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24/12/2019

Science & Technology - Astronomy picture of the day : A Northern Winter Sky Panorama

2019 December 24
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A Northern Winter Sky Panorama 
Image Credit & Copyright: Tomas Slovinsky
Explanation: What stars shine in Earth's northern hemisphere during winter? The featured image highlights a number of bright stars visible earlier this month. The image is a 360-degree horizontal-composite panorama of 66 vertical frames taken consecutively with the same camera and from the same location at about 2:30 am. Famous stars visible in the picture include Castor & Pollux toward the southeast on the left, Sirius just over the horizon toward the south, Capella just over the arch of the Milky Way Galaxy toward the west, and Polaris toward the north on the right. Captured by coincidence is a meteor on the far left. In the foreground is the Museum of the Orava Village in ZuberecSlovakia. This village recreates rural life in the region hundreds of years ago, while the image captures a timeless sky surely familar to village residents, a sky also shared with northern residents around the world.

17/12/2019

Science & Technology - Astronomy picture of the day : The Horsehead Nebula

2019 December 17
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The Horsehead Nebula 
Image Credit & Copyright: Mark Hanson & Martin PughSSROPROMPTCTIONSF
Explanation: Sculpted by stellar winds and radiation, a magnificent interstellar dust cloud by chance has assumed this recognizable shape. Fittingly named the Horsehead Nebula, it is some 1,500 light-years distant, embedded in the vast Orion cloud complex. About five light-years "tall", the dark cloud is cataloged as Barnard 33 and is visible only because its obscuring dust is silhouetted against the glowing red emission nebula IC 434. Stars are forming within the dark cloud. Contrasting blue reflection nebula NGC 2023, surrounding a hot, young star, is at the lower left of the full image. The featured gorgeous color image combines both narrowband and broadband images recorded using several different telescopes.

15/12/2019

Science & Technology - Astronomy picture of the day : Mammatus Clouds over Nebraska

2019 December 15
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Mammatus Clouds over Nebraska 
Image Credit & Copyright: Jorn Olsen Photography
Explanation: When do cloud bottoms appear like bubbles? Normally, cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. As water droplets grow, an opaque cloud forms. Under some conditions, however, cloud pockets can develop that contain large droplets of water or ice that fall into clear air as they evaporate. Such pocketsmay occur in turbulent air near a thunderstorm. Resulting mammatus clouds can appear especially dramatic if sunlit from the side. The mammatus clouds pictured here were photographed over HastingsNebraska during 2004 June.

14/12/2019

Sience & Technology - Astronomy picture of the day : Interstellar Comet 2I/Borisov

2019 December 14
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Interstellar Comet 2I/Borisov 
Image Credit: NASAESA, and D. Jewitt (UCLA) et al.
Explanation: From somewhere else in the Milky Way galaxy, Comet 2I/Borisov is just visiting the Solar System. Discovered by Crimean amateur astronomer Gennady Borisov on August 30, 2019, the first known interstellar comet is captured in these two recent Hubble Space Telescope images. On the left, a distant background galaxy near the line-of-sight to Borisov is blurred as Hubble tracked the speeding comet and dust tail about 327 million kilometers from Earth. At right, 2I/Borisov appears shortly after perihelion, its closest approach to Sun. Borisov's closest approach to our fair planet, a distance of about 290 million kilometers, will come on December 28. Even though Hubble's sharp images don't resolve the comet's nucleus, they do lead to estimates of less than 1 kilometer for its diameter.

12/12/2019

Science & Technology - Astronomy picture of the day : Lines of Time

2019 December 12
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Lines of Time 
Image Credit & CopyrightAnton Komlev
Explanation: In time stars trace lines through the night sky on a rotating planet. Taken over two hours or more, these digitally added consecutive exposures were made with a camera and wide angle lens fixed to a tripod near Orel farm, Primorsky Krai, Russia, planet Earth. The stars trail in concentric arcs around the planet's south celestial pole below the scene's horizon, and north celestial pole off the frame at the upper right. Combined, the many short exposures also bring out the pretty star colours. Bluish trails are from stars hotter than Earth's Sun, while yellowish trails are from cooler stars. A long time ago this tree blossomed, but now reveals the passage of time in the wrinkled and weathered lines of its remains.

05/12/2019

Science & Technology - Astronomy picture of the day : Spiral Galaxy NGC 6744

2019 December 5
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Spiral Galaxy NGC 6744 
Image Credit & CopyrightZhuokai Liu, Jiang Yuhang
Explanation: Beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across, larger than our own Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo and appears as only a faint, extended object in small telescopes. We see the disk of the nearby island universe tilted towards our line of sight in this remarkably detailed galaxy portrait, a telescopic view that spans an area about the angular size of a full moon. In it, the giant galaxy's elongated yellowish core is dominated by the light from old, cool stars. Beyond the core, grand spiral arms are filled with young blue star clusters and speckled with pinkish star forming regions. An extended arm sweeps past a smaller satellite galaxy (NGC 6744A) at the lower right. NGC 6744's galactic companion is reminiscent of the Milky Way's satellite galaxy the Large Magellanic Cloud.

04/12/2019

Science & Technology - Astronomy picture of the day : Electric Night

2019 December 4
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Electric Night 
Image Credit & Copyright: Ivan Pedretti
Explanation: It may appear, at first, like the Galaxy is producing the lightning, but really it's the Earth. The featured nighttime landscape was taken from a southern tip of the Italian Island of Sardinia in early June. The foreground rocks and shrubs are near the famous Capo Spartivento Lighthouse, and the camera is pointed south toward Algeria in Africa. In the distance, across the Mediterranean Sea, a thunderstorm is threatening, with several electric lightning strokes caught together during this 25-second wide-angle exposure. Much farther in the distance, strewn about the sky, are hundreds of stars in the neighborhood of our Sun in the Milky Way Galaxy. Furthest away, and slanting down from the upper left, are billions of stars that together compose the central band of our Milky Way.

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