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31/05/2022

ASTRONOMY - Rocket Transits Rippling Sun

 2022 May 31

The featured image shows a Falon 9 rocket transiting 
in front of the Sun in mid May. The heat from the rocket's
exhaust makes the Sun's outline appear to ripple.
Please see the explanation for more detailed information.

Rocket Transits Rippling Sun
Image Credit & Copyright: Michael Cain

Explanation: The launch of a rocket at sunrise can result in unusual but intriguing images that feature both the rocket and the Sun. Such was the case last month when a SpaceX Falcon 9 rocket blasted off from NASA's Kennedy Space Center carrying 53 more Starlink satellites into low Earth orbit. In the featured launch picture, the rocket's exhaust plume glows beyond its projection onto the distant Sun, the rocket itself appears oddly jagged, and the Sun's lower edge shows peculiar drip-like ripples. The physical cause of all of these effects is pockets of relatively hot or rarefied air deflecting sunlight less strongly than pockets relatively cool or compressed air: refraction. Unaware of the Earthly show, active sunspot region 3014 -- on the upper left -- slowly crosses the Sun.

30/05/2022

ASTRONOMY - Red Crepuscular Rays from an Eclipse

 2022 May 30

The featured image shows crepuscular rays emanating 
from below the horizon and appearing quite red. 
Please see the explanation for more detailed information.

Red Crepuscular Rays from an Eclipse
Image Credit & Copyright: Fefo Bouvier

Explanation: What's happening behind that island? Things both expected and unexpected. Expected, perhaps, the pictured rays of light -- called crepuscular rays -- originate from the Sun. Unexpected, though, the Sun was being partially eclipsed by the Moon at the time -- late last month. Expected, perhaps, the Sun's rays are quite bright as they shine through gaps in below-horizon clouds. Unexpected, though, the crepuscular rays are quite red, likely the result an abundance of aerosols in Earth's atmosphere scattering away much of the blue light. Expected, with hope, a memorable scene featuring both the Moon and the Sun, superposed. Unfortunately, from this location -- in Uruguay looking toward Argentina -- clouds obscured the eclipse -- which wasn't completely unexpected. However, after packing up to go home, the beauty of bright red crepuscular rays emerged -- quite unexpectedly. Oh -- and that island on the horizon -- it's really two islands.

29/05/2022

MERVEILLEUX MONDE SOUS-MARIN - L'atoll de Fakarava, dans l'archipel des Tuamotu

 

Atoll de Fakarava, dans l'archipel des Tuamotu, Polynésie française - Réserve de la biosphère. Vue mi-air mi-eau sur un univers paradisiaque.

© Photographe Alexis Rosenfeld
FuturaSciences

SCIENCE INSOLITE - On en pince pour la Nature

 

Quand on vous dit que la nature est à prendre avec des pincettes…

© Mehmet Ali Uysal-sculpteur turc

FuturaSciences

ASTRONOMY - Simulation TNG50: A Galaxy Cluster Forms

 2022 May 29

Simulation TNG50: A Galaxy Cluster Forms
Video Credit: IllustrisTNG ProjectVisualization: Dylan Nelson (Max Planck Institute for Astrophysics) et al.
Music: Symphony No. 5 (Ludwig van Beethoven), via YouTube Audio Library

Explanation: How do clusters of galaxies form? Since our universe moves too slowly to watch, faster-moving computer simulations are created to help find out. A recent effort is TNG50 from IllustrisTNG, an upgrade of the famous Illustris Simulation. The first part of the featured video tracks cosmic gas (mostly hydrogen) as it evolves into galaxies and galaxy clusters from the early universe to today, with brighter colors marking faster moving gas. As the universe matures, gas falls into gravitational wells, galaxies forms, galaxies spin, galaxies collide and merge, all while black holes form in galaxy centers and expel surrounding gas at high speeds. The second half of the video switches to tracking stars, showing a galaxy cluster coming together complete with tidal tails and stellar streams. The outflow from black holes in TNG50 is surprisingly complex and details are being compared with our real universeStudying how gas coalesced in the early universe helps humanity better understand how our EarthSun, and Solar System originally formed.

26/05/2022

ASTRONOMY - NGC 4565: Galaxy on Edge

 2022 May 26

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

NGC 4565: Galaxy on Edge
Image Credit & Copyright: Michael Sherick

Explanation: Magnificent spiral galaxy NGC 4565 is viewed edge-on from planet Earth. Also known as the Needle Galaxy for its narrow profile, bright NGC 4565 is a stop on many telescopic tours of the northern sky, in the faint but well-groomed constellation Coma BerenicesThis sharp, colorful image reveals the galaxy's boxy, bulging central core cut by obscuring dust lanes that lace NGC 4565's thin galactic plane. NGC 4565 itself lies about 40 million light-years distant and spans some 100,000 light-years. Easily spotted with small telescopes, sky enthusiasts consider NGC 4565 to be a prominent celestial masterpiece Messier missed.

25/05/2022

PHOTOGRAPHIE - Le ciel et la mer


 Le ciel et la mer

Florent Martinez
Stelvision

ASTROPHOTOGRAPHIE - Sublimes aurores en Norvège


Cette photo du Norvégien Arild Heitmann nous dévoile un paysage qui apparaît comme enchanté. Nous sommes bien sur Terre, plus exactement au bord de la rivière Lomaas, dans la région de Skånland, en Norvège. Les lueurs d'une aurore boréale qui danse dans le ciel illuminent la végétation pétrifiée et se reflètent sur les eaux endormies et figées de la rivière. Dépaysement assuré. 

© Arild Heitmann, IAPY 2015

ASTRONOMY - The Lively Center of the Lagoon Nebula

 2022 May 25

The featured image shows the center of the Lagoon Nebula
complete with funnel clouds. 
Please see the explanation for more detailed information.

The Lively Center of the Lagoon Nebula
Image Credit: NASAESAHubbleProcessing & Copyright: Mehmet Hakan Özsaraç

Explanation: The center of the Lagoon Nebula is a whirlwind of spectacular star formation. Visible near the image center, at least two long funnel-shaped clouds, each roughly half a light-year long, have been formed by extreme stellar winds and intense energetic starlight. A tremendously bright nearby star, Herschel 36, lights the area. Vast walls of dust hide and redden other hot young stars. As energy from these stars pours into the cool dust and gas, large temperature differences in adjoining regions can be created generating shearing winds which may cause the funnelsThis picture, spanning about 10 light years, combines images taken in six colors by the orbiting Hubble Space Telescope. The Lagoon Nebula, also known as M8, lies about 5000 light years distant toward the constellation of the Archer (Sagittarius).

ASTRONOMY - The Local Fluff

 2024 December 22 The Local Fluff Illustration Credit:  NASA ,  SVS ,  Adler ,  U. Chicago ,  Wesleyan Explanation:  The stars are not alone...