Dark Matter and Energy

Our entire cosmic history is theoretically well-understood, but only qualitatively. It’s by observationally confirming and revealing various stages in our Universe’s past that must have occurred, like when the first stars and galaxies formed, that we can truly come to understand our cosmos. The temporal origin of dark matter and dark energy have constraints, but an exact time-of-origin is unknown. (NICOLE RAGER FULLER / NATIONAL SCIENCE FOUNDATION)

Ask Ethan: When Were Dark Matter And Dark Energy Created?

They make up 95% of our Universe today, but they weren’t always so important.

Ethan Siegel

Sep 8, 2018

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One of the most puzzling mysteries about the Universe is simply, “where is everything?” All that we can see, find, or interact with is made up of particles from the Standard Model, including photons, neutrinos, electrons, and the quarks and gluons which comprise the building blocks of our atoms. Yet when we look out at the cosmic ocean, we find that all of this makes up just under 5% of the total energy in the Universe; the rest is unseen. We call the missing components dark energy (68%) and dark matter (27%), but we don’t know what they are. Do we even know when they came into existence? That’s what Alon David wants to know, asking:

Today [normal matter] is only 4.9% while Dark Matter and Dark Energy takes the rest. Where did they come from?