ASTRONOMY - The Observable Universe

 2025 November 23

The Observable Universe
Illustration Credit & Licence: Wikipedia, Pablo Carlos Budassi

Explanation: How far can you see? Everything you can see, and everything you could possibly see, right now, assuming your eyes could detect all types of radiations around you -- is the observable universe. In light, the farthest we can see comes from the cosmic microwave background, a time 13.8 billion years ago when the universe was opaque like thick fog. Some neutrinos and gravitational waves that surround us come from even farther out, but humanity does not yet have the technology to detect them. The featured image illustrates the observable universe on an increasingly compact scale, with the Earth and Sun at the center surrounded by our Solar System, nearby stars, nearby galaxies, distant galaxies, filaments of early matter, and the cosmic microwave background. Cosmologists typically assume that our observable universe is just the nearby part of a greater entity known as "the universe" where the same physics applies. However, there are several lines of popular but speculative reasoning that assert that even our universe is part of a greater multiverse where either different physical constants occur, different physical laws apply, higher dimensions operate, or slightly different-by-chance versions of our standard universe exist.

SANTé/MEDECINE - CANCER - 12 AVANCEES REVOLUTIONNAIRES - 7. Des biopsies liquides et synthétiques moins invasives et plus rapides

Les biopsies classiques nécessitent le prélèvement de tissu, souvent par chirurgie. Aujourd’hui, la biopsie liquide offre une alternative plus douce, en détectant le cancer à partir d’une simple prise de sang. Encore plus prometteuses, les biopsies synthétiques utilisent des techniques pour inciter les cellules cancéreuses à se révéler plus tôt, facilitant une détection précise et rapide dès les premières phases de la maladie.

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OCEANOGRAPHIE - Vagues scélérates - Du mythe à la réalité (6/29)

La vague Draupner a confirmé ce que les marins rapportaient depuis des siècles : des vagues massives et soudaines existent bel et bien. Pendant des années, ces phénomènes ont été considérés comme des mythes, mais les mesures effectuées en 1995 ont fourni la première preuve scientifique de leur existence.

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ASTRONOMY - Lynds Dark Nebula 43

 2025 October 30

Lynds Dark Nebula 43
Image Credit & Copyright: Team Ciel Austral

Explanation: Sure, Halloween is an astronomy holiday. But astronomers always enjoy scanning the heavens for spook-tacular galaxies, stars, and nebulae. This favorite is item number 43 from the Beverly Lynds 1962 Catalog of Dark Nebulae, fondly known as the Cosmic Bat nebula. While its visage looks alarmingly like a scary flying mammal, Lynds Dark Nebula 43 is over 12 light-years across. Glowing with eerie light, stars are forming within the dusty interstellar molecular cloud that is dense enough to appear in silhouette against a luminous background of Milky Way stars. Watch out. This Cosmic Bat nebula is a mere 400 light-years distant toward the serpent-bearing constellation Ophiucus.

ASTRONOMY - Chamaeleon Dark Nebulas

 2025 November 19

Chamaeleon Dark Nebulas
Image Credit & Copyright: Xinran Li & Houbo Zhao

Explanation: Sometimes the dark dust of interstellar space has an angular elegance. Such is the case toward the far-south constellation of Chamaeleon. Normally too faint to see, dark dust is best known for blocking visible light from stars and galaxies behind it. In this 11.4-hour exposure, however, the dust is seen mostly in light of its own, with its strong red and near-infrared colors creating a brown hue. Contrastingly blue, a bright star Beta Chamaeleontis is visible on the upper right of the V, with the dust that surrounds it preferentially reflecting blue light from its primarily blue-white color. All of the pictured stars and dust occur in our own Milky Way Galaxy with one notable exception: a white spot just below Beta Chamaeleontis is the galaxy IC 3104, which lies far in the distance. Interstellar dust is mostly created in the cool atmospheres of giant stars and dispersed into space by stellar light, stellar winds, and stellar explosions such as supernovas.

SANTé/MEDECINE - CANCER - 12 AVANCEES REVOLUTIONNAIRES - 6. L’intelligence artificielle au service des régions mal desservies

En Inde, des technologies développées en partenariat avec le Forum économique mondial permettent à l’intelligence artificielle de repérer les signes précoces de cancer, comme le cancer du sein, même dans des régions sans radiologues. Cette technologie analyse des radiographies et établit des profils de risque, rendant la détection plus accessible dans les zones où l’expertise médicale manque cruellement.

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ASTRONOMY - Comet Lemmon's Wandering Tail

2025 November 17

Comet Lemmon's Wandering Tail
Image Credit: Ignacio Fernández

Explanation: What has happened to Comet Lemmon's tail? The answer is blowing in the wind — the wind from the Sun in this case. This continuous outflow of charged particles from the Sun has been quite variable of late, as the Sun emits bursts of energy, CMEs, that push out and deflect charged particles emitted by the comet itself. The result is a blue hued ion tail for Comet C/2025 A6 (Lemmon) that is not only impressively intricate but takes some unusual turns. This long-duration composite image taken from Alfacar, Spain last month captured this inner Solar System ionic tumult. Comet Lemmon is now fading as it heads out away from the Earth and Sun and back into the outer Solar System.

SANTé/MEDECINE - CANCER - 12 AVANCEES REVOLUTIONNAIRES - 5. Une intelligence artificielle capable de prédire un cancer des poumons

Le cancer du poumon est l’un des plus mortels, car souvent détecté trop tard. Des chercheurs du MIT ont développé un système d’intelligence artificielle appelé Sybil capable de prédire les risques de cancer du poumon jusqu’à six ans à l’avance, simplement à partir de scans à faible dose. Ce programme repère des signaux que même les radiologues ne voient pas, offrant une chance précieuse d’intervenir bien avant l’apparition des symptômes.

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ASTRONOMY - Andromeda and Friends

 2025 November 15

Andromeda and Friends
Image Credit & Copyright: Piotr Czerski

Explanation: This magnificent extragalactic skyscape looks toward the Andromeda Galaxy, the closest large spiral galaxy to the Milky Way. It also accomplishes a Messier catalog trifecta by including Andromeda, cataloged as Messier 31 (M31), along with Messier 32 (M32), and Messier 110 (M110) in the same telescopic field of view. In this frame, M32 is just left of the Andromeda Galaxy's bright core with M110 below and to the right. M32 and M110 are both elliptical galaxies themselves and satellites of the larger spiral Andromeda. By combining 60 hours of broadband and narrowband image data, the deep telescopic view also reveals tantalizing details of dust lanes, young star clusters, and star-forming regions along Andromeda's spiral arms, and faint, foreground clouds of glowing hydrogen gas. For now, Andromeda and friends are some 2.5 million light-years from our own large spiral Milky Way.

ASTRONOMIE - Spectacle grandiose

Les aurores boréales illuminent le ciel au-dessus du phare St Marys à Whitley Bay, au Royaume-Uni. Le phénomène a atteint le niveau G4 de tempête géomagnétique, créant un spectacle étonnant aux premières heures du jour. 

Humphreys Owen/PA Photos/ABACA