After about three minutes, the Universe had cooled down to about one billion K. Then, the protons and neutrons started to fuse like the interior of a star, creating the Universe's first helium. This only lasts for a few minutes, because the Universe quickly cools down, so very few elements heavier than helium are made. However, the Universe is now 75 percent hydrogen nuclei and 25 percent helium nuclei by weight, but, it is so hot that electrons are not able to join to make the Universe's first atom. The Universe cools enough for fusion to occur. Online Astro 100 The early Universe did not have any helium because
A) It was hot enough before.
B) It wasn't cool enough before.