This piece renders with WebGL, which your browser has switched off. What you would see: a pool of black ferrofluid erupting into sharp spikes wherever your pointer moves.
Kinetic study nº 3 — ferrofluid, simulated
One fluid · one field · one visitor
A magnet never touches ferrofluid. It only insists — and a liquid armoured in nanometre iron stands up in spikes to agree. Move your pointer: tonight, you are the magnet. Press and hold, and the fluid will leap for you.
Move — steer · click — pulse · hold — overcharge
Everything the piece evokes is real. Here is where the simulation ends and the laboratory begins.
Ferrofluid was invented in 1963 by NASA engineer Steve Papell, who needed a way to pump rocket fuel in zero gravity: grind magnetite into nanometre-scale grains, coat each grain so it cannot clump, suspend the lot in oil — and the fuel itself becomes something a magnet can pull.
The hedgehog peaks are the Rosensweig instability, also called the normal-field instability. When the magnetic pull on the fluid's surface beats gravity and surface tension, a flat pool becomes an array of sharp spikes that trace the field lines — and their spacing is set by exactly that balance of forces.
Bring a strong magnet close enough above the pool and ferrofluid leaps the gap: the tallest spike stretches, necks, and lets go — droplets fly to the magnet and cling to its pole for as long as the field holds them. Take the magnet away and they fall home, merging back into the pool without a seam. Press and hold to stage it.
You are watching a real-time simulation, not a magnetics solver: a signed-distance heightfield, raymarched in a fragment shader — a black pool that stands up in dense concentric rings of sharp spikes around your pointer, crowned by one tallest central needle, following you the way ferrofluid follows a magnet; and whose droplets, when you overcharge it, are spheres blended into the same distance field. It is shaped to evoke the physics — honestly, not to compute it.
Why “Magnetar”? A magnetar is a neutron star with the strongest magnetic field known in the universe — a good name for the magnet this fluid dreams about.