FYFD

Tag: physics

  • Dance of the Coral Polyps

    Dance of the Coral Polyps

    Coral reefs are made of up small organisms, called coral polyps, that live together in a colony. Individual polyps can expand, contract, and wave in the flow around them, and, in a recent study, researchers looked at whether changing conditions in temperature and light wavelength can affect polyp movement. To do so, they built a little flow control tank around a coral nubbin containing several polyps.

    Under normal light and temperature conditions, they found the polyps’ motions are correlated. (Scientists don’t know why this is the case, but it could help with foraging or photosynthesis for the organisms.) When temperatures rise and light levels shift to bluer wavelengths — simulating warmer and rising oceans — the polyps lose their coordination. Without knowing the purpose behind the motion, scientists can’t yet say what that lack of coordination means, but the team believes their experimental methods can be adapted to help answer those questions, perhaps even in natural, rather than lab-created, circumstances. (Image credit: S. Ravaloniaina; research credit: S. Li et al.; via APS Physics)

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    Backswimmers

    Backswimmers rule the surface of ponds, streams, and other bodies of water. These insects spend much of their time clinging just beneath the air-water interface, where they hunt larvae and other insects. They use oversized, oar-shaped back legs to row, and they breathe using an air bubble that clings to their abdomen like a personal scuba tank. Oxygen from the water diffuses into the bubble, keeping the insect’s air supply fresh. When the time comes to move to greener pastures, they flip to the other side of the water’s surface, unfurl their wings, and take off. (Image and video credit: Deep Look)

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    “Haut”

    In Susi Sie’s “Haut” the camera seems to fly over ever-shifting landscapes. In reality, these are macro images, created (I think) by dyes and patterns atop a water bath. But they look like vistas we could find on Earth or Mars — giant dune fields, calving glaciers, and river-divided canyons. For something similar in color, check out Roman De Giuli’s “Geodaehan.” (Video credit: S. Sie)

  • Optimizing Wind Farms Collectively

    Optimizing Wind Farms Collectively

    In a typical wind farm, each wind turbine aligns itself to the local wind direction. In an ideal world where every turbine was completely independent, this would maximize the power produced. But with changing wind directions and many turbines, it’s inevitable that upstream wind turbines will interfere with the flow their downstream neighbors see.

    So, instead, a research team investigated how to optimize the collective output of a wind farm. Their strategy involved intentionally misaligning the upstream wind turbines to improve conditions for downstream turbines. They found that the loss in power generation by upstream turbines could be more than recovered by improved performance downstream.

    After testing their models over many months in an actual wind farm, they reported that their methodology could, on average, increase overall energy output by about 1.2 percent. That may sound small, but the team estimates that if existing wind farms used the method, it would generate additional power equivalent to the needs of 3 million U.S. households. (Image credit: N. Doherty; research credit: M. Howland et al.; via Boston Globe; submitted by Larry S.)

  • Cloud Streets

    Cloud Streets

    Parallel lines of cumulus clouds stream over the Labrador Sea in this satellite image. These cloud streets are formed when cold, dry winds blow across comparatively warm waters. As the air warms and moistens over the open water, it rises until it hits a temperature inversion, which forces it to roll to the side, forming parallel cylinders of rotating air. On the rising side of the cylinder, clouds form while skies remain clear where the air is sinking. The result are these long, parallel cloud bands. (Image credit: J. Stevens; via NASA Earth Observatory)

  • Predicting Alien Ice

    Predicting Alien Ice

    Europa is an ocean world trapped beneath an ice shell tens of kilometers thick. To better understand what we might find in those oceans, researchers turn to analogs here on Earth, looking at Antarctica’s ice shelves. Beneath those shelves, ice forms via two mechanisms: the first, congelation ice, freezes directly onto the existing ice-water interface. The second, frazil ice, forms crystals in supercooled water columns, which drift upward in buoyant currents and settle on the ice shelf like upside-down snow (pictured above).

    Based on Europa’s conditions, the researchers conclude that congelation ice would gradually thicken the ice shell as the moon’s interior cools. But in areas where the shell is thinned by local rifts and Jovian tidal forces, frazil ice is likely to form. (Image credit: H. Glazer; research credit: N. Wolfenbarger et al.; via Physics World)

  • Diving Together

    Diving Together

    Two spheres dropped into water next to one another form asymmetric cavities. A single ball’s cavity is perfectly symmetric, and so are two spheres’, provided they are far enough apart. But for close impacts, the spheres influence one another, creating a mirror image. The same asymmetric cavity also forms when a sphere is dropped near a wall. In fluid dynamics, this trick — using two mirrored objects in place of a wall — is used to make calculating certain flows easier! (Image credit: A. Kiyama et al.)

  • Jupiter in Infrared

    Jupiter in Infrared

    These recent composite images from the James Webb Space Telescope show Jupiter in stunning infrared detail. They’re the result of several images taken in different infrared bands, then combined and rendered in visible light. In general, the redder colors show longer wavelengths and the bluer ones show shorter wavelengths.

    Jupiter’s cloud bands appear in beautiful detail. The Great Red Spot looks white in infrared. And the planet’s polar auroras shine bright in both images. The wide-angle shot additionally shows two of Jupiter’s moons and the planet’s rings, which are a million times fainter than the planet itself. If you look carefully, you may also see faint points of light in the lower half of the image. These are likely distant galaxies “photobombing” Jupiter’s close-up. (Image credit: NASA/ESA/Jupiter ERS Team 1, 2; via Colossal)

    This composite image of Jupiter was taken in infrared bands and rendered into visible light. In general, the redder colors represent longer wavelengths and bluer ones shorter wavelengths.
    This composite image of Jupiter was taken in infrared bands and rendered into visible light. In general, the redder colors represent longer wavelengths and bluer ones shorter wavelengths.
  • Finger Painting Physics

    Finger Painting Physics

    Spreading paint with a brush or with fingers is familiar activity for most people. It’s also similar to processes used in industry for spreading thin layers of paint and other complex fluids. In a recent study, researchers took a look at how a soft, elastic blade (similar to a paintbrush or one’s fingers) spreads shear-thinning fluids (like paint) and Newtonian fluids (like water). Surprisingly, they found that it actually takes 30% more mechanical work to spread a shear-thinning fluid than the same volume of an equivalent Newtonian one. That’s pretty much the opposite of what we’d expect since the action of spreading (and shearing) the complex fluid should reduce its viscosity. However, they did find that the shear-thinning fluid spreads to a thin layer more consistently than the Newtonian fluid does. (Image credit: A. Kolosyuk; research credit: M. Krapez et al.)

  • Blooms in the Black Sea

    Blooms in the Black Sea

    The Black Sea gains its name from its dark waters, but those waters don’t stay dark year-round. In this natural color satellite image, streaks of milky blue bloom through the summer waters, thanks to the presence of a species of phytoplankton armored with white calcium carbonate. Despite their microscopic size, the phytoplankton’s presence is visible from space. During other parts of the year, like the spring, another species of phytoplankton dominates the Black Sea, turning its waters darker. (Image credit: J. Stevens; via NASA Earth Observatory)