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.

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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.

ASTRONOMY - Apep: Unusual Dust Shells from Webb

 2025 November 24

Apep: Unusual Dust Shells from Webb
Image Credit: NASA, ESA, CSA, STScI, JWST; Science: Y. Han (Caltech), R. White (Macquarie U.); Image Processing: A. Pagan (STScI)

Explanation: What created this unusual space sculpture? Stars. This unusual system of swirls and shells, known as Apep, was observed in unprecedented detail by NASA’s James Webb Space Telescope in infrared light in 2024. Observations indicate that the unusual shape originates from two massive Wolf-Rayet stars orbiting each other every 190 years with each close passes causing a new shell of dust and gas to be expelled. Holes in these shells are thought to be caused by a third orbiting star. This stellar dust dance will likely continue for hundreds of thousands of years, possibly ending only when one of the massive stars runs out of internal nuclear fuel and explodes in a supernova punctuated by a burst of gamma-rays.

SANTé/MEDECINE - CANCER - 12 AVANCEES REVOLUTIONNAIRES - 8. Le décryptage de l’ADN tumoral pour comprendre l’origine du cancer

Au Cambridge University Hospitals, des scientifiques étudient l’ADN de 12 000 patients atteints de cancer pour en retracer l’origine. Ils identifient des mutations génétiques liées à des facteurs comme le tabac, les rayons UV ou les dommages cellulaires internes. Ces mutations sont appelées « empreintes digitales du crime ». L’étude a révélé 58 nouveaux marqueurs génétiques, qui permettront d’améliorer la prévention et les traitements ciblés.

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