In its first moments, the universe resembled dough that alternately rises rapidly and then pauses for a second. During these short bursts, called expansion of the universe with interruptions, even tiny magnetic fields could have grown like bubbles in well-beaten dough.
Usually, such fields remain weak, but the authors of the new study added one detail to their calculations: the fields could twist in one direction, like a corkscrew. This twist, known as chirality, helps the field amplify by hundreds of times. As a result, magnetic fields strong enough to survive to the present day could have emerged in the early universe.
Such fields should jiggle along with spacetime and generate gravitational waves — ripples that travel through space. Moreover, part of this ripple should be twisted in the same direction as the field itself. If future detectors catch such twisted ripples, it would be a direct indication of the violent events of the first moments.
Such waves haven't been detected yet, but the calculations suggest they could be within reach of future instruments. If they are found, we will for the first time hear the echo of the universe taking its first breaths.
Magnetic fields exist even in the void between galaxies, and scientists still debate where they came from. Perhaps they were twisted into existence in the first fractions of a second after the Big Bang.
In Greg Egan's novel 'Schild's Ladder', physicists create a new universe with different laws, and its first moments give rise to entirely different fields and particles.