ASTRONOMY - The Horsehead Nebula

 2024 November 25

The Horsehead Nebula
Image Credit & Copyright: Alex Lin (Chilescope)

Explanation: One of the most identifiable nebulas in the sky, the Horsehead Nebula in Orion, is part of a large, dark, molecular cloud. Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800s. The red glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis. The darkness of the Horsehead is caused mostly by thick dust, although the lower part of the Horsehead's neck casts a shadow to the left. Streams of gas leaving the nebula are funneled by a strong magnetic field. Bright spots in the Horsehead Nebula's base are young stars just in the process of forming. Light takes about 1,500 years to reach us from the Horsehead Nebula. The featured image was taken from the Chilescope Observatory in the mountains of Chile.

MUSICA - Luciano Pavarotti & Eros Romazotti - Se bastasse una canzone

"Se bastasse una canzone"

ASTRONOMY - Journey to the Center of the Galaxy

 2024 November 24

Journey to the Center of the Galaxy
Video Credit: ESO/MPE/Nick Risinger (skysurvey.org)/VISTA/J. Emerson/Digitized Sky Survey 2

Explanation: What lies at the center of our galaxy? In Jules Verne's science fiction classic, A Journey to the Center of the Earth, Professor Liedenbrock and his fellow explorers encounter many strange and exciting wonders. Astronomers already know of some of the bizarre objects that exist at our Galactic Center, including vast cosmic dust clouds, bright star clusters, swirling rings of gas, and even a supermassive black hole. Much of the Galactic Center is shielded from our view in visible light by the intervening dust and gas, but it can be explored using other forms of electromagnetic radiation. The featured video is actually a digital zoom into the Milky Way's center which starts by utilizing visible light images from the Digitized Sky Survey. As the movie proceeds, the light shown shifts to dust-penetrating infrared and highlights gas clouds that were recently discovered in 2013 to be falling toward the central black hole.

ASTRONOMY - Interplanetary Earth

 2024 November 23

Interplanetary Earth
Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA & NASA / JHU Applied Physics Lab / Carnegie Inst. Washington

Explanation: In an interplanetary first, on July 19, 2013 Earth was photographed on the same day from two other worlds of the Solar System, innermost planet Mercury and ringed gas giant Saturn. Pictured on the left, Earth is the pale blue dot just below the rings of Saturn, as captured by the robotic Cassini spacecraft then orbiting the outermost gas giant. On that same day people across planet Earth snapped many of their own pictures of Saturn. On the right, the Earth-Moon system is seen against the dark background of space as captured by the sunward MESSENGER spacecraft, then in Mercury orbit. MESSENGER took its image as part of a search for small natural satellites of Mercury, moons that would be expected to be quite dim. In the MESSENGER image, the brighter Earth and Moon are both overexposed and shine brightly with reflected sunlight. Destined not to return to their home world, both Cassini and MESSENGER have since retired from their missions of Solar System exploration.

METEOROLOGIE - Tempête de sable en Iraq

Les tempêtes de sable sont courantes dans les régions désertiques, comme ici à Basra en Iraq : celles-ci donnent lieu à un ciel rouge ou orange et peuvent générer de nombreux accidents sur les routes en raison du manque de visibilité.

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ASTRONOMY - The Medusa Nebula

 2024 November 22

The Medusa Nebula
Image Credit & Copyright: Bruno Rota Sargi

Explanation: Braided and serpentine filaments of glowing gas suggest this nebula's popular name, The Medusa Nebula. Also known as Abell 21, this Medusa is an old planetary nebula some 1,500 light-years away in the constellation Gemini. Like its mythological namesake, the nebula is associated with a dramatic transformation. The planetary nebula phase represents a final stage in the evolution of low mass stars like the sun as they transform themselves from red giants to hot white dwarf stars and in the process shrug off their outer layers. Ultraviolet radiation from the hot star powers the nebular glow. The Medusa's transforming star is the faint one near the center of the overall bright crescent shape. In this deep telescopic view, fainter filaments clearly extend below and to the left. The Medusa Nebula is estimated to be over 4 light-years across.

METEOROLOGIE - Sundog

Sundog en République tchèque. © Jaroslav Fous

Ce double parhélie (ou sundog) a été pris en photo à Klinovec en République tchèque. Il s'agit d'un phénomène optique qui se forme lorsque le Soleil est assez bas sur l'horizon et que l'atmosphère est chargée de cristaux de glace.

ASTRONOMY - The Elephant's Trunk in Cepheus

 2024 November 21

The Elephant's Trunk in Cepheus
Image Credit: Image Credit & Copyright: Giorgio Ferrari

Explanation: Like an illustration in a galactic Just So Story, the Elephant's Trunk Nebula winds through the emission region and young star cluster complex IC 1396, in the high and far off constellation of Cepheus. Also known as vdB 142, this cosmic elephant's trunk is over 20 light-years long. The detailed telescopic view features the bright swept-back ridges and pockets of cool interstellar dust and gas that abound in the region. But the dark, tendril-shaped clouds contain the raw material for star formation and hide protostars within. Nearly 3,000 light-years distant, the relatively faint IC 1396 complex covers a large region on the sky, spanning over 5 degrees. This rendition spans a 1 degree wide field of view though, about the angular size of 2 full moons.

BIOMES - La Corse

La Corse, au cœur de l’environnement méditerranéen

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ASTRONOMY - Earthset from Orion

 2024 November 20

Earthset from Orion
Image Credit: NASA, Artemis 1

Explanation: Eight billion people are about to disappear in this snapshot from space taken on 2022 November 21. On the sixth day of the Artemis I mission, their home world is setting behind the Moon's bright edge as viewed by an external camera on the outbound Orion spacecraft. Orion was headed for a powered flyby that took it to within 130 kilometers of the lunar surface. Velocity gained in the flyby maneuver was used to reach a distant retrograde orbit around the Moon. That orbit is considered distant because it's another 92,000 kilometers beyond the Moon, and retrograde because the spacecraft orbited in the opposite direction of the Moon's orbit around planet Earth. Orion entered its distant retrograde orbit on November 25. Swinging around the Moon, Orion reached a maximum distance (just over 400,000 kilometers) from Earth on November 28, exceeding a record set by Apollo 13 for most distant spacecraft designed for human space exploration. The Artemis II mission, carrying 4 astronauts around the moon and back again, is scheduled to launch no earlier than September 2025.