Scientist believe that the universe started as a "perfect" liquid when the Big Bang occurred.
What is the Big Bang? Cosmologists use the term Big Bang to refer to the idea that the universe was originally extremely hot and dense at some finite time in the past and has since cooled by expanding to the present diluted state and continues to expand today. Wikipedia.
What brought on the liquid theory is that in 2004 scientist smashed gold ions into each other at nearly the speed of light. To their surprise the gold turned into liquid.