Despite their microscopic size, many plankton undertake a daily migration that covers tens of meters in depth. As they journey, they must contend with currents, turbulence, and other flows that could knock them off-course. (Image credit: Picturepest/Flickr; research credit: R. Bearon and W. Durham)

Our Sun's visible surface, the photosphere, is about 5800 Kelvin, but the temperature of the wispy corona is far hotter, reaching a million Kelvin in some places. Why the corona is so hot remains something of a mystery. (Image credit: ISAS/JAXA; see also L. Sigalotti and F. Cruz)

Fog blankets the forest of the Blue Ridge Mountains in this photo by Tihomir Trichkov. (Image credit: T. Trichkov; via Gizmodo)

The United States, Europe, and Russia have all seen deadly, record-breaking heat waves in recent years, largely in areas that are ill-equipped for sustained high temperatures. A new paper presents a theory that predicts how hot these heat waves can get and what mechanism ultimately breaks the hot streak. (Image credit: T. Baginski; research credit: Y. Zhang and W. Boos; via APS Physics)

Even adding a small amount of polymers to a fluid can drastically change its behavior. Often polymer-doped fluids act more like soft solids, able to hold their shape like your toothpaste does when squeezed onto your toothpaste. (Video credit: C. Galvin et al.)

Few volcanoes are as well-studied as those of the Big Island of Hawai'i. With a host of seismic monitors and frequent eruptions, scientists know the near-surface region of Hawai'i well. But a recent study looked at nearly 200,000 seismic events after the 2018 collapse of Kilauea's crater and found hints of what goes on much deeper. (Image credit: top - USGS, illustration - J. Wilding et al.; research credit: J. Wilding et al.; via Physics Today)

Blooms of the algae Karenia brevis -- known as a red tide -- bring havoc to Gulf Coast shores. The algae can kill fish and other marine life, and it causes skin irritation and even respiratory problems for humans. But in spite of the moniker, these algae can be hard to spot; they can add a green, brown, red, or black hue to the water. (Image credit: Y. Yao/USF/Planet Labs/L. Dauphin; via NASA Earth Observatory)

Seals and sea lions often hunt fish in waters too dark or turbid to rely on eyesight. Instead, they follow their whiskers, using the turbulence generated by a fish's wake. (Image credit: seal - K. Luke, illustration - P. Gong et al.; research credit: P. Gong et al.; via APS Physics)

Inspired by a simulation, Steve Mould asks a great question in this video: can water solve a maze? Yes -- with some caveats. (Video and image credit: S. Mould)

Drying fluids can leave behind all kinds of fascinating patterns, as we've seen before with whiskey, coffee, and even blood. Here researchers study patterns left behind by lipids, dyes, and other fluids. (Image credit: M. Murali and L. Shen)

Frogs and toads shoot out their tongues to capture and envelop their prey in a fraction of a second. They owe their success in this area to two features: the squishiness of their tongues and the stickiness of their saliva. (Video credit: Deep Look/KQED; research credit: A. Noel et al.)

Without surfactants to stabilize them, bubbles don't last long at room temperature. But adding a little heat changes the picture. (Video credit: S. Nath et al.; see also)

Tomorrow mathematician Luis Caffarelli will receive the Abel Prize -- one of the highest honors in mathematics -- in part for his work in fluid dynamics. (Image credit: N. Zunk/University of Texas at Austin; via Nature; submitted by Kam-Yung Soh)

Built from approximately 90,000 individual images, "Fusion of Helios" reveals the wisp-like corona of our Sun. (Image credit: A. McCarthy and J. Guenzel; via Colossal)

When bubbles burst, they release smaller droplets from the jet that rebounds upward. Depending on their size, these droplets can fall back down or get lofted upward on air currents that spread them far and wide. (Image credit: top - J. Graj, bursting - Z. Yang et al.; research credit: Z. Yang et al.; submitted by Jie F.)