human
Can you tell me about the origin of the universe?
assistant
The Big Bang theory is the most widely accepted explanation for the origin of the universe. It states that the universe began as a hot, dense and rapidly expanding state approximately 13.8 billion years ago. This initial expansion was driven by an unknown form of energy called dark energy which permeates all space. As the universe expanded, it cooled down enough to allow protons and neutrons to combine into heavier elements such as helium and lithium. These first stars then formed from the primordial gas clouds, releasing light and other forms of radiation. Over time, these stars exploded as supernovae, leaving behind black holes, neutron stars, and white dwarfs.