Quark-gluon plasma—the Universe’s earliest known liquid—has been recreated in experiments, with researchers finding it flowed like water despite its extreme heat.
Strong interactions between quarks and gluons gave the plasma very low viscosity and almost no resistance to flow, making it unlike any ordinary substance.
As the Universe expanded and cooled, that liquid gave way to a hot ionised gas that trapped light for about 370,000 years while the first light elements formed.
Earth’s oceans appeared far later—roughly 4.4 billion to 3.8 billion years ago—with scientists still debating whether their water came mainly from icy impacts, rocks, or both.
In July 2026, scientists at CERN’s Large Hadron Collider made a breakthrough by directly confirming that the Quark-Gluon Plasma (QGP) acts as a dense, responsive fluid, just as long theorized. Using the innovative Wake Tag Technique, researchers tracked the wake left by a single quark moving through the superheated plasma. This was achieved by employing a sophisticated Z-boson tagging method, which allowed them to isolate and study these elusive wakes. The findings provide compelling observational proof of QGP’s liquid-like properties, reshaping our understanding of the universe’s earliest moments.