MadS_Mc on Instagram: "explains how the universe began. About 13.8 billion years ago, the universe started as an extremely hot, tiny, and dense point. Suddenly, it began to expand rapidly. This expansion is called the Big Bang. It was not an explosion in space — it was an expansion of space itself. At first, the universe was filled with pure energy. As it cooled: Energy turned into particles Particles formed atoms Atoms formed gas clouds Gas clouds formed stars and galaxies Over millions of year