# The when and where of water in the history of the universe

## TL;DR

This paper reviews the cosmic history of water, its emergence since the Big Bang, its distribution across the universe, and its fundamental role in supporting life, highlighting the potential for extraterrestrial life.

## Contribution

It provides a comprehensive overview of water's appearance and distribution in the universe and its critical connection to the emergence of life.

## Key findings

- Water appeared early in the universe's history.
- Water is widespread across various cosmic environments.
- Water's presence is strongly linked to potential habitats for life.

## Abstract

It is undeniable that life as we know it depends on liquid water. It is difficult to imagine any biochemical machinery that does not require water. On Earth, life adapts to the most diverse environments and, once established, it is very resilient. Considering that water is a common compound in the Universe, it seems possible (maybe even likely) that one day we will find life elsewhere in the universe. In this study, we review the main aspects of water as an essential compound for life: when it appeared since the Big Bang, and where it spread throughout the diverse cosmic sites. Then, we describe the strong relation between water and life, as we know it.