MICROPHOTOGRAPHIE - Marek Miś - L'acide malique : le plein de goût

HOOC-CH2-CHOH-COOH. C'est la formule de l'acide malique. On en trouve dans beaucoup de végétaux. Dans les pommes, les poires et le raisin, notamment. C'est aussi lui qui donne une saveur si particulière à la rhubarbe. Et un goût acidulé au vin. Il est largement utilisé comme additif alimentaire. Nom de code E296. Car l'acide malique donne un goût agréable et ralentit le brunissement des aliments. Il présente également une fonction antibactérienne et antioxydante.

C'est lui que l'on retrouve sur cette microphotographie prise en lumière polarisée et avec un grossissement de 100 fois. Sous la forme de cristaux aux reflets dorés dont l'aspect rappelle vaguement celui de quelques haches préhistoriques. Comme un clin d'œil au fait que l'acide malique -- en mélange avec l'acide citrique -- est couramment employé pour acidifier les bonbons de nos enfants, pour leur donner du peps... ou pour détartrer les cafetières !

Cliché réalisé à l'aide d'un microscope Olympus BH-2 et d'un appareil Pentax K1.

© Marek Miś.

FuturaSciences

ASTRONOMY -Video: Powers of Ten

 2022 December 4

Video: Powers of Ten
Video Credit & Copyright: Charles & Ray Eames (Eames Office)

Explanation: How different does the universe look on very small scales? On very large scales? The most famous short science film of its generation gives breathtaking comparisons. That film, Powers of Ten, originally created in the 1960s, has been officially posted to YouTube and embedded here. From a picnic blanket near Chicago out past the Virgo Cluster of Galaxies, every ten seconds the film zooms out to show a square a factor of ten times larger on each side. The 9-minute video then reverses, zooming back in a factor of ten every two seconds and ends up inside a single proton. The Powers of Ten sequence is actually based on the book Cosmic View by Kees Boeke in 1957, as is a similar but mostly animated film Cosmic Zoom that was also created in the late 1960s. The changing perspectives are so enthralling and educational that sections have been recreated using more modern computerized techniques, including the first few minutes of the movie Contact. Ray and husband Charles Eames, the film's creators, were known as quite visionary spirits and even invented their own popular chair.

AVIATION IMAGINEE - Influencée par les frères Montgolfier

 

Cette carte, datant de 1890-1900, propose une vision de l’aviation future similaire à celle de 1800, un siècle plus tôt. L’influence des frères Montgolfier a encore frappé ! © Romanet & Cie, collection 476, 2e série

FuturaSciences

ASTRONOMY - Stereo Mars near Opposition

 2022 December 3

Stereo Mars near Opposition
Image Credit & Copyright: Marco Lorenzi

Explanation: Mars looks sharp in these two rooftop telescope views captured in late November from Singapore, planet Earth. At the time, Mars was about 82 million kilometers from Singapore and approaching its opposition, opposite the Sun in planet Earth's sky on December 8. Olympus Mons, largest of the volcanoes in the Tharsis Montes region (and largest known volcano in the Solar System), is near Mars' western limb. In both the images it's the whitish donut-shape at the upper right. The dark area visible near center is the Terra Sirenum region while the long dark peninsula closest to the planet's eastern limb is Sinus Gomer. Near its tip is Gale crater, the Curiosity rover's landing site in 2012. Above Sinus Gomer, white spots are other volcanoes in the Elysium region. At top of the planet is the north polar cap covered with ice and clouds. Taken about two days apart, these images of the same martian hemisphere form a stereo pair. Look at the center of the frame and cross your eyes until the separate images come together to see the Red Planet in 3D.

ASTRONOMY - Merging Galaxy Pair IIZw096

 2022 December 2

Merging Galaxy Pair IIZw096
Image Credit: ESA/Webb, NASA & CSA, L. Armus, A. Evans

Explanation: Bright at infrared wavelengths, this merging galaxy pair is some 500 million light-years away toward the constellation Delphinus. The cosmic mashup is seen against a background of even more distant galaxies, and occasional spiky foreground stars. But the galaxy merger itself spans about 100,000 light-years in this deep James Webb Space Telescope image. The image data is from Webb's Near-InfraRed Camera (NIRCam) and Mid-InfraRed Instrument (MIRI). Their combined, sharp infrared view follows galactic scale restructuring in the dusty merger's wild jumble of intense star forming regions and distorted spiral arms

ASTRONOMY - Artemis 1: Flight Day 13

 2022 December 1

Artemis 1: Flight Day 13
Image Credit: NASA, Artemis 1

Explanation: On flight day 13 (November 28) of the Artemis 1 mission the Orion spacecraft reached its maximum distance from Earth. In fact, over 430,000 kilometers from Earth its distant retrograde orbit also put Orion nearly 70,000 kilometers from the Moon. In the same field of view in this video frame from flight day 13, planet and large natural satellite even appear about the same apparent size from the uncrewed spacecraft's perspective. Today (December 1) should see Orion depart its distant retrograde orbit. En route to planet Earth it will head toward a second powered fly by of the Moon. Splashdown on the home world is expected on December 11.

ASTRONOMY - The Light, the Dark, and the Dusty

 2022 November 30

The Light, the Dark, and the Dusty
Image Credit & Copyright: Anthony Quintile

Explanation: This colorful skyscape spans about four full moons across nebula rich starfields along the plane of our Milky Way Galaxy in the royal northern constellation Cepheus. Near the edge of the region's massive molecular cloud some 2,400 light-years away, bright reddish emission region Sharpless (Sh) 155 is at the center of the frame, also known as the Cave Nebula. About 10 light-years across the cosmic cave's bright walls of gas are ionized by ultraviolet light from the hot young stars around it. Dusty reflection nebulae, like vdB 155 to the right, and dense obscuring clouds of dust also abound on the interstellar canvas. Astronomical explorations have revealed other dramatic signs of star formation, including the bright reddish fleck of Herbig-Haro (HH) 168. Below and right of center, the Herbig-Haro object emission is generated by energetic jets from a newborn star.

BIOMIMETISME - LA NATURE INSPIRE LA SCIENCE - Le bombyx

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

ASTRONOMY - The Gum Nebula Supernova Remnant

 2022 November 29

The Gum Nebula Supernova Remnant
Image Credit & Copyright: Victor Lima

Explanation: Because the Gum Nebula is the closest supernova remnant, it is actually hard to see. Spanning 40 degrees across the sky, the nebula appears so large and faint that it is easily lost in the din of a bright and complex background. The Gum Nebula is highlighted nicely in red emission toward the right of the featured wide-angle, single-image photograph taken in late May. Also visible in the frame are the Atacama Desert in Chile in the foreground, the Carina Nebula in the plane of our Milky Way galaxy running diagonally down from the upper left, and the neighboring Large Magellanic Cloud (LMC) galaxy. The Gum Nebula is so close that we are much nearer the front edge than the back edge, each measuring 450 and 1500 light years respectively. The complicated nebula lies in the direction of the constellations of Puppis and Vela. Oddly, much remains unknown about the Gum Nebula, including the timing and even number of supernova explosions that formed it.

MUSIC - The Bands of HM Royal Marines - Brothers in arms

"Brothers in arms"