The growing radiation from those first stars ionized hydrogen atoms, split them back into protons and electrons.

随着初代恒星发出的辐射越来越大，电离的氢原子再次被分解为质子和电子。

And when the very first stars and galaxies switched on, they ionized that hydrogen.

当最早的恒星和星系启动时，它们将氢电离。