Nombre total de pages vues
10/02/2022
AERONAUTIQUE - L'Airbus A300-600ST ou l'avion " Beluga"
ASTRONOMY - T Tauri and Hind's Variable Nebula
2022 February 10
Image Credit & Copyright: Dawn Lowry, Gian Lorenzo Ferretti, Ewa Pasiak and Terry Felty
Explanation: The star with an orange tint near top center in this dusty telescopic frame is T Tauri, prototype of the class of T Tauri variable stars. Next to it (right) is a yellow cosmic cloud historically known as Hind's Variable Nebula (NGC 1555). About 650 light-years away, at the boundary of the local bubble and the Taurus molecular cloud, both star and nebula are seen to vary significantly in brightness but not necessarily at the same time, adding to the mystery of the intriguing region. T Tauri stars are now generally recognized as young (less than a few million years old), sun-like stars still in the early stages of formation. To further complicate the picture, infrared observations indicate that T Tauri itself is part of a multiple system and suggest that the associated Hind's Nebula may also contain a very young stellar object. The well-composed image spans about 8 light-years at the estimated distance of T Tauri.
08/02/2022
ASTRONOMY - Aurora and Light Pillars over Norway
2022 February 8
ART FRACTAL - Neige
07/02/2022
ASTRONOMY - NGC 4651: The Umbrella Galaxy
2022 February 7
Image Credit & Copyright: CFHT, Coelum, MegaCam, J.-C. Cuillandre (CFHT) & G. A. Anselmi (Coelum)
Explanation: It's raining stars. What appears to be a giant cosmic umbrella is now known to be a tidal stream of stars stripped from a small satellite galaxy. The main galaxy, spiral galaxy NGC 4651, is about the size of our Milky Way, while its stellar parasol appears to extend some 100 thousand light-years above this galaxy's bright disk. A small galaxy was likely torn apart by repeated encounters as it swept back and forth on eccentric orbits through NGC 4651. The remaining stars will surely fall back and become part of a combined larger galaxy over the next few million years. The featured image was captured by the Canada-France-Hawaii Telescope (CFHT) in Hawaii, USA. The Umbrella Galaxy lies about 50 million light-years distant toward the well-groomed northern constellation Coma Berenices.
06/02/2022
ASTRONOMY - Blue Marble Earth
2022 February 6
Image Credit: NASA, Apollo 17 Crew
Explanation: Welcome to planet Earth, the third planet from a star named the Sun. The Earth is shaped like a sphere and composed mostly of rock. Over 70 percent of the Earth's surface is water. The planet has a relatively thin atmosphere composed mostly of nitrogen and oxygen. The featured picture of Earth, dubbed The Blue Marble, was taken from Apollo 17 in 1972 and features Africa and Antarctica. It is thought to be one of the most widely distributed photographs of any kind. Earth has a single large Moon that is about 1/4 of its diameter and, from the planet's surface, is seen to have almost exactly the same angular size as the Sun. With its abundance of liquid water, Earth supports a large variety of life forms, including potentially intelligent species such as dolphins and humans. Please enjoy your stay on planet Earth.
05/02/2022
ASTRONOMY - Symbiotic R Aquarii
2022 February 5
Image Credit: X-ray: NASA/CXC/SAO/R. Montez et al.; Optical: Data: NASA/ESA/STScI, Processing: Judy Schmidt (CC BY-NC-SA)
Explanation: Variable star R Aquarii is actually an interacting binary star system, two stars that seem to have a close symbiotic relationship. Centered in this space-based optical/x-ray composite image it lies about 710 light years away. The intriguing system consists of a cool red giant star and hot, dense white dwarf star in mutual orbit around their common center of mass. With binoculars you can watch as R Aquarii steadily changes its brightness over the course of a year or so. The binary system's visible light is dominated by the red giant, itself a Mira-type long period variable star. But material in the cool giant star's extended envelope is pulled by gravity onto the surface of the smaller, denser white dwarf, eventually triggering a thermonuclear explosion, blasting material into space. Astronomers have seen such outbursts over recent decades. Evidence for much older outbursts is seen in these spectacular structures spanning almost a light-year as observed by the Hubble Space Telescope (in red and blue). Data from the Chandra X-ray Observatory (in purple) shows the X-ray glow from shock waves created as a jet from the white dwarf strikes surrounding material.
AERONAUTIQUE - Solar Impulse, l’avion solaire
Futura Sciences
03/02/2022
ASTRONOMY - Embraced by light
2022 February 3
Explanation: Even though Venus (left) was the brightest planet in the sky it was less than 1/30th the apparent size of the Moon on January 29. But as both rose before the Sun they shared a crescent phase. For a moment their visible disks were each about 12 percent illuminated as they stood above the southeastern horizon. The similar sunlit crescents were captured in these two separate images. Made at different magnifications, each panel is a composite of stacked video frames taken with a small telescope. Venus goes through a range of phases like the Moon as the inner planet wanders from evening sky to morning sky and back again with a period of 584 days. Of course the Moon completes its own cycle of phases, a full lunation, in about 29.5 days.
02/02/2022
AERONAUTIQUE - L'E-Fan d'Airbus, avion entièrement électrique
ASTRONOMY - Planet Earth at Twilight
2024 December 27 Planet Earth at Twilight Image Credit: ISS Expedition 2 Crew , Gateway to Astronaut Photography of Earth , NASA Explana...
-
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...