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14/07/2019

Science & Technology - Astronomy picture of the day : Eagle Aurora over Norway

2019 July 14
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Eagle Aurora over Norway 
Image Credit & Copyright: Bjørn Jørgensen
Explanation: What's that in the sky? An aurora. A large coronal mass ejection occurred on our Sun five days before this 2012 image was taken, throwing a cloud of fast moving electrons, protons, and ions toward the Earth. Although most of this cloud passed above the Earth, some of it impacted our Earth's magnetosphere and resulted in spectacular auroras being seen at high northern latitudes. Featured here is a particularly photogenic auroral corona captured above GrotfjordNorway. To some, this shimmering green glow of recombining atmospheric oxygen might appear as a large eagle, but feel free to share what it looks like to you. Although the Sun is near Solar Minimum, streams of the solar wind continue to impact the Earth and create impressive auroras visible even last week.

11/07/2019

Music - Slides - Bob Marley : "We and dem"

"We and dem"

Science & Technology - Astronomy picture of the day : The Ghost of Jupiter's Halo

2019 July 11
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The Ghost of Jupiter's Halo 
Image Credit & CopyrightCHART32 TeamProcessing - Johannes Schedler / Volker Wendel
Explanation: Close-up images of NGC 3242 show the cast off shroud of a dying, sun-like star fancifully known as The Ghost of Jupiter nebula. But this deep and wide telescopic view also finds the seldom seen outer halo of the beautiful planetary nebula at the upper left, toward Milky Way stars and background galaxies in the serpentine constellation Hydra. Intense and otherwise invisible ultraviolet radiation from the nebula's central white dwarf star powers its illusive glow in visible light. In fact, planets of NGC 3242's evolved white dwarf star may have contributed to the nebula's symmetric features and shape. Activity beginning in the star's red giant phase, long before it produced a planetary nebula, is likely the cause of the fainter more extensive halo. About a light-year across NGC 3242 is some 4,500 light-years away. The tenuous clouds of glowing material at the right could well be interstellar gas, by chance close enough to the NGC 3242's white dwarf to be energized by its ultraviolet radiation.

09/07/2019

Science & Technology - Astronomy picture of the day : Birds During a Total Solar Eclipse

2019 July 9
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Birds During a Total Solar Eclipse 
Image Credit & Copyright: Leonardo Caldas
Explanation: What do birds do during a total solar eclipse? Darkness descends more quickly in a total eclipse than during sunset, but returns just as quickly -- and perhaps unexpectedly to the avians -- just a few minutes later. Stories about the unusual behavior of birds during eclipses have been told for centuries, but bird reactions were recorded and studied systematically by citizen scientists participating in an eBird project during the total solar eclipse that crossed the USA in 2017 August. Although some unusual behaviors were observed, many observers noted birds acting like it was dusk and either landing or flying low to the ground. Radar confirmed a significant decrease in high-flying birds and insects during and just after totality. Conversely, several sightings of normally nocturnal birds were reported. Pictured, a flock of birds in La SerenaChile flew through the air together during the total solar eclipse that crossed South America last week. The photographer captured the scene in frames from an eclipse video. The next total solar eclipse in 2020 December will also cross South America, while in 2024 April a total solar eclipse will cross North Americafrom Mexico through New EnglandUSA.

08/07/2019

Science & Technology - Astronomy picture of the day : The Galactic Center in Radio from MeerKAT

2019 July 8
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The Galactic Center in Radio from MeerKAT 
Image Credit: MeerKATSARAO
Explanation: What's happening at the center of our galaxy? It's hard to tell with optical telescopes since visible light is blocked by intervening interstellar dust. In other bands of light, though, such as radio, the galactic center can be imaged and shows itself to be quite an interesting and active place. The featured picture shows the inaugural image of the MeerKAT array of 64 radio dishes just completed in South Africa. Spanning four times the angular size of the Moon (2 degrees), the image is impressively vast, deep, and detailed. Many known sources are shown in clear detail, including many with a prefix of Sgr, since the Galactic Center is in the direction of the constellation Sagittarius. In our Galaxy's Center lies Sgr A, found here just to the right of the image center, which houses the Milky Way's central supermassive black hole. Other sources in the image are not as well understood, including the Arc, just to the left of Sgr A, and numerous filamentary threads. Goals for MeerKAT include searching for radio emission from neutral hydrogen emitted in a much younger universe and brief but distant radio flashes.

Music - Live - Video - Verdi / Angela Gheorghiu (Soprano) and Roberto Alagna : La Traviata - Brindisi,

"La Traviata - Brindisi" 


During the Prom at the Palace event held to celebrate the Queen's Golden Jubilee, 2002.

07/07/2019

Science & Technology - Astronomy picture of the day : Crescent Saturn

2019 July 7
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Crescent Saturn 
Image Credit: NASAESASSICassini Imaging Team
Explanation: Saturn never shows a crescent phase -- from Earth. But when viewed from beyond, the majestic giant planet can show an unfamiliar diminutive sliver. This image of crescent Saturn in natural color was taken by the robotic Cassini spacecraft in 2007. The featured image captures Saturn's majestic rings from the side of the ring plane opposite the Sun -- the unilluminated side -- another vista not visible from Earth. Pictured are many of Saturn's photogenic wonders, including the subtle colors of cloud bands, the complex shadows of the rings on the planet, and the shadow of the planet on the rings. A careful eye will find the moons Mimas (2 o'clock) and Janus (4 o'clock), but the real challenge is to find Pandora (8 o'clock). Saturn is now nearly opposite from the Sun in the Earth's sky and so can be seen in the evening starting just after sunset for the rest of the night.

05/07/2019

Science & Technology - Astronomy picture of the day : La Silla Eclipse Sequence

2019 July 5
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La Silla Eclipse Sequence 
Image Credit & CopyrightPetr Horálek
Explanation: The road to the high mountaintop La Silla Observatory in the Chilean Atacama Desert also led in to the path of July 2nd's total solar eclipse. Recorded at regular intervals before and after the total eclipse phase, the frames in this composite sequence include the moment the Moon's dark shadow fell across some of planet Earth's advanced large telescopes. The dreamlike view looks west toward the setting Sun and the approaching Moon shadow. In fact La Silla was a little north of the shadow track's center line, so the region's stunning, clear skies are slightly brighter to the north (right) in the scene.

02/07/2019

Science & Technologie - Avions du futur : L'avion supersonique silencieux de Lockheed Martin

L'avion supersonique silencieux de Lockheed Martin
Sur ce supersonique imaginé par Lockheed Martin, les ailes forment un V assez prononcé et les moteurs sont installés au-dessus. Cette disposition devrait empêcher, ou réduire fortement, le « bang », cet énorme bruit qui suit un avion se déplaçant plus vite que les ondes sonores, franchissant ainsi le mur du son. Un tel avion pourrait donc voler en supersonique au-dessus des continents. 
© Lockheed Martin

ASTRONOMIE - Galaxies - NGC 4414

Une galaxie spirale . (photo HST, APOD 09/09/1999)