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19/06/2025

SANTé/MEDECINE - Procédé révolutionnaire dans la lutte contre le cancer - 2/6 : Une découverte qui change tout

Jusqu’à présent, la lutte contre le cancer reposait principalement sur la chimiothérapie, la radiothérapie ou la chirurgie. Ces traitements, bien que parfois efficaces, sont souvent accompagnés d’effets secondaires lourds, car ils ne ciblent pas uniquement les cellules malades. Mais aujourd’hui, une nouvelle ère s’ouvre grâce à l’utilisation de la lumière comme arme de précision contre les cellules cancéreuses.

Comment la lumière peut-elle détruire le cancer ?

La clé de cette innovation réside dans une technologie appelée photothérapie dynamique. Les chercheurs ont mis au point des molécules spéciales qui, une fois introduites dans l’organisme, s’accrochent uniquement aux cellules cancéreuses. Lorsqu’elles sont exposées à une lumière d’une certaine longueur d’onde, ces molécules s’activent et libèrent de l’énergie, détruisant ainsi les cellules malades sans toucher aux cellules saines.

Des résultats spectaculaires en laboratoire

Les premiers essais en laboratoire ont montré des résultats époustouflants. Les cellules cancéreuses traitées avec cette méthode se désintègrent littéralement sous l’effet de la lumière, tandis que les cellules saines restent intactes. Cette précision chirurgicale ouvre la voie à des traitements beaucoup moins invasifs et à une guérison plus rapide.

©Adobe Stock

ASTRONOMY - NGC 3521: Galaxy in a Bubble

2025 June 19
See Explanation.  Clicking on the picture will download
the highest resolution version available.

NGC 3521: Galaxy in a Bubble
Image Credit & CopyrightVikas Chander

Explanation: Gorgeous spiral galaxy NGC 3521 is a mere 35 million light-years away, toward the northern springtime constellation Leo. Relatively bright in planet Earth's sky, NGC 3521 is easily visible in small telescopes but often overlooked by amateur imagers in favor of other Leo spiral galaxies, like M66 and M65. It's hard to overlook in this colorful cosmic portrait though. Spanning some 50,000 light-years the galaxy sports characteristic patchy, irregular spiral arms laced with dust, pink star forming regions, and clusters of young, blue stars. The deep image also finds NGC 3521 embedded in fainter, gigantic, bubble-like shells. The shells are likely tidal debris, streams of stars torn from satellite galaxies that have undergone mergers with NGC 3521 in the distant past. 

18/06/2025

METEOROLOGIE - A sec


Des véhicules traversent le pont qui permet de traverser le réservoir de Woodhead, un lac artificiel, après une longue période sans pluie, près de Tintwistle, en Grande-Bretagne.

Phil Noble / REUTERS

ASTRONOMY - Space Station Silhouette on the Moon

 2025 June 18

A detailed view of part of Earth's Moon is shown with
many craters visible. On the lower right, silhouetted against
the comparatively bright Moon, is a small dark silhouette of
the International Space Station. Many of the solar panels on
the station are discernable. 
Please see the explanation for more detailed information.

Space Station Silhouette on the Moon
Image Credit & Copyright: Eric Holland

Explanation: What's that unusual spot on the Moon? It's the International Space Station. Using precise timing, the Earth-orbiting space platform was photographed in front of a partially lit gibbous Moon in 2019. The featured image was taken from Palo AltoCaliforniaUSA with an exposure time of only 1/667 of a second. In contrast, the duration of the transit of the ISS across the entire Moon was about half a second. A close inspection of this unusually crisp ISS silhouette will reveal the outlines of numerous solar panels and trusses. The bright crater Tycho is visible on the lower left, as well as comparatively rough, light colored terrain known as highlands and relatively smooth, dark colored areas known as maria. Downloadable apps can tell you when the International Space Station will be visible from your area.

ASTRONOMY - Rosette Nebula Deep Field

 2025 June 17

A starfield is covered with a light red glow. Several
nebulas are seen near the center. The famous Rosette nebula
appears in blue and white near the image bottom. 
Please see the explanation for more detailed information.

Rosette Nebula Deep Field
Image Credit: Toni Fabiani Méndez

Explanation: Can you find the Rosette Nebula? The red flowery-looking nebula just above the image center may seem a good choice, but that's not it. The famous Rosette Nebula is really located on the lower right, here colored blue and white, and connected to the other nebulas by gold-colored filaments. Because the featured image of Rosette's field is so wide, and because of its deep red exposure, it seems to contain other flowers. Designated NGC 2237, the center of the Rosette Nebula is populated by the bright blue stars of open cluster NGC 2244, whose winds and energetic light are evacuating the nebula's center. The Rosette Nebula is about 5,000 light years distant and, just by itself, spans about three times the diameter of a full moon. This flowery field can be found toward the constellation of the Unicorn (Monoceros).

17/06/2025

SANTé/MEDECINE - Procédé révolutionnaire dans la lutte contre le cancer - 1/6 : Introduction



Imaginez un monde où le cancer pourrait être traité sans les effets secondaires dévastateurs des médicaments ou des radiations. Ce rêve est en train de devenir réalité ! Des scientifiques viennent de franchir une étape majeure : ils ont découvert une méthode pour briser les cellules cancéreuses en utilisant simplement la lumière. Cette avancée promet de transformer la médecine et d’offrir de l’espoir à des millions de personnes.

©Adobe Stock

16/06/2025

15/06/2025

ASTRONOMY - Two Worlds, One Sun

 2025 June 15

Two images are shown side by side. On the left is
a sunset seen from Earth, while on the right is a sunset
seen from Mars. The Earth sunset is quite orange, while
the Mars sunset is quite blue. The Sun appears angularly
smaller from Mars than from the Earth. 
Please see the explanation for more detailed information.

Two Worlds, One Sun
Left Image Credit & Copyright: Damia Bouic;
Right Image Credit: NASAJPL-CaltechMSSSDigital processing: Damia Bouic

Explanation: How different does sunset appear from Mars than from Earth? For comparison, two images of our common star were taken at sunset, one from Earth and one from Mars. These images were scaled to have the same angular width and are featured here side-by-side. A quick inspection will reveal that the Sun appears slightly smaller from Mars than from Earth. This makes sense since Mars is 50% further from the Sun than Earth. More striking, perhaps, is that the Martian sunset is noticeably bluer near the Sun than the typically orange colors near the setting Sun from Earth. The reason for the blue hues from Mars is not fully understood, but thought to be related to forward scattering properties of Martian dust. The terrestrial sunset was taken in 2012 March from MarseilleFrance, while the Martian sunset was captured in 2015 by NASA's robotic Curiosity rover from Gale crater on Mars.

14/06/2025

ASTRONOMIE - Iréelle


La pleine lune se lève sur l’ancien temple grec de Poséidon au bord du cap Sounion. 

Louisa Gouliamaki / REUTERS

ASTRONOMY - Meteors and Satellite Trails over the Limay River

 2025 June 14

A night sky is shown with many stars and streaks.
In the foreground at the bottom are hills, a river, and
the red and white streaks of car lights.
Please see the explanation for more detailed information.

Meteors and Satellite Trails over the Limay River
Image Credit & CopyrightMartín Moliné

Explanation: What are all those streaks in the sky? A galaxy, many satellite trails, and a few meteors. First, far in the distance, the majestic band of our Milky Way Galaxy runs down the left. Mirroring it on the right are several parallel trails of Earth-orbiting Starlink satellites. Many fainter satellite trails also crisscross the image. The two short and bright streaks are meteors — likely members of the annual Eta Aquariids meteor shower. The planet Venus shines on the lower right. Venus and the satellites shine by reflected sunlight. The featured picture is a composite of exposures all taken in a few hours on May 4 over the Limay River in Argentina.

SANTé/MEDECINE - Procédé révolutionnaire dans la lutte contre le cancer - 2/6 : Une découverte qui change tout

Jusqu’à présent, la lutte contre le cancer reposait principalement sur la chimiothérapie, la radiothérapie ou la chirurgie. Ces traitements,...