Crédit photo: Flickr – Toby Hudson
2022 December 20
Explanation: Thor not only has his own day (Thursday), but a helmet in the heavens. Popularly called Thor's Helmet, NGC 2359 is a hat-shaped cosmic cloud with wing-like appendages. Heroically sized even for a Norse god, Thor's Helmet is about 30 light-years across. In fact, the cosmic head-covering is more like an interstellar bubble, blown with a fast wind from the bright, massive star near the bubble's center. Known as a Wolf-Rayet star, the central star is an extremely hot giant thought to be in a brief, pre-supernova stage of evolution. NGC 2359 is located about 15,000 light-years away toward the constellation of the Great Overdog. This remarkably sharp image is a mixed cocktail of data from narrowband filters, capturing not only natural looking stars but details of the nebula's filamentary structures. The star in the center of Thor's Helmet is expected to explode in a spectacular supernova sometime within the next few thousand years.
2022 December 19
Explanation: What's causing the commotion in the Tadpole Nebula? Star formation. Dusty emission in the Tadpole Nebula, IC 410, lies about 12,000 light-years away in the northern constellation of the Charioteer (Auriga). The cloud of glowing gas is over 100 light-years across, sculpted by stellar winds and radiation from embedded open star cluster NGC 1893. Formed in the interstellar cloud a mere 4 million years ago, bright newly formed cluster stars are seen all around the star-forming nebula. Notable on the lower-right of the featured image are two relatively dense streamers of material trailing away from the nebula's central regions. Potentially sites of ongoing star formation in IC 410, these cosmic tadpole shapes are about 10 light-years long. The image was processed highlighting the emission from sulfur (red), hydrogen (green), and oxygen (blue) gas -- but with the stars digitally removed.
2022 December 18
Explanation: Do you know the names of some of the brightest stars? It's likely that you do, even though some bright stars have names so old they date back to near the beginning of written language. Many world cultures have their own names for the brightest stars, and it is culturally and historically important to remember them. In the interest of clear global communication, however, the International Astronomical Union (IAU) has begun to designate standardized star names. Featured here in true color are the 25 brightest stars in the night sky, currently as seen by humans, coupled with their IAU-recognized names. Some star names have interesting meanings, including Sirius ("the scorcher" in Latin), Vega ("falling" in Arabic), and Antares ("rival to Mars" in Greek). You are likely even familiar with the name of at least one star too dim to make this list: Polaris.
Crédit photo: Wikimedia – NOAA
2022 December 17
Explanation: Get out your red/blue glasses and check out this stereo scene from Taurus-Littrow valley on the Moon! The color anaglyph features a detailed 3D view of Apollo 17's Lunar Rover in the foreground -- behind it lies the Lunar Module and distant lunar hills. Because the world was going to be able to watch the Lunar Module's ascent stage liftoff via the rover's TV camera, this parking place was also known as the VIP Site. Fifty years ago, in December of 1972, Apollo 17 astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours on the Moon, while colleague Ronald Evans orbited overhead. The crew returned with 110 kilograms of rock and soil samples, more than from any of the other lunar landing sites. Cernan and Schmitt are still the last to walk (or drive) on the Moon.
2022 December 16
Explanation: Returning from beyond the Moon, on December 11 the Orion spacecraft entered Earth's atmosphere at almost 11 kilometers per second. That's half the speed of the grain of dust that created this long fireball meteor when it entered the atmosphere on December 13, near the peak of the annual Geminid meteor shower. As our fair planet makes its yearly pass through the dust trail of mysterious asteroid 3200 Phaethon, the parallel tracks of all Geminid meteors appear to radiate from a point in the constellation Gemini. But the twin stars of Gemini hide just behind the trees on the left in this night skyscape from the beautiful Blue Moon Valley, Yunnan, China. Reflected in the still waters of the mountain lake, stars of the constellation Orion are rising near center. Captured before moonrise, dazzling Mars is still the brightest celestial beacon in the scene.
2022 December 15
Explanation: On December 8 a full Moon and a full Mars were close, both bright and opposite the Sun in planet Earth's sky. In fact Mars was occulted, passing behind the Moon when viewed from some locations across Europe and North America. Seen from the city of Kosice in eastern Slovakia, the lunar occultation of Mars happened just before sunrise. The tantalizing spectacle was recorded in this telescopic timelapse sequence of exposures. It took about an hour for the Red Planet to disappear behind the lunar disk and then reappear as a warm-hued full Moon, the last full Moon of 2022, sank toward the western horizon. The next lunar occultation of bright planet Mars will be in the new year on January 3, when the Moon is in a waxing gibbous phase. Lunar occultations are only ever visible from a fraction of the Earth's surface, though. The January 3 occultation of Mars will be visible from parts of the South Atlantic, southern Africa, and the Indian Ocean.
2022 December 14
Explanation: Why is the Moon so dusty? On Earth, rocks are weathered by wind and water, creating soil and sand. On the Moon, the history of constant micrometeorite bombardment has blasted away at the rocky surface creating a layer of powdery lunar soil or regolith. For the Apollo astronauts and their equipment, the pervasive, fine, gritty dust was definitely a problem. Fifty years ago, on the lunar surface in December 1972, Apollo 17 astronauts Harrison Schmitt and Eugene Cernan needed to repair one of their rover's fenders in an effort to keep the rooster tails of dust away from themselves and their gear. This picture reveals the wheel and fender of their dust covered rover along with the ingenious application of spare maps, clamps, and a grey strip of "duct tape".
2024 December 24 Fox Fur, Cone, and Christmas Tree Image Credit & Copyright: Tim White Explanation: What do the following things have...
