Posts

Showing posts with the label December 20

APOD:

Image
What's causing those unusual sky arcs? Ice crystals. While crossing a field of fresh snow near Füssen, Bavaria, Germany, earlier this month, the photographer noticed that he had entered an ice fog. For suspended water to freeze into an ice fog requires quite cold temperatures, and indeed the air temperature on this day was measured at well below zero. The ice fog reflected light from the Sun setting behind St. Coleman Church. The result was one of the greatest spectacles the photographer has ever seen. First, the spots in the featured picture are not background stars but suspended ice and snow. Next, two prominent ice halos are visible: the 22-degree halo and the 46-degree halo. Multiple arcs are also visible, including, from top to bottom, antisolar (subsun), circumzenithal, Parry, tangent, and parhelic (horizontal). Finally, the balloon shaped curve connecting the top arc to the Sun is the rarest of all: it is the heliac arc, created by reflection from the sides of hexagonally ...
Read more

APOD: Thors Helmet

Image
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. via NASA https://ift.tt/TUy5v6S
Read more

APOD: The Comet and the Fireball

Image
This picture was supposed to feature a comet. Specifically, a series of images of the brightest comet of 2021 were being captured: Comet Leonard. But the universe had other plans. Within a fraction of a second, a meteor so bright it could be called a fireball streaked through just below the comet. And the meteor's flash was even more green than the comet's coma. The cause of the meteor's green was likely magnesium evaporating from the meteor's pebble-sized core, while the cause of the comet's green was likely diatomic carbon recently ejected from the comet's city-sized nucleus. The images were taken 10 days ago over the Sacramento River and Mt. Lassen in California, USA. The fireball was on the leading edge of this year's Geminid Meteor Shower -- which peaked a few days later. Comet Leonard is now fading after reaching naked-eye visibility last week -- but now is moving into southern skies. via NASA https://ift.tt/3pajwg0
Read more

Popular posts from this blog

APOD: Spiral Galaxy NGC 2841

Image
A mere 46 million light-years distant, spiral galaxy NGC 2841 can be found in planet Earth's night sky toward the northern constellation of Ursa Major. This sharp image centered on the gorgeous island universe also captures spiky foreground Milky Way stars and more distant background galaxies within the same telescopic field of view. It shows off the bright nucleus of NGC 2841, along with its inclined galactic disk, and faint outer regions. Dust lanes, small star-forming regions, and young star clusters are embedded in the galaxy's patchy, tightly wound spiral arms. In contrast, many other spirals exhibit broader, sweeping arms with large star-forming regions. NGC 2841 has a diameter of over 150,000 light-years, making it even larger than our own Milky Way. X-ray images suggest that extreme outflows from giant stars and stellar explosions create plumes of hot gas extending into a halo around NGC 2841. via NASA https://ift.tt/HDshMQ9
Read more

Space News: ESA awards €10.45 million to two UK launch startups

Image
by Andrew Parsonson VALLETTA, Malta — The European Space Agency awarded UK-based launch startups Orbex and Skyrora a combined €10.45 million ($12.35 million) to support development of competing microlaunchers. The two support contracts announced March 24 were awarded under Boost!, an ESA program that aims to foster new commercial space transportation services. The agency adopted Boost! during Space19+, an ESA ministerial-level council meeting held in November 2019, and announced an open call for proposals last April. Each of the two new Boost! contracts outlines specific outcomes the funding will assist the companies in achieving. Orbital Launch Express (Orbex) is developing its two-stage Prime microlauncher which is powered by 3D-printed rocket engines and is designed to carry payloads of up 150 kilograms to low Earth orbit. The vehicle is expected to make its debut in 2022. The €7.45 million in co-funding Orbex and its partners received is the largest Boost! award to date. The...
Read more

APOD:

Image
Most photographs don't adequately portray the magnificence of the Sun's corona. Seeing the corona first-hand during a total solar eclipse is unparalleled. The human eye can adapt to see coronal features and extent that average cameras usually cannot. Welcome, however, to the digital age. The featured image digitally combined short and long exposures taken in Exmouth, Australia that were processed to highlight faint and extended features in the corona during the total solar eclipse that occurred in April of 2023. Clearly visible are intricate layers and glowing caustics of an ever changing mixture of hot gas and magnetic fields in the Sun's corona. Looping prominences appear bright pink just past the Sun's edge. Images taken seconds before and after the total eclipse show glimpses of the background Sun known as Baily's Beads and diamond ring effect. The next total solar eclipse will cross North America in April of 2024. via NASA https://ift.tt/ibLzpTC
Read more