magnetoreception

Light knocks electrons out of a crystal, and they fly toward the detector like arrows toward a target. From their trajectories, physicists reconstruct how electrons behaved inside the material: with what energy and in which direction they moved. But switch on a magnetic field, and the trajectories bend. The arrows start to curve, the target turns into a warped mirror, and the picture blurs.

In a binary star system, a white dwarf acts like a vacuum cleaner, pulling gas from its companion star. If the dwarf has a magnetic field, the gas does not fall anywhere but flows toward the poles, like iron filings to a magnet. There it accumulates into a pile. But what keeps this pile from spreading out?

Ion current through a membrane is like a queue at a turnstile. Sometimes the turnstile is free — ions pass through quickly. Sometimes it gets stuck — the flow drops. A weak magnetic field, it turns out, doesn't push ions from behind; it simply changes the number of open turnstiles.

The magnetic field increases, but the magnetization stays put. It's like a scale where you add weight, yet the needle doesn't move until enough has accumulated to jump to the next mark. That's exactly how rare-earth tetraboride crystals behave, and physicists have been puzzled for decades.

A cell crawls over a gel (sometimes viscous, sometimes elastic) and decides on its own when to speed up. It doesn't just glide: its internal chemical motor (noise in gene expression can affect the production of 'fuel') pushes the leading edge, while the rear detaches from the substrate.

A piece of magnetite, an ordinary iron stone, behaves strangely. At room temperature, it conducts electricity, but cool it below minus 150 degrees, and its resistance jumps sharply. This jump, discovered back in 1939, physicists could not explain for nearly a century. A new study offers a solution.

Eight red giants — bloated old stars like the future Sun — are not behaving by the book. Their surfaces oscillate steadily, like a bell, but within this chime there are glitches: some tones are missing, and the rhythm breaks. Scientists suspected an invisible hand inside — a magnetic field — and tried to calculate its strength.

To avoid losing a fast soccer player in the frame, a drone doesn't need a bright beacon — recognizing the silhouette is enough. Similarly, a neural network now tracks microbes: the algorithm analyzes an ordinary microscope image and instantly finds a bacterium in a drop of water.

The crystal CeB6 is like a box with a secret: inside it, electrons can occupy four nearly identical positions, like four chairs around a table. While no one is watching, the electron seems to sit on all four at once. Physicists call this hidden state quadrupolar, and it affects magnetic properties, but it is hard to see directly.

The tiny green alga Chlamydomonas spends its life rowing with two flagella toward light, like a swimmer heading for shore. It senses light with a photoreceptor protein, and behind it lies a red spot — the 'eyespot'—which casts a shadow and helps the cell figure out where the light is coming from.

A pigeon flies home from hundreds of kilometers away. Inside its head, in the inner ear, fluid sloshes around, like water in a bottle you shake. When the bird moves, the fluid moves too, helping it maintain balance. Recently, scientists proposed that this same fluid might act as a tiny generator.

A hawk soars over a field, its wings tracing an intricate dance. Each flap, each tilt is not random but a combination of simple motions that can be broken down into components. Collective behavior in the air may seem intuitive, but behind it lies strict mechanics. Scientists recorded the hawks' movements using cameras that track the position of every point on the wing and tail.

A stag beetle the size of a fingernail stands on the ground with its legs spread wider than its own height. An elephant as tall as a room, on the other hand, towers above the ground like a tower. Why is that? Both animals walk on the same ground, but they see it differently. For a beetle, each pebble is a boulder, while for an elephant, it's a grain of sand.

In the mud at the bottom of a pond live bacteria that carry tiny magnetic compass needles inside them. These needles are chains of magnetite crystals that help the bacteria swim along Earth's magnetic field, like a compass needle, in search of better conditions.

Two stars orbit so closely that their outer layers merge into a shared envelope. Matter flows from one to the other, like water spilling from an overfull cup into its neighbor. In this cosmic dance, where stars literally touch each other, astronomers have for the first time detected magnetic fields in large numbers.

An ordinary magnetic compass freezes when lightning strikes nearby. A sudden jump in the magnetic field throws the needle off. A similar problem has been hindering scientists trying to measure magnetism in strong pulsed fields: those that switch on for a thousandth of a second. The new setup tackles this with a laser beam.

Plants employ an army of perfect couriers to deliver energy. Each photon of sunlight is absorbed, and its energy is instantly, with almost no loss, transferred to reaction centers where nutrient synthesis occurs.

Birds migrate using the magnetic field. In their eyes, there's a protein called cryptochrome. It captures sunlight, especially blue light, and triggers a reaction. Absorption of light leads to the formation of a particle pair that is acutely sensitive to magnetic fields.

On the night of March 9–10, 2024, a cloud of plasma ejected by the Sun raced away from the star. It had already passed a distance of five solar radii when a ground-based array of 352 antennas in California's Owens Valley caught a brief radio signal from it.