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17/11/2019

Science & Technology - Astronomy picture of the day : Young Stars in the Rho Ophiuchi Cloud

2019 November 17
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Young Stars in the Rho Ophiuchi Cloud 
Image Credit: NASAJPL-CaltechWISE
Explanation: How do stars form? To help find out, astronomers created this tantalizing false-color composition of dust clouds and embedded newborn stars in infrared wavelengths with WISE, the Wide-field Infrared Survey Explorer. The cosmic canvas features one of the closest star forming regions, part of the Rho Ophiuchi cloud complex some 400 light-years distant near the southern edge of the pronounceable constellation Ophiuchus. After forming along a large cloud of cold molecular hydrogen gas, young stars heat the surrounding dust to produce the infrared glow. Stars in the process of formation, called young stellar objects or YSOs, are embedded in the compact pinkish nebulae seen here, but are otherwise hidden from the prying eyes of optical telescopes. An exploration of the region in penetrating infrared light has detected emerging and newly formed stars whose average age is estimated to be a mere 300,000 years. That's extremely young compared to the Sun's age of 5 billion years. The prominent reddish nebula at the lower right surrounding the star Sigma Scorpii is a reflection nebula produced by dust scattering starlight. This view from WISE, released in 2012, spans almost 2 degrees and covers about 14 light-years at the estimated distance of the Rho Ophiuchi cloud.

16/11/2019

Science & Technology - Astronomy picture of the day : The Star Streams of NGC 5907

2019 November 16
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The Star Streams of NGC 5907 
Image Credit & Copyright: R Jay Gabany (Blackbird Observatory) - collaboration; D.Martinez-Delgado(IACMPIA),
J.Penarrubia (U.Victoria) I. Trujillo (IAC) S.Majewski (U.Virginia), M.Pohlen (Cardiff)
Explanation: Grand tidal streams of stars seem to surround galaxy NGC 5907. The arcing structures form tenuous loops extending more than 150,000 light-years from the narrow, edge-on spiral, also known as the Splinter or Knife Edge Galaxy. Recorded only in very deep exposures, the streams likely represent the ghostly trail of a dwarf galaxy - debris left along the orbit of a smaller satellite galaxy that was gradually torn apart and merged with NGC 5907 over four billion years ago. Ultimately this remarkable discovery image, from a small robotic observatory in New Mexico, supports the cosmological scenario in which large spiral galaxies, including our own Milky Way, were formed by the accretion of smaller ones. NGC 5907 lies about 40 million light-years distant in the northern constellation Draco.

15/11/2019

Music - Live - Video -Copernicus Chamber Orchestra & Horst Sohm - (Haendel) : "The Sarabande in D minor "

"The Sarabande in D minor "

Science & Technology - Astronomy picture of the day : M16 and the Eagle Nebula

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M16 and the Eagle Nebula 
Image Credit & Copyright: Martin Pugh

Explanation: A star cluster around 2 million years young surrounded by natal clouds of dust and glowing gas, M16 is also known as The Eagle Nebula. This beautifully detailed portrait of the region was made with groundbased narrow and broadband image data. It includes cosmic sculptures made famous in Hubble Space Telescope close-ups of the starforming complex. Described as elephant trunks or Pillars of Creation, dense, dusty columns rising near the center are light-years in length but are gravitationally contracting to form stars. Energetic radiation from the cluster stars erodes material near the tips, eventually exposing the embedded new stars. Extending from the ridge of bright emission at lower left is another dusty starforming column known as the Fairy of Eagle Nebula. M16 lies about 7,000 light-years away, an easy target for binoculars or small telescopes in a nebula rich part of the sky toward the split constellationSerpens Cauda (the tail of the snake).

14/11/2019

Science & Technology - Astronomy picture of the day : Curiosity Rover Finds a Clay Cache on Mars

2019 October 29
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Curiosity Rover Finds a Clay Cache on Mars 
Image Credit: NASAJPL-CaltechMSSS
Explanation: Why is there clay on Mars? On Earth, clay can form at the bottom of a peaceful lake when specific minerals trap water. At the pictured site on Mars, the robotic rover Curiosity drilled into two rocks and found the highest concentration of clay yet. The clay cache is considered addition evidence that Gale Crater once held water in the distant past. Pictured, 57 images taken by Curiosity have been combined into a selfie. The images were taken by a camera at the end of its robotic arm. Many details of the car-sized rover are visible, including its rugged wheels, numerous scientific instruments, and a high mast that contains camera "eyes", one of which can shoot out an infrared laser beam. Curiosity continues to roll around and up Mount Sharp -- in the center of Gale Crater -- in a search for new clues about the ancient history of Mars and whether or not the red planet once had conditions that could support life.

13/11/2019

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

November 13, 2019
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Comet Halley's Nucleus
Credit:
 Halley Multicolour Camera Team, GiottoESA
CopyrightMPAE
Explanation: Here is what a comet nucleus really looks like. For all active comets except Halley, it was only possible to see the surrounding opaque gas cloud called the coma. During Comet Halley's most recent pass through the innerSolar System in 1986, however, spacecraft Giotto was able to go right up to the comet and photograph its nucleus. The above image is a composite of hundreds of these photographs. Although the most famous comet, Halley achieved in 1986 only 1/10th the brightness that Comet Hyakutake did last year, and a similar comparison is likely with next year's pass of Comet Hale-Bopp. Every 76 years Comet Halley comes around again, and each time the nucleus sheds about 6 meters of ice and rock into space. This debris composes Halley's tails and leaves an orbiting trail that, when falling to Earth, are called the Orionids Meteor Shower.

12/11/2019

Musica - Video - Monteverdi : "Lamento della Ninfa"

"Lamento della Ninfa"

Science & Technology - Astronomy picture of the day : NGC 3717 : A Nearly Sideways Spiral Galaxy

2019 November 12
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NGC 3717: A Nearly Sideways Spiral Galaxy 
Image Credit: ESA/Hubble & NASAProcessing: D. Rosario
Explanation: Some spiral galaxies are seen nearly sideways. Most bright stars in spiral galaxies swirl around the center in a disk, and seen from the side, this disk can be appear quite thin. Some spiral galaxies appear even thinner thanNGC 3717, which is actually seen tilted just a bit. Spiral galaxies form disks because the original gas collided with itself and cooled as it fell inward. Planets may orbit in disks for similar reasons. The featured image by the Hubble Space Telescope shows a light-colored central bulge composed of older stars beyond filaments of orbiting dark brown dustNGC 3717 spans about 100,000 light years and lies about 60 million light years away toward the constellation of the Water Snake (Hydra).

11/11/2019

Science & Technology - Astronomy picture of the day : Lunar Craters Langrenus and Petavius

2019 November 11
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Lunar Craters Langrenus and Petavius 
Image Credit & Copyright: Eduardo Schaberger Poupeau
Explanation: The history of the Moon is partly written in its craters. Pictured here is a lunar panorama taken from Earth featuring the large craters Langrenus, toward the left, and Petavius, toward the right. The craters formed in separate impactsLangrenus spans about 130 km, has a terraced rim, and sports a central peak rising about 3 km. Petavius is slightly larger with a 180 km diameter and has a distinctive fracture that runs out from its center. Although it is known that Petravius crater is about 3.9 billion years old, the origin of its large fracture is unknown. The craters are best visible a few days after a new Moon, when shadows most greatly accentuate vertical walls and hills. Thefeatured image is a composite of the best of thousands of high-resolution, infrared, video images taken through a small telescope. Although mountains on Earth will likely erode into soil over a billion years, lunar craters Langrenus and Petavius will likely survive many billions more years, possibly until the Sun expands and engulfs both the Earth and Moon.

10/11/2019

Science & Technology - Astronomy picture of the day : A Mercury Transit Sequence

2019 November 10
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A Mercury Transit Sequence 
Image Credit & Copyright: Dominique Dierick
Explanation: Tomorrow -- Monday -- Mercury will cross the face of the Sun, as seen from Earth. Called a transit, the last time this happened was in 2016. Because the plane of Mercury's orbit is not exactly coincident with the plane of Earth's orbit, Mercury usually appears to pass over or under the Sun. The featured time-lapse sequence, superimposed on a single frame, was taken from a balcony in Belgium shows the entire transit of 2003 May 7. That solar crossing lasted over five hours, so that the above 23 images were taken roughly 15 minutes apart. The north pole of the Sun, the Earth's orbit, and Mercury's orbit, although all different, all occur in directions slightly above the left of the image. Near the center and on the far right, sunspots are visible. After Monday, the next transit of Mercury will occur in 2032.

SANTé/MEDECINE - Cancer du poumon - L'importance d'un diagnostic précoce - 2/2 -

Le Dr Amy Cummings, oncologue thoracique à UCLA, conforte l'observation en indiquant qu'une toux persistante de plus de six semaines...