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.

Science & Technology - Astronomy picture of the day : NGC 6302: The Butterfly Nebula

2019 March 2
NGC 6302: The Butterfly Nebula 
Image Credit: NASA, ESA, Hubble, HLA; Reprocessing & Copyright: Robert Eder

Explanation: The bright clusters and nebulae of planet Earth's night sky are often named for flowers or insects. Though its wingspan covers over 3 light-years, NGC 6302 is no exception. With an estimated surface temperature of about 250,000 degrees C, the dying central star of this particular planetary nebula has become exceptionally hot, shining brightly in ultraviolet light but hidden from direct view by a dense torus of dust. This sharp close-up was recorded by the Hubble Space Telescope in 2009. The Hubble image data is reprocessed here, showing off the remarkable details of the complex planetary nebula. Cutting across a bright cavity of ionized gas, the dust torus surrounding the central star is near the center of this view, almost edge-on to the line-of-sight. Molecular hydrogen has been detected in the hot star's dusty cosmic shroud. NGC 6302 lies about 4,000 light-years away in the arachnologically correct constellation of the Scorpion (Scorpius).

Science et Technologie - Le monde minéral et ses trésors cachés : "Pietersite aux reflets chatoyants"

"Pietersite aux reflets chatoyants"

Sid Pieters a découvert cette forme de crocidolite en 1962 sur les terres de sa ferme, en Namibie. En 1964, cette matière a été nommée pietersite. Depuis 1993, une amphibole très fibreuse trouvée en Chine porte la même appellation car elle présente des couleurs et des chatoyances similaires.

Bruno Cupillard

Science & Technology - Astronomy picture of the day : Charioteer's Comet

2019 March 1
A Charioteer's Comet  Image Credit & Copyright: Rolando Ligustri (CARA Project, CAST)

Explanation: Still racing across planet Earth's night skies, Comet Iwamoto (C/2018 Y1) shares this pretty telescopic field of view with stars and nebulae of northern constellation Auriga, the Charioteer. Captured on February 27, Iwamoto's greenish coma and faint tail appear between a complex of reddish emission nebulae and open star cluster M36 (bottom right). The reddish emission is light from hydrogen gas ionized by ultraviolet radiation from hot stars near the region's giant molecular cloud some 6,000 light-years distant. The greenish glow from the comet, less than 5 light-minutes away, is predominantly emission from diatomic carbon molecules fluorescing in sunlight. M36, one of Auriga's more familiar star clusters, is also a background object far beyond the Solar System, about 4,000 light-years away. Comet Iwamoto passed closest to Earth on February 12 and is outward bound in a highly elliptical orbit that will carry it beyond the Kuiper belt. With an estimated orbital period of 1,317 years it should return to the inner Solar System in 3390 AD.