The world's most powerful particle accelerator smashed together lead nuclei at the highest energies possible, creating dense sub-atomic particles that reach temperatures of over ten trillion degrees. Beyond being awesome, this achievement shows the early universe was actually a liquid.
Normal matter can't exist in any form at these sort of absurdly hot temperatures. Instead, matter is thought to melt into a strange, soup-like substance known as quark-gluon plasma. Researchers are still investigating exactly what happens when this quark-gluon plasma emerges, but the early results seem to confirm the theory that the plasma acts like a liquid, not a gas.
Earlier research had shown that the sub-atomic fireballs acted like liquids at lower temperatures, but there was still some expectation that they would move into more gaseous behaviour when temperatures got hot enough for the plasma to emerge. University of Birmingham astrophysicist Dr David Evans says these findings should also reflect what the universe looked like in its first microseconds of existence:
"Although it is very early days we are already learning more about the early Universe. These first results would seem to suggest that the Universe would have behaved like a super-hot liquid immediately after the Big Bang."
Further study will be needed to better understand just how the quark-gluon plasma acts at these trillion-degree temperatures. Researchers have already made one unexpected discovery. It turns out the fireballs caused by the collision create way more subatomic particles than most models would expect, as researchers were able to observe thousands of particles radiating out from each fireball.