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23/01/2021
AERONAUTIQUE - L’avion avec cabine éjectable
16/01/2021
ASTRONOMY - The Mountains of NGC 2174
2021 January 16
Image Credit: NASA, ESA, Hubble Heritage Team (STScI/AURA)
Explanation: This fantastic skyscape lies near the edge of NGC 2174 a star forming region about 6,400 light-years away in the nebula-rich constellation of Orion. It follows mountainous clouds of gas and dust carved by winds and radiation from the region's newborn stars, now found scattered in open star clusters embedded around the center of NGC 2174, off the top of the frame. Though star formation continues within these dusty cosmic clouds they will likely be dispersed by the energetic newborn stars within a few million years. Recorded at infrared wavelengths by the Hubble Space Telescope in 2014, the interstellar scene spans about 6 light-years. Scheduled for launch in 2021, the James Webb Space Telescope is optimized for exploring the Universe at infrared wavelengths.
13/01/2021
ASTRONOMY - Arches Across an Arctic Sky
2021 January 13
Image Credit & Copyright: Giulio Cobianchi
Explanation: What are these two giant arches across the sky? Perhaps the more familiar one, on the left, is the central band of our Milky Way Galaxy. This grand disk of stars and nebulas here appears to encircle much of the southern sky. Visible below the stellar arch is the rusty-orange planet Mars and the extended Andromeda galaxy. For a few minutes during this cold artic night, a second giant arch appeared to the right, encircling part of the northern sky: an aurora. Auroras are much closer than stars as they are composed of glowing air high in Earth's atmosphere. Visible outside the green auroral arch is the group of stars popularly known as the Big Dipper. The featured digital composite of 18 images was captured in mid-December over the in Norway.
11/01/2021
ASTRONOMY - Moon Phases in 2021
2021 January 11
Video Credit: Data: Lunar Reconnaissance Orbiter ; Animation: NASA's Scientific Visualization Studio;
Music: Brandenburg Concerto No4-1 BWV1049 (Johann Sebastian Bach), by Kevin MacLeod via Incompetech
Explanation: What will the Moon phase be on your birthday this year? It is hard to predict because the Moon's appearance changes nightly. As the Moon orbits the Earth, the half illuminated by the Sun first becomes increasingly visible, then decreasingly visible. The featured video animates images taken by NASA's Moon-orbiting Lunar Reconnaissance Orbiter to show all 12 lunations that appear this year, 2021. A single lunation describes one full cycle of our Moon, including all of its phases. A full lunation takes about 29.5 days, just under a month (moon-th). As each lunation progresses, sunlight reflects from the Moon at different angles, and so illuminates different features differently. During all of this, of course, the Moon always keeps the same face toward the Earth. What is less apparent night-to-night is that the Moon's apparent size changes slightly, and that a slight wobble called a libration occurs as the Moon progresses along its elliptical orbit.
10/01/2021
AERONAUTIQUE - L’avion transparent alimenté par votre chaleur corporelle
09/01/2021
ASTRONOMY - Titan: Moon over Saturn
2021 January 9
Image Credit: NASA, JPL-Caltech, Space Science Institute
Explanation: Like Earth's moon, Saturn's largest moon Titan is locked in synchronous rotation. This mosaic of images recorded by the Cassini spacecraft in May of 2012 shows its anti-Saturn side, the side always facing away from the ringed gas giant. The only moon in the solar system with a dense atmosphere, Titan is the only solar system world besides Earth known to have standing bodies of liquid on its surface and an earthlike cycle of liquid rain and evaporation. Its high altitude layer of atmospheric haze is evident in the Cassini view of the 5,000 kilometer diameter moon over Saturn's rings and cloud tops. Near center is the dark dune-filled region known as Shangri-La. The Cassini-delivered Huygens probe rests below and left of center, after the most distant landing for a spacecraft from Earth.
07/01/2021
ASTRONOMY - Total Solar Eclipse 2020
2021 January 7
Image Credit & Copyright: Miloslav Druckmuller, Andreas Moller, (Brno University of Technology),
Explanation: Along a narrow path crossing southern South America through Chile and Argentina, the final New Moon of 2020 moved in front of the Sun on December 14 in the year's only total solar eclipse. Within about 2 days of perigee, the closest point in its elliptical orbit, the New Moon's surface is faintly lit by earthshine in this dramatic composite view. The image is a processed composite of 55 calibrated exposures ranging from 1/640 to 3 seconds. Covering a large range in brightness during totality, it reveals the dim lunar surface and faint background stars, along with planet-sized prominences at the Sun's edge, an enormous coronal mass ejection, and sweeping coronal structures normally hidden in the Sun's glare. Look closely for an ill-fated sungrazing Kreutz family comet (C/2020 X3 SOHO) approaching from the lower left, at about the 7 o'clock position. In 2021 eclipse chasers will see an annular solar eclipse coming up on June 10. They'll have to wait until December 4 for the only total solar eclipse in 2021 though. That eclipse will be total along a narrow path crossing the southernmost continent of Antarctica.
05/01/2021
ASTRONOMY - The Small Cloud of Magellan
2021 January 5
Image Credit & Copyright: José Mtanous
Explanation: What is the Small Magellanic Cloud? It has turned out to be a galaxy. People who have wondered about this little fuzzy patch in the southern sky included Portuguese navigator Ferdinand Magellan and his crew, who had plenty of time to study the unfamiliar night sky of the south during the first circumnavigation of planet Earth in the early 1500s. As a result, two celestial wonders easily visible for southern hemisphere skygazers are now known in Western culture as the Clouds of Magellan. Within the past 100 years, research has shown that these cosmic clouds are dwarf irregular galaxies, satellites of our larger spiral Milky Way Galaxy. The Small Magellanic Cloud actually spans 15,000 light-years or so and contains several hundred million stars. About 210,000 light-years away in the constellation of the Tucan (Tucana), it is more distant than other known Milky Way satellite galaxies, including the Sagittarius Dwarf galaxy and the Large Magellanic Cloud. This sharp image also includes the foreground globular star cluster 47 Tucanae on the right.
04/01/2021
AERONAUTIQUE - Vacances au Pole
Se prélasser à côté des ours polaires pour les vacances, un rêve à la portée de tous en l'an 2000 ! Enfin, c'est ce que l'on croyait dans les années 1900. Des ballons gonflants auraient emmené de larges paquebots flottants vers la destination glacée. On imagine que le chauffage était intégré aux plans du navire !
© Hildebrands
Astronomy - YOUNG MOON AND SISTER STARS
2026 April 24 Young Moon and Sister Stars Image Credit & Copyright : Giorgia Hofer Explanation: Sunlit arms of a crescent moon see...
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2025 May 11 The Surface of Venus from Venera 14 Image Credit: Soviet Planetary Exploration Program , Venera 14 ; Processing & Copyri...
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