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12/06/2022

MERVEILLEUX MONDE SOUS-MARIN - L'aurélie, la méduse commune


Mer Rouge : Région de Marsa Alam

Méduse aurélie (Aurelia aurita). Le diamètre de son ombrelle peut mesurer jusqu'à 40 centimètres. On distingue autour des centaines de petites tentacules.

Cette espèce vit dans toutes les mers du globe, elle est pélagique mais se rencontre aussi près des côtes.

Les animaux marins, et notamment les tortues et les dauphins qui se nourrisent de méduses confondent parfois les sacs en plastique avec elles, et s'étouffent. Cette forme de pollution est donc dangereuse pour la vie sauvage.

© Alexis Rosenfeld
FuturaSciences

ASTRONOMY - Find the Man in the Moon

 2022 June 12

The featured image shows a full moon over a mountain containing
a person looking through a small telescope. The rollover highlights
features on the Moon the create the

Find the Man in the Moon
Image Credit & Copyright: Dani Caxete

Explanation: Have you ever seen the Man in the Moon? This common question plays on the ability of humans to see pareidolia -- imagining familiar icons where they don't actually exist. The textured surface of Earth's full Moon is home to numerous identifications of iconic objects, not only in modern western culture but in world folklore throughout history. Examples, typically dependent on the Moon's perceived orientation, include the Woman in the Moon and the Rabbit in the Moon. One facial outline commonly identified as the Man in the Moon starts by imagining the two dark circular areas -- lunar maria -- here just above the Moon's center, to be the eyes. Surprisingly, there actually is a man in this Moon image -- a close look will reveal a real person -- with a telescope -- silhouetted against the Moon. This featured well-planned image was taken in 2016 in Cadalso de los Vidrios in MadridSpain. Do you have a favorite object that you see in the Moon?

11/06/2022

ASTRONOMY - The Road and the Milky Way

 2022 June 11

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

The Road and the Milky Way
Image Credit & CopyrightDavid Cruz

Explanation: At night you can follow this road as it passes through the Dark Sky Alqueva reserve not too far from Alentejo, Portugal. Or you could stop, look up, and follow the Milky Way through the sky. Both stretch from horizon to horizon in this 180 degree panorama recorded on June 3. Our galaxy's name, the Milky Way, does refer to its appearance as a milky path in the sky. The word galaxy itself derives from the Greek for milk. From our fair planet the arc of the Milky Way is most easily visible on moonless nights from dark sky areas, though not quite so bright or colorful as in this image. The glowing celestial band is due to the collective light of myriad stars along the galactic plane too faint to be distinguished individually. The diffuse starlight is cut by dark swaths of the galaxy's obscuring interstellar dust clouds. Standing above the Milky Way arc near the top of this panoramic nightscape is bright star Vega, with the galaxy's central bulge near the horizon at the right.

10/06/2022

ASTRONOMY - Arp 286: Trio in Virgo

 2022 June 10

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

Arp 286: Trio in Virgo
Image Credit & CopyrightNicolas RollandTelescope.Live

Explanation: This colorful telescopic field of view features a trio of interacting galaxies almost 90 million light-years away, toward the constellation Virgo. On the right two spiky, foreground Milky Way stars echo the extragalactic hues, a reminder that stars in our own galaxy are like those in distant island universes. With sweeping spiral arms and obscuring dust lanes, the dominant member of the trio, NGC 5566, is enormous, about 150,000 light-years across. Just above it lies smaller, bluish NGC 5569. Near center a third galaxy, NGC 5560, is apparently stretched and distorted by its interaction with massive NGC 5566. The trio is also included in Halton Arp's 1966 Atlas of Peculiar Galaxies as Arp 286. Of course, such cosmic interactions are now appreciated as part of the evolution of galaxies.

09/06/2022

ASTRONOMY - Cosmic Clouds in Cygnus

 2022 June 9

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

Cosmic Clouds in Cygnus
Image Credit & CopyrightWolfgang Zimmermann

Explanation: These cosmic clouds of gas and dust drift through rich star fields along the plane of our Milky Way Galaxy toward the high flying constellation Cygnus. They're too faint to be seen with the unaided eye though, even on a clear, dark night. Image data from a camera and telephoto lens using narrowband filters was used to construct this 10 degree wide field of view. The deep mosaic reveals a region that includes star forming dust clouds seen in silhouette against the characteristic glow of atomic hydrogen and oxygen gas. NGC 6888 is the standout emission nebula near the top. Blown by winds from an massive Wolf-Rayet star it's about 25 light-years across and known as the Crescent Nebula. A faint bluish curl just below center in the frame is also the signature of a Wolf-Rayet star. Burning fuel at a prodigious rate and near the end of their stellar lives, both stars will ultimately go out with a bang in a spectacular supernova explosion. Toward the right, a massive, young O type star powers the glow of Sh2-101, the Tulip Nebula.

08/06/2022

SANTé/MEDECINE - Espoir : Des bio-implants immunologiques contre le cancer

Des petites billes pourraient augmenter l’action des cellules immunitaires chargées de combattre le cancer.

Des billes de la taille d’une tête d’épingle, mises au point par des bio-ingénieurs de l'Université Rice, aux Etats-Unis, contiennent des cellules conçues pour produire d’importantes doses d’interleukine-2 (IL-2), une protéine activatrice des globules blancs chargés de combattre le cancer.

Une augmentation de l’action des cellules immunitaires tout en réduisant les effets secondaires

Implantées à proximité d’une tumeur, ces billes délivrent l’IL-2 au plus proche, augmentant l’action des cellules immunitaires tout en réduisant les effets secondaires. Chez la souris, le traitement s’est révélé redoutablement efficace, éradiquant en quelques jours les tumeurs dont souffraient les rongeurs. Des essais sur l’humain doivent commencer à l’automne.

SciencesAvenir

ASTRONOMY - Ship Tracks over the Pacific Ocean

 2022 June 8

The featured image ship tracks over the Pacific
Ocean as captured by the MODIS instrument on NASA's 
Terra satellite. The tracks appear as white streaks 
over the blue ocean.
Please see the explanation for more detailed information.

Ship Tracks over the Pacific Ocean
Image Credit: NASATerraMODISText: Raymond Shaw (MTU)

Explanation: What are those unusual streaks? Some images of planet Earth show clear bright streaks that follow the paths of ships. Known as ship tracks, these low and narrow bands are caused by the ship's engine exhaust. Water vapor condenses around small bits of exhaust known as aerosols, which soon grow into floating water drops that efficiently reflect sunlight. Ship tracks were first discovered in 1965 in Earth images taken by NASA's TIROS satellites. Multiple ship tracks are visible across the featured image that was captured in 2009 over the Pacific Ocean by the MODIS instrument on NASA's Terra satellite. Inspired by ship-tracks, some scientists have suggested deploying a network of floating buoys in the worlds' oceans that spray salt-aerosol containing sea-water into the air so that, with the help of the wind, streams of sunlight-reflecting clouds would also form. Why do this? These human-made clouds could reflect so much sunlight they might help fight global warming.

07/06/2022

ASTRONOMY - NGC 6188: Dragons of Ara

 2022 June 7

The featured image shows the nebulae NGC 6188 and NGC 6164.
The former is a star forming region filled with glowing gas and
laced with dust that resembles dragons. The smaller NGC 6164 is
seen on the lower right is an emission nebula created by a single
massive star in its center.
Please see the explanation for more detailed information.

NGC 6188: Dragons of Ara
Image Credit & Copyright: Shaun Robertson

Explanation: Do dragons fight on the altar of the sky? Although it might appear that way, these dragons are illusions made of thin gas and dust. The emission nebula NGC 6188, home to the glowing clouds, is found about 4,000 light years away near the edge of a large molecular cloud unseen at visible wavelengths, in the southern constellation Ara (the Altar). Massive, young stars of the embedded Ara OB1 association were formed in that region only a few million years ago, sculpting the dark shapes and powering the nebular glow with stellar winds and intense ultraviolet radiation. The recent star formation itself was likely triggered by winds and supernova explosions, from previous generations of massive stars, that swept up and compressed the molecular gas. Joining NGC 6188 on this cosmic canvas, visible toward the lower right, is rare emission nebula NGC 6164, also created by one of the region's massive O-type stars. Similar in appearance to many planetary nebulae, NGC 6164's striking, symmetric gaseous shroud and faint halo surround its bright central star near the bottom edge. This impressively wide field of view spans over 2 degrees (four full Moons), corresponding to over 150 light years at the estimated distance of NGC 6188.

06/06/2022

MERVEILLEUX MONDE SOUS-MARIN - Jardin Corallien


 © Alexis Rosenfeld

ASTRONOMY - Milky Way Galaxy Doomed: Collision with Andromeda Pending

 2022 June 6

The featured image is a combination graphic showing the Andromeda
galaxy on approach toward our Milky Way galaxy, set for a collision
in about 4.5 billion years.
Please see the explanation for more detailed information.

Milky Way Galaxy Doomed: Collision with Andromeda Pending
Image Credit: NASAESAZ. Levay and R. van der Marel (STScI); T. Hallas; and A. Mellinger

Explanation: Will our Milky Way Galaxy collide one day with its larger neighbor, the Andromeda Galaxy? Most likely, yes. Careful plotting of slight displacements of M31's stars relative to background galaxies on recent Hubble Space Telescope images indicate that the center of M31 could be on a direct collision course with the center of our home galaxy. Still, the errors in sideways velocity appear sufficiently large to admit a good chance that the central parts of the two galaxies will miss, slightly, but will become close enough for their outer halos to become gravitationally entangled. Once that happens, the two galaxies will become bound, dance around, and eventually merge to become one large elliptical galaxy -- over the next few billion years. Pictured here is a combination of images depicting the sky of a world (Earth?) in the distant future when the outer parts of each galaxy begin to collide. The exact future of our Milky Way and the entire surrounding Local Group of Galaxies is likely to remain an active topic of research for years to come.

LA TERRE VUE DU CIEL - Endeavour quelques minutes avant son amarrage à l'ISS

Cette image a cela d'intéressant qu'elle permet de distinguer trois des couches qui composent l' atmosphère . La troposphère ap...