ASTRONOMY - Juno Flyby of Ganymede and Jupiter

 2025 December 14

Juno Flyby of Ganymede and Jupiter
Video Credit: NASA, JPL-Caltech, SWRI, MSSS;
Animation: Koji Kuramura, Gerald Eichstädt, Mike Stetson; Music: Vangelis

Explanation: What would it be like to fly over the largest moon in the Solar System? In 2021, the robotic Juno spacecraft flew past Jupiter's huge moon Ganymede and took images that have been digitally constructed into a detailed flyby. As the featured video begins, Juno swoops over the two-toned surface of the 2,000-km wide moon, revealing an icy alien landscape filled with grooves and craters. The grooves are likely caused by shifting surface plates, while the craters are caused by violent impacts. Continuing on in its orbit, Juno then performed its 34th close pass over Jupiter's clouds. The digitally-constructed video shows numerous swirling clouds in the north, colorful planet-circling zones and bands across the middle -- featuring several white-oval clouds from the String of Pearls, and finally more swirling clouds in the south.

ASTRONOMY - Orion and the Ocean of Storms

 2025 December 13

Orion and the Ocean of Storms
Image Credit: NASA, Artemis 1

Explanation: On December 5, 2022, a camera on board the uncrewed Orion spacecraft captured this view as Orion approached its return powered flyby of the Moon. Beyond one of Orion's extended solar arrays lies dark, smooth, terrain along the western edge of the Oceanus Procellarum. Prominent on the lunar nearside Oceanus Procellarum, the Ocean of Storms, is the largest of the Moon's lava-flooded maria. The lunar terminator, the shadow line between lunar night and day, runs along the left of this frame. The 41 kilometer diameter crater Marius is top center, with ray crater Kepler peeking in at the edge, just right of the solar array wing. Kepler's bright rays extend to the north and west, reaching the dark-floored Marius. By December 11, 2022 the Orion spacecraft had returned to its home world. The historic Artemis 1 mission ended with Orion's successful splashdown in planet Earth's water-flooded Pacific Ocean.

OCEANOGRAPHIE - Vagues scélérates - (7/29) Leur origine

Francesco Fedele, professeur agrégé à la Georgia Tech School of Civil and Environmental Engineering et depuis longtemps sceptique quant aux explications conventionnelles, a dirigé une équipe internationale chargée d'étudier la formation des vagues scélérates et les causes de ces géants océaniques soudains.

©Getty Images

ASTRONOMY - Northern Fox Fires

 2025 December 12

Northern Fox Fires
Image Credit & Copyright: Dennis Lehtonen

Explanation: In a Finnish myth, when an arctic fox runs so fast that its bushy tail brushes the mountains, flaming sparks are cast into the heavens creating the northern lights. In fact the Finnish word "revontulet", a name for the aurora borealis or northern lights, can be translated as fire fox. So that evocative myth took on a special significance for the photographer of this northern night skyscape from Finnish Lapland near Kilpisjarvi Lake. The snowy scene is illuminated by moonlight. Saana, an iconic fell or mountain of Lapland, rises at the right in the background. But as the beautiful nothern lights danced overhead, the wild fire fox in the foreground enthusiastically ran around the photographer and his equipment, making it difficult to capture in this lucky single shot.

ASTRONOMY - Galaxies in the River

 2025 December 11

Galaxies in the River
Image Credit & Copyright: Vikas Chander

Explanation: Large galaxies grow by eating small ones. Even our own galaxy engages in a sort of galactic cannibalism, absorbing small galaxies that are too close and are captured by the Milky Way's gravity. In fact, the practice is common in the universe and illustrated by this striking pair of interacting galaxies from the banks of the southern constellation Eridanus, The River. Located over 50 million light years away, the large, distorted spiral NGC 1532 is seen locked in a gravitational struggle with dwarf galaxy NGC 1531, a struggle the smaller galaxy will eventually lose. Seen nearly edge-on, in this sharp image, spiral NGC 1532 spans about 100,000 light-years. The NGC 1532/1531 pair is thought to be similar to the well-studied system of face-on spiral and small companion known as M51.

VULCANOLOGIE - Les volcans sous-marins : Les bâtisseurs cachés des fonds marins

Les volcans sous-marins se forment lorsque le magma remonte par des fissures dans le fond de l'océan et crée d'immenses montagnes volcaniques qui restent cachées sous les vagues.

©Getty Images

ASTRONOMY - The Heart of the Soul Nebula

 2025 December 9

The Heart of the Soul Nebula
Image Credit & Copyright: Nicola Bugin

Explanation: This cosmic close-up looks deep inside the Soul Nebula. The dark and brooding dust clouds outlined by bright ridges of glowing gas are cataloged as IC 1871. About 25 light-years across, the telescopic field of view spans only a small part of the much larger Heart and Soul nebulae. At an estimated distance of 6,500 light-years, the star-forming complex lies within the Perseus spiral arm of the Milky Way, seen in planet Earth's skies toward the constellation of the Queen of Aethiopia (Cassiopeia). An example of triggered star formation, the dense star-forming clouds of IC 1871 are themselves sculpted by the intense winds and radiation of the region's massive young stars. This color image adopts a palette made popular in Hubble images of star-forming regions.

SANTé/MEDECINE - CANCER - 12 AVANCéES REVOLUTIONNAIRES - 12. Une pilule qui pourrait réduire le risque de cancer du sein

Le médicament Anastrozole, déjà utilisé contre le cancer du sein, est testé sur près de 300 000 femmes à haut risque dans le cadre d’un programme du NHS. Cette petite pilule agit en réduisant le taux d’œstrogènes, une hormone liée à certains cancers du sein. Ce traitement pourrait prévenir l’apparition de la maladie, surtout dans les pays où les ressources médicales sont limitées. En effet, 70 % des décès liés au cancer surviennent dans les pays à revenu faible ou intermédiaire, où l’accès aux soins reste inégal.

Important : Bien que ces avancées soient prometteuses, elles sont encore en cours d’étude ou en phase d’essai pour la plupart. Il est donc essentiel de consulter votre médecin avant toute décision médicale, et de ne pas interrompre un traitement en cours sans avis professionnel.

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LES BELLES INVENTIONS DE LEONARD DE VINCI - Ses machines volantes

Voici une des machines volantes de Léonard de Vinci.

Elle semble plus tenir du planeur que des inventions dessinées pour faire du vol battu Léonard de Vinci était limité par les sources d'énergie disponibles à son époque. Il semble avoir compris au fil du temps qu'il devait s'orienter vers ce type de machine imitant les oiseaux en vol plané.

Le but ? Réaliser l'un des plus vieux rêves de l'Homme : voler.

© Diagram Lajard, DP

ASTRONOMY - Visualization: Near a Black Hole and Disk

 2025 December 3

Visualization: Near a Black Hole and Disk
Illustration Credit: NASA's GSFC, J. Schnittman & B. Powell; Text: Francis Reddy (U. Maryland, NASA's GSFC)

Explanation: What would it look like to plunge into a monster black hole? This image from a supercomputer visualization shows the entire sky as seen from a simulated camera plunging toward a 4-million-solar-mass black hole, similar to the one at the center of our galaxy. The camera lies about 16 million kilometers from the black hole’s event horizon and is moving inward at 62% the speed of light. Thanks to gravity’s funhouse effects, the starry band of the Milky Way appears both as a compact loop at the top of this view and as a secondary image stretching across the bottom. Move the cursor over the image for additional explanations. Visualizations like this allow astronomers to explore black holes in ways not otherwise possible.

ASTRONOMY - Apollo 17 at Shorty Crater

 2025 December 6

Apollo 17 at Shorty Crater
Apollo 17 Crew, NASA

Explanation: Fifty three years ago, in December of 1972, Apollo 17 astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours on the Moon exploring the Taurus-Littrow valley, while colleague Ronald Evans orbited overhead. This snapshot from another world was taken by Cernan as he and Schmitt roamed the lunar valley's floor. The image shows Schmitt next to the lunar rover parked at the southeast rim of Shorty Crater. That location is near the spot where geologist Schmitt discovered orange lunar soil. The Apollo 17 crew returned with 110 kilograms of rock and soil samples, more than was returned from any of the other lunar landing sites. And for now, Cernan and Schmitt are the last to walk on the Moon.

SANTé/MEDECINE - CANCER - 12 AVANCéES REVOLUTIONNAIRES - 11. Une thérapie qui utilise les propres cellules du patient

Les médecins ont mis au point un traitement très spécial appelé « thérapie CAR-T ». Il s’agit d’un procédé où on prélève certaines cellules du système immunitaire du patient, puis on les modifie en laboratoire pour qu’elles sachent reconnaître et attaquer les cellules cancéreuses. Ensuite, on réinjecte ces cellules au patient pour qu’elles fassent le travail à l’intérieur du corps.

Ce traitement a donné de très bons résultats chez certaines personnes atteintes de leucémie (un cancer du sang). Par exemple, une femme qui a reçu ce traitement est toujours en bonne santé 19 ans plus tard. Cela montre que ce genre de thérapie peut parfois fonctionner pendant très longtemps.

Cependant, les autorités de santé, comme la FDA aux États-Unis, ont remarqué que chez environ 30 personnes, un autre cancer est apparu après la thérapie. On ne sait pas encore si c’est directement lié au traitement, mais par prudence, les médecins ajoutent maintenant des avertissements pendant que les recherches se poursuivent.

LaNatureCa

ASTRONOMY - The Surface of Titan from Huygens

 2025 November 30

The Surface of Titan from Huygens
Image Credit: ESA, NASA, JPL, U. Arizona, Huygens Lander

Explanation: If you could stand on Titan -- what would you see? The featured color view from Titan gazes across an unfamiliar and distant landscape on Saturn's largest moon. The scene was recorded by ESA's Huygens probe in 2005 after a 2.5-hour descent through a thick atmosphere of nitrogen laced with methane. Bathed in an eerie orange light at ground level, rocks strewn about the scene could well be composed of water and hydrocarbons frozen solid at an inhospitable temperature of negative 179 degrees C. The large light-toned rock below and left of center is only about 15 centimeters across and lies 85 centimeters away. The saucer-shaped spacecraft is believed to have penetrated about 15 centimeters into a place on Titan's surface that had the consistency of wet sand or clay. Huygen's batteries enabled the probe to take and transmit data for more than 90 minutes after landing. Titan's bizarre chemical environment may bear similarities to planet Earth's before life evolved.

LES BELLES INVENTIONS DE LEONARD DE VINCI - La mitrailleuse ou ribaudequin

Voici une invention qui illustre bien la passion de Léonard de Vinci pour les armes. N'oublions pas qu'il s'était présenté au duc de Milan comme un ingénieur militaire tout autant qu'un artiste. On voit ici l'une de ses mitrailleuses, encore appelées « ribaudequins » au moment du développement des armes à feu en Europe.

© Sémhur GFDL

ASTRONOMY - Moon Games

2025 November 29

Moon Games
Image Credit & Copyright: Giorgia Hofer

Explanation: This is not a screen from a video game. Nestled below the tree-line, the small mountain church does look like it might be hiding from Moon though. In the well-composed telephoto snapshot, taken on November 23, the church walls are partly reflecting light from terrestrial flood lights. Of course, the Moon is reflecting light from the Sun. At any given time the Sun illuminates fully half of the Moon's surface, also known as the lunar dayside, but on that night only a sliver of its sunlit surface was visible. About three days after New Moon, the Moon was in a waxing crescent phase. The single exposure was captured shortly after sunset in skies near Danta di Cadore, northern Italy, planet Earth. 

ASTRONOMY - Portrait of NGC 1055

 2025 November 27

Portrait of NGC 1055
Image Credit & Copyright: John Hayes

Explanation: Big, beautiful spiral galaxy NGC 1055 is a dominant member of a small galaxy group a mere 60 million light-years away toward the aquatically intimidating constellation Cetus. Seen edge-on, the island universe spans over 100,000 light-years, a little larger than our own Milky Way galaxy. The colorful, spiky stars decorating this cosmic portrait of NGC 1055 are in the foreground, well within the Milky Way. But telltale pinkish star forming regions and young blue star clusters are scattered through winding dust lanes along the distant galaxy's thin disk. With a smattering of even more distant background galaxies, the deep image also reveals a boxy halo that extends far above and below the central bulge and disk of NGC 1055. The halo itself is laced with faint, narrow structures, and could represent the mixed and spread out debris from a satellite galaxy disrupted by the larger spiral some 10 billion years ago.

SANTé/MEDECINE - CANCER - 12 AVANCEES REVOLUTIONNAIRES - 10. Une goutte de sang pour détecter le cancer du pancréas

Le cancer du pancréas est connu pour être extrêmement agressif et difficile à diagnostiquer à temps, avec un taux de survie à 5 ans inférieur à 5 %. Des chercheurs de l’université de San Diego ont développé un test nommé PAC-MANN qui peut détecter 95 % des cas précoces à partir de biomarqueurs présents dans une simple goutte de sang. Une autre étude a montré comment ce cancer bloque certaines molécules essentielles, ouvrant la voie à de nouveaux traitements ciblés.

LaNatureCa

ASTRONOMY - Globular Cluster M15 Deep Field

 2025 November 26

Globular Cluster M15 Deep Field
Image Credit & Copyright: Alvaro Ibanez Perez

Explanation: Stars, like bees, swarm around the center of bright globular cluster M15. The central ball of over 100,000 stars is a relic from the early years of our Galaxy, and continues to orbit the Milky Way's center. M15, one of about 150 globular clusters remaining, is noted for being easily visible with only binoculars, having at its center one of the densest concentrations of stars known, and containing a high abundance of variable stars and pulsars. The featured image of M15 was taken by combining very long exposures -- 122 hours in all -- and so brings up faint wisps of gas and dust in front of the giant ball of stars. M15 lies about 35,000 light years away toward the constellation of the Winged Horse (Pegasus).

SANTé/MEDECINE - CANCER - 12 AVANCEES REVOLUTIONNAIRES - 9. Un traitement du cancer du col de l’utérus qui réduit drastiquement la mortalité

Une étude internationale appelée INTERLACE, menée dans 5 pays, a démontré qu’un cycle de chimiothérapie avant le traitement classique du cancer du col de l’utérus réduit de 40 % le risque de décès et de 35 % le risque de récidive. Cette percée, annoncée en octobre 2024, est la plus importante de ces 20 dernières années pour ce type de cancer. Les médicaments utilisés sont déjà disponibles et peu coûteux, rendant ce traitement accessible au plus grand nombre.

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ASTRONOMY - Comet Lemmon and the Milky Way

 2025 November 25

Comet Lemmon and the Milky Way
Image Credit & Copyright: Lin Zixuan (Tsinghua U.)

Explanation: What did Comet Lemmon look like when it was at its best? One example is pictured here, featuring three celestial spectacles all at different distances. The closest spectacle is the snowcapped Meili Mountains, part of the Himalayas in China. The middle marvel is Comet Lemmon near its picturesque best early this month, showing not only a white dust tail trailing off to the right but its blue solar wind-distorted ion tail trailing off to the left. Far in the distance on the left is the magnificent central plane of our Milky Way Galaxy, featuring dark dust, red nebula, and including billions of Sun-like stars. Comet C/2025 A6 (Lemmon) is already fading as it heads back into the outer Solar System, while the Himalayan mountains will gradually erode over the next billion years. The Milky Way Galaxy, though, will live on -- forming new mountains and comets -- for many billions of years into the future.