The weird hum coming from the start of the Universe
The weird hum coming from the start of the Universe Before stars or planets, before black holes and white dwarfs, before even atoms or rays of light, the Universe reverberated with something surprising – sound. This primordial hum moved at more than half the speed of light through a superheated plasma of baryons, photons, and dark matter.big bangcmbcosmologydark energysoundlink