Researchers at the CERN have produced a miniature format of the primordial soup that made up the universe shortly after it was born.
Soon after the Big Bang, the universe was filled with hot and dense soup composed of all kinds of particles that move at near light speed. The mixture is dominantly composed of quarks, a fundamental constituent of matter, and gluons, which carry the strong force that binds quarks together.
A few billionth of a second after the Big Bang, however, quarks and gluons were bound weakly and were free to move on their own in what's called as a state of quark-gluon plasma.
Researchers used the world's largest particle accelerator, the Large Hadron Collider (LHC) to collide atoms with extremely high energy to reproduce this primordial soup, following their recent move to replicate the first moments of the universe with the upgraded LHC. CERN explained that powerful accelerators collided massive ions such as nuclei of gold and lead to recreate the conditions of the very early universe.
"In these heavy-ion collisions the hundreds of protons and neutrons in two such nuclei smash into one another at energies of upwards of a few trillion electronvolts each," CERN explains. "This forms a miniscule fireball in which everything 'melts' into a quark-gluon plasma."
You Zhou, from the Niels Bohr Institute at the University of Copenhagen, and colleagues measured how the plasma flows and fluctuates after its formation. The measurements analyzed the correlation between many particles and allowed researchers to determine the viscosity of the fluid with great accuracy.
By focusing on the collective properties of the quark-gluon plasma, the researchers found that its behavior is more comparable to that of a liquid than gas albeit it is not made up of molecules of water but of fundamental particles of quarks and gluons.
"The analyses of the collisions make it possible, for the first time, to measure the precise characteristics of a quark-gluon plasma at the highest energy ever and to determine how it flows," Zhou says.
Jens Jørgen Gaardhøje, also from the Niels Bohr Institute, said that it is remarkable they were able to get a detailed measurement on a drop of the early universe. He added that the results are consistent with the physical laws of hydrodynamics.