#reionization

#reionization

Out there, in the vast Universe, are clumps of matter that come in many different sizes and masses. We might be most familiar with galaxies like our Milky Way: with hundreds of billions of solar masses worth of stars, even more gas and plasma, and more than a trillion solar masses worth of dark matter. At smaller masses, however, it takes longer, and becomes more and more difficult, for clouds of normal matter to collapse.

Stars in young galaxies must have been responsible for stripping most intergalactic gas of its electrons.