Month: October 2021

Dark Matter in a Simulated Universe

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Is our universe haunted? It might look that way on this dark matter map. The gravity of unseen dark matter is the leading explanation for why galaxies rotate so fast, why galaxies orbit clusters so fast, why gravitational lenses so strongly deflect light, and why visible matter is distributed as it is both in the local universe and on the cosmic microwave background. The featured image from the American Museum of Natural History’s Hayden Planetarium Space Show Dark Universe highlights one example of how pervasive dark matter might haunt our universe. In this frame from a detailed computer simulation, complex filaments of dark matter, shown in black, are strewn about the universe like spider webs, while the relatively rare clumps of familiar baryonic matter are colored orange. These simulations are good statistical matches to astronomical observations. In what is perhaps a scarier turn of events, dark matter — although quite strange and in an unknown form — is no longer thought to be the strangest source of gravity in the universe. That honor now falls to dark energy, a more uniform source of repulsive gravity that seems to now dominate the expansion of the entire universe. via NASA https://ift.tt/2ZNKLmF

A Rorschach Aurora

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If you see this as a monster’s face, don’t panic. It’s only pareidolia, often experienced as the tendency to see faces in patterns of light and shadow. In fact, the startling visual scene is actually a 180 degree panorama of Northern Lights, digitally mirrored like inkblots on a folded piece of paper. Frames used to construct it were captured on a September night from the middle of a waterfall-crossing suspension bridge in Jamtland, Sweden. With geomagnetic storms triggered by recent solar activity, auroral displays could be very active at planet Earth’s high latitudes in the coming days. But if you see a monster’s face in your own neighborhood tomorrow night, it might just be Halloween. via NASA https://ift.tt/3bvoA6V

Haunting the Cepheus Flare

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Spooky shapes seem to haunt this dusty expanse, drifting through the night in the royal constellation Cepheus. Of course, the shapes are cosmic dust clouds visible in dimly reflected starlight. Far from your own neighborhood, they lurk above the plane of the Milky Way at the edge of the Cepheus Flare molecular cloud complex some 1,200 light-years away. Over 2 light-years across and brighter than most of the other ghostly apparitions, vdB 141 or Sh2-136 is also known as the Ghost Nebula, seen at the right of the starry field of view. Inside the nebula are the telltale signs of dense cores collapsing in the early stages of star formation. With the eerie hue of dust reflecting bluish light from hot young stars of NGC 7023, the Iris Nebula stands out against the dark just left of center. In the broad telescopic frame, these fertile interstellar dust fields stretch almost seven full moons across the sky. via NASA https://ift.tt/31dQlPN

Mirach s Ghost

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As far as ghosts go, Mirach’s Ghost isn’t really that scary. Mirach’s Ghost is just a faint, fuzzy galaxy, well known to astronomers, that happens to be seen nearly along the line-of-sight to Mirach, a bright star. Centered in this star field, Mirach is also called Beta Andromedae. About 200 light-years distant, Mirach is a red giant star, cooler than the Sun but much larger and so intrinsically much brighter than our parent star. In most telescopic views, glare and diffraction spikes tend to hide things that lie near Mirach and make the faint, fuzzy galaxy look like a ghostly internal reflection of the almost overwhelming starlight. Still, appearing in this sharp image just above and to the right of Mirach, Mirach’s Ghost is cataloged as galaxy NGC 404 and is estimated to be some 10 million light-years away. via NASA https://ift.tt/3GwBSyi