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07/12/2023
GEMMOLOGIE - Joaillerie Céleste (Et spaciale) - La conquête de l’espace (A partir des années 1950)
ASTRONOMY - Orion and the Ocean of Storms
023 December 7
Image Credit: NASA, Artemis 1
Explanation: On December 5, 2022, a camera on board the uncrewed Orion spacecraft captured this view as Orion approached its return powered flyby of the Moon. Beyond one of Orion's extended solar arrays lies dark, smooth, terrain along the western edge of the Oceanus Procellarum. Prominent on the lunar nearside Oceanus Procellarum, the Ocean of Storms, is the largest of the Moon's lava-flooded maria. The lunar terminator, shadow line between lunar night and day, runs along the left of this frame. The 41 kilometer diameter crater Marius is top center, with ray crater Kepler peeking in at the edge, just right of the solar array wing. Kepler's bright rays extend to the north and west, reaching the dark-floored Marius. On December 11, 2022 the Orion spacecraft reached its home world. The historic Artemis 1 mission ended with Orion's successful splashdown in planet Earth's water-flooded Pacific Ocean.
06/12/2023
ASTRONOMY - Stars Versus Dust in the Carina Nebula
2023 December 6
Image Credit: NASA, ESA, Hubble Heritage (STScI/AURA); Processing: Franco Meconi (Terraza al Cosmos)
Explanation: It's stars versus dust in the Carina Nebula and the stars are winning. More precisely, the energetic light and winds from massive newly formed stars are evaporating and dispersing the dusty stellar nurseries in which they formed. Located in the Carina Nebula and inside a region known informally as Mystic Mountain, these pillars' appearance is dominated by opaque brown dust even though it is composed mostly of clear hydrogen gas. Even though some of the dust pillars look like torches, their ends are not on fire -- rather, they are illuminated by nearby stars. About 7,500 light-years distant, the featured image was taken with the Hubble Space Telescope and highlights an interior region of Carina known as HH1066 which spans nearly a light year. Within a few million years, the stars will likely win out completely and the dust torches will completely evaporate.
05/12/2023
GEMMOLOGIE - Joaillerie Céleste (Et spaciale) - Les croissants de lune (Époque Victorienne et après)
ASTRONOMY - Energetic Particle Strikes the Earth
2023 December 5
Illustration Credit: Osaka Metropolitan U./L-INSIGHT, Kyoto U./Ryuunosuke Takeshige
Explanation: It was one of the most energetic particles ever known to strike the Earth -- but where did it come from? Dubbed Amaterasu after the Shinto sun goddess, this particle, as do all cosmic rays that strike the Earth's atmosphere, caused an air shower of electrons, protons, and other elementary particles to spray down onto the Earth below. In the featured illustration, a cosmic ray air shower is pictured striking the Telescope Array in Utah, USA, which recorded the Amaterasu event in 2021 May. Cosmic ray air showers are common enough that you likely have been in a particle spray yourself, although you likely wouldn't have noticed. The origin of this energetic particle, likely the nucleus of an atom, remains a mystery in two ways. First, it is not known how any single particle or atomic nucleus can practically acquire so much energy, and second, attempts to trace the particle back to where it originated did not indicate any likely potential source.
04/12/2023
ASTRONOMY - Plane Crossing Crescent Moon
2023 December 4
Image Credit & Copyright: Juned Patel
Explanation: No, the Moon is not a bow, and no, it did not shoot out a plane like an arrow. What is pictured is a chance superposition. The plane's contrail would normally appear white, but the large volume of air toward the rising Sun preferentially knocked away blue light, not only making the sky blue, but giving the reflected trail a bright red hue. Far in the distance, well behind the plane, the crescent Moon also appears slightly reddened. Captured early last month from Bolton, UK, the featured image was taken so soon after sunrise that the plane was sunlit from below, as was its contrail. Within minutes, unfortunately, the impromptu sky show ended. The plane moved out of sight. The Moon kept rising but became harder to see through a brightening sky. And the contrail gradually dispersed.
03/12/2023
ASTRONOMY - Moon Setting Behind Teide Volcano
2023 December 3
Video Credit & Copyright: Daniel López (El Cielo de Canarias); Music: Piano della Moon (Dan Silva)
Explanation: These people are not in danger. What is coming down from the left is just the Moon, far in the distance. Luna appears so large here because she is being photographed through a telescopic lens. What is moving is mostly the Earth, whose spin causes the Moon to slowly disappear behind Mount Teide, a volcano in the Canary Islands off the northwest coast of Africa. The people pictured are 16 kilometers away and many are facing the camera because they are watching the Sun rise behind the photographer. It is not a coincidence that a full moon rises just when the Sun sets because the Sun is always on the opposite side of the sky from a full moon. The featured video was made in 2018 during the full Milk Moon. The video is not time-lapse -- this was really how fast the Moon was setting.
02/12/2023
ASTRONOMY - Startrails over Beijing Ancient Observatory
Image Credit & Copyright: Jeff Dai (TWAN)
Explanation: You can take a subway ride to visit this observatory in Beijing, China but you won't find any telescopes there. Starting in the 1400s astronomers erected devices at the Beijing Ancient Observatory site to enable them to accurately measure and track the positions of naked-eye stars and planets. Some of the large, ornate astronomical instruments are still standing. You can even see stars from the star observation platform today, but now only the very brightest celestial beacons are visible against the city lights. In this time series of exposures from a camera fixed to a tripod to record graceful arcing startrails, the brightest trail is actually the Moon. Its broad arc is seen behind the ancient observatory's brass armillary sphere. Compare this picture from the Beijing Ancient Observatory taken in September 2023 to one taken in 1895.
01/12/2023
GEMMOLOGIE - Joaillerie Céleste (Et spaciale) - Les bijoux dédiés à l’étoile polaire (Époque Victorienne et après)
AERONAUTIQUE - Les plus gros avions du monde - Antonov AN-225 Mriya
ASTRONOMIE - Galaxies - NGC 4414
Une galaxie spirale . (photo HST, APOD 09/09/1999)
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2021 May 11 Lightning and Orion Beyond Uluru Image Credit & Copyright: Park Liu Explanation: What's happening behind Uluru? A Un...
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2021 January 3 A Phoenix Aurora over Iceland Image Credit & Copyright: Hallgrimur P. Helgason ; Rollover Annotation: Judy Schmidt Ex...