Mark Vogelsberger is an astrophysicist who has dedicated his research to a simulation of galaxies that allows us to better understand the universe
In science, a simulation is a model of reality capable of showing a series of events, so as to allow evaluation and prediction of the unfolding of certain phenomena.
Much used in the theoretical sciences, but also in the disciplines that study the behaviors of groups of animals or persons, the simulation models are in the last years becoming a fundamental support for the sciences that investigate the birth and the life of the universe.
See the stars up close
A few months ago, news broke of the creation of Uchuu, the largest simulation of the universe ever created, available as a free download – despite its cyclopean size reaching 300 TeraBytes.
Simulations of our universe don’t begin with Uchuu, however: Mark Vogelsberger, an astrophysicist at the Massachusetts Institute of Technology, has been building simulations of the universe for nearly a decade.
Interviewed by the campus magazine MIT News, Vogelsberger justifies his lifelong commitment to the service of simulating the universe this way: “I’ve always loved looking through a telescope as a hobby, but using a computer to experiment with the entire universe was a completely different perspective.”
In astrophysics we only have this one universe to look at, whereas with a computer you can “create different universes that we can control.”
Investigating simulated universes has made it possible, for example, to understand that our galaxy, despite “a couple of surprising features like the exact number of structures and satellites surrounding it,” is a “pretty normal” place in the universe.
Vogelsberger has spent nearly his entire career creating simulations of the birth and evolution of hundreds of thousands of galaxies, from the earliest moments of the formation of the known universe to the present.
Thanks to the computational power of supercomputers scattered around the world, Vogelsberger has produced some of the most accurate theoretical models of galaxy formation, so much so that many astronomy centers require their use for their science outreach activities.
The simulations actually allow us to observe different universes and much closer than we could do with the most powerful telescopes in the world: it is therefore not only a matter of controlling and investigating the unfolding of events, but also of opening a new window on the observation of celestial objects.
Simulation and understanding of the universe
Vogelsberger’s simulations of the universe have shown that galaxies can evolve into different shapes, sizes and colors, proving astronomers’ hypothesis that there can be substantial differences between the various galaxies that populate the universe.
Using the simulation to go back in time, it is possible to observe not only all the processes that occur during the birth of a galaxy, but also how dark matter is distributed contextually throughout the universe.
Vogelsberger’s numerical simulations have indeed shown how dark matter can thicken and move in streams that traverse space and have also allowed them to be measured for the first time.
The project of a lifetime dedicated to understanding the universe finally took shape in 2014, when the results of Illustris, the name of the then most complete simulation of the universe, carried out at Harvard by Vogelsberger and colleagues, were first published in Nature.
Illustris begins at the very beginning of the formation of the universe, just 400,000 years after the Big Bang, and covers the evolution of the universe for 13.8 billion years, virtually the entire life cycle of the universe we know.
An even larger and more detailed simulation of the formation of the universe, Illustris TNG, has recently been released, and MIT is working on an entirely new simulation that can investigate radiation fields in the early moments of the universe’s life and explore different models for the movement of dark matter.
“All the simulations start with a uniform universe – nothing but helium, hydrogen and dark matter,” says Vogelsberger. “Watching how everything evolved to look like something like our universe shows how far we’ve come in understanding the laws of physics.”