ASTRONOMY - Perseverance Sol 354

 2022 February 28

Perseverance Sol 354
Image Credit: NASA, JPL-Caltech, Processing; Kenneth Kremer

Explanation: This Navcam mosaic from Perseverance looks out over the car-sized rover's deck, across the floor of Jezero crater on Mars. Frames used to construct the mosaic view were captured on mission sol 354. That corresponds to Earth calendar date February 17, 2022, nearly one Earth year after the rover's landing. With a mass of over 1,000 kilograms, six-wheeled Perseverance is the heaviest rover to touch down on Mars. During its first year of exploration the rover has collected six (so far) rock core samples for later return to planet Earth, served as the base station for Ingenuity, the first helicopter on Mars, and tested MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment), converting some of the Red Planet’s thin, carbon dioxide-rich atmosphere into oxygen.

ASTRONOMY - Earthrise 1: Historic Image Remastered

 2022 February 27

Earthrise 1: Historic Image Remastered
Image Credit: NASA, Apollo 8 Crew, Bill Anders; Processing and License: Jim Weigang

Explanation: "Oh my God! Look at that picture over there! Here's the Earth coming up. Wow is that pretty!" Soon after that pronouncement, about 53 years ago, one of the most famous images ever taken was snapped from the orbit of the Moon. Now known as "Earthrise", the iconic image shows the Earth rising above the limb of the Moon, as taken by the crew of Apollo 8. But the well-known Earthrise image was actually the second image taken of the Earth rising above the lunar limb -- it was just the first in color. With modern digital technology, however, the real first Earthrise image -- originally in black and white -- has now been remastered to have the combined resolution and color of the first three images. Behold! The featured image is a close-up of the picture that Apollo 8 astronaut Bill Anders was talking about. Thanks to modern technology and human ingenuity, now we can all see it. (Historical note: A different historic black & white image of the Earth setting behind the lunar limb was taken by the robotic Lunar Orbiter 1 two years earlier.)

SANTé/MEDECINE - Quelques instants avant et après la mort

Une nouvelle étude pourrait expliquer ce qui se passe dans notre cerveau juste avant et juste après notre mort.

Selon cette nouvelle étude, publiée dans Frontiers in Aging Neuroscience, nous serions dans un état proche de celui de la méditation, du rêve ou d’un rappel de la mémoire juste avant notre décès. Cela procurerait probablement un sentiment final de sérénité juste avant de mourir.

Le Dr Ajmal Zemmar, co-auteur de l’étude, a déclaré dans un communiqué : "Bien que nos proches aient les yeux fermés et semblent prêts à partir, il se peut que leur cerveau rejoue certains des plus beaux moments qu’ils ont vécus dans leur vie."

"En générant des oscillations impliquées dans la récupération de la mémoire, le cerveau peut jouer un dernier rappel d’événements importants de la vie juste avant notre mort, similaires à ceux rapportés dans les expériences de mort imminente", explique Zemmar.

Notre cerveau reste actif pendant une courte période, même après que notre cœur a cessé de battre…

"Ces résultats remettent en question notre compréhension de la fin exacte de la vie et génèrent d’importantes questions ultérieures, telles que celles liées au moment du don d’organes", conclut Zemmar.

RTB

MUSICA - Luigi Boccherini - Minuetto

"Minuetto"

ASTRONOMY - Aurora over White Dome Geyser

 2022 February 23

Aurora Over White Dome Geyser
Image Credit & Copyright: Robert Howell

Explanation: Sometimes both heaven and Earth erupt. Colorful auroras erupted unexpectedly a few years ago, with green aurora appearing near the horizon and brilliant bands of red aurora blooming high overhead. A bright Moon lit the foreground of this picturesque scene, while familiar stars could be seen far in the distance. With planning, the careful astrophotographer shot this image mosaic in the field of White Dome Geyser in Yellowstone National Park in the western USA. Sure enough, just after midnight, White Dome erupted -- spraying a stream of water and vapor many meters into the air. Geyser water is heated to steam by scalding magma several kilometers below, and rises through rock cracks to the surface. About half of all known geysers occur in Yellowstone National Park. Although the geomagnetic storm that caused the auroras subsided within a day, eruptions of White Dome Geyser continue about every 30 minutes.

ASTRONOMY - Illustration: An Early Quasar

 2022 February 22

Illustration: An Early Quasar
Illustration Credit & License: ESO, M. Kornmesser

Explanation: What did the first quasars look like? The nearest quasars are now known to involve supermassive black holes in the centers of active galaxies. Gas and dust that falls toward a quasar glows brightly, sometimes outglowing the entire home galaxy. The quasars that formed in the first billion years of the universe are more mysterious, though. Featured, recent data has enabled an artist's impression of an early-universe quasar as it might have been: centered on a massive black hole, surrounded by sheets of gas and an accretion disk, and expelling a powerful jet. Quasars are among the most distant objects we see and give humanity unique information about the early and intervening universe. The oldest quasars currently known are seen at just short of redshift 8 -- only 700 million years after the Big Bang -- when the universe was only a few percent of its current age.

ASTRONOMY - Barred Spiral Galaxy NGC 6217

 2022 February 21

Barred Spiral Galaxy NGC 6217
Image Credit: NASA, ESA, and the Hubble SM4 ERO Team

Explanation: Many spiral galaxies have bars across their centers. Even our own Milky Way Galaxy is thought to have a modest central bar. Prominently barred spiral galaxy NGC 6217, featured here, was captured in spectacular detail in this image taken by the Advanced Camera for Surveys on the orbiting Hubble Space Telescope in 2009. Visible are dark filamentary dust lanes, young clusters of bright blue stars, red emission nebulas of glowing hydrogen gas, a long bar of stars across the center, and a bright active nucleus that likely houses a supermassive black hole. Light takes about 60 million years to reach us from NGC 6217, which spans about 30,000 light years across and can be found toward the constellation of the Little Bear (Ursa Minor).

ASTRONOMY - Peculiar Galaxies of Arp 273

 2022 February 19

Peculiar Galaxies of Arp 273
Image Credit & Copyright: Jason Guenzel

Explanation: The spiky stars in the foreground of this backyard telescopic frame are well within our own Milky Way Galaxy. But the two eye-catching galaxies lie far beyond the Milky Way, at a distance of over 300 million light-years. Their distorted appearance is due to gravitational tides as the pair engage in close encounters. Cataloged as Arp 273 (also as UGC 1810), the galaxies do look peculiar, but interacting galaxies are now understood to be common in the universe. Nearby, the large spiral Andromeda Galaxy is known to be some 2 million light-years away and approaching the Milky Way. The peculiar galaxies of Arp 273 may offer an analog of their far future encounter. Repeated galaxy encounters on a cosmic timescale can ultimately result in a merger into a single galaxy of stars. From our perspective, the bright cores of the Arp 273 galaxies are separated by only a little over 100,000 light-years.

AERONAUTIQUE - AirFish 8

L'AirFish 8 de Wigetworks arrive en fin d'expérimentation. Il ne s'agit pas vraiment d'un avion, ni même d'un bateau, mais d'une espèce d'aérodyne hybride exploitant le phénomène d'effet de sol pour voler à quelques mètres de hauteur d'une surface plane.

Il ne s'agit pas d'un hydravion, ni d'un hydroglisseur... Conçu et testé depuis dix ans par la firme singapourienne Wigetworks, l'AirFish 8 est ce que l'on appelle un ekranoplan. Ce terme est la transcription russe d'un aérodyne à effet de sol. Russe, car cette invention date de la guerre froide et c'est l'armée soviétique qui a développé ce type d'engin. L'effet de sol permet d'augmenter la portance d'un aérodyne et de diminuer sa traînée. Avec moins de traînée, la finesse de l'appareil est augmentée et il peut parcourir plus de distance avec beaucoup moins d'énergie.

FuturaSciences

ASTRONOMY - Chamaeleon I Molecular Cloud

 2022 February 18

Chamaeleon I Molecular Cloud
Image Credit & Copyright: Acquisition: Stas Volskiy (Chilescope.com), Processing: Robert Eder

Explanation: Dark markings and bright nebulae in this telescopic southern sky view are telltale signs of young stars and active star formation. They lie a mere 650 light-years away, at the boundary of the local bubble and the Chamaeleon molecular cloud complex. Regions with young stars identified as dusty reflection nebulae from the 1946 Cederblad catalog include the C-shaped Ced 110 just above and left of center, and bluish Ced 111 below it. Also a standout in the frame, the orange tinted V-shape of the Chamaeleon Infrared Nebula (Cha IRN) was carved by material streaming from a newly formed low-mass star. The well-composed image spans 1.5 degrees. That's about 17 light-years at the estimated distance of the nearby Chamaeleon I molecular cloud.

The Romanian Foundation for Excellence in Music - Wolfgang Amadeus Mozart

"Ave Verum Corpus"

POURQUOI - SANTé/MéDECINE - Pourquoi a-t-on soif quand on mange un aliment salé ?

Le sel est essentiel à la vie, mais l'organisme n'en a besoin que d'une petite quantité. Quand le corps reçoit trop de sel, que la concentration de sel devient trop élevée dans son sang, il doit faire en sorte de s'en débarrasser. Le corps élimine le surplus de sel dans l'urine, via les reins.Mais en éliminant le sel, ils éliminent aussi de l'eau, parce que le sel entraîne naturellement l'eau avec lui. Il y a alors un déséquilibre dans le sang. Le sang manque d'eau. Quand la quantité d'eau diminue dans le sang, le sang en informe le cerveau.

Afin de rétablir l'équilibre en eau dans le sang, le cerveau nous donne la sensation de soif, en ordonnant entre autres aux glandes salivaires de réduire leurs sécrétions.

Notre bouche et notre gorge sont sèches, on a soif, on boit un grand verre d'eau.

Tout ce liquide fournit à l'organisme l'eau qui lui manque pour rétablir l'équilibre du sang en eau.

Pourquoi

ASTRONOMY - Eiffel Tower Prominence on the Sun

 2022 February 16

Eiffel Tower Prominence on the Sun
Video Credit & Copyright: Hawk Wolinski

Explanation: What's that on the Sun? Although it may look like a flowing version of the Eiffel Tower, it is a solar prominence that is actually much bigger -- about the height of Jupiter. The huge prominence emerged about ten days ago, hovered over the Sun's surface for about two days, and then erupted -- throwing a coronal mass ejection (CME) into the Solar System. The featured video, captured from the astrophotographer's backyard in Hendersonville, Tennessee, USA, shows an hour time-lapse played both forwards and backwards. That CME did not impact the Earth, but our Sun had unleashed other recent CMEs that not only triggered Earthly auroras, but puffed out the Earth's atmosphere enough to cause just-launched Starlink satellites to fall back. Activity on the Sun, including sunspots, prominences, CMEs and flares, continues to increase as the Sun evolves away from a deep minimum in its 11-year magnetic cycle.

AERONAUTIQUE - Le SpaceLiner : un avion suborbital

SpaceLiner est un projet d'avion suborbital réutilisable sur lequel le Centre allemand pour l'aéronautique et l'astronautique a commencé à travailler en 2005. Cet avion pouvant transporter 50 passagers décollerait à la verticale comme les navettes spatiales.

Une fois propulsé par son lanceur muni de 9 moteurs cryogéniques, l'engin pourra planer à très haute vitesse en parcourant de grandes distances. Théoriquement, un SpaceLiner pourrait relier l'Australie et le continent européen en 90 minutes. Cependant, ce projet très ambitieux n'aboutira pas, au mieux, avant 2040-2050.

© ToSch1983, Deutsches Zentrum für Luft und Raumfahrt, GFDL

ASTRONOMY - The Galactic Center in Radio from MeerKAT

 2022 February 15

The Galactic Center in Radio from MeerKAT
Image Credit: Ian Heywood (Oxford U.), SARAO; Color Processing: Juan Carlos Munoz-Mateos (ESO)

Explanation: What's happening at the center of our galaxy? It's hard to tell with optical telescopes since visible light is blocked by intervening interstellar dust. In other bands of light, though, such as radio, the galactic center can be imaged and shows itself to be quite an interesting and active place. The featured picture shows the latest image of our Milky Way's center by the MeerKAT array of 64 radio dishes in South Africa. Spanning four times the angular size of the Moon (2 degrees), the image is impressively vast, deep, and detailed. Many known sources are shown in clear detail, including many with a prefix of Sgr, since the galactic center is in the direction of the constellation Sagittarius. In our Galaxy's Center lies Sgr A, found here in the image center, which houses the Milky Way's central supermassive black hole. Other sources in the image are not as well understood, including the Arc, just to the left of Sgr A, and numerous filamentary threads. Goals for MeerKAT include searching for radio emission from neutral hydrogen emitted in a much younger universe and brief but distant radio flashes.

ASTRONOMY - In the Heart of the Heart Nebula

 2022 February 14

In the Heart of the Heart Nebula
Image Credit & Copyright: Adam Jensen

Explanation: What excites the Heart Nebula? First, the large emission nebula dubbed IC 1805 looks, in whole, like a human heart. Its shape perhaps fitting of the Valentine's Day, this heart glows brightly in red light emitted by its most prominent element: excited hydrogen. The red glow and the larger shape are all created by a small group of stars near the nebula's center. In the heart of the Heart Nebula are young stars from the open star cluster Melotte 15 that are eroding away several picturesque dust pillars with their energetic light and winds. The open cluster of stars contains a few bright stars nearly 50 times the mass of our Sun, many dim stars only a fraction of the mass of our Sun, and an absent microquasar that was expelled millions of years ago. The Heart Nebula is located about 7,500 light years away toward the constellation of the mythological Queen of Aethiopia (Cassiopeia).

ASTRONOMY - Earth at night

 2022 February 13

Earth at Night
Image Credit: NASA, Suomi NPP VIIRS; Data: Miguel Román (NASA GSFC); Processing: Joshua Stevens

Explanation: This is what the Earth looks like at night. Can you find your favorite country or city? Surprisingly, city lights make this task quite possible. Human-made lights highlight particularly developed or populated areas of the Earth's surface, including the seaboards of Europe, the eastern United States, and Japan. Many large cities are located near rivers or oceans so that they can exchange goods cheaply by boat. Particularly dark areas include the central parts of South America, Africa, Asia, and Australia. The featured image, nicknamed Black Marble, is actually a composite of hundreds of pictures remade in 2016 from data taken by the orbiting Suomi NPP satellite.

ASTRONOMY - Aurora by Moonlight

 2022 February 12

Aurora by Moonlight
Image Credit & Copyright: P-M Hedén (Clear Skies, TWAN)

Explanation: The ice was singing as light from a bright gibbous Moon cast shadows across this frozen lake, about 20 kilometers north of Stockholm, Sweden, planet Earth. In the alluring night skyscape captured on February 10, shimmering auroral curtains of light dance in the evening sky. On that northern night nature's performance included the auroral displays fostered by a minor geomagnetic storm. Stormy space weather was the result of a coronal mass ejection, erupting from a solar prominence days earlier and brushing our fair planet's magnetosphere.

AERONAUTIQUE - L'Airbus A300-600ST ou l'avion " Beluga"

Il tient son surnom de « Beluga » en raison de la forme de sa carlingue qui évoque immédiatement l'apparence du cétacé du même nom. L'A300-600ST est un avion construit en cinq exemplaires par Airbus. Il sert à l'avionneur pour transporter les pièces volumineuses des appareils entre ses différents sites de production européens.

Le Beluga peut emporter une charge utile de 50 tonnes. Dans sa soute qui mesure 7,4 mètres de diamètre et 37,7 mètres de long, il peut par exemple transporter deux ailes d'Airbus A330 ou un fuselage d'Airbus A320+.

© Laurent ERRERA, CC by-sa 2.0

FuturaSciences

ASTRONOMY - T Tauri and Hind's Variable Nebula

 2022 February 10

T Tauri and Hind's Variable Nebula
Image Credit & Copyright: Dawn Lowry, Gian Lorenzo Ferretti, Ewa Pasiak and Terry Felty

Explanation: The star with an orange tint near top center in this dusty telescopic frame is T Tauri, prototype of the class of T Tauri variable stars. Next to it (right) is a yellow cosmic cloud historically known as Hind's Variable Nebula (NGC 1555). About 650 light-years away, at the boundary of the local bubble and the Taurus molecular cloud, both star and nebula are seen to vary significantly in brightness but not necessarily at the same time, adding to the mystery of the intriguing region. T Tauri stars are now generally recognized as young (less than a few million years old), sun-like stars still in the early stages of formation. To further complicate the picture, infrared observations indicate that T Tauri itself is part of a multiple system and suggest that the associated Hind's Nebula may also contain a very young stellar object. The well-composed image spans about 8 light-years at the estimated distance of T Tauri.

ASTRONOMY - Aurora and Light Pillars over Norway

 2022 February 8

Aurora and Light Pillars over Norway

Image Credit & Copyright: Alexandre Correia

Explanation: Which half of this sky is your favorite? On the left, the night sky is lit up by particles expelled from the Sun that later collided with Earth's upper atmosphere — creating bright auroras. On the right, the night glows with ground lights reflected by millions of tiny ice crystals falling from the sky — creating light pillars. And in the center, the astrophotographer presents your choices. The light pillars are vertical columns because the fluttering ice-crystals are mostly flat to the ground, and their colors are those of the ground lights. The auroras cover the sky and ground in the green hue of glowing oxygen, while their transparency is clear because you can see stars right through them. Distant stars dot the background, including bright stars from the iconic constellation of Orion. The featured image was captured in a single exposure two months ago near Kautokeino, Norway.

ART FRACTAL - Neige

 

L'eau se cristallise en neige par des courbes fractales. 

© Michael, Wikimedia Commons, CC by-sa 2.0

FuturaSciences

ASTRONOMY - NGC 4651: The Umbrella Galaxy

 2022 February 7

NGC 4651: The Umbrella Galaxy
Image Credit & Copyright: CFHT, Coelum, MegaCam, J.-C. Cuillandre (CFHT) & G. A. Anselmi (Coelum)

Explanation: It's raining stars. What appears to be a giant cosmic umbrella is now known to be a tidal stream of stars stripped from a small satellite galaxy. The main galaxy, spiral galaxy NGC 4651, is about the size of our Milky Way, while its stellar parasol appears to extend some 100 thousand light-years above this galaxy's bright disk. A small galaxy was likely torn apart by repeated encounters as it swept back and forth on eccentric orbits through NGC 4651. The remaining stars will surely fall back and become part of a combined larger galaxy over the next few million years. The featured image was captured by the Canada-France-Hawaii Telescope (CFHT) in Hawaii, USA. The Umbrella Galaxy lies about 50 million light-years distant toward the well-groomed northern constellation Coma Berenices.

ASTRONOMY - Blue Marble Earth

 2022 February 6

Blue Marble Earth
Image Credit: NASA, Apollo 17 Crew

Explanation: Welcome to planet Earth, the third planet from a star named the Sun. The Earth is shaped like a sphere and composed mostly of rock. Over 70 percent of the Earth's surface is water. The planet has a relatively thin atmosphere composed mostly of nitrogen and oxygen. The featured picture of Earth, dubbed The Blue Marble, was taken from Apollo 17 in 1972 and features Africa and Antarctica. It is thought to be one of the most widely distributed photographs of any kind. Earth has a single large Moon that is about 1/4 of its diameter and, from the planet's surface, is seen to have almost exactly the same angular size as the Sun. With its abundance of liquid water, Earth supports a large variety of life forms, including potentially intelligent species such as dolphins and humans. Please enjoy your stay on planet Earth.

ASTRONOMY - Symbiotic R Aquarii

 2022 February 5

Symbiotic R Aquarii
Image Credit: X-ray: NASA/CXC/SAO/R. Montez et al.; Optical: Data: NASA/ESA/STScI, Processing: Judy Schmidt (CC BY-NC-SA)

Explanation: Variable star R Aquarii is actually an interacting binary star system, two stars that seem to have a close symbiotic relationship. Centered in this space-based optical/x-ray composite image it lies about 710 light years away. The intriguing system consists of a cool red giant star and hot, dense white dwarf star in mutual orbit around their common center of mass. With binoculars you can watch as R Aquarii steadily changes its brightness over the course of a year or so. The binary system's visible light is dominated by the red giant, itself a Mira-type long period variable star. But material in the cool giant star's extended envelope is pulled by gravity onto the surface of the smaller, denser white dwarf, eventually triggering a thermonuclear explosion, blasting material into space. Astronomers have seen such outbursts over recent decades. Evidence for much older outbursts is seen in these spectacular structures spanning almost a light-year as observed by the Hubble Space Telescope (in red and blue). Data from the Chandra X-ray Observatory (in purple) shows the X-ray glow from shock waves created as a jet from the white dwarf strikes surrounding material.

AERONAUTIQUE - Solar Impulse, l’avion solaire

Solar Impulse est un projet d'avion solaire initié en 2003 par l'aventurier suisse Bertrand Piccard et le pilote André Borschberg, accompagnés par l'École polytechnique fédérale de Lausanne. Ce monoplace dispose d'une envergure de 72 mètres et de quatre moteurs électriques (de 13,5 kW chacun) alimentés par 11.628 cellules photovoltaïques.

© Matth1, GFDL
Futura Sciences

ASTRONOMY - Embraced by light

 2022 February 3

Embraced by Sunlight

Image Credit & Copyright: Juan Luis Cánovas Pérez

Explanation: Even though Venus (left) was the brightest planet in the sky it was less than 1/30th the apparent size of the Moon on January 29. But as both rose before the Sun they shared a crescent phase. For a moment their visible disks were each about 12 percent illuminated as they stood above the southeastern horizon. The similar sunlit crescents were captured in these two separate images. Made at different magnifications, each panel is a composite of stacked video frames taken with a small telescope. Venus goes through a range of phases like the Moon as the inner planet wanders from evening sky to morning sky and back again with a period of 584 days. Of course the Moon completes its own cycle of phases, a full lunation, in about 29.5 days.

AERONAUTIQUE - L'E-Fan d'Airbus, avion entièrement électrique

L'E-Fan est un avion électrique bimoteur dont le développement par Airbus Group Innovations a débuté en 2011. Il peut voler durant une heure à 160 km/h de moyenne grâce à ses batteries lithium-ion situées dans les ailes et ses deux moteurs électriques développant 60 kW. Le 10 juillet 2015, l'E-Fan a effectué une traversée de la Manche en reliant Lydd, en Angleterre, à Calais.

© Marc Schieferdecker, CC by-nc 2.0

FuturaSciences

ASTRONOMY - Moon phases 2022

 2022 February 1

Moon Phases 2022
Video Credit: Data: Lunar Reconnaissance Orbiter ; Animation: NASA's Scientific Visualization Studio;
Music: Build the Future (Universal Production Music), Alexander Hitchens

Explanation: What will the Moon phase be on your birthday this year? It is hard to predict because the Moon's appearance changes nightly. As the Moon orbits the Earth, the half illuminated by the Sun first becomes increasingly visible, then decreasingly visible. The featured video animates images and altitude data taken by NASA's Moon-orbiting Lunar Reconnaissance Orbiter to show all 12 lunations that appear this year, 2022 -- as seen from Earth's northern (southern) hemisphere. A single lunation describes one full cycle of our Moon, including all of its phases. A full lunation takes about 29.5 days, just under a month (moon-th). As each lunation progresses, sunlight reflects from the Moon at different angles, and so illuminates different features differently. During all of this, of course, the Moon always keeps the same face toward the Earth. What is less apparent night-to-night is that the Moon's apparent size changes slightly, and that a slight wobble called a libration occurs as the Moon progresses along its elliptical orbit.