By smashing together lead ions instead of protons, researchers at the Large Hadron Collider have produced a "mini-Big Bang".
The collisions obtained were able to generate the highest temperatures and densities ever produced in an experiment. "This process took place in a safe, controlled environment, generating incredibly hot and dense sub-atomic fireballs with temperatures of over ten trillion degrees, a million times hotter than the centre of the Sun.
"At these temperatures even protons and neutrons, which make up the nuclei of atoms, melt resulting in a hot dense soup of quarks and gluons known as a quark-gluon plasma." Quarks and gluons are sub-atomic particles — some of the building blocks of matter. In the state known as quark-gluon plasma, they are freed of their attraction to one another. This plasma is believed to have existed just after the Big Bang.
