Life and death of cosmic giants: A journey into the existence of galaxies

Life and death of cosmic giants: A journey into the existence of galaxies

Galaxies are the building bricks of the Universe and cradles of life, containing billions of stars like our Sun and planets. These wonderful systems are far from being cold, immobile, immutable objects: Similarly to any living organisms we know, galaxies were born some time in the past; they grow and expand, eating material around them; they run and dance frantically, group in couples or large families, merge in spectacular events, and give life to new stars; eventually, they age, become quiet and pass away.

In this talk I will take the audience on a journey through the Universe to discover the typical life of a galaxy and present some of the secrets we still have to unveil.

Our star, the Sun, and the eight planets revolving around it are part of a much larger system, the 'Milky Way' or the 'Galaxy', consisting of billions of stars, plus gas, dust, and a mysterious component, the 'dark matter'. Moreover, less than 100 years ago, we discovered that the Milky Way is not the only galaxy in the Universe, but billions of similar systems exist around us. What are all these galaxies? Have they always been there? What is their fate?

Decades of investigation revealed that these objects go through a series of processes similar to a 'life cycle': They were born from immense clouds of gas, they grow forming new stars and merging with other galaxies, but at some point they become quiet and eventually die. Using the analogy with organic life, I will show the typical existence of galaxies and some of the most puzzling problems we still have to solve.

Kort og godt






45 - 60 minutes


Francesco Valentino


Københavns Universitet, Niels Bohr Institutet