Science & Technology - Le monde minéral et ses trésors cachés : "Chrysocolle de Katanga aux airs de mangrove"

"Chrysocolle de Katanga aux airs de mangrove"

La chrysocolle est un minéral d'altération des minéraux de cuivre. Elle est généralement associée à d'autres minéraux de cuivre, comme ici à la malachite. Ces associations procurent des verts et des bleus plus ou moins intenses et zonés aux motifs contrastés. Elle se présente en formes massives, en concrétions, en stalactites ou en croûtes et enduits, mais très rarement en cristaux aciculaires.

Cet échantillon provient de la province du Katanga, dans la ceinture cuprifère de Kolwezi et Likasi, au sud de la République démocratique du Congo, près de Lubumbashi (ancienne Elisabethville).

Bruno Cupillard

Science & Technology - Astronomy picture of the day : Stardust and Starlight in M78

2019 March 8
Stardust and Starlight in M78 
Image Credit & Copyright: Richard S. Wright Jr.

Explanation: Interstellar dust clouds and bright nebulae abound in the fertile constellation of Orion. One of the brightest, M78, is near the center in this colorful telescopic view, covering an area north of Orion's belt. At a distance of about 1,500 light-years, the bluish nebula itself is about 5 light-years across. Its blue tint is due to dust preferentially reflecting the blue light of hot, young stars in the region. Dark dust lanes and other nebulae can easily be traced through the gorgeous skyscape that includes many Herbig- Haro objects, energetic jets from stars in the process of formation. But missing from this image is McNeil's nebula. A major discovery only recognized in 2004, the enigmatic, variable nebula was found along the dark lane of dust above and right of larger M78. McNeil's nebula is associated with a protostar and seen to be sometimes present and sometimes absent in photos of the well-imaged region. McNeil's nebula faded from view late last year and is still absent in this deep image recorded in February 2019.

Science et Technologie - Astronomy picture of the day : "Sharpless 249 and the Jellyfish Nebula"

2019 March 7
"Sharpless 249 and the Jellyfish Nebula" Image Credit & Copyright: Data - Steve Milne & Barry Wilson, Processing - Steve Milne

Explanation: Normally faint and elusive, the Jellyfish Nebula is caught in this alluring telescopic field of view. The entire scene is a two panel mosaic constructed using narrowband image data, with emission from sulfur, hydrogen and oxygen atoms shown in red, green and blue hues. It's anchored right and left by two bright stars, Mu and Eta Geminorum, at the foot of the celestial twin. The Jellyfish Nebula itself is right of center, the brighter arcing ridge of emission with dangling tentacles. In fact, the cosmic jellyfish is part of bubble-shaped supernova remnant IC 443, the expanding debris cloud from a massive star that exploded. Light from the explosion first reached planet Earth over 30,000 years ago. Like its cousin in astrophysical waters the Crab Nebula supernova remnant, the Jellyfish Nebula is known to harbor a neutron star, the remnant of the collapsed stellar core. An emission nebula cataloged as Sharpless 249 fills the field at the upper left. The Jellyfish Nebula is about 5,000 light-years away. At that distance, this image would be about 300 light-years across.

Science et Technologie - Le monde minéral et ses trésors cachés : "Stromatolite de la mine de Corsica, Minnesota"

"Stromatolite de la mine de Corsica, Minnesota"

Certains stromatolites datent de près de 3,5 milliards d'années. Elles étaient présentes dans des eaux peu profondes. Il s'agit de la première manifestation de vie dont la trace nous soit parvenue.

Ciência e Tecnologia - Saude e Medecina - Adeus mamografia : testes ao sangue para detetar o cancro da mama

Nos últimos tempos, vários centros de investigação estão na corrida para criar testes ao sangue para detetar marcadores de cancro da mama antes de este ser visível na mamografia. A Universidade de Heidelberg anuncia ter um teste pronto para entrar no mercado ainda em 2019.

Sarah Schott, do Hospital Universitário de Heidelberg, na Alemanha, está convicta de que o teste que a sua equipa desenvolveu estará disponível no mercado ainda este ano e poderá com grande vantagem substituir a mamografia na deteção do cancro da mama, pelo menos nas mulheres com menos de 50 anos.

Descrito pelos investigadores como "uma biopsia líquida" e "não invasiva", o teste, intitulado HeiScreen, já detetou 15 tipos diferentes de células de cancro da mama e tem ainda a vantagem de identificar o cancro antes de este ser visível através das técnicas de raios X ou ecografia. É também mais económico, requerendo apenas alguns mililitros de sangue e podendo ser feito em qualquer laboratório.

Diario de Noticias - Portugal

Science & Technology - Astronomy picture of the day : "X-Ray Superbubbles in Galaxy NGC 3079"

2019 March 5
X-Ray Superbubbles in Galaxy NGC 3079 
Image Credit: X-ray: NASA, CXC, U. Michigan, J-T Li et al.; Optical: NASA, STScI

Explanation: What created these huge galactic superbubbles? Two of these unusual bubbles, each spanning thousands of light-years, were recently discovered near the center of spiral galaxy NGC 3079. The superbubbles, shown in purple on the image right, are so hot they emit X-rays detected by NASA's Earth-orbiting Chandra X-Ray Observatory. Since the bubbles straddle the center of NGC 3079, a leading hypothesis is that they were somehow created by the interaction of the central supermassive black hole with surrounding gas. Alternatively, the superbubbles might have been created primarily by the energetic winds from many young and hot stars near that galaxy's center. The only similar known phenomenon is the gamma-ray emitting Fermi bubbles emanating from the center of our Milky Way Galaxy, discovered 10 years ago in images taken by NASA's Fermi satellite. Research into the nature of the NGC 3079superbubbles will surely continue, as well as searches for high-energy superbubbles in other galaxies.

Science et Technologie - Le monde minéral et ses trésors cachés : Gypse et ses cristaux monocliniques

Le gypse est un sulfate de calcium. Souvent enchâssé dans des marnes imperméables, il est alors préservé de la dissolution comme c'est le cas à Grozon, dans le Jura. Translucide, il présente ici, à la surface de ses parois, le contour de cristaux monocliniques.

Bruno Cupillard

Science & Technology - Astronomy picture of the day : Celestial Alignment over Sicilian Shore

2019 March 4
Celestial Alignment over Sicilian Shore  
Image Credit & Copyright: Dario Giannobile

Explanation: This was a sunrise to remember. About a month ago, just before the dawn of the Sun, an impressive alignment of celestial objects was on display to the east. Pictured, brightest and closest to the horizon, is the Moon. The Moon's orange glow is caused by the scattering away of blue light by the intervening atmosphere. Next brightest and next closest to the horizon is the planet Venus. Compared to the Moon, Venus appears more blue -- as can (also) be seen in its reflection from the water. Next up is Jupiter, while the bright object above Jupiter is the star Antares. Although this display was visible from almost anywhere on planet Earth, the featured image was taken along a picturesque seashore near the city of Syracuse, on the island of Sicily, in the country of Italy. This month Saturn appears between Venus and Jupiter before sunrise, while Mars is visible just after sunset.

Science et Technologie - Le monde minéral et ses trésors cachés : Gypse noir et blanc aux impuretés contrastées

Le gypse est un minéral très fréquent des terrains sédimentaires. C'est un sulfate hydraté decalcium CaSO4 qui cristallise sous des formes très diverses : concrétions en forme de rose, flèches ou masses de cristaux aux parois accolées.

Les couleurs sont tout autant variées : incolore, blanc, jaune, rose à rouge, gris à noir, etc.

Bruno Cupillard

Science & Technology - Astronomy picture of the day : The Orion Bullets

2019 March 3
The Orion Bullets 
Image Credit: GeMS/GSAOI Team, Gemini Observatory, AURA, NSF;
Processing: Rodrigo Carrasco (Gemini Obs.), Travis Rector (Univ. Alaska Anchorage)

Explanation: Why are bullets of gas shooting out of the Orion Nebula? Nobody is yet sure. First discovered in 1983, each bullet is actually about the size of our Solar System, and moving at about 400 km/sec from a central source dubbed IRc2. The age of the bullets, which can be found from their speed and distance from IRc2, is very young -- typically less than 1,000 years. As the bullets expand out the top of the Kleinmann-Low section of the Orion Nebula, a small percentage of iron gas causes the tip of each bullet to glow blue, while each bullet leaves a tubular pillar that glows by the light of heated hydrogen gas. The detailed image was created using the 8.1 meter Gemini South telescope inChile with an adaptive optics system (GeMS). GeMS uses five laser generated guide stars to help compensate for the blurring effects of planet Earth's atmosphere.