ASTRONOMY - Gemini Meteors over Snow Capped Mountains

 2025 December 15

Gemini Meteors over Snow Capped Mountains
Image Credit & Copyright: Tomáš Slovinský

Explanation: Where are all of these meteors coming from? In terms of direction on the sky, the pointed answer is the constellation of Gemini. That is why the major meteor shower in December is known as the Geminids -- because shower meteors all appear to come from a radiant toward Gemini. Three dimensionally, however, sand-sized debris expelled from the unusual asteroid 3200 Phaethon follows a well-defined orbit about our Sun, and the part of the orbit that approaches Earth is superposed in front of the constellation of Gemini. Therefore, when Earth crosses this orbit, the radiant point of falling debris appears in Gemini. Featured here is a composite of many images taken over the past few days through dark skies from Slovakia and capturing the snow-covered peaks of the Belianske Tatra mountains Numerous bright meteor streaks from the Geminids meteor shower are visible. Orion is visible above the horizon, while the bright star nearest the radiant is Castor.

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.

LaNatureCa

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