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28/05/2020

Science & Technology - Astronomy picture of the day : The Milky Way over Snow-Capped Himalayas

2020 May 26
See Explanation.  Clicking on the picture will download
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Image Credit & Copyright: Tomas Havel
Explanation: What’s higher than the Himalayas? Although the Himalayan Mountains are the tallest on planet Earth, they don't measure up to the Milky Way. Visible above the snow-capped mountains in the featured image is the arcing central band of our home galaxy. The bright spot just above the central plane is the planet Jupiter, while the brightest orange spot on the upper right is the star Antares. The astrophotographer braved below-zero temperatures at nearly 4,000-meters altitude to take the photographs that compose this image. The featured picture is a composite of eight exposures taken with same camera and from the same location over three hours, just after sunset, in 2019 April, from near Bimtang Lake in Nepal. Over much of planet Earth, the planets Mercury (faint) and Venus (bright) will be visible this week after sunset.

22/05/2020

Science & Technology - Astronomy picture of the day : South of Carina

2020 May 22
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South of Carina
Image Credit & Copyright: Ignacio Diaz Bobillo

Explanation: With natal dust clouds in silhouette against glowing atomic gas, this colorful and chaotic vista lies within one of the largest star forming regions in the Milky Way galaxy, the Great Carina Nebula. The telescopic close-up frames a field of view about 80 light-years across, a little south and east of Eta Carinae, the nebula's most energetic and enigmatic star. Captured under suburban skies improved during national restrictions, a composite of narrowband image data was used to create the final image. In it, characteristic emission from the nebula's ionized sulfur, hydrogen, and oxygen atoms is mapped to red, green, and blue hues, a color palette also popular in Hubble Space Telescope images. The celestial landscape of bright ridges of emission bordered by cool, obscuring dust lies about 7,500 light-years away toward the southern constellation Carina.

19/05/2020

Science & Technologie - Le monde vu du ciel : Dunes dans le désert de Namibie

Dunes dans le désert de Namibie
Le mot « désert » est dérivé du latin desertum et désigne un lieu vaste et inculte, abandonné, livré à la solitude. Cela concerne autant les forêts inoccupées par l'Homme que les espaces secs. Au Moyen Âge, le terme avait une connotation religieuse, associé aux retraites, ermitages, par opposition au monde.

18/05/2020

Science & Technology - Astronomy picture of the day : Journey into the Cosmic Reef

Journey into the Cosmic Reef
Video Credit: NASA's GSFC, SVS; Lead Producer & Music: Joseph DePasquale (STScI)
Explanation: What would you see if you could fly into the Cosmic Reef? The nebular cloud NGC 2014 appear to some like an ocean reef that resides in the sky, specifically in the LMC, the largest satellite galaxy of our Milky Way Galaxy. A detailed image of this distant nebula was taken by the Hubble Space Telescope to help commemorate 30 years of investigating the cosmos. Data and images of this cosmic reef have been combined into the three-dimensional model flown through in the featured video. The computer animated sequence first takes you past a star cluster highlighted by bright blue stars, below pillars of gas and dust slowly being destroyed by the energetic light and winds emitted by these massive stars. Filaments of gas and dust are everywhere, glowing in the red light of hydrogen and nitrogen. The animation next takes you to the blue-colored nebula NGC 2020, glowing in light emitted by oxygen and surrounding a Wolf-Rayet star about 200,000 times brighter than our Sun -- a nebula thought to be the ejected outer atmosphere of this stellar monster. As the animation concludes, the virtual camera pivots to show that NGC 2020 has a familiar hourglass shape when viewed from the side.

17/05/2020

Science & Technology - Astronomy picture of the day : A Waterspout in Florida

2020 May 17
See Explanation.  Clicking on the picture will download
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A Waterspout in Florida
Image Credit & Copyright: Joey Mole

Explanation: What's happening over the water? Pictured here is one of the better images yet recorded of a waterspout, a type of tornado that occurs over water. Waterspouts are spinning columns of rising moist air that typically form over warm water. Waterspouts can be as dangerous as tornadoes and can feature wind speeds over 200 kilometers per hour. Some waterspouts form away from thunderstorms and even during relatively fair weather. Waterspouts may be relatively transparent and initially visible only by an unusual pattern they create on the water. The featured image was taken in 2013 July near Tampa Bay, Florida. The Atlantic Ocean off the coast of Florida is arguably the most active area in the world for waterspouts, with hundreds forming each year.

04/05/2020

Science & Technologie - Santé - Le virus décodé ?

Coronavirus : des chercheurs identifient un anticorps prometteurUn anticorps monoclonal capable en laboratoire de neutraliser le virus SARS-CoV-2, responsable du Covid-19, a été identifié par une équipe de chercheurs néerlandais.

Cet anticorps neutralisant contre le coronavirus responsable du Covid et aussi contre celui responsable du Sras de 2003, pourrait constituer une piste pour la "prévention et le traitement" de ces maladies, selon l'article des chercheurs publié lundi par la revue scientifique Nature.

L'équipe associée à l'Université d'Utrecht et au Centre médical Erasmus de Rotterdam sous la direction de Berend-Jan Bosch et de Frank Grosveld, a créé 51 lignées cellulaires produisant des anticorps visant une protéine remarquable à la surface des deux coronavirus. Cette même protéine est impliquée dans l'arrimage du virus SARS-CoV-2 au récepteur ACE2 à la surface des cellules humaines et joue un rôle clé dans le processus infectieux du Covid-19. Un test a ensuite été mis au point pour déterminer si les anticorps étaient capables de neutraliser les deux coronavirus. Un de ces anticorps a montré une "activité neutralisante" tant sur le virus du Covid-19 que sur celui du Sras.

D H - Belgique 

02/05/2020

Science & Technology - Astronomy picture of the day : Cassini Approaches Saturn

2020 may 02
Cassini Approaches Saturn
Video Credit & Copyright: Cassini Imaging Team, ISS, JPL, ESA, NASA, S. Van Vuuren et al.;
Music: Adagio for Strings (NY Philharmonic)
Explanation: What would it look like to approach Saturn in a spaceship? One doesn't have to just imagine -- the Cassini spacecraft did just this in 2004, recording thousands of images along the way, and hundreds of thousands more since entering orbit. Some of Cassini's early images have been digitally tweaked, cropped, and compiled into the featured inspiring video which is part of a larger developing IMAX movie project named In Saturn's Rings. In the concluding sequence, Saturn looms increasingly large on approach as cloudy Titan swoops below. With Saturn whirling around in the background, Cassini is next depicted flying over Mimas, with large Herschel Crater clearly visible. Saturn's majestic rings then take over the show as Cassini crosses Saturn's thin ring plane. Dark shadows of the ring appear on Saturn itself. Finally, the enigmatic ice-geyser moon Enceladus appears in the distance and then is approached just as the video clip ends. After more than a decade of exploration and discovery, the Cassini spacecraft ran low on fuel in 2017 was directed to enter Saturn's atmosphere, where it surely melted.

01/05/2020

Science & Technologie - La Terre vue du ciel : L’île de Kyūshū au Japon

L’île de Kyūshū au Japon
L'île de Kyūshū est la parfaite illustration de la complexité de l'œkoumène du Japon qui se trouve à l'intersection de quatre plaques tectoniques : le Pacifique, la mer des Philippines, l'Amérique du Nord, et l'Eurasie. Kyūshū se situe sur une zone de subduction où une plaque tectonique plonge sous une autre, donnant naissance à une topographie mêlant montagnes, plaines, volcans actifs (mont Unzen) et éteints (mont Tara).

Sur cette image satellite dont les couleurs ont été simulées, l'eau est bleue, la végétation verte et les zones urbaines sont en blanc et dégradé de bleu-gris. On peut ainsi se rendre compte de l'intrication complexe entre les zones habitées et montagneuses.

© Nasa

Science & Technology - Astronomy picture of the day : Around the World at Night

Around the World at Night
Video Credit & Copyright: Jeff Dai (TWAN, IDA), Music: Peter Jeremias
Explanation: Watch this video. In only a minute or so you can explore the night skies around planet Earth through a compilation of stunning timelapse sequences. The presentation will take you to sites in the United States, Germany, Russia, Iran, Nepal, Thailand, Laos and China. You might even catch the view from a small island in the southeastern Pacific Ocean. But remember that while you're home tonight, the night sky will come to you. Look up and celebrate the night during this International Dark Sky Week.



SANTé/MEDECINE - Virus et bactéries mortels - Le virus de la rage

Grâce aux travaux de Louis Pasteur , la rage a très nettement reculé dans le monde. On dénombre tout de même plus de 50.000 morts humains s...