Wikipedia picture of the day on April 24, 2018: The Spring path at the island of Mainau during the tulip blooming. Wikipedia"
Monday, April 23, 2018
The Blue Horsehead Nebula looks quite different in infrared light. In visible light, the reflecting dust of the nebula appears blue and shaped like a horse's head. In infrared light, however, a complex labyrinth of filaments, caverns, and cocoons of glowing dust and gas emerges, making it hard to even identify the equine icon. The featured image of the nebula was created in three infrared colors (R=22, G=12, B=4.6 microns) from data taken by NASA's orbiting Wide Field Infrared Survey Explorer (WISE) spacecraft. The nebula is cataloged as IC 4592 and spans about 40 light years, lying about 400 light years away toward the constellation Scorpius along the plane of our Milky Way Galaxy. IC 4592 is fainter but covers an angularly greater region than the better known Horsehead Nebula of Orion. The star that predominantly illuminates and heats the dust is Nu Scorpii, visible as the yellow star left of center. via NASA
Sunday, April 22, 2018
Did you see it? One of the more common questions during a meteor shower occurs because the time it takes for a meteor to flash is typically less than the time it takes for a head to turn. Possibly, though, the glory of seeing bright meteors shoot across and knowing that they were once small granules on another world might make it all worthwhile, even if your observing partner(s) could not share in every particular experience. Peaking late tonight, a dark sky should enable the Lyrids meteor shower to exhibit as many as 20 visible meteors per hour from some locations. In the featured composite of nine exposures taken during the 2012 shower, a bright Lyrid meteor streaks above picturesque Crater Lake in Oregon, USA. Snow covers the foreground, while the majestic central band of our home galaxy arches well behind the serene lake. Other meteor showers this year -- and every year -- include the Perseids in mid-August and the Leonids in mid-November. via NASA
Saturday, April 21, 2018
Friday, April 20, 2018
Wikipedia picture of the day on April 21, 2018: A port security boat assigned to Martime Expeditionary Squadron (MSRON) 1 patrols the waters near Kuwait Naval Base. MSRON-1 is deployed supporting maritime security operations and port security operations in the U.S. 5th Fleet area of responsibility. Wikipedia"
Have you seen the Moon lately? On April 18, its waxing sunlit crescent moved through planet Earth's night across a background of stars in the Hyades. Anchored by bright star Aldebaran, the nearby, V-shaped star cluster and complete lunar orb appear in this telephoto image. The engaging skyview is actually digitally composed from a series of varying exposures. Recorded in 1/60th of a second, the shortest in the series captures the Moon's bright crescent in sharp detail. Longer exposures, ranging up to 15 seconds, capture fainter background stars as well as earthshine, visible to the eye as the earthlit lunar night side. via NASA
Tuesday, April 17, 2018
Except for the rings of Saturn, the Ring Nebula (M57) is probably the most famous celestial band. Its classic appearance is understood to be due to our own perspective, though. The recent mapping of the expanding nebula's 3-D structure, based in part on this clear Hubble image,indicates that the nebula is a relatively dense, donut-like ring wrapped around the middle of a (American) football-shaped cloud of glowing gas. The view from planet Earth looks down the long axis of the football, face-on to the ring. Of course, in this well-studied example of a planetary nebula, the glowing material does not come from planets. Instead, the gaseous shroud represents outer layers expelled from the dying, once sun-like star, now a tiny pinprick of light seen at the nebula's center. Intense ultraviolet light from the hot central star ionizes atoms in the gas. The Ring Nebula is about one light-year across and 2,000 light-years away. via NASA
Monday, April 16, 2018
Wikipedia picture of the day on April 17, 2018: View of the Castle of Zafra, Campillo de Dueñas, Guadalajara, Spain. The castle was built in the late 12th or early 13th centuries on a sandstone outcrop and stands on the site of a former Visigothic and Moorish fortification that fell into Christian hands in 1129. It had considerable strategic importance as a virtually impregnable defensive work on the border between Christian and Muslim-ruled territory. The castle was never conquered and was successfully defended against the King of Castile in the 13th century. The successful completion of the Reconquista at the end of the 15th century ended its military significance. Wikipedia"
What would it look like to fly over the North Pole of Jupiter? A fictional animation made from real images and data captured by NASA's Juno spacecraft shows an answer. Since the pole is presently in shadow, the video uses infrared light emitted by Jupiter -- specifically an infrared color where the hottest features glows the brightest. As the animation starts, Juno zooms in on the enormous world. Soon, one of the eight cyclones orbiting the North Pole is featured. One by one, all eight cyclones circling the pole are inspected, each the size of an entire continent on Earth, and each containing bumpy and fragmented spiral walls. The virtual trip ends with a zoom out. Studying Jovian cyclones helps humanity to better understand dangerous storm systems that occur here on Earth. Juno has recently concluded another close pass by Jupiter -- Perijove 12 -- and seems healthy enough to complete several more of the two-month orbits. via NASA
Sunday, April 15, 2018
Wikipedia picture of the day on April 16, 2018: A MK-46 exercise torpedo is launched from the deck of Arleigh Burke-class guided-missile destroyer USS Mustin (DDG 89) during a torpedo launch exercise in Philippine Sea. Wikipedia"