Science & Technologie - Astronomy picture of the day : The Very Large Array at Moonset

 2020 10 octobre

The Very Large Array at Moonset
Image Credit: Jeff Hellermann, NRAO / AUI / NSF

Explication : Un spectacle inspirant, ces antennes géantes du Karl G. Jansky Very Large Array (VLA) s’élèvent au-dessus du désert du Nouveau-Mexique à moonset. Montées sur des piliers mais transportables sur les voies ferrées pour modifier la configuration du VLA, ses 27 antennes de fonctionnement sont chacune de la taille d’une maison (25 mètres de diamètre) et peuvent être organisées en un réseau couvrant la taille d’une ville (35 kilomètres). Un cheval de bataille prolifique de radioastronomie, le VLA a été utilisé pour découvrir l’eau sur la planète Mercure,coronae radio-brillante autour des étoiles, micro-quasars dans notre galaxie, gravitationnellement induit anneaux Einstein autour des galaxies lointaines, et les homologues radio à cosmologiquement lointains sursauts gamma. Sa grande taille a permis aux astronomes d’étudier les détails des galaxies radio, des jets cosmiques ultra-rapides, et de cartographier le centre de notre propre Voie lactée. Aujourd’hui, 40 ans après son dévouement, le VLA a été utilisé dans plus de 14 000 projets d’observation et a contribué à plus de 500 thèses de doctorat. Le 10 octobre, l’Observatoire national de radioastronomie organisera une journée de célébration en ligne de l’ALV à 40 ans avec des visites virtuelles et des présentations sur l’histoire, les opérations, la science et l’avenir du Very Large Array.

Science & Technologie - Astronomy picture of the day

2020 October 8

Mare Frigoris
Image Credit & Copyright: Matt Smith

Explanation: Lighter than typically dark, smooth, mare the Mare Frigoris lies in the far lunar north. Also known as the Sea of Cold, it stretches across the familiar lunar nearside in this close up of the waxing gibbous Moon's north polar region. Dark-floored, 95 kilometer wide crater Plato is just left of the center. Sunlit peaks of the lunar Alps (Montes Alpes) are highlighted below and right of Plato, between the more southern Mare Imbrium (Sea of Rains) and Mare Frigoris. The prominent straight feature cutting through the mountains is the lunar Alpine Valley (Vallis Alpes). Joining the Mare Imbrium and Mare Frigoris, the lunar valley is about 160 kilometers long and up to 10 kilometers wide.

Corn Moon Rising - (Science & Technology - Astronomy picture of the day)

2020 September 14
Corn Moon Rising 
Image Credit & Copyright: Zarcos Palma

Explanation: A rising moon can be a dramatic sight. A rising Full Corn Moon was captured early this month in time-lapse with a telephoto lens from nearly 30 kilometers away -- making Earth's ascending half-degree companion appear unusually impressive. The image was captured from Portugal, although much of the foreground -- including lights from the village of Puebla de Guzmán -- is in Spain. A Full Corn Moon is the name attributed to a full moon at this time of year by cultures of some northern indigenous peoples of the Americas, as it coincides with the ripening of corn. Note that the Moon does not appear larger when it is nearer the horizon -- its seemingly larger size there is only an illusion. The next full moon -- occurring at the beginning of next month -- will be known as the Full Harvest Moon as it occurs nearest in time to the northern autumnal equinox and the northern field harvests.

Une nouvelle imagerie du cerveau (Science & Technologie - Santé/Médecine)

Des chercheurs de l’Université de Harvard ont mis au point un cerveau multirégional sur une puce afin de comprendre comment les troubles mentaux impactent simultanément les régions du cerveau.

En savoir plus : Multiregional brain on a chip

Même si la plupart des technologies mentionnées dans ce Top 10 sont ou seront utilisées exclusivement par des médecins, il peut être intéressant de souligner que deux d’entre elles sont des applications mobiles utilisées par le patient. Trois si l’on tient compte des examens médicaux à distance. 

Comme nous l’avons mentionné dans l’article Santé numérique et innovations de première ligne publié dans le cadre de notre participation au Congrès des services de première ligne, une des tendances qui gagne de plus en plus en popularité en matière de santé numérique est l’implication du patient. L’idée est de déléguer aux patients certaines tâches qui ne nécessitent pas de formation en médecine ou qui s’accomplissent avec des instructions de base afin d’alléger le système de santé.

Avant d’envisager la démocratisation de technologies médicales actuellement en développement, il faut toutefois sensibiliser les professionnels de la santé à utiliser des technologies existantes qui ont déjà fait leurs preuves comme la prise de rendez-vous en ligne pour cliniques médicales ainsi que la création et la gestion numérique d’horaires de médecins.

Pour suivre l’évolution des tendances en matière de santé numérique, joignez-vous à la Communauté PetalMD!

GW190521: Unexpected Black Holes Collide - (Science & Technology - Astronomy picture of the day)

2020 September 8
GW190521: Unexpected Black Holes Collide 
Illustration Credit: Raúl Rubio (Virgo Valencia Group, The Virgo Collaboration)

Explanation: How do black holes like this form? The two black holes that spiraled together to produce the gravitational wave event GW190521 were not only the most massive black holes ever seen by LIGO and VIRGO so far, their masses -- 66 and 85 solar masses -- were unprecedented and unexpected. Lower mass black holes, below about 65 solar masses are known to form in supernova explosions. Conversely, higher mass black holes, above about 135 solar masses, are thought to be created by very massive stars imploding after they use up their weight-bearing nuclear-fusion-producing elements. How such intermediate mass black holes came to exist is yet unknown, although one hypothesis holds that they result from consecutive collisions of stars and black holes in dense star clusters. Featured is an illustration of the black holes just before collision, annotated with arrows indicating their spin axes. In the illustration, the spiral waves indicate the production of gravitational radiation, while the surrounding stars highlight the possibility that the merger occurred in a star cluster. Seen last year but emanating from an epoch when the universe was only about half its present age (z ~ 0.8), black hole merger GW190521 is the farthest yet detected, to within measurement errors.

Edvar Grieg (Peer Gynt) : "In the hall of the mountain king" - (Music - Live - Video)

Simon R. Hudson : The Milky Way over St Michael's Mount - (Science & Technology - Astronomy picture of the day)

2020 September 7
The Milky Way over St Michael's Mount 
Image Credit: Simon R. Hudson

Explanation: Where do land and sky converge? On every horizon -- but in this case the path on the ground leads to St Michael's Mount (Cornish: Karrek Loos yn Koos), a small historic island in Cornwall, England. The Mount is usually surrounded by shallow water, but at low tide is spanned by a human-constructed causeway. The path on the sky, actually the central band of our Milky Way Galaxy, also appears to lead to St Michael's Mount, but really lies far in the distance. The red nebula in the Milky Way, just above the castle, is theLagoon Nebula, while bright Jupiter shines to the left, and a luminous meteor flashes to the right. The foreground and background images of this featured composite were taken on the same July night and from the same location. Although meteors are fleeting and the Milky Way disk shifts in the night as the Earth turns, Jupiter will remain prominent in the sunset sky into December.

Nasa : The Wizard Nebula - (Science & Technologie - Astronomy picture of the day)

2020 September 4
The Wizard Nebula
Image Credit & Copyright: Andrew Klinger

Explanation: Open star cluster NGC 7380 is still embedded in its natal cloud of interstellar gas and dust popularly known as the Wizard Nebula. Seen on the left, with foreground and background stars along the plane of our Milky Way galaxy it lies some 8,000 light-years distant, toward the constellation Cepheus. In apparent size on the sky, a full moon would cover the 4 million year young cluster and associated nebula, normally much too faint to be seen by eye. Made with telescope and camera firmly planted on Earth, the image reveals multi light-year sized shapes and structures of cosmic gas and dust within the Wizard though, in a color palette made popular in Hubble Space Telescope images. Recorded with narrowband filters, the visible wavelength light from the nebula's hydrogen, oxygen, and sulfur atoms is transformed into green, blue, and red colors in the final digital composite.

Nasa : A Halo for Andromeda - (Science & Technology - Astronomy picture of the day)

2020 September 3
A Halo for Andromeda 
Digital Illustration Credit: NASA, ESA, J. DePasquale and E. Wheatley (STScI) and Z. Levay

Explanation: M31, the Andromeda Galaxy, is the closest large spiral galaxy to our Milky Way. Some 2.5 million light-years distant it shines in Earth's night sky as a small, faint, elongated cloud just visible to the unaided eye. Invisible to the eye though, its enormous halo of hot ionized gas is represented in purplish hues for this digital illustration of our neighboring galaxy above rocky terrain. Mapped by Hubble Space Telescope observations of the absorption of ultraviolet light against distant quasars, the extent and make-up of Andromeda's gaseous halo has been recently determined by the AMIGA project. A reservoir of material for future star formation, Andromeda's halo of diffuse plasma was measured to extend around 1.3 million light-years or more from the galaxy. That's about half way to the Milky Way, likely putting it in contact with the diffuse gaseous halo of our own galaxy.

Nasa : Salt Water Remnants on Ceres - (Science & Technologie - Astronomy picture of the day)

2020 September 1
Salt Water Remnants on Ceres 
Video Credit: Dawn Mission, NASA, JPL-Caltech, UCLA, MPS/DLR/IDA

Explanation: Does Ceres have underground pockets of water? Ceres, the largest asteroid in the asteroid belt, was thought to be composed of rock and ice. At the same time, Ceres was known to have unusual bright spots on its surface. These bright spots were clearly imaged during Dawn's exciting approach in 2015. Analyses of Dawn images and spectra indicated that the bright spots arise from the residue of highly-reflective salt water that used to exist on Ceres' surface but evaporated. Recent analysis indicates that some of this water may have originated from deep inside the dwarf planet, indicating Ceres to be a kindred spirit with several Solar System moons, also thought to harbor deep water pockets. The featured video shows in false-color pink the bright evaporated brine named Cerealia Facula inOccator Crater. In 2018, the mission-successful but fuel-depleted Dawn spacecraft was placed in a distant parking orbit, keeping it away from the Ceres' surface for at least 20 years to avoid interfering with any life that might there exist.