FYFD

Author: Nicole Sharp

  • Our Best Look Yet at a Solar Flare

    Our Best Look Yet at a Solar Flare

    Scientists have unveiled the sharpest images ever captured of a solar flare. Taken by the Inouye Solar Telescope, the image includes coronal loop strands as small as 48 kilometers wide and 21 kilometers thick–the smallest ones ever imaged. The width of the overall image is about 4 Earth diameters. The captured flare belongs to the most powerful class of flares, the X class. Catching such a strong flare under the perfect observation conditions is a wonderful stroke of luck.

    Although astronomers had theorized that coronal loops included this fine-scale structure, the Inouye Solar Telescope is the first instrument with the resolution to directly observe structures of this size. Confirming their existence is a big step forward for those working to understand the details of our Sun. (Video and image credit: NSF/NSO/AURA; research credit: C. Tamburri et al.; via Gizmodo)

  • Buccaneer Archipelago

    Buccaneer Archipelago

    Off western Australian, hundreds of low-lying islands and coral reefs jut into the ocean as part of the Buccaneer Archipelago. Tides here have a range of nearly 12 meters, so water rips through the narrow channels as the tide ebbs and flows. These fast flows lift sediment that dyes the water a bright turquoise. (Image credit: M. Garrison; via NASA Earth Observatory)

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  • Salt and Sea Ice Aging

    Salt and Sea Ice Aging

    Sea ice’s high reflectivity allows it to bounce solar rays away rather than absorb them, but melting ice exposes open waters, which are better at absorbing heat and thus lead to even more melting. To understand how changing sea ice affects climate, researchers need to tease out the mechanisms that affect sea ice over its lifetime. A new study does just that, showing that sea ice loses salt as it ages, in a process that makes it less porous.

    Researchers built a tank that mimicked sea ice by holding one wall at a temperature below freezing and the opposite wall at a constant, above-freezing temperature. Over the first three days, ice formed rapidly on the cold wall. But it did not simply sit there, once formed. Instead, the researchers noticed the ice changing shape while maintaining the same average thickness. The ice got more transparent over time, too, indicating that it was losing its pores.

    Looking closer, the team realized that the aging ice was slowly losing its salt. As the water froze, it pushed salt into liquid-filled pores in the ice. One wall of the pore was always colder than the others, causing ice to continue freezing there, while the opposite wall melted. Over time, this meant that every pore slowly migrated toward the warm side of the ice. Once the pore reached the surface, the briny liquid inside was released into the water and the ice left behind had one fewer pores. Repeated over and over, the ice eventually lost all its pores. (Image credit: T. Haaja; research credit and illustration: Y. Du et al.; via APS)

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    Why Most Wind Turbines Are 3-Bladed

    Although wind turbines can have any number of blades, most that we see have three. The reasons for that are many, as explained in this Minute Physics video. In terms of physics, wind turbines with more blades produce more torque, but they pay for it with more drag. Engineering-wise, wind turbines with odd numbers of blades have less uneven forces on them, and, thus, cost less. And, finally, people just prefer the look and sound of 3-bladed wind turbines over other forms! (Video and image credit: Minute Physics)

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  • “Orion, the Horsehead and the Flame in H-alpha”

    “Orion, the Horsehead and the Flame in H-alpha”

    Photographer Daniele Borsari captured this gorgeous composite image of nebulas in black and white, emphasizing the motion underlying the gas and dust. In the upper right, the Orion Nebula shines, bright with new stars. In the lower left, you can pick out the distinctive shape of the Horsehead Nebula and, further to the left, the Flame Nebula. We often see nebulas in bright colors, but I love the way black and white highlights the turbulence surrounding them. (Image credit: D. Borsari/ZWOAPOTY; via Colossal)

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  • Kirigami Parachutes

    Kirigami Parachutes

    In kirigami, careful cuts to a flat surface can morph it into a more complicated shape. Researchers have been exploring how to use this in combination with flow; now they’ve created a new form of parachute. Like a dandelion seed, this parachute is porous, with a complex but stable wake structure. This allows the parachute to drop directly over its target, unlike conventional parachutes, which require a glide angle to avoid canopy-collapsing turbulence.

    When dropping conventional parachutes, users either have to tolerate random landings far off target or invest in complicated active control systems that guide the parachute. Kirigami parachutes, in contrast, offer a potentially simple and robust option for accurately delivering, for example, humanitarian aid. (Image and research credit: D. Lamoureux et al.; via Physics World)

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  • Circulation in a Capillary Network

    Circulation in a Capillary Network

    Today’s video shows red blood cells flowing through a capillary network in a rat’s skeletal muscle. At this resolution, our eyes can follow the paths of individual red blood cells squeezing through each capillary, as well as the faster blur of thicker capillaries where many cells can pass at once. Watching videos like this is a great way to build intuition for particle image velocimetry, streaklines, and other flow visualization methods as our brains can readily recognize where the cells are moving fast and where they are slower. (Video and image credit: Dr. G. McEvoy et al.; via Colossal)

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  • Geoengineering Trials Must Consider Unintended Costs

    Geoengineering Trials Must Consider Unintended Costs

    As the implications of climate change grow more dire, interest in geoengineering–trying to technologically counter or mitigate climate change–grows. For example, some have suggested that barriers near tidewater glaciers could restrict the inflow of warmer water, potentially slowing the rate at which a glacier melts. But there are several problems with such plans, as researchers point out.

    Firstly, there’s the technical feasibility: could we even build such barriers? In many cases, geoengineering concepts are beyond our current technology levels. Burying rocks to increase a natural sill across a fjord might be feasible, but it’s unclear whether this would actually slow melting, in part because our knowledge of melt physics is woefully lacking.

    But unintended consequences may be the biggest problem with these schemes. Researchers used existing observations and models of Greenland’s Ilulissat Icefjord, where a natural sill already restricts inflow and outflow from the fjord, to study downstream implications. Right now, the fjord’s discharge pulls nutrients from the deep Atlantic up to the surface, where a thriving fish population supports one of the country’s largest inshore fisheries. As the researchers point out, restricting the fjord’s discharge would almost certainly hurt the fishing industry, at little to no benefit in stopping sea level rise.

    Because our environment and society are so complex and interconnected, it’s critical that scientists and policymakers carefully consider the potential impacts of any geoengineering project–even a relatively localized one. (Research and image credit: M. Hopwood et al.; via Eos)

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    Protecting Wildlife from Underwater Construction

    The loud noises of construction are not just an issue for humans. Sound and pressure waves from underwater construction are a problem for water-dwellers, too. So engineers use bubble curtains around a construction site to help reduce the amount of sound that escapes. Water and air transmit sound very differently; in acoustic terms, they have very different impedance. You’ve probably experienced this yourself if you’ve ever compared the sounds of a swimming pool above and below the surface. Because some of a sound’s intensity gets lost in the water –> air –> water transition, a bubble curtain can halve the sound pressure transmitted from equipment. (Video and image credit: Practical Engineering)

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    Cornflower Roots Growing

    As children, most of us plant a seed or two and watch it sprout, but we never get a view quite like this one. This microscopic timelapse shows the roots of a cornflower plant extending into moist, porous soil, establishing xylem, and extending root hairs outward to collect water and nutrients to fuel further growth. At the end, there’s even a close-up view of flow inside the root hairs. What an incredible glimpse inside a world we so often take for granted! (Video and image credit: W. van Egmond; via Colossal)

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