The most detailed model of the universe ever created has been unveiled by computer scientists.
Dubbed ‘Illustris: The Next Generation’, or IllustrisTNG for short, the computer model boasts never-before-seen levels of details about the forces at work in the universe.
Scientists say the detail and scale provided by the advanced computer simulation has enabled them to observe how galaxies form, evolve, grow, and trigger the creation of new stars over 13 billion years.
They have already used it to provide new insights into how black holes influence the distribution of dark matter, how heavy elements are produced and distributed, and where magnetic fields originate.
Dr Shy Genel, of the Flatiron Institute’s Centre for Computational Astrophysics, said: ‘When we observe galaxies using a telescope, we can only measure certain quantities.’
‘With the simulation, we can track all the properties for all these galaxies. And not just how the galaxy looks now, but its entire formation history’, Dr Genel added.
To create this simulation, scientists used evidence of the earliest days of our universe, gathered from the cosmic microwave background leftover from the Big Bang.
Computational cosmologists use this data to model the conditions of the time, when the universe was just a few hundred thousand years old.
Into this virtual universe, they add baryonic matter, which forms stars and planets; dark matter, which enables galactic structures to grow; and dark energy, the mysterious force behind all cosmic acceleration.
These are coded into the simulation alongside equations that describe supernova explosions and black holes.
Volker Springel, of the Heidelberg Institute for Theoretical Studies, was part of the international team that developed and programmed the simulation.
Dr Springel said: ‘It is particularly fascinating that we can accurately predict the influence of supermassive black holes on the distribution of matter out to large scales.
‘This is crucial for reliably interpreting forthcoming cosmological measurements.’
Mark Vogelsberger, an assistant professor of physics at MIT and the MIT Kavli Institute for Astrophysics and Space Research, has been working to develop, test, and analyze the new IllustrisTNG simulations.
Vogelsberger used the IllustrisTNG model to show that the turbulent motions of hot, dilute gases drive small-scale magnetic dynamos that can exponentially amplify the magnetic fields in the cores of galaxies — and that the model accurately predicts the observed strength of these magnetic fields.
‘The high resolution of IllustrisTNG combined with its sophisticated galaxy formation model allowed us to explore these questions of magnetic fields in more detail than with any previous cosmological simulation,’ says Vogelsberger, an author on the three papers reporting the new work, published today in the Monthly Notices of the Royal Astronomical Society.
The universe in the computer model is only one billion light-years across, compared to the observable universe, which has a diameter of about 93 billion light-years.
The previous model generated by the team four years ago measured 350 million light-years across.
Scientists have been able to follow the formation of millions of galaxies within the model of the universe – the largest simulation to explore how cosmic structures developed.
The model predicted a cosmic web of gas and dark matter which interacted to create galaxies which were similar to real galaxies in shape and size.
Dr Dylan Nelson, of the Max Planck Institute for Astrophysics, revealed how star-forming galaxies shine brightly in the blue light of their young stars until an evolutionary shift suddenly halts the star formation.
This turns the galaxy into one dominated by old, rest stars.
Dr Nelson explained: ‘The only physical entity capable of extinguishing the star formation in our large elliptical galaxies are the supermassive black holes at their centres.
‘The ultrafast outflows of these gravity traps reach velocities up to 10 per cent of the speed of light and affect giant stellar systems that are billions of times larger than the comparably small black hole itself.’
In addition, the simulations were able to predict how the cosmic web changes over time, especially in relation to dark matter, which purportedly makes up 26.8 per cent of the universe.
By contrast, ordinary matter makes up just 4.9 per cent of the observable universe. The remaining 68.3 per cent of the observable universe is believed to be dark energy.
Annalisa Pillepich, a researcher at Max-Planck Institute for Astronomy, said: ‘Our predictions can now be systematically checked by observers.
‘This yields a critical test for the theoretical model of hierarchical galaxy formation.’
