此时宇宙已冷却到1000摄氏度，温度低到电子开始登场并结合原子核形成大量的原子。

The universe has cooled to about 1, 000C - cool enough for electrons to pair up with nuclei to form the first atoms.

youdao

所以，我认为宇宙类似于原子核(atomic nucleus)。

So, what I'm thinking of is the universe is kind of like an atomic nucleus.

youdao

考虑静质量为零的中微子背景，探讨背景场对整体宇宙弦核外引力场的影响。

Considering the background of massless neutrino, probes into the effect of the background field on the gravitational field of a global cosmic string outside the core.

youdao