Nombre total de pages vues
10/06/2024
SANTé/MEDECINE - L'imortalité pour bientôt - Vivre éternellement (ou presque)
ASTRONOMY - Sh2-132: The Lion Nebula
2024 June 10
Image Credit & Copyright: Imran Badr; Text: Natalia Lewandowska (SUNY Oswego)
Explanation: Is the Lion Nebula the real ruler of the constellation Cepheus? This powerful feline appearing nebula is powered by two massive stars, each with a mass over 20 times greater than our Sun. Formed from shells of ionized gas that have expanded, the nebula's energetic matter not only glows, but is dense enough to contract gravitationally and form stars. The angular size of the Lion Nebula, officially named Sh2-132, is slightly greater than that of the full moon. The gaseous iconic region resides about 10,000 light years away in a constellation named after the King of Aethopia in Greek mythology.
09/06/2024
SANTé/MEDECINE - L'immortalité pour bientôt - L'un des plus grands mystères de la vie
NUCLEAIRE - Comment survivre à une explosion nucléaire ? Gérez votre stress
ASTRONOMY - How to Identify that Light in the Sky
2024 June 9
Illustration Credit & Copyright: HK (The League of Lost Causes)
Explanation: What is that light in the sky? The answer to one of humanity's more common questions may emerge from a few quick observations. For example -- is it moving or blinking? If so, and if you live near a city, the answer is typically an airplane, since planes are so numerous and so few stars and satellites are bright enough to be seen over the glare of artificial city lights. If not, and if you live far from a city, that bright light is likely a planet such as Venus or Mars -- the former of which is constrained to appear near the horizon just before dawn or after dusk. Sometimes the low apparent motion of a distant airplane near the horizon makes it hard to tell from a bright planet, but even this can usually be discerned by the plane's motion over a few minutes. Still unsure? The featured chart gives a sometimes-humorous but mostly-accurate assessment. Dedicated sky enthusiasts will likely note -- and are encouraged to provide -- polite corrections.
08/06/2024
SANTé/MEDECINE - Virus et bactéries mortels - VIH : le virus du Sida et ses 30 millions de victimes
NUCLEAIRE - Comment survivre à une explosion nucléaire ? - Comment bien se préparer ?
ASTRONOMY - Pandora's Cluster of Galaxies
2024 June 8
Image Credit: NASA, ESA, CSA, Ivo Labbe (Swinburne), Rachel Bezanson (University of Pittsburgh), Processing: Alyssa Pagan (STScI)
Explanation: This deep field mosaicked image presents a stunning view of galaxy cluster Abell 2744 recorded by the James Webb Space Telescope's NIRCam. Also dubbed Pandora's Cluster, Abell 2744 itself appears to be a ponderous merger of three different massive galaxy clusters. It lies some 3.5 billion light-years away, toward the constellation Sculptor. Dominated by dark matter, the mega-cluster warps and distorts the fabric of spacetime, gravitationally lensing even more distant objects. Redder than the Pandora cluster galaxies many of the lensed sources are very distant galaxies in the early Universe, their lensed images stretched and distorted into arcs. Of course distinctive diffraction spikes mark foreground Milky Way stars. At the Pandora Cluster's estimated distance this cosmic box spans about 6 million light-years. But don't panic. You can explore the tantalizing region in a 2 minute video tour.
07/06/2024
NUCLEAIRE - Comment survivre à une explosion nucléaire - Restez connecté
ASTRONOMY - SH2-308: The Dolphin Head Nebula
2024 June 7
Image Credit & Copyright: Prabhu Kutti
Explanation: Blown by fast winds from a hot, massive star, this cosmic bubble is huge. Cataloged as Sharpless 2-308 it lies some 5,000 light-years away toward the well-trained constellation Canis Major and covers slightly more of the sky than a Full Moon. That corresponds to a diameter of 60 light-years at its estimated distance. The massive star that created the bubble, a Wolf-Rayet star, is the bright one near the center of the nebula. Wolf-Rayet stars have over 20 times the mass of the Sun and are thought to be in a brief, pre-supernova phase of massive star evolution. Fast winds from this Wolf-Rayet star create the bubble-shaped nebula as they sweep up slower moving material from an earlier phase of evolution. The windblown nebula has an age of about 70,000 years. Relatively faint emission captured by narrowband filters in the deep image is dominated by the glow of ionized oxygen atoms mapped to a blue hue. Presenting a mostly harmless outline, SH2-308 is also known as The Dolphin-head Nebula.
ASTRONOMY - Fox Fur, Cone, and Christmas Tree
2024 December 24 Fox Fur, Cone, and Christmas Tree Image Credit & Copyright: Tim White Explanation: What do the following things have...
-
2021 May 11 Lightning and Orion Beyond Uluru Image Credit & Copyright: Park Liu Explanation: What's happening behind Uluru? A Un...
-
Extraordinary Solar Halos Image Credit & Copyright : Magnus Edback Explanation: Welcome to the December Solstice, the first...