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.