"La Lune dans les ailes"
"J'avais remarqué la possibilité de faire une photo sympa moulin et lune. Parti le bon soir, avec une bonne météo et de la patience.
Ce moulin se trouve a terdeghem 59"
Pierre Derycke
31/12/2023
BIOMIMETISME - Innovations inspirées par la Nature - Des robots spatiaux équipés de patte de gecko
Comment font les geckos pour escalader des surfaces totalement lisses sans tomber ? Le dessous de leurs pattes est tapissé de milliers de replis eux-mêmes recouverts de petits poils. Ces lamelles adhésives ne sécrètent pas de mucus ou autres substances biologiques, leur capacité adhésive tient seulement dans l'apparition des forces de van der Waals entre les poils des pattes et la surface sur laquelle le gecko marche. Elles sont suffisamment fortes pour que le petit reptile puisse marcher au plafond.
Cette prouesse a inspiré les ingénieurs en aérospatial pour créer des systèmes d'adhérence sèche qui pourraient équiper des robots officiant dans le vide spatial où les ventouses sont inefficaces. Un matériau conçu à partir des pattes de gecko a été testé avec succès en 2017 par des chercheurs de l'université de Standford.
© Brian Gratwicke, Wikimedia Commons, CC by-sa 2.0 Générique
FuturaSciences
ASTRONOMY - Illustris: A Simulation of the Universe
2023 December 31
Video Credit: Illustris Collaboration, NASA, PRACE, XSEDE, MIT, Harvard CfA;
Music: The Poisoned Princess (Media Right Productions)
Explanation: How did we get here? Click play, sit back, and watch. A computer simulation of the evolution of the universe provides insight into how galaxies formed and perspectives into humanity's place in the universe. The Illustris project exhausted 20 million CPU hours in 2014 following 12 billion resolution elements spanning a cube 35 million light years on a side as it evolved over 13 billion years. The simulation tracks matter into the formation of a wide variety of galaxy types. As the virtual universe evolves, some of the matter expanding with the universe soon gravitationally condenses to form filaments, galaxies, and clusters of galaxies. The featured video takes the perspective of a virtual camera circling part of this changing universe, first showing the evolution of dark matter, then hydrogen gas coded by temperature (0:45), then heavy elements such as helium and carbon (1:30), and then back to dark matter (2:07). On the lower left the time since the Big Bang is listed, while on the lower right the type of matter being shown is listed. Explosions (0:50) depict galaxy-center supermassive black holes expelling bubbles of hot gas. Interesting discrepancies between Illustris and the real universe have been studied, including why the simulation produced an overabundance of old stars.
30/12/2023
ASTRONOMY - The Last Full Moon
2023 December 30
Image Credit & Copyright: Giacomo Venturin
Explanation: Known to some in the northern hemisphere as December's Cold Moon or the Long Night Moon, the last full moon of 2023 is rising in this surreal mountain and skyscape. The Daliesque scene was captured in a single exposure with a camera and long telephoto lens near Monte Grappa, Italy. The full moon is not melting, though. Its stretched and distorted appearance near the horizon is caused as refraction along the line of sight changes and creates shifting images or mirages of the bright lunar disk. The changes in atmospheric refraction correspond to atmospheric layers with sharply different temperatures and densities. Other effects of atmospheric refraction produced by the long sight-line to this full moon rising include the thin red rim seen faintly on the distorted lower edge of the Moon and a thin green rim along the top.
29/12/2023
ASTRONOMY - The Same Color Illusion
2023 December 18
Image Credit: Edward H. Adelson, Wikipedia
Explanation: Are squares A and B the same color? They are! To verify this, either run your cursor over the image or click here to see them connected. The featured illusion, an example of the same color illusion, illustrates that purely human perceptions in science may be ambiguous or inaccurate, even such a seemingly direct perception as relative color. Similar illusions exist on the sky, such as the size of the Moon near the horizon, or the apparent shapes of astronomical objects. The advent of automated, reproducible measuring devices such as CCDs have made science in general and astronomy in particular less prone to, but not free of, human-biased illusions.
BIOMIMETISME - Innovations inspirées par la Nature - Le bombyx du mûrier
Le bombyx du mûrier est un papillon de nuit originaire de Chine dont la larve est utilisée depuis des millénaires pour confectionner la soie. En 2016, les antennes du papillon ont donné une drôle d'idée aux scientifiques du CNRS : copier leur structure pour élaborer un détecteur d'explosif. Quand on regarde de plus près les antennes du bombyx du mûrier, on aperçoit des centaines de petits cils. Inspirés, les scientifiques ont alors mis au point un micro-levier en silicium sur lequel sont mis bout à bout 500 000 nanotubes de dioxyde de titane. Cette construction est capable de détecter des quantités infimes de TNT, mais aussi certaines drogues et substances toxiques.
Pour rappel, le bombyx du mûrier n'existe pas à l'état sauvage, c'est un papillon domestique obtenu au fil des sélections pour produire de la soie.
© Zivya, Wikimedia Commons, CC by-sa 3.0
FuturaSciences
28/12/2023
ASTRONOMY - Jupiter and the Geminid
2023 December 28
Image Credit & Copyright: Gaurav Singh
Explanation: For a brief moment, this brilliant fireball meteor outshone Jupiter in planet Earth's night. The serendipitous image was captured while hunting meteors under cold Canadian skies with a camera in timelapse mode on December 14, near the peak of the Geminid meteor shower. The Geminid meteor shower, asteroid 3200 Phaethon's annual gift, always arrives in December. Dust shed along the orbit of the mysterious asteroid causes the meteor streaks, as the vaporizing grains plow through our fair planet's upper atmosphere at 22 kilometers per second. Of course Geminid shower meteors appear to radiate from a point in the constellation of the Twins. That's below and left of this frame. With bright Jupiter on the right, also in the December night skyview are the Pleiades and Hyades star clusters.
27/12/2023
BIOMIMETISME - Innovations inspirées par la Nature - Ecrans inspirés des ailes transparentes d'un petit papillon
Le papillon Greta oto, que l'on retrouve en Amérique du Sud, est une merveille de la nature. Ses ailes sont transparentes, c'est-à-dire qu'elles ne reflètent pas la lumière plus précisément. Un moyen efficace d'échapper aux prédateurs. La partie transparente des ailes du Greta oto est en réalité composée de nanostructures en forme de colonne dont la taille varie entre 400 et 600 nm de haut. Grâce à cela, seulement 2 à 5 % de la lumière incidente qui frappe les ailes est réfléchie, les faisant apparaître transparentes.
Cette capacité a évidement éveillé la curiosité des ingénieurs, qui ont vu dans ces ailes une inspiration pour créer des surfaces antireflets, comme des écrans ou un traitement spécifique pour les lunettes.
© O. Schneider, Wikimedia Commons, CC by-sa 3.0
ASTRONOMY - Rainbow Aurora over Icelandic Waterfall
2023 December 27
Image Credit & Copyright: Stefano Pellegrini
Explanation: Yes, but can your aurora do this? First, yes, auroras can look like rainbows even though they are completely different phenomena. Auroras are caused by Sun-created particles being channeled into Earth's atmosphere by Earth's magnetic field, and create colors by exciting atoms at different heights. Conversely, rainbows are created by sunlight backscattering off falling raindrops, and different colors are refracted by slightly different angles. Unfortunately, auroras can’t create waterfalls, but if you plan well and are lucky enough, you can photograph them together. The featured picture is composed of several images taken on the same night last month near the Skógafoss waterfall in Iceland. The planning centered on capturing the central band of our Milky Way galaxy over the picturesque cascade. By luck, a spectacular aurora soon appeared just below the curving arch of the Milky Way. Far in the background, the Pleiades star cluster and the Andromeda galaxy can be found.
26/12/2023
ASTRONOMY - IC 443: The Jellyfish Nebula
2023 December 26
Image Credit & Copyright: David Payne
Explanation: Why is this jellyfish swimming in a sea of stars? Drifting near bright star Eta Geminorum, seen at the right, the Jellyfish Nebula extends its tentacles from the bright arcing ridge of emission left of center. In fact, the cosmic jellyfish is part of bubble-shaped supernova remnant IC 443, the expanding debris cloud from a massive star that exploded. Light from the explosion first reached planet Earth over 30,000 years ago. Like its cousin in astronomical waters, the Crab Nebula supernova remnant IC 443 is known to harbor a neutron star -- the remnant of the collapsed stellar core. The Jellyfish Nebula is about 5,000 light-years away. At that distance, the featured image would span about 140 light-years across.
25/12/2023
BIOMIMETISME - Innovations inspirées par la Nature - Les feuilles autonettoyantes du lotus
Le lotus (Nelumbo spp) est une plante aquatique. Pourtant l'eau, ce n'est pas vraiment son truc, surtout sur ses feuilles. En effet, ces dernières sont superhydrophobes, c'est-à-dire que leur surface repousse l'eau, elle glisse littéralement sur les feuilles. Les propriétés superhydrophobes des feuilles de lotus sont dues à une rugosité nanométrique, des petites pointes de l'ordre du nanomètre. Lorsqu'une goutte d'eau tombe sur les petites pointes, elle n'y adhère pas et emporte avec elle les impuretés présentes sur la plante.
Cette propriété physique intéresse bon nombre de domaines et cela depuis sa découverte dans les années 70. Des tissus déperlants, des parois de douche autonettoyantes ou encore des revêtements utilisés en aéronautique sont basés sur la rugosité nanométrique.
© William Thielicke, Wikimedia Commons, CC by-sa 4.0 International, 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic license
FuturaSciences
ASTRONOMY - Cathedral - Mountain - Moon
2023 December 25
Image Credit & Copyright: Valerio Minato
Explanation: Single shots like this require planning. The first step is to realize that such an amazing triple-alignment actually takes place. The second step is to find the best location to photograph it. But it was the third step: being there at exactly the right time -- and when the sky was clear -- that was the hardest. Five times over six years the photographer tried and found bad weather. Finally, just ten days ago, the weather was perfect, and a photographic dream was realized. Taken in Piemonte, Italy, the cathedral in the foreground is the Basilica of Superga, the mountain in the middle is Monviso, and, well, you know which moon is in the background. Here, even though the setting Moon was captured in a crescent phase, the exposure was long enough for doubly reflected Earthlight, called the da Vinci glow, to illuminate the entire top of the Moon.
24/12/2023
ASTRONOMY - NGC 2440: Cocoon of a New White Dwarf
2023 December 24
Image Credit: NASA, ESA, Hubble; Processing: H. Bond (STScI), R. Ciardullo (PSU), Forrest Hamilton (STScI)
Explanation: What's that in the center? Like a butterfly, a white dwarf star begins its life by casting off a cocoon of gas that enclosed its former self. In this analogy, however, the Sun would be a caterpillar and the ejected shell of gas would become the prettiest cocoon of all. In the featured cocoon, the planetary nebula designated NGC 2440 contains one of the hottest white dwarf stars known. The white dwarf can be seen as the bright orange dot near the image center. Our Sun will eventually become a white dwarf butterfly, but not for another 5 billion years.
23/12/2023
ASTRONOMY - A December Summer Night
2023 December 23
Image Credit & Copyright: Ian Griffin (Otago Museum)
Explanation: Colours of a serene evening sky are captured in this 8 minute exposure, made near this December's solstice from New Zealand, southern hemisphere, planet Earth. Looking south, star trails form the short concentric arcs around the rotating planet's south celestial pole positioned just off the top of the frame. At top and left of center are trails of the Southern Cross stars and a dark smudge from the Milky Way's Coalsack Nebula. Alpha and Beta Centauri make the brighter yellow and blue tinted trails, reflected below in the waters of Hoopers Inlet in the Pacific coast of the South Island's Otago Peninsula. On that short December summer night, aurora australis also gave luminous, green and reddish hues to the sky above the hills. An upper atmospheric glow distinct from the aurora excited by collisions with energetic particles, pale greenish bands of airglow caused by a cascade of chemical reactions excited by sunlight can be traced in diagonal bands near the top left.
22/12/2023
ASTRONOMY - 183 Days in the Sun
2023 December 22
Image Credit & Copyright: José Zarcos Palma
Explanation: A single 183 day exposure with a pinhole camera and photographic paper resulted in this long-duration solargraph. Recorded from solstice to solstice, June 21 to December 21, in 2022, it follows the Sun's daily arcing path through planet Earth's skies from Mertola, Portugal. On June 21, the Sun's highest point and longest arc represents the longest day and the astronomical beginning of summer in the northern hemisphere. The solstice date with the fewest hours of daylight is at the beginning of winter in the north, corresponding to the Sun's shortest and lowest arc in the 2022 solargraph. For 2023, the northern winter solstice was on December 22 at 3:27 UTC. That's December 21 for North America time zones.
17/12/2023
ASTRONOMY - Geminids over China's Nianhu Lake
2023 December 17
Image Credit & Copyright: Hongyang Luo
Explanation: Where are all of these meteors coming from? In terms of direction on the sky, the pointed answer is the constellation of Gemini. That is why the major meteor shower in December is known as the Geminids -- because shower meteors all appear to come from a radiant toward Gemini. Three dimensionally, however, sand-sized debris expelled from the unusual asteroid 3200 Phaethon follows a well-defined orbit about our Sun, and the part of the orbit that approaches Earth is superposed in front of the constellation of Gemini. Therefore, when Earth crosses this orbit, the radiant point of falling debris appears in Gemini. Featured here is a composite of many images taken a few days ago through dark skies from Nianhu Lake in China. Over 100 bright meteor streaks from the Geminids meteor shower are visible.
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
16/12/2023
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
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.
15/12/2023
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
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.
14/12/2023
ASTRONOMY - Supernova Remnant Cassiopeia A
2023 December 14
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.
13/12/2023
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
12/12/2023
ASTRONOMY - Aurora and Milky Way over Norway
2023 December 12
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.
11/12/2023
ASTRONOMY - Solar Minimum versus Solar Maximum
2023 December 11
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.
10/12/2023
ASTRONOMY - Big Dipper over Pyramid Mountain
2023 December 10
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.
09/12/2023
AERONAUTIQUE - Les plus gros avions du monde - Stratolaunch
Avec 117 mètres d'envergure, 230 tonnes à vide, six moteurs de Boeing 747 et 28 roues, le Stratolaunch est le plus grand avion jamais construit. Conçu et financé par le milliardaire Paul Allen, le cofondateur de Microsoft décédé en 2018, ce gigantesque appareil à double fuselage est destiné à lancer des satellites en orbite.
FuturaSciences
ASTRONOMY - Pic du Pleiades
2023 December 9
Image Credit & Copyright: Jean-Francois Graffand
Explanation: Near dawn on November 19 the Pleiades stood in still dark skies over the French Pyrenees. But just before sunrise a serendipitous moment was captured in this single 3 second exposure; a bright meteor streak appeared to pierce the heart of the galactic star cluster. From the camera's perspective, star cluster and meteor were poised directly above the mountain top observatory on the Pic du Midi de Bigorre. And though astronomers might consider the Pleiades to be relatively close by, the grain of dust vaporizing as it plowed through planet Earth's upper atmosphere actually missed the cluster's tight grouping of young stars by about 400 light-years. While recording a night sky timelapse series, the camera and telephoto lens were fixed to a tripod on the Tour-de-France-cycled slopes of the Col du Tourmalet about 5 kilometers from the Pic du Midi.
08/12/2023
ASTRONOMY - Vega and Comet 12P/Pons-Brooks
2023 December 8
Image Credit & Copyright: Dan Bartlett
Explanation: On December 4, periodic Comet 12P/Pons-Brooks shared this telescopic field of view with Vega, alpha star of the northern constellation Lyra. Fifth brightest star in planet Earth's night, Vega is some 25 light-years distant while the much fainter comet was about 21 light-minutes away. In recent months, outbursts have caused dramatic increases in brightness for Pons-Brooks though. Nicknamed the Devil Comet for its hornlike appearance, fans of interstellar spaceflight have also suggested the distorted shape of this comet's large coma looks like the Millenium Falcon. A Halley-type comet, 12P/Pons-Brooks last visited the inner Solar System in 1954. Its next perihelion passage or closest approach to the Sun will be April 21, 2024. That's just two weeks after the April 8 total solar eclipse path crosses North America. But, highly inclined to the Solar System's ecliptic plane, the orbit of periodic Comet 12P/Pons-Brooks will never cross the orbit of planet Earth.
07/12/2023
SANTé/MEDECINE - L'Histoire en images - L'Égypte antique et la momification
La momification est un processus permettant de conserver des corps pendant des milliers d'années. Le corps était éviscéré, séché au soleil, enduit d'huiles et enfin entouré de bandelettes. Les connaissances du corps humain étaient déjà développées durant l'Égypte antique.
Cette momie égyptienne date de l'époque ptolémaïque, (IIIe - IIe siècle avant J.-C.). Elle est conservée au musée du Louvre, département des antiquités égyptiennes, N 2627.
© Dada by-sa 3.0
BIOMIMETISME - Innovations inspirées par la Nature - Le Shinkansen, le train au bec d'oiseau
Le martin-pêcheur est un petit oiseau aquatique qui porte un bec long et fin pour pêcher des petits poissons, insectes ou batraciens dans l'eau. Ce bec a inspiré les ingénieurs japonais pour la conception du Shinkansen, le train à grande vitesse qui sillonne l'archipel nippon. Son avant profilé, bien visible sur les rames de la série 700, permet de réduire l'effet piston lorsqu'il entre à vive allure dans un tunnel, la vitesse de pointe du Shinkansen série 700 étant située entre 270 et 285 km/h.
Quand il s'y engouffre, le train génère une onde de choc bruyante qui ressemble à un bang et qui peut endommager la structure de l'ouvrage en plus de produire des nuisances sonores. Dans la nature, le bec du martin-pêcheur lui permet de fendre l'eau en faisant un minimum de remous, et s'avère tout aussi efficace pour attraper des proies volantes.
FuturaSciences
GEMMOLOGIE - Joaillerie Céleste (Et spaciale) - La conquête de l’espace (A partir des années 1950)
La conquète de l’espace (A partir des années 1950)
Si les lunes, les étoiles, les comètes restent des motifs régulièrement utilisés par les joailliers en ce début XXe, il faut quand même attendre la fin des années 50 pour voir un regain d’intérêt pour les bijoux inspiré du ciel. Mais ceux-ci vont prendre un tournant plus spatial avec une raison toute simple : il est temps pour les hommes de conquérir l’espace! Et ça commence par le lancement réussi de Spoutnik 1, le 7 octobre 1957 à exactement 19h28. Ce faisant, les russes inaugurent ce que l’on va appeler le Space Age ! Les bijoux « spoutnik » voient le jour. De tous les types et de toutes les tailles, ils se retrouvent sertis de nombreuses pierres mais peuvent également être tout or. Le bijou fantaisie n’est pas en reste et les créateurs de l’époque embrassent de fait cette tendance ! Cela dit, ces bijoux reprennent aussi le look d’autres satellites qui feront dates dans l’histoire spatiale tels que Luna 1 ou San Marco 1 et même Asterix.
Les années 70 sont riches en pièces évoquant la mission Apollo 11 et on croise ponctuellement chez des marchands spécialisés ou en ventes aux enchères des pièces ayant appartenu à Neil Armstrong par exemple. Des créateurs se sont également inspirés de cette lune devenue moins mystérieuse avec les missions d’exploration successives même si, depuis 69, aucun homme n’a foulé à nouveau le sol du satellite. On peut citer, par exemple, les pièces du bijoutier Tapio Wirkkala dont le travail est largement reconnu et exposé dans les plus grands musées du monde. On pense également aux bracelets en or martelé de Jackie Kennedy Onassis qui rappellent la surface de la lune mais pour lesquels la maison Van Cleef & Arpels a toujours parlé d’influence étrusque.
LeGemmologue
ASTRONOMY - Orion and the Ocean of Storms
023 December 7
Image Credit: NASA, Artemis 1
Explanation: On December 5, 2022, a camera on board the uncrewed Orion spacecraft captured this view as Orion approached its return powered flyby of the Moon. Beyond one of Orion's extended solar arrays lies dark, smooth, terrain along the western edge of the Oceanus Procellarum. Prominent on the lunar nearside Oceanus Procellarum, the Ocean of Storms, is the largest of the Moon's lava-flooded maria. The lunar terminator, shadow line between lunar night and day, runs along the left of this frame. The 41 kilometer diameter crater Marius is top center, with ray crater Kepler peeking in at the edge, just right of the solar array wing. Kepler's bright rays extend to the north and west, reaching the dark-floored Marius. On December 11, 2022 the Orion spacecraft reached its home world. The historic Artemis 1 mission ended with Orion's successful splashdown in planet Earth's water-flooded Pacific Ocean.
06/12/2023
ASTRONOMY - Stars Versus Dust in the Carina Nebula
2023 December 6
Image Credit: NASA, ESA, Hubble Heritage (STScI/AURA); Processing: Franco Meconi (Terraza al Cosmos)
Explanation: It's stars versus dust in the Carina Nebula and the stars are winning. More precisely, the energetic light and winds from massive newly formed stars are evaporating and dispersing the dusty stellar nurseries in which they formed. Located in the Carina Nebula and inside a region known informally as Mystic Mountain, these pillars' appearance is dominated by opaque brown dust even though it is composed mostly of clear hydrogen gas. Even though some of the dust pillars look like torches, their ends are not on fire -- rather, they are illuminated by nearby stars. About 7,500 light-years distant, the featured image was taken with the Hubble Space Telescope and highlights an interior region of Carina known as HH1066 which spans nearly a light year. Within a few million years, the stars will likely win out completely and the dust torches will completely evaporate.
05/12/2023
GEMMOLOGIE - Joaillerie Céleste (Et spaciale) - Les croissants de lune (Époque Victorienne et après)
A l’image des bijoux ornés d’étoiles, les bijoux en forme de lune sont également très en vogue dès la deuxième moitié du XIXe siècle. Les raisons sont à peu près similaires à celles exposées dans le paragraphe précédent sur les bijoux s’inspirant des étoiles. Mais dans ce cas précis, outre l’association classique entre lune et symbole féminin, la lune trouve plus précisément une origine dans la redécouverte de la civilisation gréco-romaine. Peut-être que l’expression « triade lunaire » ne vous est pas étrangère, elle symbolise les trois déesses autour de la lune : Séléné, Hécate et Artémis en grec (Luna, Hécate et Diane) symbolisent respectivement la pleine lune, la nouvelle lune ou lune noire et le croissant de lune. Elles sont bien entendues extrêmement honorées à leur époque et encore aujourd’hui, les mouvements Wicca continuent de célébrer Hécate, la déesse qui permet la communication entre le terrestre et l’invisible. En Mésopotamie, il existait Ishtar, déesse de la guerre, de l’amour et de la vie. Les Sumériens vénéraient Inanna qui avait des attributions similaires. Vous trouverez de très nombreux textes sur le sujet si celui-ci vous intéresse. Je vous assure qu’il est absolument passionnant. Les bijoux ornés d’une ou plusieurs lunes sont donc des bijoux très symboliques, tournés vers le féminin et ils se complètent parfois de cette fameuse bonne étoile. Le motif se décline sur tous les types de bijoux et se voit souvent agrémenté de diamants, de turquoises, de pierres gemmes diverses mais surtout d’opales.
LeGemmologue
ASTRONOMY - Energetic Particle Strikes the Earth
2023 December 5
Illustration Credit: Osaka Metropolitan U./L-INSIGHT, Kyoto U./Ryuunosuke Takeshige
Explanation: It was one of the most energetic particles ever known to strike the Earth -- but where did it come from? Dubbed Amaterasu after the Shinto sun goddess, this particle, as do all cosmic rays that strike the Earth's atmosphere, caused an air shower of electrons, protons, and other elementary particles to spray down onto the Earth below. In the featured illustration, a cosmic ray air shower is pictured striking the Telescope Array in Utah, USA, which recorded the Amaterasu event in 2021 May. Cosmic ray air showers are common enough that you likely have been in a particle spray yourself, although you likely wouldn't have noticed. The origin of this energetic particle, likely the nucleus of an atom, remains a mystery in two ways. First, it is not known how any single particle or atomic nucleus can practically acquire so much energy, and second, attempts to trace the particle back to where it originated did not indicate any likely potential source.
04/12/2023
ASTRONOMY - Plane Crossing Crescent Moon
2023 December 4
Image Credit & Copyright: Juned Patel
Explanation: No, the Moon is not a bow, and no, it did not shoot out a plane like an arrow. What is pictured is a chance superposition. The plane's contrail would normally appear white, but the large volume of air toward the rising Sun preferentially knocked away blue light, not only making the sky blue, but giving the reflected trail a bright red hue. Far in the distance, well behind the plane, the crescent Moon also appears slightly reddened. Captured early last month from Bolton, UK, the featured image was taken so soon after sunrise that the plane was sunlit from below, as was its contrail. Within minutes, unfortunately, the impromptu sky show ended. The plane moved out of sight. The Moon kept rising but became harder to see through a brightening sky. And the contrail gradually dispersed.
03/12/2023
ASTRONOMY - Moon Setting Behind Teide Volcano
2023 December 3
Video Credit & Copyright: Daniel López (El Cielo de Canarias); Music: Piano della Moon (Dan Silva)
Explanation: These people are not in danger. What is coming down from the left is just the Moon, far in the distance. Luna appears so large here because she is being photographed through a telescopic lens. What is moving is mostly the Earth, whose spin causes the Moon to slowly disappear behind Mount Teide, a volcano in the Canary Islands off the northwest coast of Africa. The people pictured are 16 kilometers away and many are facing the camera because they are watching the Sun rise behind the photographer. It is not a coincidence that a full moon rises just when the Sun sets because the Sun is always on the opposite side of the sky from a full moon. The featured video was made in 2018 during the full Milk Moon. The video is not time-lapse -- this was really how fast the Moon was setting.
02/12/2023
ASTRONOMY - Startrails over Beijing Ancient Observatory
2023 December 2
Image Credit & Copyright: Jeff Dai (TWAN)
Explanation: You can take a subway ride to visit this observatory in Beijing, China but you won't find any telescopes there. Starting in the 1400s astronomers erected devices at the Beijing Ancient Observatory site to enable them to accurately measure and track the positions of naked-eye stars and planets. Some of the large, ornate astronomical instruments are still standing. You can even see stars from the star observation platform today, but now only the very brightest celestial beacons are visible against the city lights. In this time series of exposures from a camera fixed to a tripod to record graceful arcing startrails, the brightest trail is actually the Moon. Its broad arc is seen behind the ancient observatory's brass armillary sphere. Compare this picture from the Beijing Ancient Observatory taken in September 2023 to one taken in 1895.
01/12/2023
GEMMOLOGIE - Joaillerie Céleste (Et spaciale) - Les bijoux dédiés à l’étoile polaire (Époque Victorienne et après)
Plus de l’étoile polaire, ce sont les étoiles qui trouvent le chemin des bijoux au milieu du XIXe siècle. Plusieurs raisons à cela, mais surtout des découvertes archéologiques importantes qui font redécouvrir des civilisations oubliées et qui provoquent un regain d’intérêt pour des cultures disparues dont la plupart utilisaient le ciel comme outils de détermination. Le mouvement spirite se développe aussi rapidement au cours de ce même siècle. Dans les pays anglo-saxons, les Witchcraft Acts ont réglementé la pratique de la sorcellerie jusqu’au milieu du XXe siècle. Cela semble incroyable mais c’est pourtant vrai. Derrière cet intérêt pour l’Histoire, les esprits, la mort ou du moins le culte de ce qui a disparu, il faut surtout replacer le contexte d’une époque bouleversée par la révolution industrielle. Cet intérêt pour ce qui n’est plus est une forme d’ancrage ; car ce qui n’est plus ne peut changer et c’est rassurant. Les joailliers s’emparent donc de ce phénomène. On pense forcément au portrait de Sissi avec des bijoux étoiles dans sa coiffure (Franz Xaver Winterhalter, 1865). Et on voit ainsi fleurir des bijoux avec des étoiles en général ou des bijoux avec Polaris ou Stella Maris, cette étoile polaire, symbole d’espoir et d’affection, qui donne le Nord et oriente ceux qui sont perdus…
LeGemmologue
AERONAUTIQUE - Les plus gros avions du monde - Antonov AN-225 Mriya
Avec ses 84 mètres de longueur, soit pratiquement la longueur d'un terrain de football, l'Antonov AN-225 Mriya est l'avion le plus long et le plus lourd jamais construit. Conçu en Ukraine alors que le pays était encore rattaché au bloc de l'URSS, il peut embarquer 640 tonnes de fret. Il n'en n'existe qu'un seul exemplaire, opéré par Antonov Airlines. Il ne vole qu'une ou deux fois par an pour transporter de gigantesques équipements, comme en 2009, un générateur de 187,5 tonnes à destination de l'Arménie et qui est la pièce la plus lourde jamais transportée par avion. Des discussions seraient en cours avec une compagnie chinoise pour relancer la production.
Longueur : 84 mètres
Envergure : 88,4 mètres
Premier vol : 1988
FuturaSciences
ASTRONOMY - Milky Way Rising
2023 December 1
Image Credit & Copyright: José Rodrigues
Explanation: The core of the Milky Way is rising beyond the Chilean mountain-top La Silla Observatory in this deep night skyscape. Seen toward the constellation Sagittarius, our home galaxy's center is flanked on the left, by the European Southern Observatory's New Technology Telescope which pioneered the use of active optics to accurately control the shape of large telescope mirrors. To the right stands the ESO 3.6-meter Telescope, home of the exoplanet hunting HARPS and NIRPS spectrographs. Between them, the galaxy's central bulge is filled with obscuring clouds of interstellar dust, bright stars, clusters, and nebulae. Prominent reddish hydrogen emission from the star-forming Lagoon Nebula, M8, is near center. The Trifid Nebula, M20, combines blue light of a dusty reflection nebula with reddish emission just left of the cosmic Lagoon. Both are popular stops on telescopic tours of the galactic center. The composited image is a stack of separate exposures for ground and sky made in April 2023, all captured consecutively with the same framing and camera equipment.
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