Valerie Domcke

Immediately after the Big Bang, in the seething cauldron of the cooling Universe, much like in unevenly hardening glass, stresses appeared — hairline cracks in reality, cosmic strings. Picture a tightrope walker balancing on an invisible cable stretched across the abyss of warped spacetime.

A bell rings not from the strike but from a fleeting shudder of space. A gravitational wave, like ripples on a pond, passes through a massive magnet, and it deforms ever so slightly. That deformation can be turned into an electrical signal.

In the first fraction of a second after the Big Bang, the universe expanded at an unimaginable rate. The engine behind this expansion could have been a field that behaves like a slowly rolling ball — the axion. What makes the axion special is that, like a conductor, it can drive electromagnetic waves, creating them literally out of nothing.