Our universe began with a bang that blasted every part into existence. But what occurred subsequent is a thriller. Scientists suppose that earlier than atoms shaped—and even the protons and neutrons they’re fabricated from—there was in all probability a sizzling, soupy mixture of two elementary particles referred to as quarks and gluons, churning via house as a plasma. And as a result of nobody was round to watch the primary moments of the cosmos, a coalition of researchers is attempting to re-run historical past.

Using the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, they’ve primarily created a “Little Bang” and are utilizing it to probe the properties of that quark-gluon plasma. The findings will assist cosmologists refine their still-fuzzy image of the early universe, and the way the oozy, blistering state of toddler matter cooled and coalesced into the planets, stars, and galaxies of at this time. 

“We think about a microsecond after the Big Bang, the universe was in this stage,” says physicist Rongrong Ma, who works with the Solenoidal Tracker on the Relativistic Heavy Ion Collider, or STAR, a detector dedicated to investigating the quark-gluon plasma. “So if we can understand from experiments the properties of such matter, this will feed into our understanding of how the universe evolved.” 

Scientists aren’t certain how lengthy this plasma stage lasted—it may have been anyplace from a couple of seconds to 1000’s of years. It may even nonetheless exist at this time within the dense cores of neutron stars, or get made when super-high-energy particles crash into Earth’s ambiance, so studying about its properties may assist characterize the physics of probably the most excessive cosmic environments. 

These early days of the universe are unimaginable to check with telescopes, which might solely attain way back to the cosmic microwave background—the primary mild that emerged from the dense early universe, 100 thousand years after the Big Bang. Everything earlier than that’s each actually and figuratively a darkish period of cosmology. Theoretical simulations may also help fill in that hole, says Jaki Noronha-Hostler, a nuclear physicist on the University of Illinois Urbana-Champaign, however detectors like STAR “allow you to experimentally understand a system that’s very similar to the Big Bang.”  

In addition, quarks and gluons are by no means discovered solo in nature, making it tough to check them in isolation. “We can’t just pluck one out and examine it,” says Helen Caines, a physicist at Yale University and spokesperson for the STAR experiment. Instead, they’re caught in composite states: protons, neutrons, and extra unique matter like upsilons, pions, and kaons. But at excessive sufficient temperatures, the boundaries between these composite particles start to blur. “And that is the quark-gluon plasma,” Caines says. They’re nonetheless confined to some quantity, however the quarks and gluons inside this house are not fused collectively. In reality, she says, “plasma” could be a little bit of a misnomer, as a result of it really behaves extra like a fluid, in that it flows.

In March, scientists at Brookhaven reported in Physical Review Letters that they have been in a position to generate the quark-gluon plasma for a quick blip in time by accelerating two beams of gold nuclei near the pace of sunshine, then smashing them into one another.  Then got here the intelligent bit: They used this collision to calculate how sizzling the post-Big Bang plasma would have been.