oscillation mode

A laser pulse slams into a gas cloud and knocks electrons out of it, leaving behind a bubble: a cavity almost devoid of particles. This bubble races through the plasma at nearly the speed of light, and its walls drag along the electrons trapped inside, much like a speedboat tows a water skier.

A regular laser beam travels straight, like the light from a flashlight. But light can be twisted into a spiral, like the thread of a corkscrew. Such a beam carries orbital angular momentum: it doesn't just illuminate, it also spins anything it encounters.

Imagine a string stretched between two tuning pegs. The slightest touch makes it vibrate, and from the pitch you can guess exactly how it was plucked. Physicists at the University of Arizona have stretched a similar string — not on a musical instrument, but on a silicon membrane just a hundred nanometers thick.

After a supernova explosion, a dense ball the size of a city remains at the center — a newborn neutron star. It is hot, compressed, and rings like a bell after being struck. These tremors, the star's oscillations, emit gravitational ripples that sensitive detectors on Earth can catch.

The universe rang piercingly in its first moments. During the inflation epoch, when space expanded faster than light, energies were monstrous — trillions of times higher than in the Large Hadron Collider.

A lone fold runs across a taut sheet — a sharp drop in height that doesn't spread out but moves as a whole. Physicists call such a fold a 'kink'. If you give the sheet a sharp tug in one spot, ripples will travel across it. But in some media, these ripples don't disperse; instead, they gather into a clump and tremble in place for dozens or hundreds of cycles. Such a clump is an oscillon.

Even Jocelyn Bell Burnell, who first detected the strict periodicity of radio signals, noticed that some pulses would suddenly vanish. Today we know: variability is not a whim, but the voice of intricate electrodynamics.

A crowd is trapped in a narrow corridor between two rows of mirrors. Every now and then, someone shoves the wall hard, and a rumble rolls down the corridor — similarly, in the plasma of galaxy clusters, whistler waves and ion-cyclotron waves appear.

A small ball with an iron core lies on a surface while a magnetic field spins around it. The ball starts rolling like a wheel and usually goes in the direction the field rotates. But sometimes it suddenly turns around and rolls the other way — against the field.

A tiny diamond bridge vibrates so strongly that it starts to 'sing' at many frequencies at once. Previously, such vibrations would dampen themselves: the harder the resonator swung, the harder it was to add energy. Physicists found a loophole in this rule. They used light to drive the diamond. Light pushes on the bridge, making it tremble.

If you toss a stone into a pond, ripples spread across the water. Tiny magnetic crystals also host waves — except it's not water that oscillates but the direction of magnetization. These are called spin waves. They travel through the crystal like ripples on a surface and can carry information.

A blazar is a distant galaxy with a plasma jet shooting from its center, aimed almost directly at us. Inside this jet, particles are accelerated to near-light speeds and emit powerful radiation.