According to theories beyond the Standard Model, in the first moments after the Big Bang, pairs of magnetic monopoles — particles with a single magnetic pole — were born. They ended up at the ends of a cosmic string — a thread of pure energy. This string acts like a taut rubber band: one end pulls a 'north' monopole, the other a 'south' monopole. A single monopole weighs as much as billions of protons but fits within a volume smaller than an atomic nucleus. / Over time, the string contracts, bringing the monopoles closer together. Upon merging, they cause the string to snap, and ripples spread through the fabric of spacetime — gravitational waves. Their frequency lies in the audible range: from a low hum to a piercing screech. Detectors on Earth can catch this signal. Detecting such waves would prove the existence of monopoles and strings — a step toward understanding the birth of the Universe.
Flying through a detector, a monopole would cause an electrical surge billions of times stronger than any known particle — thanks to its colossal magnetic strength.