Scientists have been able to recreate the entire Universe inside a computer for the first time ever. A simulation running on a supercomputer, tracking a mind boggling 550 billion particles as they evolve, has been able to recreate the structure of the Universe right from the Big Bang to the present day.
Simulating the Standard Model of Cosmology
This is the first in the series of three simulations to be carried out on GENCI’s new supercomputer, CURIE at CEA’s TGCC (Tres Grand Centre de Calcul) performed by researchers from Laboratoire Univers et Theorie (LUTH). This takes into account the standard model of cosmology with the cosmological constant built in. Successive runs will improve upon this result with more data, especially about the distribution of dark matter and dark energy. The project, called Deus: full Universe run, will seek answers to the cosmological questions in a way similar to what the LHC follows in order to get answers.
The physics at the LHC is massively complicated by the presence of so many particles and so many end states of a certain collision. It is impossible to analytically solve for the end state, so scientists use models before they begin an experiment. These simulations reveal what the most likely result of a certain collision is given certain parameters and bounds on certain numbers. The actual run either confirms the simulation, or discards it. This is a far more efficient process than reconstructing the interaction by looking at the end states, which is the other alternative.
The Deus simulation does something like that. They let the 550 billion points evolve and see what the end state is. This has enabled them to count the number of galaxy clusters which are more massive than a hundred thousand billion solar masses (that’s VERY heavy, by the way) and the number comes out to be 144 million. The first galaxy cluster formed 2 billion years after the Big Bang, according to the simulation. It also shows the most massive galaxy cluster – with a mass of 15 quadrillion (or 15 thousand trillion) solar masses!
Relics of the Early Universe
The simulation also revealed fingerprints of the inflationary era in the form of fluctuations in the Cosmic Microwave Background Radiation. If the Big Bang and inflation is true, then there must be radiation left over, which is constantly weakening. This permeates all of the space in the Universe, thus the name Cosmic Microwave Background (CMB). It is believed that some quantum fluctuation, growing under the effect of gravity, gave rise to the galaxy and clusters we see today. The CMB was studied thoroughly by the WMAP studies. They also showed up in the simulation.
The simulation also confirmed the presence of dark matter and gave a hint of how it might be distributed throughout the Universe. Present in this primordial virtual cosmic soup is the Baryon Acoustic Oscillations or BAO. This might be the answer to the long standing problem of baryon asymmetry – why matter outnumbers anti-matter in the Universe, whereas they should have been produced in equal numbers in the Early Universe.
Computing power – the sky is the limit
CURIE is one of the largest supercomputer facilities in the world. The whole simulation has taken a few years to put together. The whole project is expected to use more than 30 million hours (or 3500 years) of computing time on all CPU’s of CURIE. The amount of data processed comes out to be 150 PB (peta bytes). This amounts to all the data on 30 million DVD’s. State-of-the-art compression technology has allowed researchers to reduce this entire jungle to 1 PB.
Two more simulations are to follow! They will test out rival cosmological models. The simulation is also expected to reveal structures we have not been familiar with before. This will provide scientists a search parameter for current projects like PLANCK and future ones like EUCLID.