If someone perceives the biblical legend of the World Flood as a literary exaggeration, then the scientists went further and calculated that the water in the universe was in abundance after 100-200 million years after the Big Bang. Moreover, the early Universe figuratively “drowned” in the water, which forces us to consider the tempting possibility of the origin of the first biological life at the very early stages of its evolution.
The artistic idea of the first stars in the universe. Image source: Noirlab/nsf/aura
As you know, a water molecule is two connected hydrogen atom and one oxygen atom. Free hydrogen in the universe has always been in abundance – he was present from the very first moments after the big explosion. Oxygen is believed to appear in the stars during thermonuclear synthesis reactions. He began to be developed in the stars and scattered through the universe after their death during the explosions of the supernova. Thus, it can be assumed that oxygen gradually increased its presence in space, which also led to a gradual increase in water in the universe.
A team of scientists in the journal Nature Astronomy prepared a peer-reviewed study that argues that this was not the case at all. At least at the dawn of the Universe. According to the generally accepted theory, the first stars contained nothing but hydrogen and helium and had low metallicity. In astrophysics, all elements heavier than helium are considered metals, and oxygen is also considered a metal. Therefore, in theory, oxygen was produced by second generation stars (population II) and population I stars (like our Sun). Population III stars—the very first stars (population counts down)—were not supposed to produce oxygen. However, new work refutes this claim.
Researchers have suggested (no one knows for sure, since Population III stars – the very first in the Universe – have not yet been observed by anyone) that the first stars were of two main classes: small with a mass of about 13 solar masses and large with a mass of 200 solar masses. Small stars were formed as usual from stellar nurseries (gas, dust and gravity) and had low metallicity. And large stars were formed directly from primordial clouds of matter. Small stars exploded as normal supernovae, but large ones exploded as pair-unstable supernovae, which led to interesting results.
Modeling shows that large stars at death should have significantly enriched the environment with oxygen and, as a result, water. The proportion of water in molecular clouds remaining after such explosions should be 10-30 times higher than the share of water in diffuse molecular clouds in the Milky Way that scientists observe today. This gives the reason to conclude that after 100-200 million years after a large explosion in molecular clouds, there were enough water and other elements for the formation of biological life.
Alas, to answer the question whether life has appeared then, scientists are unlikely to be able to. But even if life then began to appear, the level of ionization in the universe was so high that the living organisms known to us could not survive in such an environment. Normal conditions for the emergence of life created stars of subsequent generations. But there is a chance that water molecules in a cup of morning coffee are much ancient than it was commonly believed.