AERONAUTIQUE - Les plus gros avions du monde - Antonov An-124 (Condor)

D'une capacité de 120 tonnes de fret sur une distance de 5.400 km, l'Antonov An-124 est le plus gros avion de transport civil et militaire du monde produit en série. Surnommé « Condor » à l'OTAN, il permet de transporter des charges hors norme telles que des locomotives, des grues, des satellites, des bateaux... et même un obélisque éthiopien, en 2005. L'armée française y a, elle-même, recours de temps en temps. Conçu dans les années 1980, le quadriréacteur a été modernisé plusieurs fois et peut être chargé par le nez ou par l'arrière avec des rampes de chargement spéciales.

Longueur : 68,9 mètres

Envergure : 73,3 mètres

Premier vol : 1982

FuturaSciences

LA FRANCE A L'AFFICHE - Place du Capitole - Toulouse

Le capitole, place emblématique de la ville de Toulouse. Egalement la place de l’hôtel de ville, très beau monument tout en longueur.

Doz

ASTRONOMY - Crescent Enceladus

 2023 December 16

Crescent Enceladus
Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

Explanation: Peering from the shadows, the Saturn-facing hemisphere of tantalizing inner moon Enceladus poses in this Cassini spacecraft image. North is up in the dramatic scene captured during November 2016 as Cassini's camera was pointed in a nearly sunward direction about 130,000 kilometers from the moon's bright crescent. In fact, the distant world reflects over 90 percent of the sunlight it receives, giving its surface about the same reflectivity as fresh snow. A mere 500 kilometers in diameter, Enceladus is a surprisingly active moon. Data and images collected during Cassini's flybys have revealed water vapor and ice grains spewing from south polar geysers and evidence of an ocean of liquid water hidden beneath the moon's icy crust.

AERONAUTIQUE - Les plus gros avions du monde - Tupolev Tu-160 (Cygne blanc)

D'une masse au décollage atteignant 275 tonnes, le Tupolev Tu-160 (aussi surnommé « Cygne blanc ») affiche une vitesse maximale de plus de 2.000 km/h et peut emporter jusqu'à 40 tonnes d'armements (missiles de croisière, ogives nucléaires...). Mis en service en 1987 lors de la guerre froide, ce bombardier russe est le plus puissant avion de combat du monde et possède une autonomie allant jusqu'à 18.000 km avec un ravitaillement en vol. Il est loin d'avoir dit son dernier mot : une toute nouvelle version avec une motorisation, des systèmes de défense et de communication dernier cri, est en cours de production.

FuturaSciences

ASTRONOMY - Betelgeuse Eclipsed

 2023 December 15

Betelgeuse Eclipsed
Image Credit & Copyright: Sebastian Voltmer

Explanation: Asteroid 319 Leona cast a shadow across planet Earth on December 12, as it passed in front of bright star Betelgeuse. But to see everyone's favorite red giant star fade this time, you had to stand near the center of the narrow shadow path starting in central Mexico and extending eastward across southern Florida, the Atlantic Ocean, southern Europe, and Eurasia. The geocentric celestial event is captured in these two panels taken at Almodovar del Rio, Spain from before (left) and during the asteroid-star occultation. In both panels Betelgeuse is seen above and left, at the shoulder of the familiar constellation Orion. Its brightness diminishes noticeably during the exceedingly rare occultation when, for several seconds, the giant star was briefly eclipsed by a roughly 60 kilometer diameter main-belt asteroid.

ASTRONOMY - Supernova Remnant Cassiopeia A

 2023 December 14

Supernova Remnant Cassiopeia A
Image Credit: NASA, ESA, CSA, STScI; D. Milisavljevic (Purdue University), T. Temim (Princeton University), I. De Looze (University of Gent)

Explanation: Massive stars in our Milky Way Galaxy live spectacular lives. Collapsing from vast cosmic clouds, their nuclear furnaces ignite and create heavy elements in their cores. After only a few million years for the most massive stars, the enriched material is blasted back into interstellar space where star formation can begin anew. The expanding debris cloud known as Cassiopeia A is an example of this final phase of the stellar life cycle. Light from the supernova explosion that created this remnant would have been first seen in planet Earth's sky about 350 years ago, although it took that light 11,000 years to reach us. This sharp NIRCam image from the James Webb Space Telescope shows the still hot filaments and knots in the supernova remnant. The whitish, smoke-like outer shell of the expanding blast wave is about 20 light-years across, while the bright speck near center is a neutron star, the incredibly dense, collapsed remains of the massive stellar core. Light echoes from the massive star's cataclysmic explosion are also identified in Webb's detailed image of supernova remnant Cassiopeia A.

AERONAUTIQUE - Les plus gros avions du monde - Hughes H-4 Hercules (Spruce Goose)

 

En attendant l'envol du Stratolaunch, le Hughes H-4 Hercules reste le plus gros avion ayant jamais volé avec ses 97,50 mètres d'envergure et ses 24 mètres de haut. Enfin, presque : cet hydravion de transport militaire n'a décollé qu'une seule fois en 1947 et n'est resté en l'air qu'une minute à 21 mètres au-dessus de l'eau. Manifestement sous-motorisé, le « Spruce Goose » (l'oie en épicéa) avait été construit entièrement en bois en raison du rationnement de guerre sur les matériaux stratégiques. L'unique exemplaire se trouve aujourd'hui au Musée de l'aviation d'Evergreen à McMinnville dans l'Oregon (États-Unis).

FuturaSciences

ASTRONOMY - Aurora and Milky Way over Norway

 2023 December 12

Aurora and Milky Way over Norway
Image Credit & Copyright: Giulio Cobianchi

Explanation: What are these two giant arches across the sky? Perhaps the more familiar one, on the left, is the central band of our Milky Way Galaxy. This grand disk of stars and nebulas here appears to encircle much of the southern sky. Visible below the stellar arch is the rusty-orange planet Mars and the extended Andromeda galaxy. But this night had more! For a few minutes during this cold arctic night, a second giant arch appeared encircling part of the northern sky: an aurora. Auroras are much closer than stars as they are composed of glowing air high in Earth's atmosphere. Visible outside the green auroral arch is the group of stars popularly known as the Big Dipper. The featured digital composite of 20 images was captured in mid-November 2022 over the Lofoten Islands in Norway.

ASTRONOMY - Solar Minimum versus Solar Maximum

 2023 December 11

AS
Video Credit: NASA, SDO, SVS

Explanation: The surface of our Sun is constantly changing. Some years it is quiet, showing relatively few sunspots and active regions. Other years it is churning, showing many sunspots and throwing frequent Coronal Mass Ejections (CMEs) and flares. Reacting to magnetism, our Sun's surface goes through periods of relative calm, called Solar Minimum and relative unrest, called Solar Maximum, every 11 years. The featured video shows on the left a month in late 2019 when the Sun was near Solar Minimum, while on the right a month in 2014 when near Solar Maximum. The video was taken by NASA's Solar Dynamic Observatory in far ultraviolet light. Our Sun is progressing again toward Solar Maximum in 2025, but displaying even now a surface with a surprisingly high amount of activity.

ASTRONOMY - Big Dipper over Pyramid Mountain

 2023 December 10

Big Dipper over Pyramid Mountain
Image Credit & Copyright: Steve Cullen

Explanation: When did you first learn to identify this group of stars? Although they are familiar to many people around the world, different cultures have associated this asterism with different icons and folklore. Known in the USA as the Big Dipper, the stars are part of a constellation designated by the International Astronomical Union in 1922 as the Great Bear (Ursa Major). The recognized star names of these stars are (left to right) Alkaid, Mizar/Alcor, Alioth, Megrez, Phecda, Merak, and Dubhe. Of course, stars in any given constellation are unlikely to be physically related. But surprisingly, most of the Big Dipper stars do seem to be headed in the same direction as they plough through space, a property they share with other stars spread out over an even larger area across the sky. Their measured common motion suggests that they all belong to a loose, nearby star cluster, thought to be on average only about 75 light-years away and up to 30 light-years across. The cluster is more properly known as the Ursa Major Moving Group. The featured image captured the iconic stars recently above Pyramid Mountain in Alberta, Canada.