In how many ways does the center of our Galaxy glow? This enigmatic region, about 26,000 light years away toward the constellation of the Archer (Sagittarius), glows in every type of light that we can see. In the featured image, high-energy X-ray emission captured by NASA’s orbiting Chandra X-Ray Observatory appears in green and blue, while low-energy radio emission captured by SARAO’s ground-based MeerKAT telescope array is colored red. Just on the right of the colorful central region lies Sagittarius A (Sag A), a strong radio source that coincides with Sag A*, our Galaxy’s central supermassive black hole. Hot gas surrounds Sag A, as well as a series of parallel radio filaments known as the Arc, seen just left of the image center. Numerous unusual single radio filaments are visible around the image. Many stars orbit in and around Sag A, as well as numerous small black holes and dense stellar cores known as neutron stars and white dwarfs. The Milky Way’s central supermassive black hole is currently being imaged by the Event Horizon Telescope. via NASA https://ift.tt/2QY1fBk
What creates Saturn’s colors? The featured picture of Saturn only slightly exaggerates what a human would see if hovering close to the giant ringed world. The image was taken in 2005 by the robot Cassini spacecraft that orbited Saturn from 2004 to 2017. Here Saturn’s majestic rings appear directly only as a curved line, appearing brown, in part, from its infrared glow. The rings best show their complex structure in the dark shadows they create across the upper part of the planet. The northern hemisphere of Saturn can appear partly blue for the same reason that Earth’s skies can appear blue — molecules in the cloudless portions of both planet’s atmospheres are better at scattering blue light than red. When looking deep into Saturn’s clouds, however, the natural gold hue of Saturn’s clouds becomes dominant. It is not known why southern Saturn does not show the same blue hue — one hypothesis holds that clouds are higher there. It is also not known why some of Saturn’s clouds are colored gold. via NASA https://ift.tt/3dOhoD8
The constellation of Orion is much more than three stars in a row. It is a direction in space that is rich with impressive nebulas. To better appreciate this well-known swath of sky, an extremely long exposure was taken over many clear nights in 2013 and 2014. After 212 hours of camera time and an additional year of processing, the featured 1400-exposure collage spanning over 40 times the angular diameter of the Moon emerged. Of the many interesting details that have become visible, one that particularly draws the eye is Barnard’s Loop, the bright red circular filament arcing down from the middle. The Rosette Nebula is not the giant red nebula near the top of the image — that is a larger but lesser known nebula known as Lambda Orionis. The Rosette Nebula is visible, though: it is the red and white nebula on the upper left. The bright orange star just above the frame center is Betelgeuse, while the bright blue star on the lower right is Rigel. Other famous nebulas visible include the Witch Head Nebula, the Flame Nebula, the Fox Fur Nebula, and, if you know just where to look, the comparatively small Horsehead Nebula. About those famous three stars that cross the belt of Orion the Hunter — in this busy frame they can be hard to locate, but a discerning eye will find them just below and to the right of the image center. via NASA https://ift.tt/3apIyhm
In trying times, stars still trail in the night. Taken on March 14, this night skyscape was made by combining 230 exposures each 15 seconds long to follow the stars’ circular paths. The camera was fixed to a tripod on an isolated terrace near the center of Ragusa, Italy, on the island of Sicily. But the night sky was shared around the rotating planet. A friend to celestial navigators and astrophotographers alike Polaris, the north star, makes the short bright trail near the center of the concentric celestial arcs. via NASA https://ift.tt/2Jnsgts
A drop of water seems to hold an entire galaxy in this creative macro-astrophotograph. In the imaginative work of cosmic nature photography a close-up lens was used to image a previously made picture of a galaxy, viewed through a water drop suspended from a stem. A favorite of many telescope-wielding astroimagers, the galaxy is the Andromeda Galaxy, also known as M31. About 100,000 light-years across that majestic galaxy’s spiral arms and dust lanes are curved and distorted in the image contained in the centimeter-sized droplet. Andromeda is some 2.5 million light-years distant, but this project was still carried out while spending time indoors. via NASA https://ift.tt/2UD8uiR
This surreal picture isn’t from a special effects sci-fi movie. It is a digital composite of frames of the real Andromeda Galaxy, also known as M31, rising over a real mountain. Exposures tracking the galaxy and background stars have been digitally combined with separate exposures of the foreground terrain. All background and foreground exposures were made back to back with the same camera and telephoto lens on the same night from the same location. In the « Deepscape » combination they produce a stunning image that reveals a range of brightness and color that your eye can’t quite see on its own. Still, it does look like you could ride a cable car up this mountain and get off at the station right next to Andromeda. But at 2.5 million light-years from Earth the big beautiful spiral galaxy really is a little out of reach as a destination. Don’t worry, though. Just wait 5 billion years and the Andromeda Galaxy will come to you. This Andromeda Station is better known as Weisshorn, the highest peak of the ski area in Arosa, Switzerland. via NASA https://ift.tt/33Omk65
Massive star IRS 4 is beginning to spread its wings. Born only about 100,000 years ago, material streaming out from this newborn star has formed the nebula dubbed Sharpless 2-106 Nebula (S106), featured here. A large disk of dust and gas orbiting Infrared Source 4 (IRS 4), visible in brown near the image center, gives the nebula an hourglass or butterfly shape. S106 gas near IRS 4 acts as an emission nebula as it emits light after being ionized, while dust far from IRS 4 reflects light from the central star and so acts as a reflection nebula. Detailed inspection of a relevant infrared image of S106 reveal hundreds of low-mass brown dwarf stars lurking in the nebula’s gas. S106 spans about 2 light-years and lies about 2000 light-years away toward the constellation of the Swan (Cygnus). via NASA https://ift.tt/3dqw8aZ
What happens to a star that goes near a black hole? If the star directly impacts a massive black hole, then the star falls in completely — and everything vanishes. More likely, though, the star goes close enough to have the black hole’s gravity pull away the outer layers of the star, or disrupt the star. Then most of the star’s gas does not fall into the black hole. These stellar tidal disruption events can be as bright as a supernova, and an increasing amount of them are being discovered by automated sky surveys. In the featured artist’s illustration, a star has just passed a massive black hole and sheds gas that continues to orbit. The inner edge of a disk of gas and dust surrounding the black hole is heated by the disruption event and may glow long after the star is gone. via NASA https://ift.tt/2WKA93Y
If you stare at an interesting patch of sky long enough, will it look different? In the case of Pleiades and Hyades star clusters — and surrounding regions — the answer is: yes, pretty different. Long duration camera exposures reveal an intricate network of interwoven interstellar dust and gas that was previously invisible not only to the eye but to lower exposure images. In the featured wide and deep mosaic, the dust stands out spectacularly, with the familiar Pleaides star cluster visible as the blue patch near the top of the image. Blue is the color of the Pleiades’ most massive stars, whose distinctive light reflects from nearby fine dust. On the upper left is the Hyades star cluster surrounding the bright, orange, foreground-star Aldebaran. Red glowing emission nebula highlight the bottom of the image, including the curving vertical red ribbon known as the Eridanus Loop. The pervasive dust clouds appear typically in light brown and are dotted with unrelated stars. via NASA https://ift.tt/2vHAFVr
Comme tout le monde en France (enfin normalement) je subis le confinement.
Une chose commence à me manquer….le pain.
Donc en ce dimanche (en fait déjà hier soir pour préparer la pâte), je m’occupe comme je peux…
C’est bon je ne mourrai pas de faim !!!