ASTRONOMY - The Belt of Venus over Mount Everest

 2023 June 26

The Belt of Venus over Mount Everest
Image Credit & Copyright: Soumyadeep Mukherjee

Explanation: You've surely seen it, but you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly dark and off-color. Called the Belt of Venus, this transitional band between the dark eclipsed sky and the bright day sky can be seen most prominently in the direction opposite the Sun. Straight above, blue sky is normal sunlight reflecting off the atmosphere, while near the horizon the clear sky can appear more orange or red. In the Belt of Venus, the atmosphere reflects more light from the setting (or rising) Sun and so appears more red. Featured here, the Belt of Venus was photographed over several Himalayan mountains including, second from the right, Mount Everest, the tallest mountain on Earth. Although usually not mentioned, the belt is frequently caught by accident in other photographs.

PHOTOGRAPHIE - Le monde explosif d'Alan Sailer - Une bille de paintball qui explose au ralenti

Une bille de peinture du jeu paintball qui explose sous l'impact d'une balle de plomb très rapide qui se déplace à environ 200 mètres par seconde. Tirée à partir d'un fusil à plomb, la balle a une énergie totale d'environ 10 joules.

FuturaSciences

ASTRONOMY - Messier 24: Sagittarius Star Cloud

 2023 June 28

Messier 24: Sagittarius Star Cloud
Image Credit & Copyright: Emmanuel Astronomono

Explanation: Unlike most entries in Charles Messier's famous catalog of deep sky objects, M24 is not a bright galaxy, star cluster, or nebula. It's a gap in nearby, obscuring interstellar dust clouds that allows a view of the distant stars in the Sagittarius spiral arm of our Milky Way galaxy. Direct your gaze through this gap with binoculars or small telescope and you are looking through a window over 300 light-years wide at stars some 10,000 light-years or more from Earth. Sometimes called the Small Sagittarius Star Cloud, M24's luminous stars fill this gorgeous starscape. Covering over 3 degrees or the width of 6 full moons in the constellation Sagittarius, the telescopic field of view includes dark markings B92 and B93 near center, along with other clouds of dust and glowing nebulae toward the center of the Milky Way.

PHOTOGRAPHIE - le monde explosif d'Alan Sailer

Cette photo montre ce qui se passe quand on tire avec une carabine à air comprimé un plomb à travers un globe de verre rempli de gélatine rouge. La vitesse du plomb, de 4,5 mm, est d'environ 200 mètres / seconde.

© Alan Sailer

FuturaSciences

ASTRONOMY - Lightning on Jupiter

 2023 June 25

Lightning on Jupiter
Image Credit: NASA/JPL-Caltech/SwRI/MSSS; Processing & License: Kevin M. Gill

Explanation: Does lightning occur only on Earth? No. Spacecraft in our Solar System have detected lightning on other planets, including Mars, Jupiter and Saturn, and lightning is likely on Venus, Uranus, and Neptune. Lightning is a sudden rush of electrically charged particles from one location to another. On Earth, drafts of colliding ice and water droplets usually create lightning-generating charge separation, but what happens on Jupiter? Images and data from NASA's Jupiter-orbiting Juno spacecraft bolster previous speculation that Jovian lightning is also created in clouds containing water and ice. In the featured Juno photograph, an optical flash was captured in a large cloud vortex near Jupiter's north pole. During the next few months, Juno will perform several close sweeps over Jupiter's night side, likely allowing the robotic probe to capture more data and images of Jovian lightning.

ASTRONOMY - Sublime carte postale de Mars

Il explore la planète Mars depuis plus de dix ans maintenant. Et le rover Curiosity vient encore de nous en renvoyer des images à couper le souffle. Une spectaculaire carte postale de la Planète rouge.

Le résultat final est saisissant. Le rover qui apparaît au bas de l'image se situe dans les contreforts du mont Sharp. Celui-ci s'élève à 5 kilomètres de hauteur, dans le cratère Gale. C'est le cratère que Curiosity explore depuis son atterrissage en 2012. Au loin au-delà de ses traces se trouve Marker Band Valley, une zone sinueuse dans le « région sulfatée » dans laquelle le rover a découvert des signes inattendus d'un ancien lac. Plus près du rover -- au centre de la carte postale -- se trouvent deux collines, Bolívar et Deepdale, que Curiosity a parcourues tout en explorant Paraitepuy Pass.

FuturaSciences

GEMMOLOGIE - La topaze, un silicate

 

La topaze fait partie des nésosubsilicates tout comme l'andalousite, le disthène et le sillimanite. Elle a longtemps été confondue avec l'olivine jaune. Son nom est d'ailleurs tiré de l'île de Topazios qui était un gisement d'olivine de la mer Rouge. La topaze peut changer de teinte par procédé artificiel. Couleurs : variées. © DidierDescouens, 

Wikimedia Commons, CC by-sa 3.0

FuturaSciences

ASTRONOMY - 3D Ingenuity

 2023 June 24

3D Ingenuity
Image Credit: NASA, JPL-Caltech, MSSS, ASU

Explanation: The multicolor, stereo imaging Mastcam-Z on the Perseverance rover zoomed in to capture this 3D close-up (get out your red/blue glasses) of the Mars Ingenuity helicopter on mission sol 45. That's Earth-date 2021 April 5. Casting a shadow on the Martian surface, Ingenuity is standing alone on its four landing legs next to the rover's wheel tracks. The experimental helicopter's solar panel, charging batteries that keep it warm through the cold Martian nights and power its flight, sits just above Ingenuity's two 1.2 meter (4 foot) long counter-rotating blades. Thirteen sols later, on April 19, Ingenuity became the first aircraft to perform powered, controlled flight on another planet. It has since gone on to complete more than 50 flights through the thin atmosphere of Mars.

ASTRONOMY - Stars and Dust across Corona Australis

 2023 June 22

Stars and Dust across Corona Australis
Image Credit & Copyright: Alessandro Cipolat Bares

Explanation: Cosmic dust clouds cross a rich field of stars in this telescopic vista near the northern boundary of Corona Australis, the Southern Crown. Part of a sprawling molecular cloud complex this star forming region is a mere 500 light-years away. That's about one third the distance of the more famous stellar nursery known as the Orion Nebula. The 2 degree wide frame would span 15 light-years at the clouds' estimated distance. Mixed with bright nebulosities the dust clouds effectively block light from more distant background stars in the Milky Way and obscure from view embedded stars still in the process of formation. Large dark nebula Bernes 157 is on the left. To its right are a group of pretty reflection nebulae cataloged as NGC 6726, 6727, 6729, and IC 4812. Their characteristic blue color is produced as light from hot stars is reflected by the cosmic dust. The more compact NGC 6729 surrounds young variable star R Coronae Australis. Just below it, filamentary arcs and loops are identified as Herbig Haro objects associated with energetic newborn stars. In fact, at the heart of this area lies the Coronet Cluster, one of the nearest and most active star forming regions.

ART FRACTAL - Fractale électrisante

 

Du jaune, de l'orange, du rose et du noir : les fractales peuvent rassembler tout un arsenal de formes et de couleurs. Sur cette image de fractale, les bandes noires ressemblent à des antennes électriques à travers desquelles circule un courant rose électrique. 

© Futura

GEMMOLOGIE - La rhodochrosite, une couleur éclatante

La rhodochrosite est un carbonate de manganèse (MnCO3) relativement rare. Sa belle couleur rose rouge, très appréciée en joaillerie, est due à la présence de manganèse. Couleur : rose rouge.

© The_Wookies, Wikimedia Commons, CC by 2.5
FuturaSciences

ASTRONOMY - The Ñandú in the Milky Way

 2023 June 20

The Ñandú in the Milky Way
Image Credit & Copyright: Fefo Bouvier; Line Drawing: Alfonso Rosso

Explanation: Have you seen the bird in the Milky Way? Beyond the man in the Moon, the night sky is filled with stories, and cultures throughout history have projected some of their most enduring legends onto the stars and dust above. Generations of people see these celestial icons, hear their associated stories, and pass them down. Pictured here is not only a segment of the central band of our Milky Way galaxy, but, according to folklore of several native peoples of Uruguay, the outline of a great bird called Ñandú. Furthermore, Ñandú's footprint is associated with the Southern Cross asterism. In the foreground, in silhouette, is a statue of María Micaela Guyunusa, an indigenous woman of the Charrúa people who lived in the 1800s and endures as a symbol of colonial resistance. The composite image was taken in mid-April in Cabo Polonio, Uruguay, with the Atlantic Ocean in the background.

DELICIEUSES HERBES AROMATIQUES - La verveine, pour faciliter la digestion

Les verveines appartiennent à la famille des Verbénacées. La plus connue du genre Verbena est la verveine officinale. Elle est connue depuis la nuit des temps sous le nom d'herbe aux sorciers, comme philtre d'amour, porte-bonheur ou pour lever des sorts. Elle peut être utilisée en cuisine pour aromatiser les sorbets, les crèmes, les entremets ou pour réaliser des sirops mais c'est surtout en infusion qu'on la consomme. Ses vertus thérapeutiques sont connues depuis l'Antiquité. Cette plante traite essentiellement les digestions difficiles, les vertiges et les migraines. La plante possède des propriétés apaisantes. Elle est également utilisée pour soigner les rhumatismes et les blessures. 

© Fvslb, CC by-sa 3.0 ; H. Zell, CC by-sa 3.0

FuturaSciences

ASTRONOMY - The Busy Center of the Lagoon Nebula

 2023 June 19

The Busy Center of the Lagoon Nebula
Image Credit: NASA, ESA, Hubble; Processing: Francisco Javier Pobes Serrano

Explanation: The center of the Lagoon Nebula is a whirlwind of spectacular star formation. Visible near the image center, at least two long funnel-shaped clouds, each roughly half a light-year long, have been formed by extreme stellar winds and intense energetic starlight. A tremendously bright nearby star, Herschel 36, lights the area. Vast walls of dust hide and redden other hot young stars. As energy from these stars pours into the cool dust and gas, large temperature differences in adjoining regions can be created generating shearing winds which may cause the funnels. This picture, spanning about 15 light years, combines images taken in four colors by the orbiting Hubble Space Telescope. The Lagoon Nebula, also known as M8, lies about 5000 light years distant toward the constellation of the Archer (Sagittarius).

ASTRONOMY - The Shark Nebula

 2023 June 14

The Shark Nebula
Image Credit & Copyright: Stephen Kennedy

Explanation: There is no sea on Earth large enough to contain the Shark nebula. This predator apparition poses us no danger as it is composed only of interstellar gas and dust. Dark dust like that featured here is somewhat like cigarette smoke and created in the cool atmospheres of giant stars. After being expelled with gas and gravitationally recondensing, massive stars may carve intricate structures into their birth cloud using their high energy light and fast stellar winds as sculpting tools. The heat they generate evaporates the murky molecular cloud as well as causing ambient hydrogen gas to disperse and glow red. During disintegration, we humans can enjoy imagining these great clouds as common icons, like we do for water clouds on Earth. Including smaller dust nebulae such as Lynds Dark Nebula 1235 and Van den Bergh 149 & 150, the Shark nebula spans about 15 light years and lies about 650 light years away toward the constellation of the King of Aethiopia (Cepheus).

ASTRONOMY - Moons Across Jupiter

 2023 June 13

Moons Across Jupiter
Image Credit: NASA; ESA, JPL, Cassini Imaging Team, SSI; Processing: Kevin M. Gill

Explanation: Jupiter's moons circle Jupiter. The featured video depicts Europa and Io, two of Jupiter's largest moons, crossing in front of the grand planet's Great Red Spot, the largest known storm system in our Solar System. The video was composed from images taken by the robotic Cassini spacecraft as it passed Jupiter in 2000, on its way to Saturn. The two moons visible are volcanic Io, in the distance, and icy Europa. In the time-lapse video, Europa appears to overtake Io, which is odd because Io is closer to Jupiter and moves faster. The explanation is that the motion of the fast Cassini spacecraft changes the camera location significantly during imaging. Jupiter is currently being visited by NASA's robotic Juno spacecraft, while ESA's Jupiter Icy Moons Explorer (JUICE), launched in April, is enroute.

DELICIEUSES HERBES AROMATIQUES - Le romarin

Le romarin officinal, reconnaissable à ses fleurs bleutées, est un arbrisseau de la famille des Lamiacées. Il pousse à l'état sauvage sur le pourtour méditerranéen, dans les garrigues arides et rocailleuses.

La plante s'utilise de préférence fraîche mais les fleurs séchées parfument agréablement un plat ou un dessert. Il sert également à aromatiser les grillades ou à rehausser les ragoûts, les civets, les soupes ou les sauces.

Le romarin est mellifère et contient plusieurs agents actifs antimycosiques, antibactériens et antioxydants. Il est également utilisé en parfumerie depuis le XIVe siècle.  

© Cyclonebill, CC by-sa 2.0 et Tony Hisgett, CC by 2.0

ASTROPHOTOGRAPHIE - La lune dans les ailes

"La Lune dans les ailes" 

Pierre Derycke

ASTRONOMY - Simulation: A Disk Galaxy Forms

 2023 May 31

Simulation: A Disk Galaxy Forms
Video Credit: TNG Collaboration, MPCDF, FAS Harvard U.; Music: World's Sunrise (YouTube: Jimena Contreras)

Explanation: How did we get here? We know that we live on a planet orbiting a star orbiting a galaxy, but how did all of this form? Since our universe moves too slowly to watch, faster-moving computer simulations are created to help find out. Specifically, this featured video from the IllustrisTNG collaboration tracks gas from the early universe (redshift 12) until today (redshift 0). As the simulation begins, ambient gas falls into and accumulates in a region of relatively high gravity. After a few billion years, a well-defined center materializes from a strange and fascinating cosmic dance. Gas blobs -- some representing small satellite galaxies -- continue to fall into and become absorbed by the rotating galaxy as the present epoch is reached and the video ends. For the Milky Way Galaxy, however, big mergers may not be over -- recent evidence indicates that our large spiral disk Galaxy will collide and coalesce with the slightly larger Andromeda spiral disk galaxy in the next few billion years.

ASTRONOMY - Elephant's Trunk and Caravan

 2023 June 8

Elephant's Trunk and Caravan
Image Credit & Copyright: Steve Cannistra (StarryWonders)

Explanation: Like an illustration in a galactic Just So Story, the Elephant's Trunk Nebula winds through the emission region and young star cluster complex IC 1396, in the high and far off constellation of Cepheus. Seen on the left the cosmic elephant's trunk, also known as vdB 142, is over 20 light-years long. This detailed telescopic view features the bright swept-back ridges and pockets of cool interstellar dust and gas that abound in the region. But the dark, tendril-shaped clouds contain the raw material for star formation and hide protostars within. Nearly 3,000 light-years distant, the relatively faint IC 1396 complex covers a large region on the sky, spanning over 5 degrees. This rendition spans a 1 degree wide field of view though, about the angular size of 2 full moons. Of course the dark shapes below and to the right of the outstretched Elephant's Trunk, are known to some as The Caravan.

ASTRONOMY - M94: A Double Ring Galaxy

 2023 June 7

M94: A Double Ring Galaxy
Image Credit & Copyright: Brian Brennan

Explanation: Most galaxies don't have any rings of stars and gas -- why does M94 have two? First, spiral galaxy M94 has an inner ring of newly formed stars surrounding its nucleus, giving it not only an unusual appearance but also a strong interior glow. A leading origin hypothesis holds that an elongated knot of stars known as a bar rotates in M94 and has generated a burst of star formation in this inner ring. Observations have also revealed another ring, an outer ring, one that is more faint, different in color, not closed, and relatively complex. What caused this outer ring is currently unknown. M94, pictured here, spans about 45,000 light years in total, lies about 15 million light years away, and can be seen with a small telescope toward the constellation of the Hunting Dogs (Canes Venatici).

AERONAUTIQUE - Avions de légende - Le Canadair CL 415 - un bombardier d'eau à la capacité impressionnante

Le Canadair CL-415 est un avion bombardier d’eau fabriqué par la firme canadienne Bombardier Aéronautique. Spécialisé dans la lutte contre les incendies, il est utilisé par de nombreux pays, dont la France où il est affublé du surnom de « Pélican ». Cet avion réputé pour sa fiabilité possède deux réservoirs qui peuvent emmagasiner un peu plus de 6.000 litres d’eau.

© Claudio, CC by-nc 2.0

GEMMOLOGIE - La magnifique topaze

Espèce minérale de formule Al2SiO4(F,OH)2, la topaze peut contenir des traces de fer, de chrome, de magnésium et de titane. Lorsqu'on expose longtemps cette pierre fine à la lumière solaire, elle peut changer de couleur. Couleurs : incolore à blanc, bleu, verdâtre, brun jaune, orange, rose, rougeâtre, violet, brun.

© Rob Lavinsky, Wikimedia Commons, CC by-sa 3.0

ASTRONOMY - Star Eats Planet

 2023 June 6

Star Eats Planet
Illustrative Video Credit: K. Miller & R. Hurt (Caltech, IPAC)

Explanation: It’s the end of a world as we know it. Specifically, the Sun-like star ZTF SLRN-2020 was seen eating one of its own planets. Although many a planet eventually dies by spiraling into their central star, the 2020 event, involving a Jupiter-like planet, was the first time it was seen directly. The star ZTF SLRN-2020 lies about 12,000 light years from the Sun toward the constellation of the Eagle (Aquila). In the featured animated illustration of the incident, the gas planet's atmosphere is first pictured being stripped away as it skims along the outskirts of the attracting star. Some of the planet's gas is absorbed into the star's atmosphere, while other gas is expelled into space. By the video's end, the planet is completely engulfed and falls into the star's center, causing the star's outer atmosphere to briefly expand, heat up, and brighten. One day, about eight billion years from now, planet Earth may spiral into our Sun.

ASTRONOMY - In the Center of the Trifid Nebula

 2023 June 5

In the Center of the Trifid Nebula
Image Credit & Copyright: Martin Pugh

Explanation: What's happening at the center of the Trifid Nebula? Three prominent dust lanes that give the Trifid its name all come together. Mountains of opaque dust appear near the bottom, while other dark filaments of dust are visible threaded throughout the nebula. A single massive star visible near the center causes much of the Trifid's glow. The Trifid, cataloged as M20, is only about 300,000 years old, making it among the youngest emission nebulas known. The star forming nebula lies about 9,000 light years away toward the constellation of the Archer (Sagittarius). The region pictured here spans about 20 light years.

ART FRACTAL - Fractales symétriques envoûtantes

Sur cette fractale, deux formes géométriques jumelles ressemblant à des dragons, l'un jaune et l'autre rouge, se font dos. En grossissant des détails de leurs contours, on peut quasiment reproduire la figure d'origine. Les deux pseudo-dragons sont englobés dans une bulle psychédélique verte. 

© Futura

ASTRONOMY - Charon: Moon of Pluto

 2023 June 3

Charon: Moon of Pluto
Image Credit: NASA, Johns Hopkins Univ./APL, Southwest Research Institute, U.S. Naval Observatory

Explanation: A darkened and mysterious north polar region known to some as Mordor Macula caps this premier high-resolution view. The portrait of Charon, Pluto's largest moon, was captured by New Horizons near the spacecraft's closest approach on July 14, 2015. The combined blue, red, and infrared data was processed to enhance colors and follow variations in Charon's surface properties with a resolution of about 2.9 kilometers (1.8 miles). A stunning image of Charon's Pluto-facing hemisphere, it also features a clear view of an apparently moon-girdling belt of fractures and canyons that seems to separate smooth southern plains from varied northern terrain. Charon is 1,214 kilometers (754 miles) across. That's about 1/10th the size of planet Earth but a whopping 1/2 the diameter of Pluto itself, and makes it the largest satellite relative to its parent body in the Solar System. Still, the moon appears as a small bump at about the 1 o'clock position on Pluto's disk in the grainy, negative,telescopic picture inset at upper left. That view was used by James Christy and Robert Harrington at the U.S. Naval Observatory in Flagstaff to discover Charon in June of

ASTRONOMY - Messier 101

 2023 June 2

Messier 101
Image Credit: NASA, ESA, CFHT, NOAO;
Acknowledgement - K.Kuntz (GSFC), F.Bresolin (U.Hawaii), J.Trauger (JPL), J.Mould (NOAO), Y.-H.Chu (U. Illinois)

Explanation: Big, beautiful spiral galaxy M101 is one of the last entries in Charles Messier's famous catalog, but definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own Milky Way. M101 was also one of the original spiral nebulae observed by Lord Rosse's large 19th century telescope, the Leviathan of Parsontown. Assembled from 51 exposures recorded by the Hubble Space Telescope in the 20th and 21st centuries, with additional data from ground based telescopes, this mosaic spans about 40,000 light-years across the central region of M101 in one of the highest definition spiral galaxy portraits ever released from Hubble. The sharp image shows stunning features of the galaxy's face-on disk of stars and dust along with background galaxies, some visible right through M101 itself. Also known as the Pinwheel Galaxy, M101 lies within the boundaries of the northern constellation Ursa Major, about 25 million light-years away.

CLIMAT - Une invasion impressionnante de méduses sur les plages de la côte Atlantique

Des centaines de milliers de méduses se sont échouées entre le week-end dernier et ce mercredi sur la côte Atlantique. Du Finistère jusqu'aux Landes, quasiment aucune côte de l'arc atlantique n'a échappé à l'invasion des méduses ces derniers jours. En cause, de multiples facteurs.

Le phénomène est courant au mois de mai et juin, mais cette année, la quantité de méduses présentes est exceptionnelle, aux dires des habitants comme des spécialistes du littoral.

En ce début de semaine, Châtelaillon-Plage, la Rochelle, Royan, Pornic, Pornichet, Quiberon et Lorient sont les communes de la côte Atlantique les plus concernées par cette invasion.

L'arrivée massive de méduses sur le littoral et ses plages peut s'expliquer par ces trois facteurs :une hausse rapide des températures de l'eau : sur la côte Atlantique, l'eau s'est réchauffée de 3 à 4 °C en moyenne en l'espace de trois semaines. La température atteint désormais 16 °C au nord de la côte Atlantique, et 18 à 19 °C au sud-ouest. La hausse des températures est la principale cause de prolifération des méduses.

les courants marins : les méduses se laissent porter par les courants en surface, d'autant plus lorsqu'ils sont chauds.

des facteurs environnementaux : la surpêche supprime le nombre de prédateurs potentiels des méduses. Là où les poissons disparaissent, les méduses prolifèrent, de même que la pollution maritime, surtout d'origine agricole, leur est favorable.

FuturaSciences

ASTRONOMY - Simulation: A Disk Galaxy Forms

 2023 May 31

Simulation: A Disk Galaxy Forms
Video Credit: TNG Collaboration, MPCDF, FAS Harvard U.; Music: World's Sunrise (YouTube: Jimena Contreras)

Explanation: How did we get here? We know that we live on a planet orbiting a star orbiting a galaxy, but how did all of this form? Since our universe moves too slowly to watch, faster-moving computer simulations are created to help find out. Specifically, this featured video from the IllustrisTNG collaboration tracks gas from the early universe (redshift 12) until today (redshift 0). As the simulation begins, ambient gas falls into and accumulates in a region of relatively high gravity. After a few billion years, a well-defined center materializes from a strange and fascinating cosmic dance. Gas blobs -- some representing small satellite galaxies -- continue to fall into and become absorbed by the rotating galaxy as the present epoch is reached and the video ends. For the Milky Way Galaxy, however, big mergers may not be over -- recent evidence indicates that our large spiral disk Galaxy will collide and coalesce with the slightly larger Andromeda spiral disk galaxy in the next few billion years.