly interesting region on Mars in July. The picture's most famous feature is Olympus Mons, the largest volcano in the Solar System, visible on the upper right. Another large Martian volcano is visible on the right horizon: Pavonis Mons. Several circular impact craters can be seen on the surface of the aptly named red planet. Impressively, this image was timed to capture the dark and doomed Martian moon Phobos, visible just left of center. The surface feature on the lower left, known as Orcus Patera, is unusual for its large size and oblong shape, and mysterious because the processes that created it still remain unknown. ESA's robotic Mars Express spacecraft was launched in 2003 and, among many notable science discoveries, bolstered evidence that Mars was once home to large bodies of water.
08/09/2024
ASTRONOMY - M31: The Andromeda Galaxy
Image Credit: Subaru (NAOJ), Hubble (NASA/ESA), Mayall (NSF);
Processing & Copyright: R. Gendler & R. Croman
Explanation: The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy. Even at some two and a half million light-years distant, this immense spiral galaxy -- spanning over 200,000 light years -- is visible, although as a faint, nebulous cloud in the constellation Andromeda. A bright yellow nucleus, dark winding dust lanes, and expansive spiral arms dotted with blue star clusters and red nebulae, are recorded in this stunning telescopic image which combines data from orbiting Hubble with ground-based images from Subaru and Mayall. In only about 5 billion years, the Andromeda galaxy may be even easier to see -- as it will likely span the entire night sky -- just before it merges with, or passes right by, our Milky Way Galaxy.
07/09/2024
INVENTIONS A L'HORIZON 2050 - Des arbres lampadaires pour éclairer les rues
ASTRONOMY - Small Moon Deimos
2024 September 7
Image Credit: HiRISE, MRO, LPL (U. Arizona), NASA
Explanation: Mars has two tiny moons, Phobos and Deimos, named for the figures in Greek mythology Fear and Panic. Detailed surface views of smaller moon Deimos are shown in both these panels. The images were taken in 2009, by the HiRISE camera on board the Mars Reconnaissance Orbiter spacecraft, NASA's long-lived interplanetary internet satellite. The outermost of the two Martian moons, Deimos is one of the smallest known moons in the Solar System, measuring only about 15 kilometers across. Both Martian moons were discovered in 1877 by Asaph Hall, an American astronomer working at the US Naval Observatory in Washington D.C. But their existence was postulated around 1610 by Johannes Kepler, the astronomer who derived the laws of planetary motion. In this case, Kepler's prediction was not based on scientific principles, but his writings and ideas were so influential that the two Martian moons are discussed in works of fiction such as Jonathan Swift's Gulliver's Travels, written in 1726, over 150 years before their discovery.
PHENOMENES METEOROLOGIQUES - Un orage enragé
06/09/2024
PLANTES FASCINANTES - L'Orchis d'Italie recouverte de petits hommes nus
ASTRONOMY - Ringed Ice Giant Neptune
2024 September 6
Image Credit: NASA, ESA, CSA, STScI, NIRCam
Explanation: Ringed ice giant Neptune lies near the center of this sharp near-infrared image from the James Webb Space Telescope. The dim and distant world is the farthest planet from the Sun, about 30 times farther away than planet Earth. But in the stunning Webb view, the planet's dark and ghostly appearance is due to atmospheric methane that absorbs infrared light. High altitude clouds that reach above most of Neptune's absorbing methane easily stand out in the image though. Coated with frozen nitrogen, Neptune's largest moon Triton is brighter than Neptune in reflected sunlight, seen at the upper left sporting the Webb telescope's characteristic diffraction spikes. Including Triton, seven of Neptune's 14 known moons can be identified in the field of view. Neptune's faint rings are striking in this space-based planetary portrait. Details of the complex ring system are seen here for the first time since Neptune was visited by the Voyager 2 spacecraft in August 1989.
05/09/2024
PHENOMENES METEOROLOGIQUES - Un pont entre ciel et terre fait de pluie et de grêle
BIOMES - La mangrove
La mangrove, c’est ce paysage étonnant s’il en est où l’on voit des arbres littéralement sortir de l’eau avec leurs racines, ici, mises à jo...
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2021 May 11 Lightning and Orion Beyond Uluru Image Credit & Copyright: Park Liu Explanation: What's happening behind Uluru? A Un...
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Extraordinary Solar Halos Image Credit & Copyright : Magnus Edback Explanation: Welcome to the December Solstice, the first...