ASTRONOMY - Moon phases 2022

 2022 February 1

Moon Phases 2022
Video Credit: Data: Lunar Reconnaissance Orbiter ; Animation: NASA's Scientific Visualization Studio;
Music: Build the Future (Universal Production Music), Alexander Hitchens

Explanation: What will the Moon phase be on your birthday this year? It is hard to predict because the Moon's appearance changes nightly. As the Moon orbits the Earth, the half illuminated by the Sun first becomes increasingly visible, then decreasingly visible. The featured video animates images and altitude data taken by NASA's Moon-orbiting Lunar Reconnaissance Orbiter to show all 12 lunations that appear this year, 2022 -- as seen from Earth's northern (southern) hemisphere. A single lunation describes one full cycle of our Moon, including all of its phases. A full lunation takes about 29.5 days, just under a month (moon-th). As each lunation progresses, sunlight reflects from the Moon at different angles, and so illuminates different features differently. During all of this, of course, the Moon always keeps the same face toward the Earth. What is less apparent night-to-night is that the Moon's apparent size changes slightly, and that a slight wobble called a libration occurs as the Moon progresses along its elliptical orbit.

MICROPHOTOGRAPHIE - Mélange à base d'acide citrique

Des escarpements rocheux tombant à pic. Peut-être le résultat de l'action de l'eau. Des falaises donc, présentées en fausses couleurs pour en faire ressortir les reliefs. C'est le travail que Marek Miś aime mener. Dévoiler dans l'infiniment petit, des motifs qui ressemblent aux paysages qui nous sont familiers. Ou presque.

Pour cette fois, il a choisi de mélanger acide citrique et hématoxyline. L'acide citrique, comme son nom le laisse entendre, c'est celui que l'on trouve abondamment dans le citron. Mais il se trouve aussi dans d'autres fruits et légumes. Il est notamment employé comme acidifiant ou dans un autre registre, pour réduire la rouille ! L'hématoxyline, de son côté, est un colorant couramment utilisé en histologie. Il teinte les noyaux des cellules en bleu violet. De quoi étudier les tissus biologiques.

Mais sur cette photo, pas de vivant. Comme d'habitude, Marek Miś a simplement laissé faire la nature morte, une lumière polarisée avec laquelle il éclaire la scène et un grossissement de 100 fois.

Cliché réalisé à l'aide d'un microscope Olympus BH-2 et d'un appareil Pentax K5.

© Marek Miś, Tous droits réservés.

FuturaSciences

ART FRACTAL - Fractale naturelle de cristal de gallium

 

Ce cristal de gallium est une fractale trouvée sous terre. On trouve cet élément chimique (de symbole Ga et de numéro atomique 31) dans le minerai de bauxite et dans les minerais de zinc.

© Foobar, Wikimedia Commons, CC by-sa 3.0

FuturaSciences

AERONAUTIQUE - Avions de légende - Airbus A380

 

L'A380 d'Airbus est un avion de ligne long-courrier qui fait partie des plus gros avions civils de transport. Ce quadriréacteur à double pont peut emporter jusqu'à 853 passagers ou 150 tonnes de fret selon sa configuration. Il dispose d'une autonomie de 15.400 kilomètres, ce qui lui permet de relier New York à Hong Kong sans escale.

© Steevie, GFDL

FuturaSciences

ASTRONOMY - A solar prominence from SOHO

 2022 January 30

A Solar Prominence from SOHO
Image Credit: NASA, ESA, SOHO-EIT Consortium

Explanation: How can gas float above the Sun? Twisted magnetic fields arching from the solar surface can trap ionized gas, suspending it in huge looping structures. These majestic plasma arches are seen as prominences above the solar limb. In 1999, this dramatic and detailed image was recorded by the Extreme ultraviolet Image Telescope (EIT) on board the space-based SOHO observatory in the light emitted by ionized Helium. It shows hot plasma escaping into space as a fiery prominence breaks free from magnetic confinement a hundred thousand kilometers above the Sun. These awesome events bear watching as they can affect communications and power systems over 100 million kilometers away on planet Earth. In late 2020 our Sun passed the solar minimum of its 11-year cycle and is now showing increased surface activity.

ASTRONOMY - Road to the Galactic Center

 2022 January 29

Road to the Galactic Center
Image Credit & Copyright: Michael Abramyan

Explanation: Does the road to our galaxy's center go through Monument Valley? It doesn't have to, but if your road does -- take a picture. In this case, the road is US Route 163 and iconic buttes on the Navajo National Reservation populate the horizon. The band of Milky Way Galaxy stretches down from the sky and appears to be a continuation of the road on Earth. Filaments of dust darken the Milky Way, in contrast to billions of bright stars and several colorful glowing gas clouds including the Lagoon and Trifid nebulas. The featured picture is a composite of images taken with the same camera and from the same location -- Forest Gump Point in Utah, USA. The foreground was taken just after sunset in early September during the blue hour, while the background is a mosaic of four exposures captured a few hours later.

ASTRONOMY - Western moon, Eastern sea

 2022 January 28

Western Moon, Eastern Sea
Image Credit & Copyright: Tom Glenn

Explanation: The Mare Orientale, Latin for Eastern Sea, is one of the most striking large scale lunar features. The youngest of the large lunar impact basins it's very difficult to see from an earthbound perspective. Still, taken during a period of favorable tilt, or libration of the lunar nearside, the Eastern Sea can be found near top center in this sharp telescopic view, extremely foreshortened along the Moon's western edge. Formed by the impact of an asteroid over 3 billion years ago and nearly 1000 kilometers across, the impact basin's concentric circular features, ripples in the lunar crust, are a little easier to spot in spacecraft images of the Moon, though. So why is the Eastern Sea at the Moon's western edge? The Mare Orientale lunar feature was named before 1961. That's when the convention labeling east and west on lunar maps was reversed.

AERONAUTIQUE - Avions de légende - L'Antonov An-225

L'Antonov An-225 - le plus long et lourd avion au monde - cumule les superlatifs. Cet avion fabriqué en Ukraine à l'époque où le pays était encore rattaché à l'URSS est tout simplement le premier avion porteur en longueur et en masse. Muni de six réacteurs et capable de transporter 250 tonnes de charge utile, il fut initialement conçu pour emporter sur son dos la navette spatiale russe Bourane, dont le programme a été abandonné en 1988. Ceci porta un coup fatal au destin de l'Antonov An-225, qui ne fut construit qu'en un seul exemplaire.

© DAIHYUN JI, CC by-nc 2.0

MUSIC - George Frederic Haendel - The arrival of queen of Sheba

"The arrival of queen of Sheba"

ASTRONOMY - South of Orion

 2022 January 27

South of Orion
Image Credit & Copyright: Vikas Chander

Explanation: South of the large star-forming region known as the Orion Nebula, lies bright blue reflection nebula NGC 1999. At the edge of the Orion molecular cloud complex some 1,500 light-years distant, NGC 1999's illumination is provided by the embedded variable star V380 Orionis. The nebula is marked with a dark sideways T-shape at center right in this telescopic vista that spans about two full moons on the sky. Its dark shape was once assumed to be an obscuring dust cloud seen in silhouette. But infrared data suggest the shape is likely a hole blown through the nebula itself by energetic young stars. In fact, this region abounds with energetic young stars producing jets and outflows with luminous shock waves. Cataloged as Herbig-Haro (HH) objects, named for astronomers George Herbig and Guillermo Haro, the shocks have intense reddish hues. HH1 and HH2 are just below and right of NGC 1999. HH222, also known as the Waterfall nebula, looks like a red gash near top right in the frame. To create the shocks stellar jets push through the surrounding material at speeds of hundreds of kilometers per second.