The images presented here show the history of a galaxy like the Milky Way over a few billion years. These films are the result of digital simulations of the Universe which took into account many mechanisms and parameters so that researchers could better understand the role these played in the formation and evolution of galaxies.

The idea of this work was to understand which physical processes affected the formation of the spiral galaxies we can see today. Digital modelling enables researchers to carry out virtual experiments on parts of the Universe and thus see how different physical scenarios influence the evolution of the Universe over cosmological lengths of time. Here we can see galaxies spinning and merging under the effect of their gravitational attraction. This history of turbulence produced a spiral galaxy such as our own which hosts the stellar relics of this violent past. Colour here indicates the density of gas and shows us that gas is concentrated along spiral arms in the form of lumps which then give birth to stars. This type of simulation enables us to understand where stars form within disks and how these stars affect the evolution of gas. Thanks to these videos, we may observe the way in which stars eject their gas from the disk via explosions without actually being able to see where the gas goes. Researchers however have found the answer to this - the gas leaves the galaxy and is dispersed in the intergalactic medium.

Researchers at the Lyon Centre for Astrophysics Research (CRAL) work with simulations on high-performance computers which enable them to both carry out experiments and visualize what happens in the Universe better. In this way, this work contributes to increasing knowledge of galaxies and their behaviour.

Thanks to Jeremy Blaizot for his contribution.

Find out more

• Centre de recherche en astrophysique de Lyon - Observatoire de Lyon (CRAL)