Science & Technologie - Aeronautique - Avions du futur : Des moteurs au-dessus de l'avion plutôt que dessous

Pour réduire le bruit des avions perçu au sol, une excellente solution, simple mais efficace, est d'installer les moteurs au-dessus de l'avion. Pourquoi n'y a-t-on pas pensé plus tôt ? Parce que les équipes de maintenance n'aiment pas... L'accès aisé aux moteurs est en effet un gage de sécurité mais aussi d'économie puisqu'il est plus rapide. Les placer sur le fuselage ou les ailes, voire les intégrer dans le corps de l'avion, comme dans les ailes volantes, a toujours fait peur aux avionneurs. Mais si les moteurs du futur sont plus fiables ? © Bauhaus Luftfahrt

Science & Technology - Astronomy picture of the day : Gigantic Jet Lightning over India

2019 September 18
Gigantic Jet Lightning over India 
Image Credit & Copyright: Hung-Hsi Chang

Explanation: Yes, but can your lightning bolt do this? While flying from Munich to Singapore earlier this month, an industrious passenger took images of a passing lightning storm and caught something unexpected: gigantic jet lightning. The jet was captured on a single 3.2-second exposure above Bhadrak, India. Although the gigantic jet appears connected to the airplane's wing, it likely started in a more distant thundercloud, and can be seen extending upwards towards Earth's ionosphere. The nature of gigantic jets and their possible association with other types of Transient Luminous Events (TLEs) such as blue jets and red sprites remains an active topic of research.

Science & Technology - Astronomy picture of the day : Water Vapor Discovered on Distant Exoplanet

2019 September 17
Water Vapor Discovered on Distant Exoplanet 
Illustration Credit: ESA, NASA, Hubble; Artist: M. Kornmesser

Explanation: Where else might life exist? One of humanity's great outstanding questions, locating planets where extrasolar life might survive took a step forward recently with the discovery of a significant amount of water vapor in the atmosphere of distant exoplanet K2-18b. The planet and it parent star, K2-18, lie about 124 light years away toward the constellation of the Lion (Leo). The exoplanet is significantly larger and more massive than our Earth, but orbits in the habitable zone of its home star. K2-18, although more red than our Sun, shines in K2-18b's sky with a brightness similar to the Sun in Earth's sky. The discovery was made in data from three space telescopes: Hubble, Spitzer, and Kepler, by noting the absorption of water-vapor colors when the planet moved in front of the star. The featured illustration imagines exoplanet K2-18b on the right, its parent red dwarf star K2-18 on the left, and an unconfirmed sister planet between them.

Science & Technology - Astronomy picture of the day : A Lunar Corona over Turin

2019 September 16
A Lunar Corona over Turin 
Image Credit & Copyright: Giorgia Hofer (Cortina Astronomical Association)

Explanation: What are those colorful rings around the Moon? A corona. Rings like this will sometimes appear when the Moon is seen through thin clouds. The effect is created by the quantum mechanical diffraction of light around individual, similarly-sized water droplets in an intervening but mostly-transparent cloud. Since light of different colors has different wavelengths, each color diffracts differently. Lunar Coronae are one of the few quantum mechanical color effects that can be easily seen with the unaided eye. The featured lunar corona was captured around full Moon above Turin, Italy in 2014. Similar coronae that form around the Sun are usually harder to see because of the Sun's great brightness.

Music - Video - Phil Spitalny/Evelyn : "Here Come the Co-Eds"

"Here Come the Co-Eds"

Phil Spitalny fue un músico, crítico musical, compositor y líder de banda estadounidense, habitual en la programación radiofónica de las décadas de 1930 y 1940. Se hizo famoso por formar una orquesta en la que todos sus componentes eran mujeres, algo novedoso en esa época. En esta edición podemos apreciar a la orquesta en su plenitud, teniendo como solista a Evelyn y su Violin Mágico. Las escenas pertenecen a la película "Here Come the Co-Eds", de 1945, protagonizada por el dúo Abbott & Costello.

Music - Wolfgang Amadeus Mozart - "Piano Concerto No. 21 - Andante"

"Piano Concerto No. 21 - Andante"

Science & Technology - Astronomy picture of the day : A Harvest Moon

2019 September 13
A Harvest Moon 
Image Credit & Copyright: Jean-Francois Graffand

Explanation: Famed in festival, story, and song the best known full moon is the Harvest Moon. For northern hemisphere dwellers that's a traditional name of the closest full moon to the September equinox. In most North America time zones this year's Harvest Moon will officially rise on Friday, September 13. In fact the same Harvest Moon will rise on September 14 for much of the planet though. Of course the Moon will look almost full in the surrounding days. Regardless of your time zone the Harvest Moon, like any other full moon, will rise just opposite the setting Sun. Near the horizon, the Moon Illusion might make it appear bigger and brighter to you but this Harvest Moon will be nearlunar apogee. That's the closest point in its orbit, making it the most distant, and so the smallest, full moon of the year. On August 15 a wheat field harvested in south central France made this a harvest moon scene too, the full moon shining on with beautiful iridescent clouds at sunset.

Science & Technology - Astronomy picture of the day : IC 1805: The Heart Nebula

2019 September 11
IC 1805: The Heart Nebula 
Image Credit & Copyright: Bray Falls

Explanation: What energizes the Heart Nebula? First, the large emission nebula dubbed IC 1805 looks, in whole, like a human heart. The nebula glows brightly in red light emitted by its most prominent element: hydrogen. The red glow and the larger shape are all powered by a small group of stars near the nebula's center. In the center of the Heart Nebula are young stars from the open star cluster Melotte 15 that are eroding away several picturesque dust pillarswith their energetic light and winds. The open cluster of stars contains a few bright stars nearly 50 times the mass of our Sun, many dim stars only a fraction of the mass of our Sun, and an absent microquasar that was expelled millions of years ago. The Heart Nebula is located about 7,500 light years away toward the constellation of Cassiopeia. Coincidentally, a small meteor was captured in the foreground during imaging and is visible above the dust pillars. At the top right is the companion Fishhead Nebula.

Science & Technology - Astronomy picture of the day : "Pluto in True Color"

2019 September 10
Pluto in True Color 
Image Credit: NASA, JHU APL, SwRI, Alex Parker

Explanation: What color is Pluto, really? It took some effort to figure out. Even given all of the images sent back to Earth when the robotic New Horizons spacecraft sped past Pluto in 2015, processing these multi-spectral frames to approximate what the human eye would see was challenging. The result featured here, released three years after the raw data was acquired by New Horizons, is the highest resolution true color image of Pluto ever taken. Visible in the image is the light-colored, heart-shaped, Tombaugh Regio, with the unexpectedly smooth Sputnik Planitia, made of frozen nitrogen, filling its western lobe. New Horizons found the dwarf-planet to have a surprisingly complex surfacecomposed of many regions having perceptibly different hues. In total, though, Pluto is mostly brown, with much of its muted color originating from small amounts of surface methane energized by ultraviolet light from the Sun.

Science & Technology - Astronomy picture of the day : M31: The Andromeda Galaxy

2019 September 9
M31: The Andromeda Galaxy 
Image Credit & Copyright: Amir H. Abolfath (TWAN)

Explanation: How far can you see? The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy, over two million light-years away. Without a telescope, even this immense spiral galaxy appears as an unremarkable, faint, nebulous cloud in the constellation Andromeda. But a bright yellow nucleus, dark winding dust lanes, luminous blue spiral arms, and bright red emission nebulas are recorded in this stunning six-hour telescopic digital mosaic of our closest major galactic neighbor. While even casual skygazers are now inspired by the knowledge that there are many distant galaxies like M31, astronomers seriously debated this fundamental concept only 100 years ago. Were these "spiral nebulae" simply outlying gas clouds in our own Milky Way Galaxy or were they "island universes" -- distant galaxies of stars comparable to the Milky Way itself? This question was central to the famous Shapley-Curtis debate of 1920, which was later resolved by observations favoring Andromeda being just like our Milky Way Galaxy -- a conclusion making the rest of the universe much more vast than many had ever imagined.