And the only reason why any of this exists is because of those tiny density fluctuations that appeared when the observable universe was smaller than a grain of sand.

这一切的产生，归根究底，都缘于那微不足道的密度涟漪，而在那时，整个宇宙甚至比一颗沙粒还小。

One would also have expected the density fluctuations in such a model to have led to the formation of many more primordial black holes than the upper limit that has been set by observations of the gamma ray background.

人们还预计，这种模型中的密度波动会导致形成比伽马射线背景观测所设定的上限更多的原始黑洞。