Nombre total de pages vues
25/10/2023
SANTE/MEDECINE - (4/11) - Quand le blanc des yeux n'est plus blanc
ASTRONOMY - Gone in 60 Seconds: A Green Flash Sunset
2023 October 25
Video Credit & Copyright: Tengyu Cai
Explanation: In 60 seconds, this setting Sun will turn green. Actually, the top of the Sun already appears not only green, but wavey -- along with all of its edges. The Sun itself is unchanged -- both effects are caused by looking along hot and cold layers in Earth's atmosphere. The unusual color is known as a green flash and occurs because these atmospheric layers not only shift background images but disperse colors into slightly different directions, like a prism. The featured video was captured earlier this month off the coast of Hawaii, USA. After waiting those 60 seconds, at the video's end, the upper part of the Sun seems to hover alone in space, while turning not only green, but blue. Then suddenly, the Sun appears to shrink to nothing -- only to return tomorrow.
24/10/2023
SANTE/MEDECINE - (3/11) : Quand les sourcils retrécissent
Maux de tête, toux ou nez qui coule ? Ce sont des symptômes que nous connaissons tous et que nous pouvons tous interpréter. Mais que se passe-t-il quand vous perdez du poil aux sourcils ?
Les sourcils qui rétrécissent
Si vous perdez des poils aux extrémités externes de vos sourcils, il y a de quoi vous inquiéter. C’est peut-être un signe d’hypothyroïdie. Elle peut néanmoins être détectée par un test sanguin et traitée assez facilement.
Lastucerie
ASTRONOMY - Arp 87: Merging Galaxies from Hubble
2023 October 24
Image Credit: NASA, ESA, Hubble; Processing: Harshwardhan Pathak
Explanation: This dance is to the death. As these two large galaxies duel, a cosmic bridge of stars, gas, and dust currently stretches over 75,000 light-years and joins them. The bridge itself is strong evidence that these two immense star systems have passed close to each other and experienced violent tides induced by mutual gravity. As further evidence, the face-on spiral galaxy on the right, also known as NGC 3808A, exhibits many young blue star clusters produced in a burst of star formation. The twisted edge-on spiral on the left (NGC 3808B) seems to be wrapped in the material bridging the galaxies and surrounded by a curious polar ring. Together, the system is known as Arp 87. While such interactions are drawn out over billions of years, repeated close passages will ultimately create one merged galaxy. Although this scenario does look unusual, galactic mergers are thought to be common, with Arp 87 representing a stage in this inevitable process. The Arp 87 dancing pair are about 300 million light-years distant toward the constellation of the Lion (Leo). The prominent edge-on spiral galaxy at the far left appears to be a more distant background galaxy and not involved in the on-going merger.
23/10/2023
SANTE/MEDECINE - (2/11) - Les cheveux gris avant 40 ans
ASTRONOMY - Moon Io from Spacecraft Juno
2023 October 23
Image Credit: NASA, JPL-Caltech, SwRI, MSSS; Processing & Copyright: Ted Stryk & Fernando García Navarro
Explanation: There goes another one! Volcanoes on Jupiter's moon Io keep erupting. To investigate, NASA's robotic Juno spacecraft has begun a series of visits to this very strange moon. Io is about the size of Earth's moon, but because of gravitational flexing by Jupiter and other moons, Io's interior gets heated and its surface has become covered with volcanoes. The featured image is from last week's flyby, passing within 12,000 kilometers above the dangerously active world. The surface of Io is covered with sulfur and frozen sulfur dioxide, making it appear yellow, orange and brown. As hoped, Juno flew by just as a volcano was erupting -- with its faint plume visible near the top of the featured image. Studying Io's volcanoes and plumes helps humanity better understand how Jupiter's complex system of moons, rings, and auroras interact. Juno is scheduled to make two flybys of Io during the coming months that are almost 10 times closer: one in December and another in February 2024.
22/10/2023
SANTE/MEDECINE - (1/11) : La maladie bronzée
ASTRONOMY - Ghost Aurora over Canada
2023 October 22
Image Credit & Copyright: Yuichi Takasaka, TWAN
Explanation: What does this aurora look like to you? While braving the cold to watch the skies above northern Canada early one morning in 2013, a most unusual aurora appeared. The aurora definitely appeared to be shaped like something, but what? Two ghostly possibilities recorded by the astrophotographer were "witch" and "goddess of dawn", but please feel free to suggest your own Halloween-enhanced impressions. Regardless of fantastical pareidolic interpretations, the pictured aurora had a typical green color and was surely caused by the scientifically commonplace action of high-energy particles from space interacting with oxygen in Earth's upper atmosphere. In the image foreground, at the bottom, is a frozen Alexandra Falls, while evergreen trees cross the middle.
21/10/2023
ASTRONOMY - Quarter Moons
023 October 21
Image Credit & Copyright: Marcella Giulia Pace
Explanation: Half way between New Moon and Full Moon is the Moon's first quarter phase. That's a quarter of the way around its moonthly orbit. At the first quarter phase, half the Moon's visible side is illuminated by sunlight. For the Moon's third quarter phase, half way between Full Moon and New Moon, sunlight illuminates the other half of the visible lunar disk. At both first and third quarter phases, the terminator, or shadow line separating the lunar night and day, runs down the middle. Near the terminator, long shadows bring lunar craters and mountains in to sharp relief, making the quarter phases a good time to observe the Moon. But in case you missed some, all the quarter phases of the Moon and their calendar dates during 2022 can be found in this well-planned array of telephoto images. Of course, you can observe a first quarter Moon tonight.
20/10/2023
SANTE/MEDECINE - Le CBD et le Sommeil (3/3)
ASTRONOMY - Red Sprites and Circular Elves Lightning over Italy
2025 December 23 Red Sprites and Circular Elves Lightning over Italy Image Credit & Copyright: Valter Binotto Explanation: What's...
-
2022 September 26 All the Water on Planet Earth Illustration Credit: Jack Cook, Adam Nieman, Woods Hole Oceanographic Institution ; Data ...
-
2025 May 11 The Surface of Venus from Venera 14 Image Credit: Soviet Planetary Exploration Program , Venera 14 ; Processing & Copyri...



