To understand the origin of the universe we travel through the history of cosmology guided by the discoveries and advances of each era.
While most scientists can carry out experiments to test their theories, the astronomer must limit himself to observing the sky and hope to find clues in it to understand the phenomena he detects. Cosmology is an even more extreme case: one of its main tasks, that of understanding the origin of the universe, is not directly observable, so its work is similar to that of a forensic investigator, who must find out the answers from the clues you find at the crime scene. Fortunately, the ingenuity of several generations of astronomers has managed to discover and organize many of these clues, until building a case that can pass the review of the most severe judge.

In this book we will follow these clues to get closer to the origin of the universe, and we will witness decades of astronomical discoveries guided by the expertise of their discoverers and the advances in technology in each era: from the expansion of the universe in 1929 to the wide distribution scale of galaxies in 2005, passing through the cosmic microwave background in 1965. And, once the origin of the universe is something we are familiar with, we will look to the opposite extreme to ask ourselves: how will it all end?