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05/08/2022

ASTRONOMY - A Beautiful Trifid

 2022 August 5

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

A Beautiful Trifid
Image Credit & Copyright: Vikas Chander

Explanation: The beautiful Trifid Nebula is a cosmic study in contrasts. Also known as M20, it lies about 5,000 light-years away toward the nebula rich constellation Sagittarius. A star forming region in the plane of our galaxy, the Trifid does illustrate three different types of astronomical nebulae; red emission nebulae dominated by light from hydrogen atoms, blue reflection nebulae produced by dust reflecting starlight, and dark nebulae where dense dust clouds appear in silhouette. But the red emission region, roughly separated into three parts by obscuring dust lanes, is what lends the Trifid its popular name. Pillars and jets sculpted by newborn stars, above and right of the emission nebula's center, appear in famous Hubble Space Telescope close-up images of the region. The Trifid Nebula is about 40 light-years across. Too faint to be seen by the unaided eye, it almost covers the area of a full moon in planet Earth's sky. Open star cluster M21 just peeks into this telescopic field of view along the bottom right edge of the frame.

04/08/2022

AERONAUTIQUE - L’inventeur Franky Zapata présente son aéronef à décollage vertical

"JetRacer"

Dans sa vidéo diffusée jeudi, Franky Zapata vole au-dessus de l’étang de Berre (Bouches-du-Rhône), harnaché dans un châssis léger entouré de dix petits réacteurs, et réalise quelques acrobaties

Trois ans après sa traversée de la Manche, l’inventeur Franky Zapata a diffusé jeudi des images de son nouvel engin volant, une variante de son « Flyboard » qui permettrait d’emporter dans les airs un pilote assis. Cet aéronef à décollage et atterrissage vertical (VTOL) pourrait atteindre une vitesse de 250 km/h, avec une autonomie d’une quarantaine de kilomètres, a indiqué la société.

Cet appareil appelé « JetRacer », alimenté en kérosène, met l’accent sur « l’agilité » et il est « facile à prendre à main », a souligné Zapata. Pouvant être « piloté à distance », il est destiné aux forces de secours, à l’armée ou pour des loisirs extrêmes, mais pas pour les déplacements du quotidien.

Sud-Ouest

ASTRONOMY - M13: The Great Globular Cluster in Hercules

 2022 August 4

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

M13: The Great Globular Cluster in Hercules
Image Credit & Copyright: Joan Josep Isach Cogollos

Explanation: In 1716, English astronomer Edmond Halley noted, "This is but a little Patch, but it shows itself to the naked Eye, when the Sky is serene and the Moon absent." Of course, M13 is now less modestly recognized as the Great Globular Cluster in Hercules, one of the brightest globular star clusters in the northern sky. Sharp telescopic views like this one reveal the spectacular cluster's hundreds of thousands of stars. At a distance of 25,000 light-years, the cluster stars crowd into a region 150 light-years in diameter. Approaching the cluster core upwards of 100 stars could be contained in a cube just 3 light-years on a side. For comparison, the closest star to the Sun is over 4 light-years away. The remarkable range of brightness recorded in this image follows stars into the dense cluster core. Distant background galaxies in the medium-wide field of view include NGC 6207 at the upper left.

03/08/2022

LA VOIE LACTEE SUR TERRE - Italie : le Seiser Alm au Tyrol

 

La région du Seiser Alm ou Alpe de Siusi est l'un des paysages les plus spectaculaires du sud-tyrolien avec en toile de fond les Dolomites. C'est le haut alpage le plus vaste d'Europe, culminant à une altitude moyenne de 1.850 m et s'étendant sur 52 km², il est situé à environ 20 km au nord-est de Bolzano et au-dessus des célèbres stations touristiques de Siusi allo Sciliar, Castelrotto et Ortisei à Val Gardena.

Cette photo est une seule prise de vue. Il s'agit d'une couche unique, mais elle a été suivie en demi-mode.

© Delil Geyik
FuturaSciences

MERVEILLEUX MONDE SOUS-MARIN - L'anémone Heteractis magnifica


Mer rouge - Egypte - Saint John's Reef.

Une anémone magnifique : Heteractis magnifica. Cette espèce est une grande anémone pouvant atteindre un diamètre de 50 centimètres, exceptionnellement un mètre. Ses tentacules mesurent de 5 à 8 centimètres. Cette espèce est présente de la surface jusqu'à une trentaine de mètres de profondeur. Lorsque l'anémone est contractée, l'ensemble des tentacules disparaissent, l'anémone se présente alors sous la forme d'une grosse boule. Cette espèce abrite 12 espèces de poissons-clowns.

© Alexis Rosenfeld
FuturaSciences

ASTROPHOTOGRAPHIE - La comète C/2013 A1 rencontre Mars

 


Magnifique photo de la comète C/2013 A1 aux côtés de Mars. Notre voisine, la Planète rouge, apparaît ici flamboyante. La comète (son noyau ne mesure en réalité que quelques kilomètres) semble se mesurer à la planète. On dirait même qu'elle se précipite dessus, ce qui n'est qu'un effet de perspective, du fait de leur alignement avec la Terre. À l'arrière-plan, les étoiles et les nuages de gaz rougeâtres composent une superbe tapisserie aux détails très fins. Cette photo a été prise à l'Observatoire de Siding Spring, dans la Nouvelle-Galles du Sud, en Australie. 

© Sebastian Voltmer

ASTRONOMY - Halo of the Cat's Eye

 2022 August 3

The featured image shows a wide field image of the 
Cat's Eye nebula showing it to be surrounded by a large
halo with many vertexes. 
Please see the explanation for more detailed information.

Halo of the Cat's Eye
Image Credit & Copyright: Bray Falls

Explanation: What created the unusual halo around the Cat's Eye nebula? No one is sure. What is sure is that the Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae on the sky. Although haunting symmetries are seen in the bright central region, this image was taken to feature its intricately structured outer halo, which spans over three light-years across. Planetary nebulae have long been appreciated as a final phase in the life of a Sun-like star. Only recently however, have some planetaries been found to have expansive halos, likely formed from material shrugged off during earlier puzzling episodes in the star's evolution. While the planetary nebula phase is thought to last for around 10,000 years, astronomers estimate the age of the outer filamentary portions of the Cat's Eye Nebula's halo to be 50,000 to 90,000 years.

02/08/2022

ASTRONOMY - A Moon Dressed Like Saturn

 2022 August 2

The featured image shows a crescent Moon over a city
and volcano with a flat cloud running through the center that
makes the Moon like a bit like the planet Saturn.
Please see the explanation for more detailed information.

A Moon Dressed Like Saturn
Image Credit & Copyright: Francisco Sojuel

Explanation: Why does Saturn appear so big? It doesn't -- what is pictured are foreground clouds on Earth crossing in front of the Moon. The Moon shows a slight crescent phase with most of its surface visible by reflected Earthlight known as ashen glow. The Sun directly illuminates the brightly lit lunar crescent from the bottom, which means that the Sun must be below the horizon and so the image was taken before sunrise. This double take-inducing picture was captured on 2019 December 24, two days before the Moon slid in front of the Sun to create a solar eclipse. In the foreground, lights from small Guatemalan towns are visible behind the huge volcano Pacaya.

01/08/2022

ASTRONOMY - Mountains of Dust in the Carina Nebula

 2022 August 1

The featured image shows a large pillar of dust and
gas in the Carina Nebula. The pillar has many humps and 
several jets.
Please see the explanation for more detailed information.

Mountains of Dust in the Carina Nebula
Image Credit: NASAESAHubbleProccessing: Javier Pobes

Explanation: It's stars versus dust in the Carina Nebula and the stars are winning. More precisely, the energetic light and winds from massive newly formed stars are evaporating and dispersing the dusty stellar nurseries in which they formed. Located in the Carina Nebula and known informally as Mystic Mountain, these pillar's appearance is dominated by the dark dust even though it is composed mostly of clear hydrogen gas. Dust pillars such as these are actually much thinner than air and only appear as mountains due to relatively small amounts of opaque interstellar dust. About 7,500 light-years distant, the featured image was taken with the Hubble Space Telescope and highlights an interior region of Carina which spans about three light years. Within a few million years, the stars will likely win out completely and the entire dust mountain will evaporate.

31/07/2022

ASTRONOMY - Starburst Galaxy M94 from Hubble

 2022 July 31

The featured image shows a bright center surrounded
by dark dust lanes and wide ring of bright blue stars.
Please see the explanation for more detailed information.

Starburst Galaxy M94 from Hubble
Image Credit: ESA/Hubble & NASA

Explanation: Why does this galaxy have a ring of bright blue stars? Beautiful island universe Messier 94 lies a mere 15 million light-years distant in the northern constellation of the Hunting Dogs (Canes Venatici). A popular target for Earth-based astronomers, the face-on spiral galaxy is about 30,000 light-years across, with spiral arms sweeping through the outskirts of its broad disk. But this Hubble Space Telescope field of view spans about 7,000 light-years across M94's central region. The featured close-up highlights the galaxy's compact, bright nucleus, prominent inner dust lanes, and the remarkable bluish ring of young massive stars. The ring stars are all likely less than 10 million years old, indicating that M94 is a starburst galaxy that is experiencing an epoch of rapid star formation from inspiraling gas. The circular ripple of blue stars is likely a wave propagating outward, having been triggered by the gravity and rotation of a oval matter distributions. Because M94 is relatively nearby, astronomers can better explore details of its starburst ring.

ASTRONOMIE - LES PLUS BEAUX ASTRES DE LA VOIE LACTéE - Antiope : l’astéroïde double

Découvert en 1866, (90) Antiope est un astéroïde qui possède la caractéristique d'être binaire . Cela signifie qu'il est constitué ...