LES NUAGES DIEUX DU CIEL - Stratocumulus en Nouvelle-Zélande

Stratocumulus photographiés en Nouvelle-Zélande. 

© John Day, Cloudman's Gallery, www.cloudman.com

ASTRONOMY - LDN 43: The Cosmic Bat Nebula

 2024 October 27

LDN 43: The Cosmic Bat Nebula
Credit & Copyright: Mark Hanson and Mike Selby; Text: Michelle Thaller (NASA's GSFC)

Explanation: What is the most spook-tacular nebula in the galaxy? One contender is LDN 43, which bears an astonishing resemblance to a vast cosmic bat flying amongst the stars on a dark Halloween night. Located about 1400 light years away in the constellation Ophiuchus, this molecular cloud is dense enough to block light not only from background stars, but from wisps of gas lit up by the nearby reflection nebula LBN 7. Far from being a harbinger of death, this 12-light year-long filament of gas and dust is actually a stellar nursery. Glowing with eerie light, the bat is lit up from inside by dense gaseous knots that have just formed young stars.

VILLES BIONIQUES DU FUTUR - Dragonfly : un projet bionique pour New York

Ces deux ailes de libellule forment un ensemble d'habitation, de travail et de production agricole. Conçu pour New York et ses fortes fluctuations de température, ce prototype ménage en son centre un immense volume fermé par un voile de verre et d'acier. Les lieux habités se trouvent sur la circonférence des ailes et l'espace entre les deux constitue une serre où prennent place des cultures variées. La moitié de l'énergie vient du bouclier photovoltaïque sur la proue sud et l'autre de trois éoliennes.

© Vincent Callebaut

ASTRONOMY - Phantoms in Cassiopeia

 2024 October 26

Phantoms in Cassiopeia
Image Credit & Copyright: Christophe Vergnes, Hervé Laur

Explanation: These brightly outlined flowing shapes look ghostly on a cosmic scale. A telescopic view toward the constellation Cassiopeia, the colorful skyscape features the swept-back, comet-shaped clouds IC 59 (left) and IC 63. About 600 light-years distant, the clouds aren't actually ghosts. They are slowly disappearing though, under the influence of energetic radiation from hot, luminous star gamma Cas. Gamma Cas is physically located only 3 to 4 light-years from the nebulae and lies just above the right edge of the frame. Slightly closer to gamma Cas, IC 63 is dominated by red H-alpha light emitted as hydrogen atoms ionized by the hot star's ultraviolet radiation recombine with electrons. Farther from the star, IC 59 shows less H-alpha emission but more of the characteristic blue tint of dust reflected star light. The field of view spans over 1 degree or 10 light-years at the estimated distance of the interstellar apparitions.

ASTRONOMY - NGC 7293: The Helix Nebula

 2024 October 24

NGC 7293: The Helix Nebula
Image Credit & Copyright: Patrick Winkler

Explanation: A mere seven hundred light years from Earth toward the constellation Aquarius, a star is dying. The once sun-like star's last few thousand years have produced the Helix Nebula. Also known as NGC 7293, the cosmic Helix is a well studied and nearby example of a Planetary Nebula, typical of this final phase of stellar evolution. Combining narrow band data from emission lines of hydrogen atoms in red and oxygen atoms in blue-green hues, this deep image shows tantalizing details of the Helix, including its bright inner region about 3 light-years across. The white dot at the Helix's center is this Planetary Nebula's hot, dying central star. A simple looking nebula at first glance, the Helix is now understood to have a surprisingly complex geometry.

ASTRONOMY - Caught

 2024 October 23

Caught
Credit & Copyright: SpaceX

Explanation: What if a rocket could return to its launch tower -- and be caught? This happened for the first time 10 days ago, after a SpaceX Starship rocket blasted off from its pad in Boca Chica, Texas, USA. Starship then split, as planned, with its upper stage landing in the Pacific Ocean. The big difference was the lower stage, Super Heavy Booster 12, was caught by its launch tower about 7 minutes later. Catching a rocket for reuse is a new and innovative way to help reduce the cost of rocket flight by making rockets more easily reusable. Starship rockets may be used by NASA in the future to send spacecraft to Earth orbit, the Moon, and even other planets.

ASTRONOMY -M16: Pillars of Star Creation

2024 October 22

M16: Pillars of Star Creation
Image Credit: NASA, ESA, CSA, STScI; Processing: Diego Pisano

Explanation: These dark pillars may look destructive, but they are creating stars. This pillar-capturing picture of the Eagle Nebula combines visible light exposures taken with the Hubble Space Telescope with infrared images taken with the James Webb Space Telescope to highlight evaporating gaseous globules (EGGs) emerging from pillars of molecular hydrogen gas and dust. The giant pillars are light years in length and are so dense that interior gas contracts gravitationally to form stars. At each pillar's end, the intense radiation of bright young stars causes low density material to boil away, leaving stellar nurseries of dense EGGs exposed. The Eagle Nebula, associated with the open star cluster M16, lies about 7000 light years away. 

ASTRONOMY - Comet Tsuchinshan-ATLAS over California

 2024 October 21

Comet Tsuchinshan-ATLAS over California
Credit & Copyright: Brian Fulda

Explanation: The tails of Comet Tsuchinshan-ATLAS were a sight to behold. Pictured, C/2023 A3 (Tsuchinshan–ATLAS) was captured near peak impressiveness last week over the Eastern Sierra Mountains in California, USA. The comet not only showed a bright tail, but a distinct anti-tail pointing in nearly the opposite direction. The globular star cluster M5 can be seen on the right, far in the distance. As it approached, it was unclear if this crumbling iceberg would disintegrate completely as it warmed in the bright sunlight. In reality, the comet survived to become brighter than any star in the night (magnitude -4.9), but unfortunately was then so nearly in front of the Sun that it was hard for many casual observers to locate. Whether Comet Tsuchinshan-Atlas becomes known as the Great Comet of 2024 now depends, in part, on how impressive incoming comet C/2024 S1 (ATLAS) becomes over the next two weeks.

MUSIC - Antonio Vivaldi : Concert pour deux trompettes en do majeur

"Concert pour deux trompettes en do majeur"

LES NUAGES DIEUX DU CIEL - Un cirrus en forme de squelette de poisson (cirrus fibratus vertebratus)

Différents nuages sont visibles sur cette photo prise à Karlsruhe (Bade-Wurtemberg, Allemagne) : des cirrus fibratus vertebratus, des cumulus humilis et des cumulus mediocris. Les cirrus, sont des nuages séparés, en forme de filaments blancs et délicats, de bancs ou de bandes étroites, blancs ou en majeure partie blancs. Ces nuages ont un aspect fibreux (chevelu) ou un éclat soyeux, ou les deux à la fois. Sur cette photo, on peut voir un cirrus dans la partie supérieure de la photo. L'aspect du cirrus est fibreux (fibratus) et montre en haut à droite, une forme à l'aspect d'un squelette de poisson (vertebratus). Il s'agit exclusivement de cristaux de glace qui sont portés par le vent.

© Bernhard Mühr, Der Karlsruher Wolkenatlas, www.wolkenatlas.de