Magnetic rings make ball stable

Atoms align in one direction

1 An extremely thin gas of about 200,000 atoms is cooled close to absolute zero, -273.15 degrees, producing a Bose-Einstein condensate, in which almost all atoms are in the lowest possible energy state. Scientists align the spin of the individual atoms – a special property of the quantum world – with a magnetic field.

Rings get tangled up

2 The scientists alter the magnetic field, making the atoms' spin rotate and producing rings. The spin direction of an atom points at another atom, which points at another one, etc., until an atom's spin direction points back at the first atom: a ring has been completed. The rings are stable and make up circular, electromagnetic fields.

Magnetic rings are twisted

3 The condensate is filled with rings, which have become entangled. The process produces a knot of electromagnetic rings, which is twisted, as the spin directions are still rotating. The knot maintains an overall magnetic field for the ball, holding individual components in place – like the interior of ball lightning is kept stable, according to theory.