Etoiles filantes - AVERSE DE PERSEIDES EN UKRAINE

Image composite réunissant deux heures d'exposition de la pluie annuelle d'étoiles filantes, les Perséides, le 12 août 2016 (nuit du maximum d'activité), au-dessus du lac Svityaz, en Ukraine.

© Ihor Khomych, via Spaceweather

Astronomy - THE CRANIUM NEBULA FROM THE WEBB TELESCOPE

 2026 March 9

The Cranium Nebula from the Webb Telescope
Image Credit: NASA, ESA, CSA, STScI; Processing: J. DePasquale (STScI)

Explanation: What's going on inside the head of this nebula? Dubbed the Exposed Cranium Nebula for its similarity to the human brain, what created the nebula remains a mystery. One thought is that the Cranium Nebula, also known as PMR 1, is a planetary nebula surrounding a white dwarf star. In this mode, the outer atmosphere was expelled when the original Sun-like star ran out of central nuclear fuel and contracted. A competing thought is that the central star is much more massive, possibly a Wolf-Rayet star, that is ejecting gas and dust via turbulent stellar winds. Adding to the intrigue is the dark vertical central division and the thin outer gaseous shell. The featured image was taken by the Webb Space Telescope in mid- infrared light, while a second image, included as a rollover, is in near-infrared. Future observations may reveal if this brainy system will quietly just fade from view or, many years from now, suddenly erupt in a powerful supernova.

Les belles inventions de Leonard de Vinci - LE BATEAU A AUBES

Léonard de Vinci n'est pas l'inventeur du concept du bateau à aubes : on le trouve déjà dans les œuvres de l'ingénieur et architecte romain Vitruve, mais aussi dans des traités datant du Moyen Âge et même chez les Chinois, il y a plus de 1 000 ans. Toutefois, comme toujours, Léonard en fait des illustrations esthétiques inimitables.

© Crochet.david, CC by-sa 3.0

Astronomy - TOTAL LUNAR ECLIPSE OVER TSE BIT'A'I

 2026 March 5

Total Lunar Eclipse over Tsé Bit'a'í
Image Credit & Copyright: Satoru Murata; Text: Keighley Rockcliffe (NASA GSFC, UMCP, CRESST II)

Explanation: Earlier this week, Earth’s shadow swept across the full Moon in the year’s only total lunar eclipse. This stunning sequence combines images showing the Moon’s path across the night sky. Each lunar image captures our planet’s shadow gradually engulfing the Moon, culminating in its red glow. Sunlight scatters and refracts as it passes through Earth’s atmosphere toward the Moon. Shorter wavelength light (blue and green) scatters more efficiently, leaving red, orange, and yellow hues to paint the lunar surface. Tsé Bit'a'í (”rock with wings”, also known as Shiprock), located in Navajo Nation, provides a powerful volcanic foreground central to this photo and to stories of Navajo origin, adventure, and heroism. As the first full moon of the lunar new year, this eclipse held significance across cultures. Visible from East Asia to North America, this eclipse united observers across great distances, a cosmic reminder that we share the same sky.

Astronomy - SHAPLEY 1 : AN ANNULAR PLANETARY NEBULA

 2026 March 4

Shapley 1: An Annular Planetary Nebula
Image Credit & Copyright: Peter Bresseler; Text: Keighley Rockcliffe (NASA GSFC, UMBC CSST, CRESST II)

Explanation: What’s looking back at you isn’t a cosmic eye, but Shapley 1, a beautifully symmetric planetary nebula. Shapley 1, also known as the Fine Ring Nebula or PLN 329+2.1, bejewels the southern sky constellation of the Carpenter's Square (Norma). The nebula is the result of a star near the mass of our Sun running out of fuel and shedding its outer layers. Glowing oxygen from those expelled layers makes up the circular halo. The bright central point is actually a binary: a white dwarf, the remaining stellar core after the outer layers are expelled into space, and another star, orbiting each other every 2.9 days. Shapley 1’s annular shape is due to our top-down view of the system and provides insight into the influence of central stars on planetary nebula structures.

Microphotographie - COMME UNE BOULE DE CORAIL

Pollution, changement climatique, surpêche. Les récifs coralliens apparaissent aujourd'hui en danger. Et quoi de mieux qu'une belle photo pour sensibiliser le public à la nécessité d'agir en urgence pour leur venir en aide ?

Un seul souci ici : cette micrographie ne présente pas des coraux, mais des microstructures de carbonate-silice cultivées dans un système dynamique de réaction-diffusion. De quoi sculpter avec précision une grande variété de formes élémentaires par diffusion de dioxyde de carbone dans une solution de chlorure de baryum et de métasilicate de sodium.

Les échantillons ont été préparés à l'Institut Amolf, Amsterdam, Pays-Bas par Lukas Helmbrecht avec Wim L. Noorduin. Ils ont été scannés dans un microscope électronique à balayage à émission de champ Tescan Mira3 et colorés à la volée avec un système d'imagerie multidétecteur à quatre canaux développé par Point electronic Halle.

Le champ de vision est de 28 microns de large.

© Stefan Diller

Astronomy - FLYING OVER NORTH POLE OF MARCH

Flying over the North Pole of Mars
Video Credit: ESA, Mars Express, VMC; Processing & License: Simeon Schmauß

Explanation: If you could fly over the North Pole of Mars, what would you see?  Images from ESA’s Mars Express mission in 2019 were compiled into the featured video which shows just such a trip. First you see below you a landscape tinted orange by rusted iron in the fine soil, with some land appearing darker due to exposed rock. Soon the northern polar cap comes into view, mostly white because of its reflective frozen water. Surrounding the polar cap is the North Polar Basin, a layered depression covered with dust and sand. The frames in the featured video were captured during northern Martian Spring when the carbon-dioxide ice is evaporating, leaving the underlying water-ice in the cap. Mars Express continues to study the Martian surface and look for clues about the Red Planet's ancient climate and potential for life.

Astronomy - THE DUSTY SURROUNDINGS OF ORION AND THE PLEIADES

 The Dusty Surroundings of Orion and the Pleiades

Image Credit & Copyright: Ignacio Fernández

Explanation: How well do you know the night sky? OK, but how well can you identify famous sky objects in a very deep image? Either way, here is a test: see if you can find some well-known night-sky icons in a deep image filled with filaments of normally faint dust and gas. This image contains the Pleiades star cluster, Barnard's Loop, Orion Nebula, Aldebaran, Betelgeuse, Witch Head Nebula, Eridanus Loop, and the California Nebula. To find their real locations, here is an annotated image version. The reason this task might be difficult is similar to the reason it is initially hard to identify familiar constellations in a very dark sky: the tapestry of our night sky has an extremely deep hidden complexity. The featured composite reveals some of this complexity in a 16 hours of sky exposure in dark skies over Granada, Spain.

Musique classique - PEER GYNT / EDVARD GRIEG - DANS L'ANTRE DU ROI DE LA MONTAGNE

"Dans l'Antre du Roi de la Montagne"

Astronomy - LUNAR OCCULTATION OF MERCURY

 2026 February 28

Lunar Occultation of Mercury
Image Credit & Copyright: Fabrizio Melandri

Explanation: Fans of the western sky after sunset have lately enjoyed this month's remarkable array of bright planets. Witnessed from some locations, on February 18 planet Mercury even appeared to slide behind the Moon, an event known as a lunar occultation. These two snapshots, taken in early evening skies show before and after telescopic views of the rare disappearance of innermost planet behind young Moon. The top panel finds bright Mercury just visible at the northern (right) edge of the earthshine-illuminated lunar disk. In the bottom panel the bright planet has emerged in darker skies beyond the Moon's sunlit crescent. As seen south of Sallisaw, Oklahoma, planet Earth, this lunar occultation of Mercury lasted only about 3 minutes (video). But you can still check out a parade of planets tonight.