ASTRONOMY - Planets of the Solar System

 2022 June 25

Planets of the Solar System
Image Credit & Copyright: Antonio Canaveras, Chiara Tronci, Giovanni Esposito, Giuseppe Conzo, Luciana Guariglia, (Gruppo Astrofili Palidoro)

Explanation: Simultaneous images from four cameras were combined to construct this atmospheric predawn skyscape. The cooperative astro-panorama captures all the planets of the Solar System, just before sunrise on June 24. That foggy morning found innermost planet Mercury close to the horizon but just visible against the twilight, below and left of brilliant Venus. Along with the waning crescent Moon, the other bright naked-eye planets, Mars, Jupiter, and Saturn lie near the ecliptic, arcing up and to the right across the wide field of view. Binoculars would have been required to spot the much fainter planets Uranus and Neptune, though they also were along the ecliptic in the sky. In the foreground are excavations at an ancient Roman villa near Marina di San Nicola, Italy, planet Earth.

ASTRONOMY - Filaprom on the Western Limb

 2022 June 24

Filaprom on the Western Limb
Image Credit & Copyright: Martin Wise

Explanation: A solar filament is an enormous stream of incandescent plasma suspended above the active surface of the Sun by looping magnetic fields. Seen against the solar disk it looks dark only because it's a little cooler, and so slightly dimmer, than the solar photosphere. Suspended above the solar limb the same structure looks bright when viewed against the blackness of space and is called a solar prominence. A filaprom would be both of course, a stream of magnetized plasma that crosses in front of the solar disk and extends beyond the Sun's edge. In this hydrogen-alpha close-up of the Sun captured on June 22, active region AR3038 is near the center of the frame. Active region AR3032 is seen at the far right, close to the Sun's western limb. As AR3032 is carried by rotation toward the Sun's visible edge, what was once a giant filament above it is now partly seen as a prominence, How big is AR3032's filaprom? For scale planet Earth is shown near the top right corner.

MERVEILLEUX MONDE SOUS-MARIN - Le dugon

Egypte : Mer Rouge : Region de Marsa Alam.

Le dugong (Dugong dugong) vit dans les eaux côtières peu profondes et chaudes de la mer Rouge et de l'océan Indien ainsi que dans le Pacifique.

Incapable de se défendre contre un quelconque prédateur, il choisit souvent, pour se dissimuler, de vivre dans des zones où la visibilité est assez mauvaise. Très bon apnéiste, il peut rester sous l'eau plus de 15 minutes, avant de remonter respirer en surface.

Le male, plus gros que la femelle, peut mesurer trois mètres de long et peser 200 kilos. Il est en général accompagné de remoras, et de carangues royales juvèniles.

Herbivore, il se nourrit de phanerogames.

Inscrits à l'annexe 1 de la CITES depuis la confèrence de Nairobi en avril 2000, ce qui en interdit le commerce, les dugongs ou vaches marines continuent pourtant a être gravement menacés, notamment par la disparition des herbiers qui leur servent d'habitat.

© Alexis Rosenfeld

METEO EXTREME - L’éclair le plus long

 

Les éclairs ne s’étendent généralement pas sur une distance de plus de 12 kilomètres et ne durent que quelques centièmes de seconde. © Jean-Marie Muggianu, Flickr, CC by-NC-ND 2.0

Selon les experts de l'OMM, un éclair enregistré en juin 2007 dans l'Oklahoma a parcouru une distance record de 321 kilomètres. Généralement, la longueur d'un éclair se situe aux alentours de 12 kilomètres...

Quant à l'éclair qui a duré le plus longtemps, il a été enregistré dans le sud de la France - du côté de la Drôme pour être plus précis - en août 2012. Il a duré pas moins de 7,74 secondes alors que la plupart des éclairs ne brillent pas plus de quelques centièmes de seconde.

FuturaSciences

ASTRONOMY - Spiral Galaxy NGC 6744

 2022 June 23

Spiral Galaxy NGC 6744
Image Credit & Copyright: Basudeb Chakrabarti

Explanation: Beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across, larger than our own Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo but appears as only a faint, extended object in small telescopes. We see the disk of the nearby island universe tilted towards our line of sight in this remarkably detailed galaxy portrait, a telescopic view that spans an area about the angular size of a full moon. In it, the giant galaxy's elongated yellowish core is dominated by the light from old, cool stars. Beyond the core, grand spiral arms are filled with young blue star clusters and speckled with pinkish star forming regions. An extended arm sweeps past smaller satellite galaxy NGC 6744A at the lower right. NGC 6744's galactic companion is reminiscent of the Milky Way's satellite galaxy the Large Magellanic Cloud.

ASTRONOMY - Supernova Remnant: The Veil Nebula

 2022 June 22

Supernova Remnant: The Veil Nebula
Image Credit & Copyright: Craig Stocks (Utah Desert Remote Observatories)

Explanation: Ten thousand years ago, before the dawn of recorded human history, a new light would have suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was from a supernova, or exploding star, and record the expanding debris cloud as the Veil Nebula, a supernova remnant. Imaged with color filters featuring light emitted by sulfur (red), hydrogen (green), and oxygen (blue), this deep wide-angle view was processed to remove the stars and so better capture the impressive glowing filaments of the Veil. Also known as the Cygnus Loop, the Veil Nebula is roughly circular in shape and covers nearly 3 degrees on the sky toward the constellation of the Swan (Cygnus). Famous nebular sections include the Bat Nebula, the Witch's Broom Nebula, and Fleming's Triangular Wisp. The complete supernova remnant lies about 1,400 light-years away.

ASTROPHOTOGRAPHIE - Éclipse hybride du Soleil

D'Eugen Kamenew (Allemagne) cette magnifique composition « Hybrid Solar Eclipse 2 » mettant en scène, dans le nord du Kenya, le jour de l'éclipse hybride du Soleil du 3 novembre 2013, Geoffrey Lowa et une barque solaire. Sur la pointe du rocher, l'homme embarque à la fin du jour, dans un croissant lumineux, notre étoile en partie occultée par la Lune.

© Eugen Kamenew, Flickr

ASTRONOMY - Analemma over Taipei

 2022 June 21

Analemma over Taipei
Image Credit & Copyright: Meiying Lee

Explanation: Does the Sun return to the same spot on the sky every day? No. A better and more visual answer to that question is an analemma, a composite of images taken at the same time and from the same place over the course of a year. The featured analemma was compiled at 4:30 pm many afternoons from Taiwan during 2021, with the city skyline of Taipei in the foreground, including tall Taipei 101. The Sun's location in December -- at the December solstice -- is shown on the far left, while its location at the June solstice is captured on the far right. Also shown are the positions of the Sun throughout the rest of the day on the solstices and equinoxes. Today is the June solstice of 2022, the day in Earth's northern hemisphere when the Sun spends the longest time in the sky. In many countries, today marks the official beginning of a new season, for example winter in Earth's southern hemisphere.

ASTRONOMY - Rock Fingers on Mars

 2022 June 20

Rock Fingers on Mars
Image Credit: NASA, JPL-Caltech, MSSS

Explanation: There, just right of center, what is that? The surface of Mars keeps revealing new surprises with the recent discovery of finger-like rock spires. The small nearly-vertical rock outcrops were imaged last month by the robotic Curiosity rover on Mars. Although similar in size and shape to small snakes, the leading explanation for their origin is as conglomerations of small minerals left by water flowing through rock crevices. After these relatively dense minerals filled the crevices, they were left behind when the surrounding rock eroded away. Famous rock outcrops on Earth with a similar origin are called hoodoos. NASA's Curiosity Rover continues to search for new signs of ancient water in Gale Crater on Mars, while also providing a geologic background important for future human exploration.

ASTRONOMY - The Gamma Cygni Nebula

 2022 June 18

The Gamma Cygni Nebula
Image Credit & Copyright: Min Xie, Chen Wu, Yizhou Zhang, and Benchu Tang

Explanation: Supergiant star Gamma Cygni is at the center of the Northern Cross. Near the plane of our Milky Way galaxy, that famous asterism flies high in northern summer night skies in the constellation Cygnus the Swan. Known by the proper name Sadr, Gamma Cygni also lies just below center in this telescopic skyscape, with colors mapped from both broadband and narrowband image data. The field of view spans about 3 degrees (six Full Moons) on the sky and includes emission nebula IC 1318 and open star cluster NGC 6910. Filling the upper part of the frame and shaped like two glowing cosmic wings divided by a long dark dust lane, IC 1318's popular name is understandably the Butterfly Nebula. Right of Gamma Cygni, are the young, still tightly grouped stars of NGC 6910. The distance to Gamma Cygni is around 560 parsecs or 1,800 light-years. Estimates for IC 1318 and NGC 6910 range from 2,000 to 5,000 light-years.