AERONAUTIQUE - M4 Bison

"M4 Bison"

ASTRONOMY - M51: The Whirlpool Galaxy

 2021 September 2

M51: The Whirlpool Galaxy
Image Credit & Copyright: Josep Drudis

Explanation: Find the Big Dipper and follow the handle away from the dipper's bowl until you get to the last bright star. Then, just slide your telescope a little south and west and you'll come upon this stunning pair of interacting galaxies, the 51st entry in Charles Messier's famous catalog. Perhaps the original spiral nebula, the large galaxy with well defined spiral structure is also cataloged as NGC 5194. Its spiral arms and dust lanes clearly sweep in front of its companion galaxy (top), NGC 5195. The pair are about 31 million light-years distant and officially lie within the angular boundaries of the small constellation Canes Venatici. Though M51 looks faint and fuzzy to the eye, deep images like this one reveal its striking colors and galactic tidal debris.

ASTRONOMY - Dancing Ghosts: Curved Jets from Active Galaxies

2021 September 1

Dancing Ghosts: Curved Jets from Active Galaxies
Image Credit: Jayanne English & Ray Norris, EMU-ASKAP, DES; Text: Jayanne English (U. Manitoba)

Explanation: Why would galaxies emit jets that look like ghosts? And furthermore, why do they appear to be dancing? The curled and fluffy jets from the supermassive black holes at the centers of two host galaxies (top center and lower left) are unlike anything seen before. They were found by astronomers using the Australian Square Kilometer Array Pathfinder (ASKAP) radio telescope when creating maps tracing the evolution of galaxies. Images preceding this Evolutionary Map of the Universe survey only showed amorphous blobs. Eventually, comparisons of relative amounts of energy emitted revealed the glowing elongated structures were created by electrons streaming around magnetic field lines. Overlaying the radio data on an optical view of the sky (Dark Energy Survey) confirmed that the electron streams originated from the centers of active galaxies. Usually such Active Galactic Nuclei (AGN) produce straight jets. A leading hypothesis for the geometric origin of these unusually graceful shapes involves the flow of large-scale intergalactic winds. 

ASTRONOMY - A Blue Hour Full Moon

 2021 August 26

A Blue Hour Full Moon
Image Credit & Copyright: Giorgia Hofer

Explanation: Nature photographers and other fans of planet Earth always look forward to the blue hour. That's the transition in twilight, just before sunrise or after sunset, when the Sun is below the horizon but land and sky are still suffused with a beautiful blue light. After sunset on August 21, this blue hour snapshot captured the nearly full Moon as it rose opposite the Sun, above the rugged Italian Alps from Cortina d'Ampezzo, Italy. Sharing bluish hues with the sky, the rocky pyramid of Monte Antelao, also known as the King of the Dolomites, is the region's prominent alpine peak. The moonlight is yellow, but even so this full Moon was known to some as a seasonal Blue Moon. That's because by one definition the third full Moon of a season with four full moons in it is called a Blue Moon. Recognizing a season as the time between a solstice and an equinox, this season's fourth full Moon will be rising in the blue hour of September 20, just before September's equinox.

MINERAUX - Le sélénite, une pierre de lune

Considéré comme une variété de gypse, le sélénite permet de voir « l'éclat de la Lune ». Son nom provient d'ailleurs de selentis, qui signifie « pierre de Lune » en grec. La région de Bologne, en Italie, est connue pour en contenir beaucoup. Elle fut d'ailleurs utilisée pour construire les premières fortifications de la ville, aujourd'hui disparue.

Couleur : incolore à rougeâtre.

© mockbird, Flickr, CC by-sa 2.0

ASTRONOMY - Mars Rock Rochette

 2021 August 28

Mars Rock Rochette
Image Credit: NASA, JPL-Caltech

Explanation: Taken on mission sol 180 (August 22) this sharp image from a Hazard Camera on the Perseverance rover looks out across a rock strewn floor of Jezero crater on Mars. At 52.5 centimeters (21 inches) in diameter, one of the rover's steerable front wheels is at lower left in the frame. Near center is a large rock nicknamed Rochette. Mission planners don't want to avoid Rochette though. Instead Perseverance will be instructed to reach out with its 2 meter long robotic arm and abrade the rock's surface, to determine whether it has a consistency suitable for obtaining a sample, slightly thicker than a pencil, using the rover's coring bit. Samples collected by Perseverance would be returned to Earth by a future Mars mission.

ASTRONOMY - Solar System Ball Drop

 2021 August 25

Solar System Ball Drop
Video Credit & Copyright: James O'Donoghue (JAXA) & Rami Mandow (Space Australia); Text: James O'Donoghue

Explanation: Does a ball drop faster on Earth, Jupiter, or Uranus? The featured animation shows a ball dropping from one kilometer high toward the surfaces of famous solar system bodies, assuming no air resistance. The force of gravity depends on the mass of the attracting object, with higher masses pulling down with greater forces. But gravitational force also depends on distance from the center of gravity, with shorter distances causing the ball to drop faster. Combining both mass and distance, it might be surprising to see that Uranus pulls the ball down slightly slower than Earth, despite containing over 14 times more mass. This happens because Uranus has a much lower density, which puts its cloud tops further away from its center of mass. Although the falling ball always speeds up, if you were on the ball you would not feel this acceleration because you would be in free-fall. Of the three planets mentioned, the video demonstrates a ball drops even faster on Jupiter than either Earth and Uranus.

PRATIQUE - Comment Déboucher Un Évier En 3 Étapes Faciles

L'évier de la cuisine est complètement bouché ? Il reflue et en plus, ça pue dans la maison ? Et pour ne rien arranger, ça tombe un dimanche.... Heureusement, mon plombier m'a partagé une astuce super efficace pour déboucher un évier facilement. C'est une méthode rapide et économique en 3 étapes faciles. Elle évite d'appeler un plombier ou d'utiliser des produits toxiques comme le Destop. L'astuce naturelle est de mettre du bicarbonate, du vinaigre blanc et enfin de l'eau bouillante. Regardez :

Comment faire 1. Mettez le bicarbonate dans le siphon bouché. 2. Faites chauffer le vinaigre blanc dans la casserole. 3. Versez la moitié du vinaigre blanc sur le bicarbonate. 4. Laissez mousser et agir pendant une minute. 5. Une fois la mousse estompée, versez le reste du vinaigre blanc. 6. Laissez agir au moins 30 min. 7. Faites bouillir l'eau dans la casserole. 8. Versez l'eau bouillante dans le siphon. Résultat Et voilà ! Vous avez débouché votre évier en 3 étapes faciles et rapides :-) Simple, économique et efficace, n'est-ce pas ? Même pas besoin d'appeler un plombier qui coûte un bras ou de produits ultra chimiques pour nettoyer les canalisations. C'est bon pour le porte-monnaie et la planète !

PRATIQUE/POURQUOI - Pourquoi a-t-on une meilleure réception lorsqu'on touche l'antenne d'une radio ?

En fait, le corps humain, essentiellement composé d'eau est très conducteur.

En touchant une antenne radio, le corps humain fait office d'extension de cette même antenne.

Ainsi, nous améliorons la réception de l'antenne.

Le corps humain étant en plus assez grand et avec 4 membres dirigés dans des directions souvent différentes, la probabilité de se situer dans un ''espace captant mieux" est plus importante.

ASTRONOMY - Island Universe, Cosmic Sand

 2021 August 14

Island Universe, Cosmic Sand
Image Credit & Copyright: Marzena Rogozinska

Explanation: Stars in our own Milky Way Galaxy are scattered through this eye-catching field of view. From the early hours after midnight on August 13, the 30 second exposure of the night sky over Busko-Zdroj, Poland records the colorful and bright trail of a Perseid meteor. Seen near the peak of the annual Perseid meteor shower it flashes from lower left to upper right. The hurtling grain of cosmic sand, a piece of dust from periodic comet Swift-Tuttle, vaporized as it passed through planet Earth's atmosphere at almost 60 kilometers per second. Just above and right of center, well beyond the stars of the Milky Way, lies the island universe known as M31 or the Andromeda Galaxy. The Andromeda Galaxy is the most distant object easily visible to the naked-eye, about 2.5 million light-years away. The visible meteor trail begins only about 100 kilometers above Earth's surface, though. It points back to the meteor shower radiant in the constellation Perseus off the lower left edge of the frame. Follow this bright perseid meteor trail below and left to the stars of NGC 869and NGC 884, the double star cluster in Perseus.