It used to be point like, an infinitely dense point of energy. Then it expanded. We have absolutely no clue why or how, only that it is expanding today. There is leftover radiation called the Cosmic microwave background that is sort of a baby picture of the young universe we can observe that confirms the idea it’s expanding. Even more interesting is it’s expanding faster due to “dark energy”, a placeholder name for a phenomena we have no clue about.
The answer to your question is also the answer to “what made/started the universe?”
Latest Answers