27% of the material world is made up of dark matter. The existence of dark matter is widely accepted by most astronomers today, but they have no idea what this mysterious substance actually is.
That's why they use the word dark. They could have said mysterious
matter, weird matter, or unknown matter, but they prefer the word
dark. They understand that it must exist, as evidenced by the observation of how galaxies revolve and the expansion of the universe, but they don't know what it is.
Ordinary matter and ordinary energy, the stuff
that physicists can detect with their powerful high-tech instruments,
constitute less than 5% of the universe.
*
The being that you believe
is you and your consciousness is only the tip of an iceberg. The
central part of you is hidden. Freud called that part the unconscious.
You do not know who you
are. You do not know what life is all about, really. The central part of you is a
mystery. The world remains a mystery.
The world we live in, the world we can see and touch, hear and smell, is just a tiny fraction of it all.
When you think you understand what life is all about and believe you are realistic, then you are deluded.
https://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy
https://en.wikipedia.org/wiki/Agnosticism
https://en.wikipedia.org/wiki/Agnosticism