ASTRONOMY - Jupiter et Vénus au-dessus de l'Italie

 2023 mars 5

Jupiter et Vénus au-dessus de l'Italie
Crédit d'image et droit d'auteur :  Giovanni Tumino

Explication :  Quels sont ces deux points lumineux ?  Planètes.  Il y a quelques jours, les deux planètes les plus brillantes du  ciel nocturne  sont passées à un degré près l'une de l'autre dans ce qu'on appelle une  conjonction  .  Visibles juste après le coucher du soleil dans une grande partie du monde, les deux points lumineux étaient  Jupiter  (à gauche) et  Vénus  (à droite).  L'  image présentée  a été prise près de l'approche la plus proche de  Cirica  ,  Sicile  ,  Italie  .  La semaine précédente, Vénus s'élève plus haut dans le  ciel du coucher du soleil pour rencontrer la chute de Jupiter.  Maintenant, ils ont  changé de place  .  Bien sûr,  Vénus reste beaucoup plus proche à la fois du  Soleil  et de la Terre que Jupiter - la proximité apparente entre les planètes dans le ciel de  la Terre  n'était  qu'angulaire  .  Vous pouvez toujours  voir  la  paire populaire  pendant environ une heure après le coucher du soleil ce mois-ci, bien qu'ils continuent de se séparer, et  Jupiter  continue de se coucher plus tôt chaque nuit.

ASTRONOMY - 10 Days of Venus and Jupiter

 2023 March 4

10 Days of Venus and Jupiter
Image Credit & Copyright: Soumyadeep Mukherjee

Explanation: Venus and Jupiter may have caught your attention lately. The impending close conjunction of the two brightest planets visible in clear evening skies has been hard to miss. With Jupiter at the top, starting on February 21 and ending on March 2, their close approach is chronicled daily, left to right, in these panels recorded from Dhanbad, India. Near the western horizon, the evening sky colors and exposures used for each panel depend on the local conditions near sunset. On February 22, Jupiter and Venus were joined by the young crescent Moon. The celestial pair appeared to be only the width of a full moon apart by March 2. Of course on that date the two planets were physically separated by over 600 million kilometers in their orbits around the Sun. In the coming days Jupiter will slowly settle into the glare at sunset, but Venus will continue to move farther from the Sun in the western sky to excel in its current role as the brilliant evening star.

MUSICA - Rossini - William Tell

"William Tell"

ASTRONOMY - Crescent Moon Beyond Greek Temple

 2023 February 28

Crescent Moon Beyond Greek Temple
Image Credit & Copyright: Elias Chasiotis

Explanation: Why is a thin crescent moon never seen far from a horizon? Because the only geometry that gives a thin crescent lunar phase occurs when the Moon appears close to the Sun in the sky. The crescent is not caused by the shadow of the Earth, but by seeing only a small part of the Moon directly illuminated by the Sun. Moreover, the thickest part of the crescent always occurs in the direction of the Sun. In the evening, a thin crescent Moon will set shortly after the Sun and not be seen for the rest of the night. Alternatively, in the morning, a crescent Moon will rise shortly before the Sun after not being seen for most of the night. Pictured two weeks ago, a crescent moon was captured near the horizon, just before sunrise, far behind remnants of the ancient Temple of Poseidon in Greece.

ASTRONOMY - Jones-Emberson 1

 023 February 24

Jones-Emberson 1
Image Credit & Copyright: Serge Brunier, Jean-François Bax, David Vernet, C2PU/OCA

Explanation: Planetary nebula Jones-Emberson 1 is the death shroud of a dying Sun-like star. It lies some 1,600 light-years from Earth toward the sharp-eyed constellation Lynx. About 4 light-years across, the expanding remnant of the dying star's atmosphere was shrugged off into interstellar space, as the star's central supply of hydrogen and then helium for fusion was finally depleted after billions of years. Visible near the center of the planetary nebula is what remains of the stellar core, a blue-hot white dwarf star. Also known as PK 164 +31.1, the nebula is faint and very difficult to glimpse at a telescope's eyepiece. But this deep broadband image combining 22 hours of exposure time does show it off in exceptional detail. Stars within our own Milky Way galaxy as well as background galaxies across the universe are scattered through the clear field of view. Ephemeral on the cosmic stage, Jones-Emberson 1 will fade away over the next few thousand years. Its hot, central white dwarf star will take billions of years to cool.

ASTRONOMY - Arp 78: Peculiar Galaxy in Aries

 2023 February 23

Arp 78: Peculiar Galaxy in Aries
Image Credit & Copyright: Josep Drudis

Explanation: Peculiar spiral galaxy Arp 78 is found within the boundaries of the head strong constellation Aries. Some 100 million light-years beyond the stars and nebulae of our Milky Way galaxy, the island universe is an enormous 200,000 light-years across. Also known as NGC 772, it sports a prominent, outer spiral arm in this detailed cosmic portrait. Tracking along sweeping dust lanes and lined with young blue star clusters, Arp 78's overdeveloped spiral arm is pumped-up by galactic-scale gravitational tides. Interactions with its brightest companion galaxy, the more compact NGC 770 seen above and right of the larger spiral, are likely responsible. Embedded in faint star streams revealed in the deep telescopic exposure, NGC 770's fuzzy, elliptical appearance contrasts nicely with spiky foreground Milky Way stars in matching yellowish hues.

ASTRONOMY - Our Increasingly Active Sun

 2023 February 22

Our Increasingly Active Sun
Image Credit & Copyright: Mehmet Ergün

Explanation: Our Sun is becoming a busy place. Only two years ago, the Sun was emerging from a solar minimum so quiet that months would go by without even a single sunspot. In contrast, already this year and well ahead of schedule, our Sun is unusually active, already nearing solar activity levels seen a decade ago during the last solar maximum. Our increasingly active Sun was captured two weeks ago sporting numerous interesting features. The image was recorded in a single color of light called Hydrogen Alpha, color-inverted, and false colored. Spicules carpet much of the Sun's face. The brightening towards the Sun's edges is caused by increased absorption of relatively cool solar gas and called limb darkening. Just outside the Sun's disk, several scintillating prominences protrude, while prominences on the Sun's face are known as filaments and show as light streaks. Magnetically tangled active regions are both dark and light and contain cool sunspots. As our Sun's magnetic field winds toward solar maximum over the next few years, whether the Sun's high activity will continue to increase is unknown.

ASTRONOMY - Comet ZTF over Yosemite Falls

 2023 February 21

Comet ZTF over Yosemite Falls
Image Credit & Copyright: Tara Mostofi

Explanation: They are both falling. The water in Yosemite Falls, California, USA, is falling toward the Earth. Comet ZTF is falling toward the Sun. This double cosmic cascade was captured late last month as fading Comet C/2022 E3 (ZTF) had just passed its closest to planet Earth. The orange star just over the falls is Kochab. With the exception of a brief encounter with a black bear, the featured image was a well-planned composite of a moonlit-foreground and long-duration background exposures - all designed to reconstruct a deep version of an actual single sight. Although Comet ZTF is now fading as it glides back to the outer Solar System, its path is determined by gravity and so it can be considered to still be falling toward the Sun -- but backwards.

ASTRONOMY - NGC 1850: Not Found in the Milky Way

 2023 February 20

NGC 1850: Not Found in the Milky Way
Image Credit: NASA, ESA and P. Goudfrooij (STScI); Processing: M. H. Özsaraç (Türkiye Astronomi Derneği)

Explanation: There is nothing like this ball of stars in our Milky Way Galaxy. This is surprising because, at first glance, this featured image by the Hubble Space Telescope suggests that star cluster NGC 1850's size and shape are reminiscent of the many ancient globular star clusters which roam our own Milky Way Galaxy's halo. But NGC 1850's stars are all too young, making it a type of star cluster with no known counterpart in the Milky Way. Moreover, NGC 1850 is also a double star cluster, with a second, compact cluster of stars visible here just to the right of the large cluster's center. Stars in the large cluster are estimated to be 50 million years young, while stars in the compact cluster are younger still, with an age of about 4 million years. A mere 168,000 light-years distant, NGC 1850 is located near the outskirts of the Large Magellanic Cloud galaxy. The glowing gas filaments across the image left, like supernova remnants in our own galaxy, testify to violent stellar explosions and indicate that short-lived massive stars have recently been present in the region.

ASTRONOMY - Seven Dusty Sisters in Infrared

 2023 February 19

Seven Dusty Sisters in Infrared
Image Credit: NASA, WISE, IRSA, Processing & Copyright : Francesco Antonucci

Explanation: Is this really the famous Pleiades star cluster? Known for its iconic blue stars, the Pleiades is shown here in infrared light where the surrounding dust outshines the stars. Here three infrared colors have been mapped into visual colors (R=24, G=12, B=4.6 microns). The base images were taken by NASA's orbiting Wide Field Infrared Survey Explorer (WISE) spacecraft. Cataloged as M45 and nicknamed the Seven Sisters, the Pleiades star cluster is by chance situated in a passing dust cloud. The light and winds from the massive Pleiades stars preferentially repel smaller dust particles, causing the dust to become stratified into filaments, as seen. The featured image spans about 20 light years at the distance of the Pleiades, which lies about 450 light years distant toward the constellation of the Bull (Taurus).