After the Big Bang, the Universe simmered as a fiery 'soup' of fundamental particles. Expanding and cooling, the soup gradually 'solidified' into protons and neutrons — much like crystallization. Had the solidifying been instantaneous, like a lake cracking in a deep freeze, the fabric of spacetime would have convulsed. That convulsion would have produced gravitational waves — ripples with a crest lasting years. You could spot them via glitches in the signals of pulsars — natural lighthouses whose pulses are as precise as atomic clocks.

Yet calculations revealed: even in the most violent scenario, where matter stayed liquid far beyond the 'freezing' point, the energy wasn't enough for a jolt. The Universe set flawlessly smooth, like glass without a single bubble.

So, most likely, no gravitational waves came from the primordial transition. That doesn't diminish the early Universe's mysteries — on the contrary, it motivates searching for traces of other cataclysms, like the cosmic inflation proposed by Alan Guth.