Galaxies are fascinating not only for what is visible, but for what is invisible. Grand spiral galaxy NGC 1232, captured in detail by one of the Very Large Telescopes, is a good example. The visible is dominated by millions of bright stars and dark dust, caught up in a gravitational swirl of spiral arms revolving about the center. Open clusters containing bright blue stars can be seen sprinkled along these spiral arms, while dark lanes of dense interstellar dust can be seen sprinkled between them. Less visible, but detectable, are billions of dim normal stars and vast tracts of interstellar gas, together wielding such high mass that they dominate the dynamics of the inner galaxy. Leading theories indicate that even greater amounts of matter are invisible, in a form we don’t yet know. This pervasive dark matter is postulated, in part, to explain the motions of the visible matter in the outer regions of galaxies. via NASA https://ift.tt/M5N0tp9

How did we get here? Click play, sit back, and watch. A computer simulation of the evolution of the universe provides insight into how galaxies formed and perspectives into humanity’s place in the universe. The Illustris project exhausted 20 million CPU hours in 2014 following 12 billion resolution elements spanning a cube 35 million light years on a side as it evolved over 13 billion years. The simulation tracks matter into the formation of a wide variety of galaxy types. As the virtual universe evolves, some of the matter expanding with the universe soon gravitationally condenses to form filaments, galaxies, and clusters of galaxies. The featured video takes the perspective of a virtual camera circling part of this changing universe, first showing the evolution of dark matter, then hydrogen gas coded by temperature (0:45), then heavy elements such as helium and carbon (1:30), and then back to dark matter (2:07). On the lower left the time since the Big Bang is listed, while on the lower right the type of matter being shown is listed. Explosions (0:50) depict galaxy-center supermassive black holes expelling bubbles of hot gas. Interesting discrepancies between Illustris and the real universe have been studied, including why the simulation produced an overabundance of old stars. via NASA https://ift.tt/ulrACqj

0:07 Intro 1:27 Robot Rock / 5:20 Oh Yeah 6:27 Touch It / 9:00 Technologic 11:56 Television Rules the Nation / 14:43 Crescendolls 16:47 Too Long / Steam Machine 23:49 Around the World / 25:50 Harder, Better, Faster, Stronger 29:31 Burnin’ / 33:32 Too Long 36:41 Face to Face / Short Circuit 41:38 One More Time / Aerodynamic 47:48 Aerodynamic Beats / Gabrielle , Forget About the World 51:20 Prime Time of Your Life / Brainwasher / Rollin’ & Scratchin’ /Alive 1:01:48 Da Funk / Daftendirekt 1:08:20 Superheroes / Human After All / Rock’n Roll Encore: 1:14:12 Human After All / 1:18:13 Together / 1:19:54 One More Time (Reprise) / 1:21:08 Music Sounds Better With You

Known to some in the northern hemisphere as December’s Cold Moon or the Long Night Moon, the last full moon of 2023 is rising in this surreal mountain and skyscape. The Daliesque scene was captured in a single exposure with a camera and long telephoto lens near Monte Grappa, Italy. The full moon is not melting, though. Its stretched and distorted appearance near the horizon is caused as refraction along the line of sight changes and creates shifting images or mirages of the bright lunar disk. The changes in atmospheric refraction correspond to atmospheric layers with sharply different temperatures and densities. Other effects of atmospheric refraction produced by the long sight-line to this full moon rising include the thin red rim seen faintly on the distorted lower edge of the Moon and a thin green rim along the top. via NASA https://ift.tt/WoqezFx

In 1986, Voyager 2 became the only spacecraft to explore ice giant planet Uranus close up. Still, this newly released image from the NIRCam (Near-Infrared Camera) on the James Webb Space Telescope offers a detailed look at the distant world. The tilted outer planet rotates on its axis once in about 17 hours. Its north pole is presently pointed near our line of sight, offering direct views of its northern hemisphere and a faint but extensive system of rings. Of the giant planet’s 27 known moons, 14 are annotated in the image. The brighter ones show hints of Webb’s characteristic diffraction spikes. And though these worlds of the outer Solar System were unknown in Shakespearean times, all but two of the 27 Uranian moons are named for characters in the English Bard’s plays. via NASA https://ift.tt/BJKb36E