Ask Ethan: When Were Dark Matter And Dark Energy Created?
“Today [normal matter] is only 4.9% while Dark Matter and Dark Energy takes the rest. Where did they come from?”
The Universe, as we know it, got its start in earnest when the hot Big Bang began. Space was filled with all the particles and antiparticles of the Standard Model, up at tremendous energies, while the Universe then expanded, cooled, and gave rise to all we know. But when did dark matter and dark energy, which make up 95% of the Universe we know today, come into the picture? Was the Universe born with these components of energy? Or were they created at a later time? We have some inklings that dark matter was likely created in the extremely early stages, but may not have been present from the Universe’s birth. On the other hand, all theoretical signs point to dark energy always existing, but observationally, we have about 4 billion years where we cannot measure its presence at all.