ASTRONOMY - Dueling Bands in the Night

 2022 March 1

Dueling Bands in the Night
Image Credit & Copyright: Jeff Dai (TWAN)

Explanation: What are these two bands in the sky? The more commonly seen band is the one on the right and is the central band of our Milky Way galaxy. Our Sun orbits in the disk of this spiral galaxy, so that from inside, this disk appears as a band of comparable brightness all the way around the sky. The Milky Way band can also be seen all year -- if out away from city lights. The less commonly seem band, on the left, is zodiacal light -- sunlight reflected from dust orbiting the Sun in our Solar System. Zodiacal light is brightest near the Sun and so is best seen just before sunrise or just after sunset. On some evenings in the north, particularly during the months of March and April, this ribbon of zodiacal light can appear quite prominent after sunset. It was determined only this century that zodiacal dust was mostly expelled by comets that have passed near Jupiter. Only on certain times of the year will the two bands be seen side by side, in parts of the sky, like this. The featured image, including the Andromeda galaxy and a meteor, was captured in late January over a frozen lake in Kanding, Sichuan, China.

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