By Peter Weiss
When matter was new in the universe, it was an exotic gas whose components later congealed into the more-ordinary matter made of atoms. At least, that was the story. Now, physicists trying to re-create that gas in an accelerator say that the universe’s original stuff appears to have been a liquid.
Like the gas that had been expected, the ur-liquid the physicists made is ultrahot and ultradense—up to 150,000 times as hot as the sun’s core and 100 times as dense as ordinary atomic nuclei.