Threads in the Flow: How Noise Creates Order and Chaos express
A thin thread in a water flow is like a hair in a shower stream. If you jerk the water back and forth, the hair either stretches out with the flow or crumples up. The researchers took real protein threads (actin, which makes up muscles) and placed them in a microscopic channel where the fluid oscillated at different frequencies.
At fast oscillations, the thread obediently returned to its original position after each cycle, like a pendulum. But when the oscillations slowed down, everything changed. The thread began to 'get stuck' in one of two states: either stretched out or crumpled. Both states were stable, and the thread could suddenly jump from one to the other due to thermal noise — random kicks from water molecules.
This discovery is like a coin that can land heads or tails, but sometimes flips over on its own. For engineers, it's a way to control soft materials: by changing the oscillation frequency, you can make threads align or, conversely, tumble chaotically.
Actin filaments are part of the cell's cytoskeleton. They are so thin that about one hundred thousand of them laid side by side would fit in a single millimeter.